Change in Plant-Based Diet Quality Is Associated with Changes in Plasma Adiposity-Associated Biomarker Concentrations in Women

The Role of Adipose Tissue and Nutrition in the Regulation of Adiponectin

Adipose tissue (AT), composed mainly of adipocytes, plays a critical role in lipid control, metabolism, and energy storage. Once considered metabolically inert, AT is now recognized as a dynamic endocrine organ that regulates food intake, energy homeostasis, insulin sensitivity, thermoregulation, and immune responses. This review examines the multifaceted role of adiponectin, a predominant adipokine released by AT, in glucose and fatty acid metabolism. We explore the regulatory mechanisms of adiponectin, its physiological effects and its potential as a therapeutic target for metabolic diseases such as type 2 diabetes, cardiovascular disease and fatty liver disease. Furthermore, we analyze the impact of various dietary patterns, specific nutrients, and physical activities on adiponectin levels, highlighting strategies to improve metabolic health. Our comprehensive review provides insights into the critical functions of adiponectin and its importance in maintaining systemic metabolic homeostasis.

Plant-Based Diets and Risk of Multimorbidity: The Health and Retirement Study

BACKGROUND

Plant-based diets have gained attention due to their beneficial effects against major chronic diseases, although their association with multimorbidity is mostly unknown.

OBJECTIVES

We examined the association between the healthful (hPDI) and unhealthful plant-based diet indices (uPDI) with multimorbidity among middle-aged and older adults from the United States.

METHODS

Data on 4262 adults aged >50 y was obtained from the 2012-2020 Health and Retirement Study (HRS) and 2013 Health Care and Nutrition Study (HCNS). Food consumption was collected at baseline with a food frequency questionnaire and 2 PDIs were derived: the hPDI, with positive scores for healthy plant foods and reverse scores for less healthy plant foods and animal foods; and the uPDI, with only positive scoring for less healthy plant foods. Complex multimorbidity, defined as ≥3 coexistent conditions, was ascertained from 8 self-reported conditions: hypertension, diabetes, cancer, chronic lung disease, heart disease, stroke, arthritis, and depression. Cox proportional hazards models were used to estimate the hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

After a median follow-up of 7.8 y, we documented 1202 incident cases of multimorbidity. Compared with the lowest quartile, higher adherence to the hPDI was inversely associated with multimorbidity (HR for quartile 3: 0.77; 95% CI: 0.62, 0.96 and HR for quartile 4: 0.79; 95% CI, 0.63, 0.98; P-trend = 0.02). In addition, a 10-point increment in the hPDI was associated with a 11% lower incidence of multimorbidity (95% CI: 1, 20%). No significant associations were found for the uPDI after adjusting for sociodemographic and lifestyle factors.

CONCLUSIONS

Higher adherence to the hPDI was inversely associated with multimorbidity among middle-aged and older adults. Plant-based diets that emphasize consumption of high-quality plant foods may help prevent the development of complex multimorbidity.

A plant-based diet index to study the relation between diet and disease risk among adults: a narrative review

Plant-based diets (PBD) may offer various health benefits and contribute to a sustainable way of life, but, if not planned correctly, may also confer risks, e.g., by focusing on plant foods with low nutrient density, such as foods primarily consisting of refined carbohydrates. A plant-based diet index (PDI) differentiating between a healthful, unhealthful, and overall PBD, offers a promising approach to standardize and compare studies and integrate results. In this review we (1) summarize current evidence on the PDI and disease risk of relevance to public health, (2) discuss the methodology of the PDI and how it can be sensibly applied in further studies and (3) indicate areas with a lack of knowledge, such as vulnerable populations. In summary, our amalgamation shows, that adherence to a healthier plant-based diet is associated with an 8-68% lower risk for metabolic risk factors, diabetes, and cardiovascular disease, while adherence to an unhealthier plant-based diet is associated with a 10-63% higher risk. Although differences in calculation methods and underlying diet patterns between populations should be accounted for, the PDI can be a useful tool to assess adherence to different plant-based diet patterns and their association with health outcomes in cohort studies across cultures.

Plant-Based Food for the Prevention of Type 2 Diabetes: Scoping Review

Type 2 Diabetes Mellitus (T2DM) is a chronic condition with growing worldwide prevalence. Besides genetic factors, a sedentary lifestyle, excess weight, and inadequate eating habits, characterized by an excess intake of refined carbohydrates and ultra-processed foods, are contributing factors for the development of the disease. In this scenario, promoting a plant-based diet, and limiting animal product consumption while increasing the intake of vegetables, concurrently with healthy lifestyle habits, is a promising strategy to prevent T2DM. This scoping review, carried out between 2017 and 2022, aimed to gather evidence substantiating the benefits of a plant-based diet in T2DM prevention, considering different eating patterns, such as vegetarian, vegan, Mediterranean, and DASH diets. Several studies demonstrate a significant reduction in T2DM incidence among individuals adopting plant-based eating patterns or emphasizing healthy plant-based food alongside decreased intake or exclusion of animal-based foods. There are still no robust data regarding plant-based diets and the prevention of diabetes without loss in body weight. Hence, prospective studies in plant-based diets with weight control are needed. Nevertheless, adopting plant-based diets appears to induce significant weight loss, which is crucial in an obesity-endemic context. Thus, embracing plant-based diets, along with healthy habits, emerges as a relevant strategy in obesity and T2DM prevention.

The Association Between Overall, Healthy, and Unhealthy Plant-Based Diet Index and Risk of Prediabetes and Type 2 Diabetes Mellitus: A Systematic Review and Dose-Response Meta-Analysis of Prospective Studies

CONTEXT

The global incidence of prediabetes and type 2 diabetes mellitus (T2DM) has increased substantially in recent years. Among the established, modifiable lifestyle factors associated with favorable prediabetes and T2DM risk, healthy dietary patterns have attracted considerable attention.

OBJECTIVE

The association between adherence to plant-based dietary pattern indices (PDIs), including the overall PDI (O-PDI), healthy PDI (H-PDI), and unhealthy PDI (U-PDI), and the risk of prediabetes and T2DM was investigated in this study.

DATA SOURCES

A literature search was conducted of the PubMed/Medline, Scopus, and Web of Sciences databases from their inception to February 2024. A systematic review and meta-analysis were conducted using random effects models and dose-response analyses. The Cochran Q test and the I2 statistic were used to evaluate heterogeneity between studies.

DATA EXTRACTION

A total of 16 publications, with data on a total of 721 012 participants, were identified for the meta-analysis.

DATA ANALYSIS

According to a pooled analysis, compared with the lowest category of O-PDI and H-PDI adherence, the highest category was associated with a 14% and 19% reduction in T2DM risk, respectively, for O-PDI (effect size [ES] = 0.86; 95%CI, 0.82-0.90; I2 = 57.7) and H-PDI (ES = 0.81; 95%CI, 0.75-0.88; I2 = 82.6). Greater adherence to U-PDI was significantly associated with an 10% increase in the risk of T2DM (ES = 1.10; 95%CI, 1.04-1.16). Consistent associations were found within the predetermined subgroups. As well, there was a nonlinear inverse association between O-PDI, H-PDI, and T2DM risk. No significant association was found between adherence to O-PDI (ES = 0.87; 95%CI, 0.75-1.01; I2 = 68%), H-PDI (ES = 0.99; 95%CI, 0.87-1.13; I2 = 0.0%), and U-PDI (ES = 1.09; 95%CI, 0.94-1.21; I2 = 22.9%) and risk of prediabetes.

CONCLUSION

These findings underscore the importance of dietary selections within the framework of a plant-based dietary pattern, particularly when incorporating healthful, plant-based foods, which may have potential benefits in reducing the T2DM risk.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023459851.

Change analysis for intermediate disease markers in nutritional epidemiology: a causal inference perspective

BACKGROUND

Several approaches are commonly used to estimate the effect of diet on changes of various intermediate disease markers in prospective studies, including "change-score analysis", "concurrent change-change analysis" and "lagged change-change analysis". Although empirical evidence suggests that concurrent change-change analysis is most robust, consistent, and biologically plausible, in-depth dissection and comparison of these approaches from a causal inference perspective is lacking. We intend to explicitly elucidate and compare the underlying causal model, causal estimand and interpretation of these approaches, intuitively illustrate it with directed acyclic graph (DAG), and further clarify strengths and limitations of the recommended concurrent change-change analysis through simulations.

METHODS

Causal model and DAG are deployed to clarify the causal estimand and interpretation of each approach theoretically. Monte Carlo simulation is used to explore the performance of distinct approaches under different extents of time-invariant heterogeneity and the performance of concurrent change-change analysis when its causal identification assumptions are violated.

RESULTS

Concurrent change-change analysis targets the contemporaneous effect of exposure on outcome (measured at the same survey wave), which is more relevant and plausible in studying the associations of diet and intermediate biomarkers in prospective studies, while change-score analysis and lagged change-change analysis target the effect of exposure on outcome after one-period timespan (typically several years). Concurrent change-change analysis always yields unbiased estimates even with severe unobserved time-invariant confounding, while the other two approaches are always biased even without time-invariant heterogeneity. However, concurrent change-change analysis produces almost linearly increasing estimation bias with violation of its causal identification assumptions becoming more serious.

CONCLUSIONS

Concurrent change-change analysis might be the most superior method in studying the diet and intermediate biomarkers in prospective studies, which targets the most plausible estimand and circumvents the bias from unobserved individual heterogeneity. Importantly, careful examination of the vital identification assumptions behind it should be underscored before applying this promising method.

