Dietary fiber and health outcomes: an umbrella review of systematic reviews and meta-analyses

Ultra-processed food intake and all-cause mortality: DRECE cohort study

OBJECTIVE

To determine the association between ultra-processed food (UPF) intake and all-cause mortality in a representative sample of Spanish population.

DESIGN

Prospective cohort design in which follow-up lasted from baseline (1991) to mortality date or 31 December 2017, whichever was first. Dietary information was collected using a validated frequency questionnaire and categorised following the NOVA classification according to the extent of food processing. The association between consumption of UPF and mortality was analysed using Cox models. Isoenergetic substitution models were constructed to compare the health effects of the NOVA groups.

SETTING

Cohort from the Diet and Risk of Cardiovascular Diseases (CVD) in Spain (DRECE) study, representative of the Spanish population.

PARTICIPANTS

Totally, 4679 subjects between 5 and 59 years old.

RESULTS

Average consumption of UPF was 370·8 g/d (24·4 % of energy intake). After a median follow-up of 27 years, 450 deaths occurred. Those who consumed the highest amount of UPF had higher risk of mortality. For every 10 % of the energy intake from UPF consumption, an increase of 15 % in the hazard of all-cause mortality was observed (HR 1·15; (95 % CI 1·03, 1·27); P-value = 0·012). Substitution of UPF with minimally processed foods was significantly associated with a decreased risk of mortality.

CONCLUSIONS

An increase in UPF consumption was associated with higher risk of all-cause mortality in a representative sample of the Spanish population. Moreover, the theoretical substitution of UPF with unprocessed or minimally processed foods leads to a decrease in mortality. These results support the need to promote diets based on unprocessed or minimally processed foods.

An Infancy-Onset 20-Year Dietary Counselling Intervention and Gut Microbiota Composition in Adulthood

The randomized controlled Special Turku Coronary Risk Factor Intervention Project (STRIP) has completed a 20-year infancy-onset dietary counselling intervention to reduce exposure to atherosclerotic cardiovascular disease risk factors via promotion of a heart-healthy diet. The counselling on, e.g., low intake of saturated fat and cholesterol and promotion of fruit, vegetable, and whole-grain consumption has affected the dietary characteristics of the intervention participants. By leveraging this unique cohort, we further investigated whether this long-term dietary intervention affected the gut microbiota bacterial profile six years after the intervention ceased. Our sub-study comprised 357 individuals aged 26 years (intervention n = 174, control n = 183), whose gut microbiota were profiled using 16S rRNA amplicon sequencing. We observed no differences in microbiota profiles between the intervention and control groups. However, out of the 77 detected microbial genera, the Veillonella genus was more abundant in the intervention group compared to the controls (log2 fold-change 1.58, p < 0.001) after adjusting for multiple comparison. In addition, an association between the study group and overall gut microbiota profile was found only in males. The subtle differences in gut microbiota abundances observed in this unique intervention setting suggest that long-term dietary counselling reflecting dietary guidelines may be associated with alterations in gut microbiota.

Therapeutic Benefits and Dietary Restrictions of Fiber Intake: A State of the Art Review

Throughout history, malnutrition and deficiency diseases have been a problem for our planet’s population. A balanced diet significantly influences everyone’s health, and fiber intake appears to play a more important role than previously thought. The natural dietary fibers are a category of carbohydrates in the constitution of plants that are not completely digested in the human intestine. High-fiber foods, such as fruits, vegetables and whole grains, have consistently been highly beneficial to health and effectively reduced the risk of disease. Although the mode of action of dietary fiber in the consumer body is not fully understood, nutritionists and health professionals unanimously recognize the therapeutic benefits. This paper presents the fiber consumption in different countries, the metabolism of fiber and the range of health benefits associated with fiber intake. In addition, the influence of fiber intake on the intestinal microbiome, metabolic diseases (obesity and diabetes), neurological aspects, cardiovascular diseases, autoimmune diseases and cancer prevention are discussed. Finally, dietary restrictions and excess fiber are addressed, which can cause episodes of diarrhea and dehydration and increase the likelihood of bloating and flatulence or even bowel obstruction. However, extensive studies are needed regarding the composition and required amount of fiber in relation to the metabolism of saprotrophic microorganisms from the enteral level and the benefits of the various pathologies with which they can be correlated.

The nutritional impact of replacing dietary meat with meat alternatives in the UK: a modelling analysis using nationally representative data

Dietary patterns high in meat compromise both planetary and human health. Meat alternatives may help to facilitate meat reduction; however, the nutritional implications of displacing meat with meat alternatives does not appear to have been evaluated. Here, the ninth cycle of the National Diet and Nutrition Survey was used as the basis of models to assess the effect of meat substitution on nutritional intake. We implemented three models; model 1 replaced 25 %, 50 %, 75 % or 100 % of the current meat intake with a weighted mean of meat alternatives within the UK market. Model 2 compared different ingredient categories of meat alternative; vegetable, mycoprotein, a combination of bean and pea, tofu, nut and soya. Model 3 compared fortified v. unfortified meat alternatives. The models elicited significant shifts in nutrients. Overall, carbohydrate, fibre, sugars and Na increased, whereas reductions were found for protein, total and saturated fat, Fe and B₁₂. Greatest effects were seen for vegetable-based (+24·63g/d carbohydrates), mycoprotein-based (-6·12g/d total fat), nut-based (-19·79g/d protein, +10·23g/d fibre; -4·80g/d saturated fat, +7·44g/d sugars), soya-based (+495·98mg/d Na) and tofu-based (+7·63mg/d Fe, -2·02μg/d B₁₂). Our results suggest that meat alternatives can be a healthful replacement for meat if chosen correctly. Consumers should choose meat alternatives low in Na and sugar, high in fibre, protein and with high micronutrient density, to avoid compromising nutritional intake if reducing meat intake. Manufacturers and policy makers should consider fortification of meat alternatives with nutrients such as Fe and B₁₂ and focus on reducing Na and sugar content.