Effect of a plant-based diet on oxidative stress biomarkers in male footballers

Proper nutrition plays a vital role in modulating oxidative status. There is an increasing popularity of plant-based dietary patterns among athletes. Therefore, the present study aimed to determine the plant-based diet index (PDI) score among male footballers and their non-athlete controls, as well as its relationship with oxidative biomarkers by evaluating the urinary excretion of F2alpha-isoprostane (F2a-IP) and 8-hydroxy-2'-deoxyguanosine (8-OHdG). A group of footballers (n = 45) and a healthy non-athlete group (n = 45) were selected. The two groups were matched based on body mass index (BMI) and age. The mean (standard deviation (SD)) age of the subjects was 22.88 (2.41) years, and their BMI was 22.08 (1.35) kg/m2. Anthropometric indices were evaluated, and fasting morning urine samples were analyzed to measure oxidative biomarkers. The PDI, unhealthy plant-based diet index (uPDI), and healthy plant-based diet index (hPDI) were calculated using valid food frequency questionnaire data. Generalized estimating equation models were used for all analyses. Compared to the non-athlete group, the PDI score was significantly greater in the footballer group (β = 9.8; P < 0.001), while the differences between the two groups in uPDI and hPDI scores were not significant. Overall, footballers consumed more plant-based foods. By examining the relationship between dietary indices and oxidative biomarkers, only a negative association was observed between PDI score and F2a-IP level (β = -1.25; P = 0.03). Based on the results, footballers were more adherent to a plant-based diet than non-athletes. In addition, it seems that following plant-based diets (the higher PDI) may exert beneficial effects on lowering F2a-IP levels due to improving the body's antioxidant status.

Vegetarian Nutrition in Chronic Kidney Disease

There is rising interest globally with respect to the health implications of vegetarian or plant-based diets. A growing body of evidence has demonstrated that higher consumption of plant-based foods and the nutrients found in vegetarian and plant-based diets are associated with numerous health benefits, including improved blood pressure, glycemic control, lipid levels, body mass index, and acid-base parameters. Furthermore, there has been increasing recognition that vegetarian and plant-based diets may have potential salutary benefits in preventing the development and progression of chronic kidney disease (CKD). While increasing evidence shows that vegetarian and plant-based diets have nephroprotective effects, there remains some degree of uncertainty about their nutritional adequacy and safety in CKD (with respect to protein-energy wasting, hyperkalemia, etc.). In this review, we focus on the potential roles of and existing data on the efficacy/effectiveness and safety of various vegetarian and plant-based diets in CKD, as well as their practical application in CKD management.

Plant-based dietary indices and biomarkers of chronic low-grade inflammation: a cross-sectional analysis of adults in Ireland

PURPOSE

There is increasing interest in the health benefits of plant-based diets (PBDs). Evidence reports favourable associations with inflammatory profiles and reduced cardiovascular disease risk. However, limited studies have examined relationships between PBD indices (PDIs) and inflammatory biomarkers. We explored overall PDI, healthful PDI (hPDI) and unhealthful PDI (uPDI) associations with inflammatory biomarker profiles.

METHODS

This cross-sectional analysis included 1986 middle- to older-aged adults from the Mitchelstown Cohort. PDI scores were calculated using validated food frequency questionnaires. PDI score associations with inflammatory biomarkers were assessed via linear regression analysis, with adjustment for potential confounders.

RESULTS

Comparison of quintiles (Q5 vs Q1) revealed lower concentrations of C-reactive protein (CRP), interleukin 6 (IL-6), white blood cells (WBCs), neutrophils and monocytes, and the leptin-to-adiponectin ratio (PDI and hPDI P < 0.05); lower leptin (PDI, P < 0.05), and complement component 3 (C3), tumour necrosis factor alpha (TNF-α), plasminogen activator inhibitor 1, lymphocytes and eosinophils (hPDI, P < 0.05); and higher concentrations of adiponectin (PDI and hPDI, P < 0.05). Conversely, higher concentrations of C3, CRP, IL-6, TNF-α, resistin, WBCs, neutrophils, lymphocytes, monocytes and eosinophils, and the neutrophil-to-lymphocyte ratio, and lower adiponectin concentrations were observed comparing uPDI quintiles (P < 0.05). In fully adjusted regression models, higher hPDI scores were associated with lower concentrations of C3, TNF-α, WBCs, neutrophils and monocytes (all P < 0.01). Higher uPDI scores were associated with higher C3 and TNF-α concentrations (all P < 0.01).

CONCLUSION

This study provides evidence that a more healthful PBD is associated with a more favourable inflammatory profile and that a more unhealthful PBD is associated with the reverse.

Portfolio Diet Score and Risk of Cardiovascular Disease: Findings From 3 Prospective Cohort Studies

BACKGROUND

The plant-based Portfolio dietary pattern includes recognized cholesterol-lowering foods (ie, plant protein, nuts, viscous fiber, phytosterols, and plant monounsaturated fats) shown to improve several cardiovascular disease (CVD) risk factors in randomized controlled trials. However, there is limited evidence on the role of long-term adherence to the diet and CVD risk. The primary objective was to examine the relationship between the Portfolio Diet Score (PDS) and the risk of total CVD, coronary heart disease (CHD), and stroke.

METHODS

We prospectively followed 73 924 women in the Nurses' Health Study (1984-2016), 92 346 women in the Nurses' Health Study II (1991-2017), and 43 970 men in the Health Professionals Follow-up Study (1986-2016) without CVD or cancer at baseline. Diet was assessed using validated food frequency questionnaires at baseline and every 4 years using a PDS that positively ranks plant protein (legumes), nuts and seeds, viscous fiber sources, phytosterols (mg/day), and plant monounsaturated fat sources, and negatively ranks foods high in saturated fat and cholesterol.

RESULTS

During up to 30 years of follow-up, 16 917 incident CVD cases, including 10 666 CHD cases and 6473 strokes, were documented. After multivariable adjustment for lifestyle factors and a modified Alternate Healthy Eating Index (excluding overlapping components), comparing the highest with the lowest quintile, participants with a higher PDS had a lower risk of total CVD (pooled hazard ratio [HR], 0.86 [95% CI, 0.81-0.92]; Ptrend<0.001), CHD (pooled HR, 0.86 [95% CI, 0.80-0.93]; Ptrend=0.0001), and stroke (pooled HR, 0.86 [95% CI, 0.78-0.95]; Ptrend=0.0003). In addition, a 25-percentile higher PDS was associated with a lower risk of total CVD (pooled HR, 0.92 [95% CI, 0.89-0.95]), CHD (pooled HR, 0.92 [95% CI, 0.88-0.95]), and stroke (pooled HR, 0.92 [95% CI, 0.87-0.96]). Results remained consistent across sensitivity and most subgroup analyses, and there was no evidence of departure from linearity for CVD, CHD, or stroke. In a subset of participants, a higher PDS was associated with a more favorable blood lipid and inflammatory profile.

CONCLUSIONS

The PDS was associated with a lower risk of CVD, including CHD and stroke, and a more favorable blood lipid and inflammatory profile, in 3 large prospective cohorts.

The association between diet quality, plant-based diets, systemic inflammation, and mortality risk: findings from NHANES

PURPOSE

To our knowledge, no studies have examined the association of diet quality and plant-based diets (PBD) with inflammatory-related mortality in obesity. Therefore, this study aimed to determine the joint associations of Healthy Eating Index-2015 (HEI-2015), plant-based dietary index (PDI), healthy PDI (hPDI), unhealthy PDI (uPDI), pro-vegetarian dietary index (PVD), and systemic inflammation with all-cause, cardiovascular disease (CVD), and cancer mortality risks by obesity status.

METHODS

Participants from NHANES were included in cross-sectional (N = 27,915, cycle 1999-2010, 2015-2018) and longitudinal analysis (N = 11,939, cycle 1999-2008). HEI-2015, PDI, hPDI, uPDI, and PVD were constructed based on the 24-h recall dietary interview. The grade of inflammation (low, moderate, and high) was determined based on C-reactive protein (CRP) values and multivariable ordinal logistic regression was used to determine the association. Cox proportional hazard models were used to determine the joint associations of diet and inflammation with mortality.

RESULTS

In the fully adjusted model, HEI-2015 (ORT3vsT1 = 0.76, 95% CI 0.69-0.84; p-trend =  < 0.001), PDI (ORT3vsT1 = 0.83, 95% CI 0.75-0.91; p trend =  < 0.001), hPDI (ORT3vsT1 = 0.79, 95% CI 0.71-0.88; p trend =  < 0.001), and PVD (ORT3vsT1 = 0.85, 95% CI 0.75-0.97; p trend = 0.02) were associated with lower systemic inflammation. In contrast, uPDI was associated with higher systemic inflammation (ORT3vsT1 = 1.18, 95% CI 1.06-1.31; p-trend = 0.03). Severe inflammation was associated with a 25% increase in all-cause mortality (ORT3vsT1 = 1.25, 95% CI 1.03-1.53, p trend = 0.02). No association was found between PDI, hPDI, uPDI, and PVD with mortality. The joint association, between HEI-2015, levels of systemic inflammation, and all-cause, CVD and cancer mortality, was not significant. However, a greater reduction in mortality risk with an increase in HEI-2015 scores was observed in individuals with low and moderate inflammation, especially those with obesity.

CONCLUSION

Higher scores of HEI-2015 and increased intake of a healthy plant-based diet were associated with lower inflammation, while an unhealthy plant-based diet was associated with higher inflammation. A greater adherence to the 2015 dietary guidelines may reduce the risk of mortality associated with inflammation and may also benefit individuals with obesity who had low and moderate inflammation.

Plant-based dietary patterns, genetic predisposition and risk of colorectal cancer: a prospective study from the UK Biobank

BACKGROUND

Plant-based dietary patterns may affect colorectal cancer (CRC) related outcomes, while risks differ in the quality of plant foods. We aimed to examine the association of plant-based diet quality with risks of CRC incidence and mortality and whether this association was modified by genetic risk.

METHODS

This prospective cohort study included 186,675 participants free of cancer when the last dietary recall was completed. We calculated three plant-based diet indices (PDIs), i.e., the overall plant-based diet index (PDI), the healthful plant-based diet index (hPDI), and the unhealthful plant-based diet index (uPDI) representing adherence to plant-based diets with diverse quality. Genetic risk was characterized using a weighted polygenic risk score (PRS), capturing overall risk variants associated with CRC. Hazard ratios (HR) and 95% confidential intervals (CI) were estimated by the cause-specific Cox proportional hazards model.