Associations between diabetic retinopathy and modifiable risk factors: An umbrella review of meta-analyses

AIMS

Several modifiable risk factors have been meta-analysed for diabetic retinopathy (DR), such as physical activity and vitamin D status. To date, these factors have not been systematically aggregated and the credibility of evidence assessed. Therefore, the aim of this umbrella review was to aggregate all modifiable risks of DR and assess the credibility of the evidence.

METHODS

An umbrella review of meta-analyses was undertaken. For each meta-analytic association, random-effects effect size, 95% confidence intervals (CIs), heterogeneity, small-study effects, excess significance bias and 95% prediction intervals were calculated. The credibility of significant evidence (p < 0.05) was graded from I to IV, using pre-defined criteria.

RESULTS

After initial searches, 13 studies were included covering 34 independent outcomes (total participants = 824,372). Positive associations were found between insulin usage and diabetic macular oedema (RR = 4.5; 95% CI 3.1-6.6), and DR risk (RR = 2.3; 95% CI 1.4-3.9) in people with type 2 diabetes. Vitamin D deficiency was associated with DR risk (OR = 2.8; 95% CI 1.1-7.1), as was obesity (RR = 1.34; 95% CI 1.06-1.68) and sedentary behaviour (RR = 1.22; 95%CI 1.03-1.44). Intensive blood pressure targets (RR = 0.8 95%CI 0.8-1.0), and moderate physical activity (RR = 0.69; 95%CI 0.53-0.91) yielded significant protective associations with DR.

CONCLUSIONS

People with type 2 diabetes on insulin have a high risk of macular oedema and DR. Vitamin D deficiency yielded almost three times greater odds of DR, while intensive blood pressure control reduces DR risk by 20% and moderate physical activity by 31%. Healthcare professionals should use this evidence to identify those people most at risk to ensure that proper treatment and healthy lifestyles are recommended.

The health benefits of anthocyanins: an umbrella review of systematic reviews and meta-analyses of observational studies and controlled clinical trials

Anthocyanins (ACNs) are phenolic compounds present in foods and have undefined health benefits. The present umbrella review aimed to analyze the effects of ACNs on multiple aspects of human health (from systematic reviews and meta-analyses [SRMs] of randomized controlled trials [RCTs]), and the associations of ACNs with the risk of various diseases (from SRMs of observational studies [OSs]). Following the PRISMA methodology, the PubMed, SCOPUS, and Cochrane databases were searched up to November 1, 2020 for OS-SRMs and RCT-SRMs that examined the effects of ACNs on health. The risk of bias of RCT-SRMs was assessed using the AMSTAR 2, and that of OS-SRMs was assessed using the Joanna Briggs Institute methodology. Based on 5 OS-SRMs (57 studies and 2 134 336 participants), ACNs of various sources were significantly associated with a reduction in the risks of hypertension and type 2 diabetes mellitus. According to 8 RCT-SRMs (139 interventions and >4984 participants), ACNs improved plasmatic lipids, glucose metabolism, and endothelial function, without affecting blood pressure. No associations between ACNs and breast or gastric cancer risks were found. ACN intake opens new pathways for the management of glucose metabolism, the plasmatic lipid profile, and the improvement of endothelial function in humans.

Micronutrient status of individuals with overweight and obesity following 3 months' supplementation with PolyGlycopleX (PGX®) or psyllium: a randomized controlled trial

Background

Safe and effective weight control strategies are needed to curtail the current obesity epidemic worldwide. Increasing dietary fibre has shown positive results with weight loss as well as in the reduction of metabolic syndrome risk factors. However, fibre can act as an inhibitor to the bioavailability of micronutrients in the gastrointestinal tract. While there is a substantial amount of scientific research into psyllium fibre, PolyGlycopleX (PGX®) is a novel fibre and as yet the effects of PGX® on micronutrient status is not well researched.

Aim

To determine whether 3-months’ supplementation with 15 g of psyllium or PGX® fibre daily affects micronutrient status of overweight and obese adults.

Methods

Overweight and obese individuals with a BMI between 25–40 kg/m² and aged between 18 and 65 years, but otherwise healthy, were instructed to consume a 5 g sachet of psyllium, PGX® fibre or a rice flour placebo three times a day for 52 weeks as part of a larger long-term study. Blood sample data for the first 3 months were analysed for associations between serum micronutrient levels and psyllium fibre and/or PGX® supplements.

Results

No significant differences between fibre supplement groups and micronutrient status were found after 3 months at p > 0.05. Dietary intake of vitamin C was significantly lower for PGX® at 3 months compared to baseline and compared to control (p < 0.05). Folate was significantly lower in the control group after 3 months (p < 0.05). In the psyllium group, folate, sodium, zinc and magnesium intake decreased after 3 months (p < 0.05). A limitation of dietary intake data (tertiary measure) is the potential for inaccurate self-reporting, although reduced nutrient intake could be due to the satiating effect of dietary fibre.

Conclusions

There were no significant between group differences in serum micronutrient concentrations after a 3-month psyllium fibre or PGX® supplementation intervention of 15 g per day. Fibre supplementation is unlikely to compromise the nutritional status of overweight and obese individuals in the short term. Further research is recommended to monitor micronutrient status over a longer period or with a higher fibre dosage.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40795-022-00534-7.

The effects of dietary fiber on common complications in critically ill patients; with a special focus on viral infections; a systematic reveiw

Background

Viral infections are mostly highly contagious and may cause widespread health problems. Some studies reported that the dietary fiber (DF) may be effective in reducing the complications of viral infections in intensive care unit (ICU) patients. The present review study aimed to investigate the effect of DF on common complications in critically ill patients with viral infections.

Methods

A literature review was conducted for the published papers in English from January 2001 to July 2021 using related keywords. Studies with clinical trial or case‐control design described the effects of fiber intake on the complications of viral infections in patients admitted to the ICU were collected.

Results

DF may reduce the mortality rate of viral infections through modulating inflammatory processes. A higher intake of DF intake may improve hyperglycemia and impaired glucose tolerance in patients with viral infections. A high‐fiber formula in enteral nutrition was reported to reduce the risk of diarrhea in patients with viral infections.

Conclusion

DF may reduce the complications of viral infections such as inflammation, diarrhea, hyperglycemia, and mortality in critically ill patients. Future longitudinal studies on the amount and type of DF are warranted.

Ultra-processed foods and risk of all-cause mortality in renal transplant recipients

BACKGROUND

Renal transplant recipients (RTRs) have a 6-fold higher risk of mortality than age- and sex-matched controls. Whether high consumption of ultra-processed foods is associated with survival in RTRs is unknown.

OBJECTIVES

We aimed to study the association between high consumption of ultra-processed foods and all-cause mortality in stable RTRs.

METHODS

We conducted a prospective cohort study in adult RTRs with a stable graft. Dietary intake was assessed using a validated 177-item FFQ. Food items were categorized according to the NOVA classification system and the proportion ultra-processed foods comprised of total food weight per day was calculated.

RESULTS

We included 632 stable RTRs (mean ± SD age: 53.0 ± 12.7 y, 57% men). Mean ± SD consumption of ultra-processed foods was 721 ± 341 g/d (28% of total weight of food intake), whereas the intake of unprocessed and minimally processed foods, processed culinary ingredients, and processed foods accounted for 57%, 1%, and 14%, respectively. During median follow-up of 5.4 y [IQR: 4.9-6.0 y], 129 (20%) RTRs died. In Cox regression analyses, ultra-processed foods were associated with all-cause mortality (HR per doubling of percentage of total weight: 2.13; 95% CI: 1.46, 3.10; P < 0.001), independently of potential confounders. This association was independent from the quality of the overall dietary pattern, expressed by the Mediterranean Diet Score (MDS) or Dietary Approaches to Stop Hypertension (DASH) score. When analyzing ultra-processed foods by groups, only sugar-sweetened beverages (HR: 1.21; 95% CI: 1.05, 1.39; P = 0.007), desserts (HR: 1.24; 95% CI: 1.02, 1.49; P = 0.03), and processed meats (HR: 1.87; 95% CI: 1.22, 2.86; P = 0.004) were associated with all-cause mortality.

CONCLUSIONS

Consumption of ultra-processed foods, in particular sugar-sweetened beverages, desserts, and processed meats, is associated with a higher risk of all-cause mortality after renal transplantation, independently of low adherence to high-quality dietary patterns, such as the Mediterranean diet and the DASH diet.This trial was registered at clinicaltrials.gov as NCT02811835.

Olympic Cycle Comparison of the Nutritional and Cardiovascular Health Status of an Elite-Level Female Swimmer: Case Study Report from Slovenia

Monitoring the many aspects that are crucial to an athlete’s performance progress is vital for further training planning and for the development of performance and the sport. We evaluated a four-year change (2018 vs. 2022) in the current nutritional and cardiovascular health status of the most successful elite-level female swimmer in Slovenia. Body composition and dietary intake were assessed using dual-energy X-ray absorptiometry and a standardized food questionnaire. The concentration of blood lipids, blood pressure, and serum micronutrients (B₁₂, 25(OH)D), potassium, calcium, phosphorus, magnesium, and iron) were measured. The four-year comparison showed an improved body composition status (i.e., increased body mass and decreased body fat (percentage and mass), increased lean soft tissue and total bone mineral density (BMD) (i.e., significantly decreased BMD of a left femoral neck and increased BMD of a spine and head)). We also measured an improvement in the cardiovascular health status of some markers (i.e., decreased total cholesterol, triglycerides, and blood pressure but increased low-density lipoprotein cholesterol), most likely due to the differences in assessed dietary intake (i.e., lower carbohydrate intake, higher total and saturated fat intake, and lower sodium intake). Notably, nutrient intakes that are generally of concern (eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), vitamin B₁₂ and D, calcium, iron, and zinc (except for fiber intake)) were all within recommended ranges. However, the athlete’s vitamin K and potassium intake were not adequate. Furthermore, in 2018, the athlete did not consume dietary supplements, while she now regularly uses several dietary supplements, including EPA and DHA omega-3, vitamin D, multivitamins, carbohydrate powder, and sports drink. Moreover, from the micronutrient serum, only iron levels deviated from the reference values (37 μmol/L vs. 10.7–28.6 μmol/L). The presented screening example using valid, sensitive, and affordable methods and with rapid organizational implementation may be a viable format for regular monitoring.

Dietary Fiber Intake and Femoral Bone Mineral Density in Middle-Aged and Older US Adults: A Cross-Sectional Study of National Health and Nutrition Examination Survey 2013-2014

Sufficient dietary fiber intake (DFI) is considered necessary for human health. However, the association between DFI and bone mineral density (BMD) remains unclear. Therefore, this study aimed to investigate the association between DFI and BMD and to determine whether sex modifies the association between DFI and BMD. Participants aged ≥ 40 years from the 2013-2014 National Health and Nutrition Examination Survey were included in the final analysis. The association between DFI and BMD was evaluated using a multivariate linear regression model. The non-linear relationship between DFI and BMD was characterized by smooth curve fittings and generalized additive models. Finally, 1,935 participants with a mean age of 58.12 ± 11.84 years were included in the final analysis. The results revealed that DFI was positively associated with femoral BMD in the unadjusted model. However, no correlation was observed between DFI and femoral BMD after adjusting for covariates. Moreover, the results showed an inverted U-shaped association between total DFI and femoral BMD among men but not women for the nonlinear relationship between DFI and femoral BMD. In conclusion, our results indicate that DFI might not follow a linear relationship with femoral BMD, and sex factors might modify the association between DFI and BMD. Particularly, high total DFI might contribute to lower femoral neck BMD. However, more studies are needed to investigate whether the negative effect of high DFI on femoral BMD does exist and whether high DFI has clear biological effects on bone metabolism, such as increasing the risk of osteoporosis.

A Pain in the Butt: Hemorrhoids, Fissures, Fistulas, and Other Anorectal Syndromes

Painful and bothersome anorectal syndromes can be a diagnostic and therapeutic challenge for clinicians because structural and functional abnormalities may often coexist and require a multidisciplinary approach to management. Although it is often difficult to attribute all of a patient's anorectal symptoms to a singular disorder with definitive intervention and cure, improving quality of life, treating coexistent conditions such as functional constipation and/or defecation disorders, addressing psychological comorbidities if present, and confirming there is no evidence of inflammatory or malignant conditions are top priorities.