RESULTS

Over a follow-up of 9.5 years, 2163 cases and 466 deaths from CRC were documented. The HR of CRC incidence was 0.88 (95% CI, 0.81-0.96) and 0.91 (95% CI, 0.84-0.99) per 10-score increase in PDI and hPDI, respectively. Compared to the lowest quartile, PDI, hPDI, and uPDI in the highest quartile were associated with a 13% decrease, a 15% decrease, and a 14% increase in risk of incident CRC, respectively. We found a joint association of genetic risk and PDIs with incident CRC, with the highest hazard observed in those carrying higher PRS and adhering to lower-quality PDIs. The inverse association of PDI and hPDI with CRC mortality was pronounced in males.

CONCLUSIONS

Our results suggested that better adherence to overall and healthful plant-based diets was associated with a lower risk of CRC, whereas an unhealthful plant-based diet was associated with a higher CRC risk. Consumption of a higher-quality plant-based diet combined with decreased genetic risk conferred less susceptibility to CRC. Our findings highlighted the importance of food quality when adhering to a plant-based dietary pattern for CRC prevention in the general population.

Plant-based Diets for Inflammatory Bowel Disease: What Is the Evidence?

BACKGROUND

Inflammatory bowel disease is a chronic incurable condition that carries a high morbidity burden for patients. Plant-based diets have emerged as a potentially safe and effective treatment strategy for this condition. However, no attempt has been made to summarize the literature in this field. In this review, we aim to define variants of plant-based diets that have been studied, evaluate their findings, and identify knowledge gaps that warrant further investigation.

METHODS

A literature search was conducted on MEDLINE and Embase.

RESULTS

Twenty-three studies with 2304 participants were included in this review. Eleven studies (48%) were case reports and 8 (35%) were single-arm trials. Semivegetarian diets were the most commonly studied plant-based diet (n = 14, 61%). Most studies reported that plant-based diets were safe and effective in managing inflammatory bowel disease. However, significant limitations restrict the quality and interpretability of these findings, including a paucity of controlled data, small sample sizes, and inconsistent reporting of dietary adherence.

CONCLUSIONS

Although initial findings appear promising, it remains unclear whether plant-based diets are an effective adjunct or sole therapy for managing inflammatory bowel disease. Future investigators should aim to conduct methodologically rigorous interventional trials with appropriate control data and consistent and meaningful outcome reporting.

Plant-based dietary index in relation to gut microbiota in Arab women

Plant-based foods may influence gut microbiota profiles and contribute to overall human health. However, not all plant-based diets are nutritionally equivalent. We aimed to assess the association between a plant-based dietary index (PDI), specifically unhealthy PDI and healthy PDI (hPDI), and gut microbial composition and diversity in young women in Saudi Arabia. This observational study included 92 healthy women aged 18 to 25 years. Dietary and anthropometric data were collected. Fecal samples were analyzed using a novel whole-genome shotgun sequencing technique. Alpha and beta diversities measured the richness and composition of the gastrointestinal system. Relationships were examined with Pearson correlation, linear regression, and Wilcoxon Rank-Sum tests. Participants with higher PDI had higher levels of Bacteroides_u_s than those with lower PDI. hPDI was positively correlated with Bifidobacterium pseudocatenulatum, Bifidobacterium longum, Oscillibacter, and Lactobacillus acidophilus and inversely correlated with Clostridioides difficile (P < .05). Unhealthy plant-based dietary index was inversely correlated with B pseudocatenulatum, B longum, and L acidophilus and positively correlated with C difficile (P < .05) and other species of interest. In conclusion, hPDI scores were significantly associated with microbiota species linked with favorable health outcomes, independent of body mass index and gut microbial richness and composition in Arab women. Future studies should investigate the modulating effect of plant-based diets on the species identified in the current study.

Associations of healthful and unhealthful plant-based diets with plasma markers of cardiometabolic risk

PURPOSE

Plant-based diets, particularly when rich in healthy plant foods, have been associated with a lower risk of type 2 diabetes and cardiovascular disease. However, the impact of plant-based diets that distinguish between healthy and unhealthy plant foods on cardiometabolic biomarkers remains unclear.

METHODS

Dietary information was collected by two 24-h recalls among 34,785 adults from a nationwide cross-sectional study. Plasma levels of insulin, C-peptide, glucose, C-reactive protein (CRP), white blood cell (WBC) count, triglycerides (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C) were measured. Linear regression was used to evaluate the percentage difference in plasma marker concentrations by three plant-based diet indices, namely the overall plant-based diet index (PDI), the healthful PDI (hPDI), and the unhealthful PDI (uPDI).

RESULTS

Greater hPDI-adherence scores (comparing extreme quartiles) were associated with lower levels of insulin, Homeostatic Model Assessment of Insulin Resistance (HOMA-IR), TG/HDL-C ratio, CRP, WBC count, and TG, and higher levels of HDL-C, with the percentage differences of  - 14.55,  - 15.72,  - 11.57,  - 14.95,  - 5.26,  - 7.10, and 5.01, respectively (all Ptrend ≤ 0.001). Conversely, uPDI was associated with higher levels of insulin, C-peptide, HOMA-IR, TG/HDL-C ratio, CRP, WBC count, and TG, but lower HDL-C, with the percentage differences of 13.71, 14.00, 14.10, 10.43, 3.32, 8.00, and  - 4.98 (all Ptrend ≤ 0.001), respectively. Overall PDI was only associated with lower levels of CRP and WBC count (all Ptrend ≤ 0.001).

CONCLUSION

Our findings suggest that hPDI may have positive, whereas uPDI may have negative impacts on multiple cardiometabolic risk markers, and underscore the need to consider the quality of plant foods in future PDI studies.

Scoping review of the association of plant-based diet quality with health outcomes

Introduction

The association of plant-based dietary patterns with health outcomes has traditionally been assessed without considering nutritional value. The plant-based dietary index (PDI), first published in 2016, overcomes this limitation with both a healthful PDI (hPDI) and an unhealthful PDI (uPDI), based on the quality of plant foods consumed plus the frequency of animal foods. We sought to summarize the breadth of research using the hPDI and uPDI to gain insight into how the quality of plant-based dietary patterns might be associated with health outcomes.

Methods

Scoping review of studies that used the PDI, hPDI, or uPDI to report associations with health outcomes. Multiple databases were searched from 2010 through April 2023 with 2 authors independently assessing eligibility and extracting data. In addition to assessing the association of the indices to health outcomes, we determined the frequency of concordant or discordant findings for hPDI versus PDI and for hPDI versus uPDI.

Results

We included 95 articles (54% longitudinal, 37% cross-sectional, and 9% case-control) with a median sample size of 3,646. Higher hPDI levels were associated with favorable health outcomes in 36% of comparisons (most often for obesity, mortality, diabetes, cardiovascular disease, and psychiatric disorders), compared to 25% for the PDI and only 2% for the uPDI. Conversely, higher levels of the uPDI were associated with unfavorable health outcomes in 33% of comparisons, in contrast to under 1% for the hPDI and 2% for the PDI. When the hPDI association to an outcome was discordant with the uPDI or PDI, the significance and directionality always favored the hPDI over the uPDI, and nearly always favored the hPDI over the PDI.

Discussion

Dietary indices that account for the quality of plant foods can show health benefits that might be missed by a generic plant-based index. A greater focus on the quality of plant foods could improve nutrition guidelines, raise awareness about the benefits of adding unrefined plant foods to the diet, and empower consumers to make incremental additions of such foods to displace unhealthy foods. We anticipate increasing use of indices that address food quality in future research.

Translating energy balance research from the bench to the clinic to the community: Parallel animal-human studies in cancer

Advances in energy balance and cancer research to date have largely occurred in siloed work in rodents or patients. However, substantial benefit can be derived from parallel studies in which animal models inform the design of clinical and population studies or in which clinical observations become the basis for animal studies. The conference Translating Energy Balance from Bench to Communities: Application of Parallel Animal-Human Studies in Cancer, held in July 2021, convened investigators from basic, translational/clinical, and population science research to share knowledge, examples of successful parallel studies, and strong research to move the field of energy balance and cancer toward practice changes. This review summarizes key topics discussed to advance research on the role of energy balance, including physical activity, body composition, and dietary intake, on cancer development, cancer outcomes, and healthy survivorship.

The relationship between a plant-based diet and mental health: Evidence from a cross-sectional multicentric community trial (LIPOKAP study)

BACKGROUND

Dietary patterns emphasizing plant foods might be neuroprotective and exert health benefits on mental health. However, there is a paucity of evidence on the association between a plant-based dietary index and mental health measures.

OBJECTIVE

This study sought to examine the association between plant-based dietary indices, depression and anxiety in a large multicentric sample of Iranian adults.

METHODS

This cross-sectional study was performed in a sample of 2,033 participants. A validated food frequency questionnaire was used to evaluate dietary intakes of participants. Three versions of PDI including an overall PDI, a healthy PDI (hPDI), and an unhealthy PDI (uPDI) were created. The presence of anxiety and depression was examined via a validated Iranian version of the Hospital Anxiety and Depression Scale (HADS).

RESULTS

PDI and hPDI were not associated to depression and anxiety after adjustment for potential covariates (age, sex, energy, marital status, physical activity level and smoking). However, in the crude model, the highest consumption of uPDI approximately doubled the risk of depression (OR= 2.07, 95% CI: 1.49, 2.87; P<0.0001) and increased the risk of anxiety by almost 50% (OR= 1.56, 95% CI: 1.14, 2.14; P= 0.001). Adjustment for potential confounders just slightly changed the associations (OR for depression in the fourth quartile= 1.96; 95% CI: 1.34, 2.85, and OR for anxiety in the fourth quartile= 1.53; 95% CI: 1.07, 2.19).

CONCLUSIONS

An unhealthy plant-based dietary index is associated with a higher risk of depression and anxiety, while plant-based dietary index and healthy plant-based dietary index were not associated to depression and anxiety.

A healthful plant-based eating pattern is longitudinally associated with higher insulin sensitivity in Australian adults

BACKGROUND

A healthful plant-based eating pattern is associated with lower type 2 diabetes risk; however, the association with its preceding state, compromised insulin sensitivity, is less well-established, particularly in younger populations with repeated measures of diet over time.