Irradiation Induces Tuft Cell Hyperplasia and Myenteric Neuronal Loss in the Absence of Dietary Fiber in a Mouse Model of Pelvic Radiotherapy

Pelvic radiotherapy is associated with chronic intestinal dysfunction. Dietary approaches, such as fiber enrichment during and after pelvic radiotherapy, have been suggested to prevent or reduce dysfunctions. In the present paper, we aimed to investigate whether a diet rich in fermentable fiber could have a positive effect on radiation-induced intestinal damage, especially focusing on tuft cells and enteric neurons. Male C57BL/6 mice were fed either a purified non-fiber diet or the same purified diet with 5% or 15% oat fiber added, starting two weeks prior to sham-irradiation or irradiation with four fractions of 8 Gray. The animals continued on the diets for 1, 6 or 18 weeks, after which the gross morphology of the colorectum was assessed together with the numbers of enteric neurons, tuft cells and crypt-surface units. The results showed that dietary fiber significantly affected the intestinal morphometrics, both in the short and long-term. The presence of dietary fiber stimulated the re-emergence of crypt-surface unit structures after irradiation. At 18 weeks, the animals fed with the non-fiber diet displayed more myenteric neurons than the animals fed with the dietary fibers, but irradiation resulted in a loss of neurons in the non-fiber fed animals. Irradiation, but not diet, affected the tuft cell numbers, and a significant increase in tuft cells was found 6 and 18 weeks after irradiation. In conclusion, dietary fiber intake has the potential to modify neuronal pathogenesis in the colorectum after irradiation. The long-lasting increase in tuft cells induced by irradiation may reflect an as yet unknown role in the mucosal pathophysiology after pelvic irradiation.

Fiber intake and health in people with chronic kidney disease

Emerging evidence suggests that diet, particularly one that is rich in dietary fiber, may prevent the progression of chronic kidney disease (CKD) and its associated complications in people with established CKD. This narrative review summarizes the current evidence and discusses the opportunities for increasing fiber intake in people with CKD to improve health and reduce disease complications. A higher consumption of fiber exerts multiple health benefits, such as increasing stool output, promoting the growth of beneficial microbiota, improving the gut barrier and decreasing inflammation, as well decreasing uremic toxin production. Despite this, the majority of people with CKD consume less than the recommended dietary fiber intake, which may be due in part to the competing dietary potassium concern. Based on existing evidence, we see benefits from adopting a higher intake of fiber-rich food, and recommend cooperation with the dietitian to ensure an adequate diet plan. We also identify knowledge gaps for future research and suggest means to improve patient adherence to a high-fiber diet.

Additional Resistant Starch from One Potato Side Dish per Day Alters the Gut Microbiota but Not Fecal Short-Chain Fatty Acid Concentrations

The composition of the gut microbiota and their metabolites are associated with cardiometabolic health and disease risk. Intake of dietary fibers, including resistant starch (RS), has been shown to favorably affect the health of the gut microbiome. The aim of this research was to measure changes in the gut microbiota and fecal short-chain fatty acids as part of a randomized, crossover supplemental feeding study. Fifty participants (68% female, aged 40 ± 13 years, BMI 24.5 ± 3.6 kg/m²) completed this study. Potato dishes (POT) contained more RS than refined grain dishes (REF) (POT: 1.31% wet basis (95% CI: 0.94, 1.71); REF: 0.73% wet basis (95% CI: 0.34, 1.14); p = 0.03). Overall, potato dish consumption decreased alpha diversity, but beta diversity was not impacted. Potato dish consumption was found to increase the abundance of Hungatella xylanolytica, as well as that of the butyrate producing Roseburia faecis, though fecal butyrate levels were unchanged. Intake of one potato-based side dish per day resulted in modest changes in gut microbiota composition and diversity, compared to isocaloric intake of refined grains in healthy adults. Studies examining foods naturally higher in RS are needed to understand microbiota changes in response to dietary intake of RS and associated health effects.

Evaluation of the Quality of Evidence of the Association of Foods and Nutrients With Cardiovascular Disease and Diabetes: A Systematic Review

IMPORTANCE

Poor diet is a leading global factor associated with cardiometabolic disease (CMD). Understanding the quality of evidence of the associations between specific dietary factors and CMD, including effect size (relative risk [RR]) and uncertainty, is essential to guide policy and consumer actions to achieve healthy diet and public health goals.

OBJECTIVE

To assess the quality of evidence of the associations between specific dietary factors and CMD as well as the quantitative evidence for RRs and the uncertainty of these risk estimates.

EVIDENCE REVIEW

PubMed and the reference lists of eligible articles were searched between May 1, 2015, and February 26, 2021, for systematic reviews with meta-analyses of randomized clinical trials and prospective cohort studies that analyzed the consumption of 1 or more of the dietary factors of interest; reported dose-response meta-analyses; included healthy adults; and assessed 1 or more of the outcomes of interest. Study characteristics and RR estimates were extracted in duplicate. For identified associations, quality of evidence was assessed using the Bradford-Hill criteria for causation.

FINDINGS

A total of 2058 potentially relevant reports were identified, from which 285 full-text articles were assessed for eligibility. The final selection of articles included 28 meta-analyses representing 62 associations between diet and CMD. Among these associations, 10 foods, 3 beverages, and 12 nutrients had at least probable evidence of associations with coronary heart disease, stroke, and/or diabetes. Most RRs ranged from 0.87 to 0.96 per daily serving change for protective associations and from 1.06 to 1.15 per daily serving change for harmful associations. Most identified associations were protective (n = 38) and a smaller number were harmful (n = 24), with a higher risk associated with higher intake.

CONCLUSIONS AND RELEVANCE

This systematic review summarized the current quality of evidence of the associations of specific dietary factors with coronary heart disease, stroke, and diabetes. These findings may inform dietary guidance, the assessment of disease burden in specific populations, policy setting, and future research.

β(2→6)-Type fructans attenuate proinflammatory responses in a structure dependent fashion via Toll-like receptors

Graminan-type fructans (GTFs) have demonstrated immune benefits. However, mechanisms underlying these benefits are unknown. We studied GTFs interaction with Toll-like receptors (TLRs), performed molecular docking and determined their impact on dendritic cells (DCs). Effects of GTFs were compared with those of inulin-type fructans (ITFs). Whereas ITFs only contained β(2→1)-linked fructans, GTFs showed higher complexity as it contains additional β(2→6)-linkages. GTFs activated NF-κB/AP-1 through MyD88 and TRIF pathways. GTFs stimulated TLR3, 7 and 9 while ITFs activated TLR2 and TLR4. GTFs strongly inhibited TLR2 and TLR4, while ITFs did not inhibit any TLR. Molecular docking demonstrated interactions of fructans with TLR2, 3, and 4 in a structure dependent fashion. Moreover, ITFs and GTFs attenuated pro-inflammatory cytokine production of stimulated DCs. These findings demonstrate immunomodulatory effects of GTFs via TLRs and attenuation of cytokine production in dendritic cells by GTFs and long-chain ITF.

Eye disease and mortality, cognition, disease, and modifiable risk factors: an umbrella review of meta-analyses of observational studies

Globally, 2.2 billion people live with some form of vision impairment and/or eye disease. To date, most systematic reviews examining associations have focused on a single eye disease and there is no systematic evaluation of the relationships between eye diseases and diverse physical and mental health outcomes. Moreover, the strength and reliability of the literature is unclear. We performed an umbrella review of observational studies with meta analyses for any physical and/or mental comorbidities associated with eye disease. For each association, random-effects summary effect size, heterogeneity, small-study effect, excess significance bias and 95% prediction intervals were calculated, and used to grade significant evidence from convincing to weak. 34 studies were included covering 58 outcomes. No outcomes yielded convincing evidence, six outcomes yielded highly suggestive results (cataract positively associated with type 2 diabetes, open-angled glaucoma positively associated with myopia and diabetes, diabetic retinopathy positively associated with cardiovascular disease and cardiovascular mortality, and retinopathy of prematurity positively associated with chorioamnionitis), eight outcomes yielded suggestive results (diabetic retinopathy positively associated with all-cause mortality and depression, diabetic macular oedema positively associated with dyslipidaemia, cataract positively associated with gout, nuclear sclerosis positively associated with all-cause mortality, open angled glaucoma positively associated with migraine and hypertension, and age-related macular degeneration positively associated with diabetes), and 18 outcomes yielded weak evidence. Results show highly suggestive or suggestive evidence for associations between several types of eye diseases with several comorbid outcomes. Practitioners and public health policies should note these findings when developing healthcare policies.

Polycystic Ovary Syndrome: An Evolutionary Adaptation to Lifestyle and the Environment

Polycystic ovary syndrome (PCOS) is increasingly recognized as a complex metabolic disorder that manifests in genetically susceptible women following a range of negative exposures to nutritional and environmental factors related to contemporary lifestyle. The hypothesis that PCOS phenotypes are derived from a mismatch between ancient genetic survival mechanisms and modern lifestyle practices is supported by a diversity of research findings. The proposed evolutionary model of the pathogenesis of PCOS incorporates evidence related to evolutionary theory, genetic studies, in utero developmental epigenetic programming, transgenerational inheritance, metabolic features including insulin resistance, obesity and the apparent paradox of lean phenotypes, reproductive effects and subfertility, the impact of the microbiome and dysbiosis, endocrine-disrupting chemical exposure, and the influence of lifestyle factors such as poor-quality diet and physical inactivity. Based on these premises, the diverse lines of research are synthesized into a composite evolutionary model of the pathogenesis of PCOS. It is hoped that this model will assist clinicians and patients to understand the importance of lifestyle interventions in the prevention and management of PCOS and provide a conceptual framework for future research. It is appreciated that this theory represents a synthesis of the current evidence and that it is expected to evolve and change over time.

Centenarian-Sourced Lactobacillus casei Combined with Dietary Fiber Complex Ameliorates Brain and Gut Function in Aged Mice

Dietary intervention could modulate age-related neurological disorders via the gut-brain axis. The potential roles of a probiotic and the dietary fiber complex (DFC) on brain and gut function in aged mice were investigated in this study. Lactobacillus casei LTL1361 and DFC were orally administrated for 12 weeks, and the learning and memory ability, as well as the oxidative parameters, inflammatory markers, gut barrier function and microbial metabolite short-chain fatty acids (SCFAs), were investigated. LTL1361 and DFC supplementation ameliorated cognitive ability, attenuated oxidative stress in brain and inflammation in serum and colon, ameliorated gut barrier function, and increased the SCFA concentrations and gene expression of SCFA receptors. The protective effect was more significantly enhanced in aged mice treated with the combination of LTL1361 and DFC than treated with LTL1361 or DFC alone. These results could be associated with the protected morphology of pyramidal nerve cells in hippocampus of mice brain and the downregulation of apoptosis marker caspase-3 in brain and upregulation of tight junction proteins in small intestine and colon. The results indicated that Lactobacillus casei LTL1361 and DFC alleviated age-related cognitive impairment, as well as protected brain and gut function. Lactobacillus casei LTL1361 and DFC might be used as novel and promising antiaging agents in human.

Association between dietary choline and betaine intake and 10.6-year cardiovascular disease in adults

Background

Several studies have assessed the association between dietary choline and betaine and cardiovascular disease (CVD), but their results are inconsistent. The present study aimed to determine the association between dietary intake of choline and betaine and the risk of CVD in the general population over a 10.6-year period of follow-up.

Methods

The present cohort study was conducted on participants in the third wave of the Tehran Lipid and Glucose Study (2006–2008) and was followed-up until March 2018. Dietary intake of choline and betaine was calculated using the United States Department of Agriculture (USDA) database. Patients’ medical records were used to collect data on CVD.

Results

In this study, 2606 subjects with no previous CVD participated and were followed-up for a median of 10.6 years. During the follow-up periods, 187 incidences of CVD were detected. Results of the Cox proportional hazards regression indicated that neither energy-adjusted total choline nor betaine was associated with the incidence of CVD. Among individual choline forms, only higher intake of free choline (FC) was associated with a lower risk of CVD (HR: 0.64, 95% CI: 0.42–0.98). There was no significant association between each 10 mg/d increase in choline and betaine content of each food category and CVD.