OBJECTIVE

We aimed to examine the longitudinal relationship between a healthful plant-based eating pattern and insulin sensitivity in young to middle-aged adults.

METHODS

We included 667 participants from the Childhood Determinants of Adult Health (CDAH) study, a population-based cohort in Australia. Healthful plant-based diet index (hPDI) scores were derived from food frequency questionnaire data. Plant foods considered 'healthful' were scored positively (e.g., whole grains, fruit, vegetables), with all remaining foods scored reversely (e.g., refined grains, soft drinks, meat). Updated homeostatic model assessment (HOMA2) estimated insulin sensitivity from fasting insulin and glucose concentrations. We used linear mixed-effects regression to analyse data from two time points: CDAH-1 (2004-06, aged 26-36 years) and CDAH-3 (2017-19, aged 36-49 years). hPDI scores were modelled as between- and within-person effects (i.e., a participant's overall mean and their deviation from said mean at each time point, respectively).

RESULTS

The median follow-up duration was 13 years. In our primary analysis, each 10-unit difference in hPDI score was associated with higher log-HOMA2 insulin sensitivity [95% confidence interval], with between-person (β = 0.11 [0.05, 0.17], P < .001) and within-person effects (β = 0.10 [0.04, 0.16], P = .001). The within-person effect persisted despite accounting for compliance with dietary guidelines. Adjustment for waist circumference attenuated the between-person effect by 70% (P = .26) and the within-person effect by 40% (P = .04).

CONCLUSIONS

In young to middle-aged Australian adults, a healthful plant-based eating pattern (determined using hPDI scores) was longitudinally associated with higher insulin sensitivity, and therefore, potentially lower type 2 diabetes risk later in life.

Exploratory analysis of the effect of a controlled lifestyle intervention on inflammatory markers - the Healthy Lifestyle Community Programme (cohort 2)

BACKGROUND

Chronic low-grade inflammation is associated with an increased risk of chronic disease and mortality. The objective of the study was to test the effect of a healthy lifestyle intervention on biomarkers of inflammation (among other risk markers).

METHODS

We conducted a non-randomized controlled trial with mostly middle-aged and elderly participants from the general population in rural northwest Germany (intervention: n = 114; control: n = 87). The intervention consisted of a 1-year lifestyle programme focusing on diet (largely plant-based; strongest emphasis), physical activity, stress management, and social support. High-sensitivity C-reactive protein (hs-CRP) was assessed at baseline, 10 weeks, 6 months, and 1 year. Homocysteine (Hcy) was assessed at baseline, 10 weeks, and 1 year. Adiponectin (Apn) was assessed at baseline and 10 weeks. An exploratory analysis of these inflammatory markers assessing the between-group differences with ANCOVA was conducted.

RESULTS

The 1-year trajectory of hs-CRP was significantly lower in the intervention group compared to control (between-group difference: -0.8 (95% CI -1.2, -0.3) mg/l; p = 0.001; adjusted for baseline). The 1-year trajectory of Hcy was non-significantly higher in the intervention compared to control (between-group difference: 0.2 (95% CI -0.3, 0.7) µmol/l; p = 0.439; adjusted for baseline). From baseline to 10 weeks, Apn decreased significantly more in the intervention group compared to control (between-group difference: -1.6 (95% CI -2.7, -0.5) µg/ml; p = 0.004; adjusted for baseline).

CONCLUSIONS

Our study shows that healthy lifestyle changes can lower hs-CRP and Apn levels and are unlikely to significantly affect Hcy levels within 1 year.

TRIAL REGISTRATION

German Clinical Trials Register (DRKS; reference: DRKS00018775 , registered 12 Sept 2019; retrospectively registered; www.drks.de ).

Healthful and Unhealthful Plant-Based Diets and Chronic Obstructive Pulmonary Disease in U.S. Adults: Prospective Study

BACKGROUND

Despite the potential protective effect of a plant-based diet against chronic obstructive pulmonary disease (COPD), it remains unknown whether intake of different types of plant foods is beneficial for COPD. Our aims were to determine whether adherence to the healthful version of a plant-based diet (healthful Plant-based Diet Index (hPDI)) is associated with a lower COPD risk, whereas adherence to the unhealthful version (unhealthful Plant-based Diet Index (uPDI)) is associated with a higher COPD risk.

METHODS

46,948 men from the Health Professionals Follow-up Study, 73,592 women from the Nurses' Health Study, and 85,515 women from the Nurses' Health Study II who completed biennial questionnaires from 1984-2018. We derived diet scores from repeated validated food frequency questionnaires. Among 5,661,994 person-years of follow-up, we documented 2605 validated COPD cases between 1984-2018.

RESULTS

After tight control for smoking and other potential confounders, COPD risk was 46% lower among participants with the highest hPDI score compared to those with the lowest score. Conversely, COPD risk was 39% higher among participants with the highest uPDI. Further adjustment for processed meat intake led to similar results.

CONCLUSIONS

These findings provide further evidence for consuming a diet that emphasizes healthful plant foods to optimize lung health.

Healthy plant-based diets improve dyslipidemias, insulin resistance, and inflammation in metabolic syndrome. A narrative review

Plant-based diets (PBDs) have become very popular in recent years and have been identified as a dietary strategy associated with protection against chronic disease. However, the classifications of PBDs vary depending on the type of diet. Some PBDs have been recognized as healthful for their high content of vitamins, minerals, antioxidants, and fiber, or unhealthful if they are high in simple sugars and saturated fat. Depending on this classification, the type of PBD impacts its protective effects against disease dramatically. Metabolic syndrome (MetS), characterized by the presence of high plasma triglycerides and low HDL cholesterol, impaired glucose metabolism, elevated blood pressure, and increased concentrations of inflammatory biomarkers, also increases the risk for heart disease and diabetes. Thus, healthful plant-based diets could be considered favorable for individuals having MetS. The different types of plant-based diets (vegan, lacto-vegetarian, lacto-ovo-vegetarian, or pescatarian) are discussed with a focus on specific effects of dietary components in maintaining a healthy weight, protecting against dyslipidemias, insulin resistance, hypertension, and low-grade inflammation.

Plant-Based Diets and Lipid, Lipoprotein, and Inflammatory Biomarkers of Cardiovascular Disease: A Review of Observational and Interventional Studies

Plant-based diets (PBDs) are becoming increasingly popular. Thus far, the literature has focused on their association with lipid profiles, with less investigation of lipoprotein and inflammatory profiles. Because pro-atherogenic lipid, lipoprotein, and inflammatory processes may facilitate the development of atherosclerosis, understanding the relation between PBDs and these processes is important to inform risk mitigation strategies. Therefore, the objective of this paper was to review the literature on PBDs and lipid, lipoprotein, and inflammatory biomarkers of cardiovascular disease (CVD). A structured literature search was performed, retrieving 752 records, of which 43 articles were included. Plant-based diets generally associated with favourable lipid and lipoprotein profiles, characterised by decreased total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein B concentrations, and less low-grade inflammation, characterised by decreased C-reactive protein concentrations. Effect sizes from PBD interventions were greatest compared to habitual dietary patterns, and for non-low-fat vegan and tightly controlled dietary interventions. Associations between PBD indices and the reviewed biomarkers were less consistent. Findings are discussed with reference to the literature on PBDs and PBD indices and CVD risk, the associations between specific plant food groups and CVD outcomes and the reviewed biomarker outcomes, and the potential mechanisms underpinning associations between PBDs and reduced CVD risk.

A Healthful Plant-Based Diet Is Associated with Lower Odds of Nonalcoholic Fatty Liver Disease

There is little evidence for the associations of the overall plant-based diet index (PDI), the healthful PDI (hPDI), and the unhealthful PDI (uPDI) with the odds of nonalcoholic fatty liver disease (NAFLD). We present a nationwide cross-sectional study among US adults aged 18 years or older. Diet was assessed by 24-h recalls. Overall PDI, hPDI, and uPDI were constructed based on 18 food groups. NAFLD was defined based on controlled attenuation parameter derived via transient elastography (TE) in the absence of other causes of chronic liver disease. Among 3900 participants with eligible TE examination, 1686 were diagnosed with NAFLD. The overall PDI was not associated with NAFLD prevalence (comparing extreme tertiles of PDI score OR = 1.03, 95% CI 0.76, 1.38, ptrend = 0.609). However, hPDI was inversely (OR = 0.50, 95% CI 0.35, 0.72, ptrend < 0.001), while uPDI was positively associated with odds of NAFLD (OR = 1.37, 95% CI 0.93, 2.02, ptrend = 0.009) in the multivariable-adjusted models without body mass index (BMI). After further adjustment for BMI, only the association of hPDI with NAFLD remained statistically significant (OR = 0.64, 95% CI 0.46, 0.87, ptrend = 0.006). Such inverse association appeared stronger in non-Hispanic whites, but not in other racial/ethnic groups (pinteraction = 0.009). Our findings suggest that a plant-based diet rich in healthy plant foods might be associated with lower odds of NAFLD, particularly among US non-Hispanic whites. Clinical trials and cohort studies to validate our findings are needed.

Plasma Leptin and Adiponectin after a 4-Week Vegan Diet: A Randomized-Controlled Pilot Trial in Healthy Participants

Adiponectin and leptin are important mediators of metabolic homeostasis. The actions of these adipokines extend beyond adipocytes and include systemic modulation of lipid and glucose metabolism, nutrient flux, and the immune response to changes in nutrition. Herein, we hypothesized that short-term intervention with a vegan diet might result in an improvement of plasma concentrations of adiponectin and leptin and the leptin/adiponectin ratio. We investigated the response of plasma adiponectin and leptin to a 4-week intervention with a vegan or meat-rich diet and its associations with sex, BMI and nutritional intake. Fifty-three healthy, omnivore participants (62% female, average age 31 years and BMI 23.1 kg/m²) were randomly assigned to a vegan or meat-rich diet for 4 weeks. Plasma adiponectin and leptin were lower in men compared to women both at the beginning and end of the trial. The concentration of adiponectin in women was significantly higher both when comparing their transition from omnivorous to vegan diet (p = 0.023) and also for vegan versus meat-rich diet at the end of the trial (p = 0.001), whereas plasma leptin did not vary significantly. No changes in adiponectin were identified in men, yet an increase in leptin occurred upon their transition from an omnivorous to a meat-rich diet (p = 0.019). Examination of plasma adiponectin/leptin ratio, a proposed marker of cardiovascular risk, did not differ after 4-weeks of dietary intervention. Our study revealed that adiponectin and leptin concentrations are sensitive to short-term dietary intervention in a sex-dependent manner. This dietary modification of leptin and adiponectin not only occurs quickly as demonstrated in our study, but it remains such as published in studies with individuals who are established (long-term) vegetarians compared to omnivorous.

Plant-based diets and body composition in Chinese omnivorous children aged 6-9 years old: A cross-sectional study

Evidence suggests that plant-based diets are beneficial for alleviating metabolic diseases. Childhood is a crucial period for body growth and development. However, it is unknown whether adherence to a plant-based diet is related to a healthy body composition in children. We aimed to assess the relationship between a plant-based diet and body composition in children. A total of 452 Chinese children aged 6–9 years old participated in this cross-sectional study. Lean mass (LM), fat mass, and fat mass percentage (FMP) were assessed via dual-energy X-ray absorptiometry. An age- and sex-specific abdominal FMP ≥85th percentile was defined as abdominal obesity. Handgrip strength was measured using a hydraulic hand dynamometer. A validated 79-item food frequency questionnaire was used to collect dietary information. Overall plant-based diet index (PDI), healthful plant-based diet index (hPDI), and unhealthful plant-based diet index (uPDI) scores were calculated. After adjusting for potential covariates, a higher hPDI score (per 10-score increment) was associated with a higher LM in the android area (0.038 kg, 3.2%), gynoid area (0.048 kg, 1.9%), and trunk (0.102 kg, 1.2%) and with a lower FMP (1.18%) in the android area. In contrast, a higher uPDI score (per 10-score increment) was associated with a lower LM in the trunk (0.091 kg, 1.1%) and android area (0.023 kg, 1.9%) and with a higher FMP (0.74%) in the android area. No significant associations were observed between the overall PDI and body composition or abdominal obesity. After stratifying by sex, higher (vs. lower) hPDI scores was associated with lower abdominal obesity risk in girls and higher handgrip strength in boys. In conclusion, in this cross-sectional study, we found that stronger adherence to a healthful plant-based diet, and less adherence to an unhealthful plant-based diet was associated with better body composition in Chinese omnivorous children aged 6–9 years old. Our results highlight the need to distinguish between healthy and unhealthy plant foods within investigating how to obtain a healthy body composition in children.

Nutrition and the state of the intestinal microflora in the formation of the metabolic syndrome

The literature review presents the results of modern studies of the relationship between diet and intestinal microbiota in the regulation of metabolic disorders. Metabolic syndrome, which is a symptom complex that combines abdominal obesity, insulin resistance, hyperglycemia, dyslipidemia and arterial hypertension, remains an important problem, being a risk factor for cardiovascular, neurodegenerative, oncological diseases and the development of type 2 diabetes mellitus. Although the pathogenesis of the metabolic syndrome has not yet been fully elucidated, it is known that visceral obesity and its associated complications, such as dyslipidemia and increased levels of pro-inflammatory cytokines, play a central role. The article presents data on the impact of the consumption of certain food products, the inclusion of plant biologically active substances (flavonoids, polyphenols, etc.) in the diet, as well as the use of elimination diets with the exclusion of carbohydrates or fats from the diet, on reducing the risk of cardiovascular accidents, levels of fasting glucose, total cholesterol, LDL, triglycerides, C-reactive protein, leptin, insulin, reduction in body weight and waist circumference, reduction in the level of circulating endotoxins and changes in the activity of immunocompetent cells. Data are presented on the possible influence of the intestinal microbiota in maintaining inflammation and the formation of degenerative changes in the body. The role of changes in the ratio of the levels of pathogenic microflora, bifidobacteria and lactobacilli in the formation of a pathological condition is shown.

Positive association of unhealthy plant-based diets with the incidence of abdominal obesity in Korea: a comparison of baseline, most recent, and cumulative average diets

OBJECTIVES

Different approaches for analyzing repeated dietary measurements may yield differences in the magnitude and interpretation of findings. We aimed to compare 3 dietary measurements (baseline, most recent, and cumulative average) in terms of the association between plant-based diet indices (PDIs) and incident abdominal obesity in Korean adults aged 40-69 years.

METHODS

This study included 6,054 participants (54% women) free of abdominal obesity (defined as waist circumference ≥90 cm for men and ≥85 cm for women) at baseline. As exposures, baseline, most recent, and cumulative average measurements for PDI, healthy-PDI (hPDI), and unhealthy-PDI (uPDI) were created. A Cox proportional-hazard model was used to estimate the hazard ratios (HRs) for abdominal obesity.

RESULTS

During 45,818 person-years of follow-up (median, 9 years), we identified 1,778 incident cases of abdominal obesity. In the multivariable-adjusted analysis, a higher uPDI was associated with a higher risk of abdominal obesity in both total and stratified analyses. The findings were consistent across all approaches (Q5 vs. Q1: HRbaseline=1.70; 95% confidence interval [CI], 1.46 to 1.98; HRmost recent=1.52; 95% CI, 1.30 to 1.78; HRcumulative average=1.76; 95% CI, 1.51 to 2.06 in the total set). PDI showed no meaningful association with abdominal obesity risk in any analyses. hPDIaverage had a suggestive inverse association with abdominal obesity risk in men, and hPDIbaseline had a positive association with abdominal obesity risk in women.

CONCLUSIONS

Greater adherence to unhealthy plant-based diets may increase the risk of developing abdominal obesity in Korean adults. The findings were generally consistent across all approaches.

Degree of Adherence to Based Diet and Total and Cause-Specific Mortality: Prospective Cohort Study in the Million Veteran Program

OBJECTIVE

To examine the associations between adherence to plant-based diets and mortality.

DESIGN

prospective study. We calculated a plant-based diet index (PDI) by assigning positive scores to plant foods and reverse scores to animal foods. We also created a healthful PDI (hPDI) and an unhealthful PDI (uPDI) by further separate the healthy plant foods from less-healthy plant foods.

SETTING

the VA Million Veteran Program.

PARTICIPANTS

315,919 men and women aged 19 to 104 years who completed a food frequency questionnaire at the baseline.

RESULTS

We documented 31,136 deaths during the follow-up. A higher PDI was significantly associated with lower total mortality [hazard ratio (HR) comparing extreme deciles =0.75, 95% confidence interval (CI): 0.71 to 0.79, Ptrend <0.001]. We observed an inverse association between hPDI and total mortality (HR comparing extreme deciles =0.64, 95% CI: 0.61 to 0.68, Ptrend <0.001), whereas uPDI was positively associated with total mortality (HR comparing extreme deciles =1.41, 95% CI: 1.33 to 1.49, Ptrend <0.001). Similar significant associations of PDI, hPDI, and uPDI were also observed for CVD and cancer mortality. The associations between the plant-based diet indices and total mortality were consistent among African and European American participants, and participants free from CVD and cancer and those who were diagnosed with major chronic disease at baseline.

CONCLUSIONS

A greater adherence to a plant-based diet was associated with substantially lower total mortality in this large population of veterans. These findings support recommending plant-rich dietary patterns for the prevention of major chronic diseases.

Association between Plant-Based Dietary Patterns and Risk of Cardiovascular Disease: A Systematic Review and Meta-Analysis of Prospective Cohort Studies

Plant-based diets, characterized by a higher consumption of plant foods and a lower consumption of animal foods, are associated with a favorable cardiovascular disease (CVD) risk, but evidence regarding the association between plant-based diets and CVD (including coronary heart disease (CHD) and stroke) incidence remain inconclusive. A literature search was conducted using the PubMed, EMBASE and Web of Science databases through December 2020 to identify prospective observational studies that examined the associations between plant-based diets and CVD incidence among adults. A systematic review and a meta-analysis using random effects models and dose–response analyses were performed. Ten studies describing nine unique cohorts were identified with a total of 698,707 participants (including 137,968 CVD, 41,162 CHD and 13,370 stroke events). Compared with the lowest adherence, the highest adherence to plant-based diets was associated with a lower risk of CVD (RR 0.84; 95% CI 0.79–0.89) and CHD (RR 0.88; 95% CI 0.81–0.94), but not of stroke (RR 0.87; 95% CI 0.73–1.03). Higher overall plant-based diet index (PDI) and healthful PDI scores were associated with a reduced CVD risk. These results support the claim that diets lower in animal foods and unhealthy plant foods, and higher in healthy plant foods are beneficial for CVD prevention. Protocol was published in PROSPERO (No. CRD42021223188).

Healthful and Unhealthful Plant-Based Diets and Risk of Breast Cancer in U.S. Women: Results from the Nurses' Health Studies

BACKGROUND

Plant-based diets have been associated with lower risk of various diseases, including type 2 diabetes, cardiovascular disease, and other cardiometabolic risk factors. However, the association between plant-based diet quality and breast cancer remains unclear.

METHODS

We prospectively followed 76,690 women from the Nurses' Health Study (NHS, 1984-2016) and 93,295 women from the NHSII (1991-2017). Adherence to an overall plant-based diet index (PDI), a healthful PDI (hPDI), and an unhealthful PDI (uPDI) was assessed using previously developed indices. Cox proportional hazards models were used to estimate HR and 95% confidence intervals (CI) for incident invasive breast cancer.