Conclusion

Our investigation indicates no association between energy-adjusted total choline and betaine and a 10.6-year risk of CVD among adults. Besides, we found no relationship between individual choline forms (except FC) and CVD. We also found energy-adjusted choline and betaine obtained from food categories were not associated with the risk of CVD.

Dietary Fiber and All-Cause and Cardiovascular Mortality in Older Adults with Hypertension: A Cohort Study Of NHANES

OBJECTIVES

Several studies have documented that dietary fiber was inversely associated with a variety of diseases, but the association of dietary fiber with the prognosis of older adults with hypertension is unknown. The aim was to assess the association of dietary fiber with all-cause and cardiovascular mortality in older adults with hypertension.

METHODS

This study enrolled 4906 participants (51.6% were female) aged 65 years or older with hypertension in the National Health and Nutrition Examination Survey (NHANES) 2003-2014 and ascertained mortality through December 31, 2015. Dietary fiber intake data were assessed by using a 24-h recall survey. Participants were grouped by dietary fiber intake quartiles: Q1(fiber < 10.20, g/day), Q2 (10.20 ≤ fiber < 14.45, g/day), Q3 (14.45 ≤ fiber < 19.85, g/day), and Q4 (19.85 ≤ fiber, g/day). Multivariate Cox proportional hazard models were used to evaluate the associations of dietary fiber intake with all-cause and cardiovascular mortality. Kaplan-Meier survival curves and restricted cubic spline models were applied to reveal the relationship between dietary fiber intake and mortality.

RESULTS

Over the median follow-up duration of 70 months (interquartile range: 38-100 months), 1369 participants were determined as all-cause mortality (27.9%) and 270 participants were identified as cardiovascular mortality (5.5%). In the fully adjusted model, the higher dietary fiber intake group was associated with relatively lower all-cause (Q4 vs Q1: 0.68 (0.58, 0.80); P for trend <0.001) and cardiovascular mortality (Q4 vs Q1: 0.64 (0.45, 0.92); P for trend =0.010). The non-linear relationship was not observed between dietary fiber intake and all-cause or cardiovascular mortality.

CONCLUSIONS

Higher dietary fiber intake was significantly associated with decreased all-cause and cardiovascular mortality in older adults with hypertension. Increasing dietary fiber intake may improve the prognosis of older adults with hypertension.

The effects of vegetarian diets on bone health: A literature review

In these recent years many people are adopting a vegetarian type diet due to the numerous positive health effects of this regimen such as the reduction of the incidence of many chronic disorders like diabetes, hypertension, obesity and cancer. However this diet is quite restrictive and so it could be possible to have a deficiency in some specific nutrients, increasing the risk of osteoporosis and fractures. Although there are conflicting results on the effects of the vegetarian diet on bone health and fracture incidence, it is always recommendable in vegetarian people to have an adequate intake of calcium and vitamin D, through an increased intake of supplements, natural and fortified foods, an adequate intake of protein, fruit, vegetables, as well as vitamin B12. The aim of this literature review is to revise the actual knowledge of the effect of some nutrients and vegetarian diets on bone health.

Hypolipidemic effect of soluble dietary fibers prepared from Asparagus officinalis and their effects on the modulation of intestinal microbiota

The soluble dietary fiber from Asparagus officinalis (ASDF) was successively prepared using enzymolysis combined with spray-drying technology. High-performance liquid chromatography analysis showed that ASDF contained two polysaccharide fractions with the average molecular weight of 2.77 × 10⁵ and 6.44 × 10³ Da, and was composed of mannose, rhamnose, galacturonic acid, glucose, galactose, and arabinose with a molecular ratio of 19.93:1.02:1.94:32.17:1.00:1.91, respectively. ASDF showed potential in vitro antioxidant activities. The oral administration of ASDF significantly reduced the levels of total cholesterol, triglyceride, and low-density lipoprotein cholesterol in HD-induced mice serum. Furthermore, 16S rRNA gene sequencing analysis showed that ASDF significantly affected the composition of intestinal microbiota, especially reducing the Firmicutes/Bacteroidotetes ratio and the relative abundances of Desulfobacterota, Proteobacteria, Actinobacteriota and increasing that of Muribaculaceae, Bacteroides, and Alloprevotella. These results demonstrated that the intake of ASDF could regulate intestinal microbiota and serum lipid levels in hyperlipidemic conditions.

Prospective Association of the Portfolio Diet with All-Cause and Cause-Specific Mortality Risk in the Mr. OS and Ms. OS Study

The Portfolio Diet has demonstrated its cardiovascular benefit from interventions, but the association between Portfolio Diet adherence and the risk of all-cause and cause-specific mortality has not been examined in Chinese population. The present study has collected Portfolio Diet adherence (assessed by food frequency questionnaire), lifestyle factors and mortality status of 3991 participants in the Mr. Osteoporosis (OS) and Ms. OS Study. Cox regression models were used to examine the association between the Portfolio Diet adherence and mortality risk (all-cause, cardiovascular disease or cancer). The highest quartile of the Portfolio Diet score was associated with a 28% lower risk of all-cause (hazard ratio, HR: 0.72) and cancer (HR: 0.72) mortality, respectively. The association between Portfolio Diet adherence and cardiovascular disease mortality did not reach statistical significance (HR: 0.90, 95% CI = 0.64, 1.26). Among male participants, the highest adherence to the Portfolio Diet was also associated with a lower risk of all-cause (HR: 0.63) and cancer mortality (HR: 0.59), and there was an inverse association between food sources of plant protein and the risk of cardiovascular mortality (HR: 0.50). However, most associations between the Portfolio Diet and mortality were not significant among females. The protection for cancer mortality risk might reach the plateau at the highest adherence to the Portfolio Diet for females. To conclude, greater adherence to the Portfolio Diet was significantly associated with a lower risk of mortality in Hong Kong older adults, and the associations appeared stronger among males.

Cancer diagnosis and suicide outcomes: Umbrella review and methodological considerations

BACKGROUND

Suicide outcomes in cancer patients represent a major public health concern. We performed an umbrella review (UR) including all meta-analyses (MAs) and systematic reviews (SRs) published on the association between cancer and suicide outcomes.