RESULTS

Over 4,841,083 person-years of follow-up, we documented 12,482 incident invasive breast cancer cases. Women with greater adherence to PDI and hPDI were at modestly lower risk of breast cancer [(HRQ5 vs. Q1, 0.89; 95% CI, 0.84-0.95); (HRQ5 vs. Q1, 0.89; 95% CI, 0.83-0.94)]. We observed significant heterogeneity by estrogen receptor (ER) status, with the strongest inverse association between hPDI and breast cancer observed with ER-negative tumors [HRQ5 vs. Q1, 0.77; 95% CI, 0.65-0.90; P trend < 0.01]. We also found an inverse association between extreme quintiles of healthy plant foods and ER-negative breast cancer [HR, 0.74; 95% CI, 0.61-0.88; P trend < 0.01].

CONCLUSIONS

This study provides evidence that adherence to a healthful plant-based diet may reduce the risk of breast cancer, especially those that are more likely to be aggressive tumors.

IMPACT

This is the first prospective study investigating the relation between healthful and unhealthful plant-based dietary indices and risk of total and subtype-specific breast cancer.

Lifestyle Adjustments in Long-COVID Management: Potential Benefits of Plant-Based Diets

Purpose of Review

The SARS-CoV-2-pandemic has caused mortality and morbidity at an unprecedented global scale. Many patients infected with SARS-CoV-2 continue to experience symptoms after the acute phase of infection and report fatigue, sleep difficulties, anxiety, and depression as well as arthralgia and muscle weakness. Summarized under the umbrella term “long-COVID,” these symptoms may last weeks to months and impose a substantial burden on affected individuals. Dietary approaches to tackle these complications have received comparably little attention. Although plant-based diets in particular were shown to exert benefits on underlying conditions linked to poor COVID-19 outcomes, their role with regard to COVID-19 sequelae is yet largely unknown. Thus, this review sought to investigate whether a plant-based diet could reduce the burden of long-COVID.

Recent Findings

The number of clinical trials investigating the role of plant-based nutrition in COVID-19 prevention and management is currently limited. Yet, there is evidence from pre-pandemic observational and clinical studies that a plant-based diet may be of general benefit with regard to several clinical conditions that can also be found in individuals with COVID-19. These include anxiety, depression, sleep disorders, and musculoskeletal pain. Adoption of a plant-based diet leads to a reduced intake in pro-inflammatory mediators and could be one accessible strategy to tackle long-COVID associated prolonged systemic inflammation.

Summary

Plant-based diets may be of general benefit with regard to some of the most commonly found COVID-19 sequelae. Additional trials investigating which plant-based eating patterns confer the greatest benefit in the battle against long-COVID are urgently warranted.

Association of plant-based diet index with inflammatory markers and sleep quality in overweight and obese female adults: A cross-sectional study

BACKGROUND

Inflammation and sleep disturbances increase the risk of multiple diseases, including cardiovascular disease, type 2 diabetes and dementia. Since diet plays a significant role in inflammatory responses and sleep quality, this study aimed to investigate the association of a plant-based diet index (PDI) with sleep quality and inflammatory markers in overweight and obese women.

METHODS

390 overweight and obese women aged 18-48 years participated in this cross-sectional study. A validated food frequency questionnaire (FFQ) was used to create an overall PDI, healthful plant-based diet index (hPDI) and unhealthful plant-based diet index (uPDI). Sleep quality was assessed by Pittsburgh Sleep Quality Index (PSQI). Higher scores on the PSQI were indicative of poor sleep. Anthropometric measurements and serum concentrations of high-sensitivity C-reactive protein (hs-CRP), interleukin 1 beta (IL-1β) and transforming growth factor-beta (TGF-β) were evaluated. Linear regression models were used to determine the association between exposure and outcomes.

RESULTS

After taking potential confounders into account, we found a significant inverse association between adherence to hPDI and hs-CRP (β = -0.14, 95% confidence interval [CI]: -0.22,0.06, P = .001) and a significant positive association between uPDI and hs-CRP (β = 0.13, 95% CI: 0.05,0.21, P = .001). Overall, PDI was significantly associated with TGF-β (β = 2.04, 95% CI: 0.54,3.55, P = .008). No association was detected between PDI indices and IL-1β. Higher adherence to uPDI was significantly associated with higher PSQI score (lower sleep quality) (β= 0.20, 95% CI:0.007,0.40, P = .04). A significant positive association was found between TGF-β (β = 0.05, 95% CI:0.005,0.10, P = .03) and hs-CRP (β = 0.32, 95% CI:0.02,0.62, P = .03) with PSQI.

CONCLUSION

Our findings indicated a significant association between adherence to a plant-based diet with inflammation and sleep quality in obese and overweight females. WHAT IS ALREADY KNOWN ABOUT THIS TOPIC?: Sleep is an essential part of life, and sleep quality has a significant impact on individual well-being and performance. There is a bidirectional relationship between disturbed sleep and elevated levels of inflammatory markers. Diet plays a major part in sleep quality and its related health consequences. Plant-based diets are associated with lower risk of chronic diseases such as coronary artery disease (CAD), type 2 diabetes, obesity and reduced level of inflammation. WHAT DOES THIS ARTICLE ADD?: Adherence to a healthful plant-based diet is associated with lower level of hs-CRP, while adherence to an unhealthful plant-based diet is associated with higher concentrations of hs-CRP. Adherence to an unhealthful plant-based diet is associated with lower sleep quality.

Plant-based dietary indices and stress in female college students: a cross-sectional study

Only a few studies have investigated the association between psychological stress and the healthfulness of plant-based diets while accounting for variances in age groups and regions. In light of this, this study aimed to identify the food groups that contribute the most to the relationship between the healthfulness of plant-based diets and psychological stress in female students in Saudi Arabia. This cross-sectional study, which included 401 female college students aged 19-35 years, collected data on blood, anthropometric indices, the perceived stress scale-10 (PSS-10) and diet using the Saudi food frequency questionnaire. An overall plant-based diet index (PDI), healthy PDI, and an unhealthy PDI (uPDI) were defined. Multiple linear regression analyses were applied to examine the associations between PSS-10 and PDI and hPDI and uPDI. No associations between the PSS-10 score and the overall PDI or uPDI scores were found; however, a six-point higher hPDI score was associated with a 0·16-point lower PSS-10 score (95 % CI, -0·24, -0·08) after controlling for lifestyle factors. Moreover, adjustments for healthy food groups, including vegetables and fruits, attenuated the association between the hPDI and PSS-10. In conclusion, healthy plant-based diets are associated with lower psychological stress in young Saudi women. This finding highlights the importance, especially for female students, of following diets that are not only plant-based but are also healthy and rich in fruits and vegetables.

Post-diagnostic reliance on plant-compared with animal-based foods and all-cause mortality in omnivorous long-term colorectal cancer survivors

BACKGROUND

Plant-rich diets are associated with lower cardiometabolic risks and longer survival in the general population, but their association with mortality in cancer survivors is still unclear.

OBJECTIVES

We aimed to examine the associations of 3 postdiagnostic plant-based diet indices with all-cause mortality in omnivorous long-term colorectal cancer (CRC) survivors.

METHODS

Diet was assessed with FFQs at a median of 6 years after diagnosis in 1404 CRC survivors (56% male; median age, 69 years) in a Northern German prospective cohort study. An overall, a healthful plant-based, and an unhealthful plant-based diet index were derived by scoring intakes of animal foods reversely and intakes of healthy (whole grains, vegetables, fruits, legumes, nuts, oils, tea/coffee) and less healthy plant foods (refined grains, fruit juices, sugar-sweetened beverages, potatoes, sweets/desserts) positively or reversely, depending on the index. Vital status follow-up was conducted via population registries. Cox proportional hazards regression was applied to estimate HRs for all-cause mortality according to plant-based diet adherence.

RESULTS

Within 7 years (median) after diet assessment, 204 deaths occurred. The overall plant-based diet index displayed a significant, inverse association with all-cause mortality (HR per 10-point increase in diet index, 0.72; 95% CI, 0.57-0.91). Although not statistically significant, higher healthful plant-based diet scores showed a strong tendency towards lower mortality (HR, 0.82; 95% CI, 0.67-1.01). The unhealthful plant-based diet index was associated with higher mortality, but lost statistical significance after multivariable adjustment (HR, 1.19; 95% CI, 0.96-1.48). A subgroup analysis revealed that the tendency towards a positive association of the unhealthful plant-based diet with mortality was restricted to less physically active individuals (<95 metabolic equivalent of task hours/week).

CONCLUSIONS

An overall plant-based diet was inversely associated with all-cause mortality in long-term CRC survivors. However, more research is needed to further disentangle the impacts of different qualities of plant-based diets on cancer survivors' health.

The Lack of Association between Plant-Based Dietary Pattern and Breast Cancer: a Hospital-Based Case-Control Study

Our purpose was to assess the association between plant-based dietary patterns and breast cancer (BrCa) among Iranian women. This hospital-based case-control study included 150 newly diagnosed BrCa cases and 150 age-matched controls from the Cancer Research Center, Imam Khomeini hospital, Iran. Three indices of a plant-based diet were first calculated: plant-based diet index (PDI), the healthy PDI (hPDI), and the unhealthy PDI (uPDI). In the overall PDI, all plant foods scored positively. In hPDI and uPDI, healthy and less healthy plant foods scored positive, respectively. The adjusted odds ratio (OR) in the highest adherence of PDI was 1.00 (95% confidence interval [CI], 0.55-1.83). In hPDI, 0.89 (95% CI, 0.49-1.62); in uPDI, 1.80 (95% CI, 0.95-3.42). The adjusted OR after subgroup analysis for body mass index (BMI) was as follow, BMI > 25: 0.77(95% CI, 0.37-1.61) comparing highest with the lowest tertile of PDI, 0.91(95% CI, 0.44-1.89) comparing highest with the lowest tertile of hPDI and this value for uPDI was 2.04 (95% CI, 0.91-4.56). BMI < 25: OR for top tertile of PDI was 1.82 (95% CI, 0.48-6.93), top tertile of hPDI was 1.47 (95% CI, 0.35-6.22) and top tertile of uPDI was 2.29 (95% CI, 0.54-9.70). Our results revealed no significant association between none of the PDIs and the chance of BrCa in Iranian women. Continued and expanded research, evaluated by different methods and BrCa is urgently needed to build the foundation for future progress in evidence-based public health efforts.

The Role of Exercise, Diet, and Cytokines in Preventing Obesity and Improving Adipose Tissue

The prevalence of obesity continues to rise worldwide despite evidence-based public health recommendations. The promise to adopt a healthy lifestyle is increasingly important for tackling this global epidemic. Calorie restriction or regular exercise or a combination of the two is accepted as an effective strategy in preventing or treating obesity. Furthermore, the benefits conferred by regular exercise to overcome obesity are attributed not only to reduced adiposity or reduced levels of circulating lipids but also to the proteins, peptides, enzymes, and metabolites that are released from contracting skeletal muscle or other organs. The secretion of these molecules called cytokines in response to exercise induces browning of white adipose tissue by increasing the expression of brown adipocyte-specific genes within the white adipose tissue, suggesting that exercise-induced cytokines may play a significant role in preventing obesity. In this review, we present research-based evidence supporting the effects of exercise and various diet interventions on preventing obesity and adipose tissue health. We also discuss the interplay between adipose tissue and the cytokines secreted from skeletal muscle and other organs that are known to affect adipose tissue and metabolism.

A review of statistical methods for dietary pattern analysis

Background

Dietary pattern analysis is a promising approach to understanding the complex relationship between diet and health. While many statistical methods exist, the literature predominantly focuses on classical methods such as dietary quality scores, principal component analysis, factor analysis, clustering analysis, and reduced rank regression. There are some emerging methods that have rarely or never been reviewed or discussed adequately.

Methods

This paper presents a landscape review of the existing statistical methods used to derive dietary patterns, especially the finite mixture model, treelet transform, data mining, least absolute shrinkage and selection operator and compositional data analysis, in terms of their underlying concepts, advantages and disadvantages, and available software and packages for implementation.

Results

While all statistical methods for dietary pattern analysis have unique features and serve distinct purposes, emerging methods warrant more attention. However, future research is needed to evaluate these emerging methods’ performance in terms of reproducibility, validity, and ability to predict different outcomes.

Conclusion

Selection of the most appropriate method mainly depends on the research questions. As an evolving subject, there is always scope for deriving dietary patterns through new analytic methodologies.

Circulating Adiponectin and Its Association with Metabolic Traits and Type 2 Diabetes: Gene-Diet Interactions Focusing on Selected Gene Variants and at the Genome-Wide Level in High-Cardiovascular Risk Mediterranean Subjects

Adiponectin is gaining renewed interest since, in addition to its possible protective role against insulin resistance and arteriosclerosis, recent studies suggest other additional favorable effects. However, the influence of gene-diet interactions on plasma adiponectin levels is still little understood. We analyzed the association between plasma adiponectin levels and various metabolic traits in a high-cardiovascular risk Mediterranean population, as well as the genetic effect of four candidate single-nucleotide polymorphisms (SNPs) in the adiponectin gene (ADIPOQ) and their interactions with the Mediterranean dietary pattern. Additionally, we explored, at the genome-wide level, the SNPs most associated with plasma adiponectin levels, as well as gene-diet interactions with the Mediterranean diet. In the 954 participants studied (aged 55-80 years), plasma adiponectin levels were strongly associated with plasma HDL-C concentrations (p = 6.6 × 10^-36) and inversely related to triglycerides (p = 4.7 × 10^-18), fasting glucose (p = 3.5 × 10^-16) and type 2 diabetes (p = 1.4 × 10^-7). Of the four pre-selected ADIPOQ candidate SNPs, the one most associated with plasma adiponectin was the -11391G > A (rs17300539) promoter SNP (p = 7.2 × 10^-5, in the multivariable adjusted model). No significant interactions with the Mediterranean diet pattern were observed for these SNPs. Additionally, in the exploratory genome-wide association study (GWAS), we found new SNPs associated with adiponectin concentrations at the suggestive genome-wide level (p < 1 × 10^-5) for the whole population, including the lead SNP rs9738548 (intergenic) and rs11647294 in the VAT1L (Vesicle Amine Transport 1 Like) gene. We also found other promising SNPs on exploring different strata such as men, women, diabetics and non-diabetics (p = 3.5 × 10^-8 for rs2850066). Similarly, we explored gene-Mediterranean diet interactions at the GWAS level and identified several SNPs with gene-diet interactions at p < 1 × 10^-5. A remarkable gene-diet interaction was revealed for the rs2917570 SNP in the OPCML (Opioid Binding Protein/Cell Adhesion Molecule Like) gene, previously reported to be associated with adiponectin levels in some populations. Our results suggest that, in this high-cardiovascular risk Mediterranean population, and even though adiponectin is favorably associated with metabolic traits and lower type 2 diabetes, the gene variants more associated with adiponectin may be population-specific, and some suggestive gene-Mediterranean diet interactions were detected.

The association of plant-based dietary patterns with visceral adiposity, lipid accumulation product, and triglyceride-glucose index in Iranian adults

BACKGROUND

We sought to investigate whether adherence to a more plant-based, and less animal-based, diet is associated with visceral adiposity, lipid accumulation product (LAP), and triglyceride-glucose index (TyG) in Iranian adults.

METHODS

This cross-sectional study was conducted on 270 adults aged between 18-75 years old. We created three plant-based diets. including an overall plant-based diet index (PDI), hPDI, and uPDI based on tertiles regarding the intake of animal- or plant-based food items obtained from a semi quantitative food-frequency questionnaire.

RESULTS

Higher hPDI was significantly associated with lower body mass index (BMI) (P-value = 0.01), lower waist circumference (P-value<0.001), and lower waist-hip ratio (P-value<0.001). A significant increase was found for high density lipoproteins (HDL) (P-trend <0.001) with a significant decrease for LAP (P-value = 0.03) in those with higher adherence to hPDI. Moreover, greater adherence to PDI was associated with a significant increase in diastolic blood pressure (DBP) (p-value = 0.01) and fat free mass (FFM) (p-value = 0.01). There were no significant associations between PDIs and TyG and VFA.

CONCLUSION

We found that a higher hPDI score was significantly associated with better anthropometric measurements. A significant increase was found for HDL and a significant decrease was found for LAP on hPDI. However, a higher PDI score was significantly associated with higher DBP and higher FFM.

Adherence to a plant-based diet in relation to adipose tissue volumes and liver fat content

BACKGROUND

Better adherence to plant-based diets has been linked to lower risk of metabolic diseases but the effect on abdominal fat distribution and liver fat content is unclear.

OBJECTIVES

We aimed to examine the association between different plant-based diet indices and measures of abdominal fat distribution and liver fat content.

METHODS

In a population-based sample of 578 individuals from Northern Germany (57% male, median age 62 y), diet was assessed with a validated FFQ and an overall, a healthy, and an unhealthy plant-based diet index were derived. Participants underwent MRI to assess volumes of visceral and subcutaneous abdominal adipose tissue and liver signal intensity (LSI), a measure of liver fat content. Fatty liver disease (FLD) was defined as log LSI ≥3.0. Cross-sectional associations of the plant-based diet indices with visceral and subcutaneous abdominal fat volumes, LSI, and FLD were assessed in linear and logistic regression analyses. The most comprehensive model adjusted for age, sex, education, smoking, alcohol, physical activity, energy intake, diabetes, hyperlipidemia, and BMI.

RESULTS

Higher overall and healthy plant-based diet indices both revealed statistically significant associations with lower visceral and subcutaneous abdominal adipose tissue volumes and with lower odds of FLD in multivariable-adjusted models without BMI. Upon additional adjustment for BMI, only the association of the healthy plant-based diet with visceral adipose tissue remained statistically significant (per 10-point higher healthy plant-based diet index, percentage change in visceral adipose tissue: -4.9%, 95% CI: -8.6%, -2.0%). None of the plant-based diet indices was associated with LSI. The unhealthy plant-based diet index was unrelated to any of the abdominal or liver fat parameters.

CONCLUSIONS

Adherence to healthy plant-based diets was associated with lower visceral adipose tissue. None of the other examined associations remained statistically significant after adjustment for BMI.

Is the Retinol-Binding Protein 4 a Possible Risk Factor for Cardiovascular Diseases in Obesity?

Although many preventive and treatment approaches have been proposed, cardiovascular disease (CVD) remains one of the leading causes of deaths worldwide. Current epidemiological data require the specification of new causative factors, as well as the development of improved diagnostic tools to provide better cardiovascular management. Excessive accumulation of adipose tissue among patients suffering from obesity not only constitutes one of the main risk factors of CVD development but also alters adipokines. Increased attention is devoted to bioactive adipokines, which are also produced by the adipose tissue. The retinol-binding protein 4 (RBP4) has been associated with numerous CVDs and is presumably associated with an increased cardiovascular risk. With this in mind, exploring the role of RBP4, particularly among patients with obesity, could be a promising direction and could lead to better CVD prevention and management in this patient group. In our review, we summarized the current knowledge about RBP4 and its association with essential aspects of cardiovascular disease-lipid profile, intima-media thickness, atherosclerotic process, and diet. We also discussed the RBP4 gene polymorphisms essential from a cardiovascular perspective.

The Impact of Plant-Based Dietary Patterns on Cancer-Related Outcomes: A Rapid Review and Meta-Analysis

Long-term cancer survivors represent a sizeable portion of the population. Plant-based foods may enhance the prevention of cancer-related outcomes in these patients. We aimed to synthesize the current evidence regarding the impact of plant-based dietary patterns (PBDPs) on cancer-related outcomes in the general population and in cancer survivors. Considered outcomes included overall cancer mortality, cancer-specific mortality, and cancer recurrence. A rapid review was conducted, whereby 2234 original articles related to the topic were identified via Pubmed/Medline. We selected 26 articles, which were classified into studies on PBDPs and cancer outcomes at pre-diagnosis: vegan/vegetarian diet (N = 5), provegetarian diet (N = 2), Mediterranean diet (N = 13), and studies considering the same at post-diagnosis (N = 6). Pooled estimates of the associations between the aforementioned PBDPs and the different cancer outcomes were obtained by applying random effects meta-analysis. The few studies available on the vegetarian diet failed to support its prevention potential against overall cancer mortality when compared with a non-vegetarian diet (e.g., pooled hazard ratio (HR) = 0.97; 95% confidence interval (CI): 0.88-1.06). The insufficient number of studies evaluating provegetarian index scores in relation to cancer mortality did not permit a comprehensive assessment of this association. The association between adherence to the Mediterranean diet and cancer mortality reached statistical significance (e.g., pooled HR = 0.84; 95% CI: 0.79-0.89). However, no study considered the influence of prognostic factors on the associations. In contrast, post-diagnostic studies accounted for prognostic factors when assessing the chemoprevention potential of PBDPs, but also were inconclusive due to the limited number of studies on well-defined plant-based diets. Thus, whether plant-based diets before or after a cancer diagnosis prevent negative cancer-related outcomes needs to be researched further, in order to define dietary guidelines for cancer survivors.