METHODS

Eligible studies were searched in the main scientific databases up to January 23rd, 2021. Eligible MAs/SRs focused on all suicide phenotypes among cancer patients. Evidence of the association was extracted; the credibility and quality of the included studies were evaluated using ad-hoc tools, including "A MeaSurement Tool to Assess systematic Reviews-2-Revised" (AMSTAR-2-R).

RESULTS

Six MAs and 6 SRs were included. The standardized mortality ratio of suicide in cancer patients was 1.5 to 1.7-fold higher than in the general population. Risk factors for suicide outcomes among cancer patients were male sex and older age, a cancer diagnosis within the prior year, and some specific cancer sites. Among 107 associations, 90 (84.1%) were supported by high credibility of evidence (class II). However, all studies reported a large heterogeneity (I2> 50%) and the majority of them reported considerable heterogeneity (I2> 75%). All MAs used random-effects measures. All MAs but one assessed publication bias and only one disclosed it. The majority of MAs/SRs showed critically low quality based on AMSTAR-2-R.

LIMITATIONS

We could not perform additional analyses due to the limited number of MAs.

CONCLUSIONS

This UR underlines the inflated risk for suicide among cancer patients. Upcoming, well-designed studies are needed to account for a broader set of variables. Several methodological issues likewise warrant attention.

A Mix of Dietary Fibres Changes Interorgan Nutrients Exchanges and Muscle-Adipose Energy Handling in Overfed Mini-Pigs

This study evaluates the capacity of a bread enriched with fermentable dietary fibres to modulate the metabolism and nutrients handling between tissues, gut and peripheral, in a context of overfeeding. Net fluxes of glucose, lactate, urea, short chain fatty acids (SCFA), and amino acids were recorded in control and overfed female mini-pigs supplemented or not with fibre-enriched bread. SCFA in fecal water and gene expressions, but not protein levels or metabolic fluxes, were measured in muscle, adipose tissue, and intestine. Fibre supplementation increased the potential for fatty acid oxidation and mitochondrial activity in muscle (acox, ucp2, sdha and cpt1-m, p < 0.05) as well as main regulatory transcription factors of metabolic activity such as pparα, pgc-1α and nrf2. All these features were associated with a reduced muscle fibre cross sectional area, resembling to controls (i.e., lean phenotype). SCFA may be direct inducers of these cross-talk alterations, as their feces content (+52%, p = 0.05) was increased in fibre-supplemented mini-pigs. The SCFA effects could be mediated at the gut level by an increased production of incretins (increased gcg mRNA, p < 0.05) and an up-regulation of SCFA receptors (increased gpr41 mRNA, p < 0.01). Hence, consumption of supplemented bread with fermentable fibres can be an appropriate strategy to activate muscle energy catabolism and limit the establishment of an obese phenotype.

Nutrients and Dietary Approaches in Patients with Type 2 Diabetes Mellitus and Cardiovascular Disease: A Narrative Review

Cardiovascular disease (CVD) is the most common cause of morbidity and mortality in developed countries. The prevalence of CVD is much higher in patients with type 2 diabetes mellitus (T2DM), who may benefit from lifestyle changes, which include adapted diets. In this review, we provide the role of different groups of nutrients in patients with T2DM and CVD, as well as dietary approaches that have been associated with better and worse outcomes in those patients. Many different diets and supplements have proved to be beneficial in T2DM and CVD, but further studies, guidelines, and dietary recommendations are particularly required for patients with both diseases.

Dietary Fibre Intake and the 10-Year Incidence of Tinnitus in Older Adults

Tinnitus is the phantom perception of sound in the ears or head that increases in prevalence as age increases. With strong evidence supporting the benefits of dietary fibre for vascular health and hearing loss, intake of dietary fibre may also have a role in the prevention of tinnitus symptoms. This longitudinal study aims to determine the association between the intake of dietary fibre and other carbohydrate nutrition variables including glycaemic index (GI), glycaemic load (GL) and total carbohydrate intakes, and incident tinnitus over 10 years. Of the 1730 participants (aged ≥50 years) from the Blue Mountains Hearing Study with complete baseline data on tinnitus symptoms and carbohydrate intakes, 536 (31%) cases of tinnitus were identified and excluded from further incidence analysis. Dietary data were collected using a validated semi-quantitative food frequency questionnaire to determine intakes of total dietary fibre and fibre contributions from cereals, vegetables, and fruit. A purpose-built database based on Australian GI values was used to calculate mean GI. Lower versus higher intakes of fruit fibre (≤3.6 g/day vs. >3.6 g/day) and cereal fibre (≤4.2 g/day vs. >4.2 g/day) were significantly associated with a 65% (HR = 1.65; 95% CI: 1.15–2.36) and 54% (HR = 1.54; 95% CI: 1.07–2.22) increased risk of developing tinnitus over 10 years, respectively. Associations between intake of other carbohydrate nutrients and incident tinnitus were mostly non-significant. In summary, our study showed modest associations between intake of dietary fibre and incident tinnitus. The protective effects of fibre, particularly insoluble fibre, could underlie observed associations by reducing the risk of tinnitus via vascular risk factors such as cardiovascular disease. Further longitudinal studies evaluating different types and sources of fibre and tinnitus risk are needed to confirm our study findings.

Dietary Fibre Intake in Relation to Asthma, Rhinitis and Lung Function Impairment-A Systematic Review of Observational Studies

A high intake of dietary fibre has been associated with a reduced risk of several chronic diseases. This study aimed to review the current evidence on dietary fibre in relation to asthma, rhinitis and lung function impairment. Electronic databases were searched in June 2021 for studies on the association between dietary fibre and asthma, rhinitis, chronic obstructive pulmonary disease (COPD) and lung function. Observational studies with cross-sectional, case–control or prospective designs were included. Studies on animals, case studies and intervention studies were excluded. The quality of the evidence from individual studies was evaluated using the RoB-NObs tool. The World Cancer Research Fund criteria were used to grade the strength of the evidence. Twenty studies were included in this systematic review, of which ten were cohort studies, eight cross-sectional and two case–control studies. Fibre intake during pregnancy or childhood was examined in three studies, while seventeen studies examined the intake during adulthood. There was probable evidence for an inverse association between dietary fibre and COPD and suggestive evidence for a positive association with lung function. However, the evidence regarding asthma and rhinitis was limited and inconsistent. Further research is needed on dietary fibre intake and asthma, rhinitis and lung function among adults and children.