Changes in plant-based diet quality and health-related quality of life in women

Few studies have evaluated the association between a healthful plant-based diet and health-related quality of life (HRQoL). We followed 50 290 women in the Nurses’ Health Study (NHS; 1992–2000) and 51 784 women in NHSII (1993–2001) for 8 years to investigate changes in plant-based diet quality in relation to changes in physical and mental HRQoL. Plant-based diet quality was assessed by three plant-based diet indices: overall plant-based diet index (PDI), healthful PDI (hPDI) and unhealthful PDI (uPDI). Physical and mental HRQoL were measured by physical component score (PCS) and mental component score (MCS) of the 36-Item Short Form Health Survey. Diet was assessed 2 years before the HRQoL measurements and both were updated every 4 years. The associations between 4-year changes in PDIs and HRQoL were evaluated. Each 10-point increase in PDI was associated with an improvement of 0·07 (95 % CI 0·01, 0·13) in PCS and 0·11 (95 % CI 0·05, 0·16) in MCS. A 10-point increase in hPDI was associated with an increment of 0·13 (95 % CI 0·08, 0·19) in PCS and 0·09 (95 % CI 0·03, 0·15) in MCS. Conversely, a 10-point increase in uPDI was associated with decreases in PCS and MCS (−0·07 (95 % CI −0·12, −0·02) and −0·10 (95 % CI −0·16, −0·05), respectively). Compared with a stable diet, an increase in hPDI was significantly associated with improvements in physical HRQoL in older women and with mental HRQoL in younger women. In conclusion, adherence to a healthful plant-based diet was modestly associated with improvements in both physical and mental dimensions of HRQoL.

Prospective Study of Long-Term Interrelationships Among Adiposity-Associated Biomarkers in Women

OBJECTIVE

This study aimed to investigate the prospective interrelationships among biomarkers that may provide mechanistic insights into obesity-related diseases.

METHODS

A total of 850 women in the Nurses' Health Study II with two fasting blood measurements (1996-1999 and 2010-2011) of adiponectin, leptin, soluble leptin receptor, insulin, retinol-binding protein 4, high-sensitivity C-reactive protein (hsCRP), and interleukin-6 were included. Biomarker interrelationships were examined in the following three ways: (1) cross-sectional associations at baseline and follow-up, (2) longitudinal associations of concurrent biomarker changes, and (3) prospective associations of each baseline biomarker with other biomarker changes.

RESULTS

In cross-sectional analyses, most biomarkers were correlated after multivariable adjustment including BMI, with the strongest correlations observed between leptin and insulin and between hsCRP and interleukin-6. In longitudinal analyses, similar results were observed after multivariable adjustment including weight change. However, in prospective analyses, only three associations observed in cross-sectional and longitudinal analyses were consistently significant (P < 0.05). Every doubling in baseline adiponectin was associated with -9.0% insulin change. The corresponding estimate was 9.3% for baseline leptin and hsCRP change and 3.1% for baseline hsCRP and leptin change.

CONCLUSIONS

Baseline adiponectin concentrations were inversely associated with subsequent insulin change, whereas baseline leptin concentrations were positively associated with hsCRP change and vice versa.

Association Between Plant-Based Dietary Patterns and Risk of Type 2 Diabetes: A Systematic Review and Meta-analysis

IMPORTANCE

Accumulating epidemiologic evidence has suggested favorable associations between plant-based dietary patterns and risk of type 2 diabetes, although there is a lack of a quantitative summary of evidence substantiating this important association.

OBJECTIVE

To quantitatively synthesize available prospective observational evidence on the association between plant-based dietary patterns and risk of type 2 diabetes.

DATA SOURCES

A systematic search of PubMed and MEDLINE, Embase, Web of Science, and reference lists through February 15, 2019, was conducted. Data analysis was conducted between December 2018 and February 2019.

STUDY SELECTION

All prospective observational studies that examined the association between adherence to plant-based dietary patterns and incidence of type 2 diabetes among adults 18 years or older were identified.

DATA EXTRACTION AND SYNTHESIS

Meta-analysis of Observational Studies in Epidemiology guidelines for data abstraction and reporting were followed, and a National Heart, Lung, and Blood Institute assessment tool was used to evaluate study quality. Two authors independently conducted full-text assessments and data abstraction. Meta-analysis was conducted using the random-effects method to calculate the overall relative risk (RR) and 95% CI.

MAIN OUTCOMES AND MEASURES

Level of adherence to a plant-based diet and incidence of type 2 diabetes.

RESULTS

A total of 9 studies were identified, totaling 307 099 participants with 23 544 cases of incident type 2 diabetes. A significant inverse association was observed between higher adherence to a plant-based dietary pattern and risk of type 2 diabetes (RR, 0.77; 95% CI, 0.71-0.84) in comparison with poorer adherence, with modest heterogeneity across studies (I2 = 44.5%; P = .07 for heterogeneity). Similar findings were obtained when using the fixed-effects model (RR, 0.80; 95% CI, 0.75-0.84). Consistent associations were observed across predefined subgroups. This association was strengthened when healthy plant-based foods, such as fruits, vegetables, whole grains, legumes, and nuts, were included in the definition of plant-based patterns (RR, 0.70; 95% CI, 0.62-0.79). Most studies were deemed to have good quality in terms of dietary assessment, disease outcomes, and statistical adjustment for confounding factors. Using restricted cubic splines, a significant inverse linear dose-response association was identified between plant-based dietary indices and risk of type 2 diabetes.

CONCLUSIONS AND RELEVANCE

Plant-based dietary patterns, especially when they are enriched with healthful plant-based foods, may be beneficial for the primary prevention of type 2 diabetes.

Changes in Plant-Based Diet Quality and Total and Cause-Specific Mortality

BACKGROUND

Plant-based diets have been associated with lower risk of type 2 diabetes mellitus and cardiovascular disease (CVD) and are recommended for both health and environmental benefits. However, the association between changes in plant-based diet quality and mortality remains unclear.

METHODS

We investigated the associations between 12-year changes (from 1986 to 1998) in plant-based diet quality assessed by 3 plant-based diet indices (score range, 18-90)-an overall plant-based diet index (PDI), a healthful PDI, and an unhealthful PDI-and subsequent total and cause-specific mortality (1998-2014). Participants were 49 407 women in the Nurses' Health Study (NHS) and 25 907 men in the Health Professionals Follow-Up Study (HPFS) who were free from CVD and cancer in 1998. Multivariable-adjusted Cox proportional-hazards models were used to estimate hazard ratios (HRs) and 95% CIs.

RESULTS

We documented 10 686 deaths including 2046 CVD deaths and 3091 cancer deaths in the NHS over 725 316 person-years of follow-up and 6490 deaths including 1872 CVD deaths and 1772 cancer deaths in the HPFS over 371 322 person-years of follow-up. Compared with participants whose indices remained stable, among those with the greatest increases in diet scores (highest quintile), the pooled multivariable-adjusted HRs for total mortality were 0.95 (95% CI, 0.90-1.00) for PDI, 0.90 (95% CI, 0.85-0.95) for healthful PDI, and 1.12 (95% CI, 1.07-1.18) for unhealthful PDI. Among participants with the greatest decrease (lowest quintile), the multivariable-adjusted HRs were 1.09 (95% CI, 1.04-1.15) for PDI, 1.10 (95% CI, 1.05-1.15) for healthful PDI, and 0.93 (95% CI, 0.88-0.98) for unhealthful PDI. For CVD mortality, the risk associated with a 10-point increase in each PDI was 7% lower (95% CI, 1-12%) for PDI, 9% lower (95% CI, 4-14%) for healthful PDI, and 8% higher (95% CI, 2-14%) for unhealthful PDI. There were no consistent associations between changes in plant-based diet indices and cancer mortality.

CONCLUSIONS

Improving plant-based diet quality over a 12-year period was associated with a lower risk of total and CVD mortality, whereas increased consumption of an unhealthful plant-based diet was associated with a higher risk of total and CVD mortality.

Health Biomarkers in Adults Are More Closely Linked to Diet Quality Attributes Than to Plant-Based Diet Categorization

Although plant-based diets are promoted for healthy outcomes, these diets are not synonymous with high-quality diets. Plant-based diets can include highly processed, less healthful foods, including savory snacks, pastries, and sugary fruit drinks. This cross-sectional study examined the diet quality of vegetarian and omnivorous adults, matched for gender, age, and adiposity, and related diet quality to standard health biomarkers. Diet quality was assessed using the Rapid Eating and Activity Assessment for Participants Short Version questionnaire. Participants (17 vegetarians and 16 omnivores; 28.2 ± 8.9 years; 22.5 ± 2.7 kg/m²) were non-smokers and healthy by self-report. The median duration of adherence to the vegetarian diet was 27 months. Physical activity level and diet quality did not differ significantly between diet groups. Moreover, health biomarkers did not differ by diet groups. When participants were regrouped by low versus high diet quality, health biomarkers differed significantly between groups for fasting insulin, HOMA-IR, triglyceride (TG)/HDL ratio, and blood folate, with more favorable levels in the group with high diet quality. These data suggest that health biomarkers more closely align with diet quality attributes than with plant-based diet categorization. Thus, messaging focused on healthy diet attributes may lead to better health outcomes than the simple promotion of plant-based diets.