Associations of Nutritional, Lifestyle, and Metabolic Factors With Non-alcoholic Fatty Liver Disease: An Umbrella Review With More Than 380,000 Participants

Background & Aims: Nonalcoholic fatty liver disease (NAFLD) is the most common liver injury. We performed this umbrella review of meta-analyses to summarize the evidence on the associations of nutritional, lifestyle, and metabolic factors with NAFLD.

Methods: We searched the PubMed, Embase, and Web of Science databases from inception until July 2, 2020, to identify meta-analyses of observational studies which explored the associations of nutritional, lifestyle, and metabolic factors with NAFLD. Evidence levels were assessed using summary effect sizes, 95% prediction intervals, between-study heterogeneity, evidence of small-study effects, and evidence of excess significance bias for each meta-analysis. (No. of PROSPERO, CRD42020200124).

Results: Twenty two risk or protective factors from 10 published meta-analyses were included and studied. Three risk factors (sugar-sweetened beverage consumption, serum fetuin-A, and waist circumference) with highly suggestive levels of evidence and three risk factors (soft drink consumption, former smoking, and body mass index) with suggestive levels of evidence were identified. Only two protective factors (physical activity and serum vitamin D level [among adults in Western countries]) with suggestive levels of evidence were identified. Furthermore, other six risk factors and two protective factors with weak levels of evidence were identified.

Conclusions: We found varying levels of evidence of associations of nutritional, lifestyle, and metabolic factors and NAFLD. The results suggest that nutritional and lifestyle management should be considered as a major primary preventive strategy for NAFLD. Moreover, considering the low quality of included meta-analyses and limited area of research topics, future high-quality original studies and meta-analyses should be performed to study these associations.

Hearing impairment and diverse health outcomes : An umbrella review of meta-analyses of observational studies

BACKGROUND

Globally, it is estimated that approximately 1.3 billion people live with some form of hearing impairment. Major causes of hearing loss include infection/disease, age-related factors, and occupational factors. Numerous systematic reviews and meta-analyses have attempted to synthesise literature on these topics. To date there has not been a systematic evaluation of the relationships between hearing impairment and diverse physical, mental, and social outcomes.

OBJECTIVE

We performed an umbrella review of systematic reviews of observational studies with meta-analyses for any physical disease, biomarkers of disease, mental health or cognitive outcomes, and/or modifiable risk factors associated with hearing impairment.

METHODS

For each meta-analytic association, random effects summary effect size, 95% confidence intervals, heterogeneity, evidence for small-study effect, excess significance bias and 95% prediction intervals were calculated, and risk of bias was assessed via the AMSTAR2 tool. These were used to grade significant evidence (p < 0.05) from I to IV, using the recommendations from the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) criteria.

RESULTS

From 3747 studies, 21 were included covering 54 outcomes. Overall, 44/54 outcomes (82%) yielded significant results. Of the highest quality evidence, age-related hearing loss and non-specific hearing impairment were negatively associated with several types of cognitive impairments; pediatric bilateral hearing loss was negatively associated with quality of life, sensorineural hearing loss was positively associated with rheumatoid arthritis and tinnitus was positively associated with temporomandibular disorders.

CONCLUSION AND RELEVANCE

Results show moderate quality evidence for associations between several types of hearing impairments and cognitive difficulties, quality of life and systemic diseases such as rheumatoid arthritis. Practitioners and public health policies should note these findings when developing relevant healthcare policies.

The Dietary Inflammatory Index and Human Health: An Umbrella Review of Meta-Analyses of Observational Studies

Numerous observational studies have investigated the role of the Dietary Inflammatory Index (DII®) in chronic disease risk. The aims of this umbrella review and integrated meta-analyses were to systematically synthesize the observational evidence reporting on the associations between the DII and health outcomes based on meta-analyses, and to assess the quality and strength of the evidence for each associated outcome. This umbrella review with integrated meta-analyses investigated the association between the DII and a range of health outcomes based on meta-analyses of observational data. A credibility assessment was conducted for each outcome using the following criteria: statistical heterogeneity, 95% prediction intervals, evidence for small-study effect and/or excess significance bias, as well as effect sizes and P values using calculated random effects meta-analyses. In total, 15 meta-analyses reporting on 38 chronic disease-related outcomes were included, incorporating a total population of 4,360,111 subjects. Outcomes (n = 38) were examined through various study designs including case-control (n = 8), cross-sectional (n = 5), prospective (n = 5), and combination (n = 20) study designs. Adherence to a pro-inflammatory dietary pattern had a significant positive association with 27 (71%) of the included health outcomes (P value < 0.05). Using the credibility assessment, Class I (Convincing) evidence was identified for myocardial infarction only, Class II (Highly suggestive) evidence was identified for increased risk of all-cause mortality, overall risk of incident cancer, and risk of incident site-specific cancers (colorectal, pancreatic, respiratory, and oral cancers) with increasing (more pro-inflammatory) DII score. Most outcomes (n = 31) presented Class III (Suggestive) or lower evidence (Weak or No association). Pro-inflammatory dietary patterns were nominally associated with an increased risk of many chronic disease outcomes. However, the strength of evidence for most outcomes was limited. Further prospective studies are required to improve the precision of the effect size.

Iron intake and multiple health outcomes: Umbrella review

Iron is an essential trace element, while excess iron can lead to different levels of physical abnormalities or diseases. This umbrella review aimed to conduct a systematic evaluation of the possible relationships between iron intake and various health outcomes. We retrieved PubMed, Embase, Web of Science, Scopus, and the Cochrane Database of Systematic Reviews from inception through May 2021. A total of 34 meta-analyses with 46 unique health outcomes were identified. Heme iron intake was positively associated with nine outcomes, including colorectal cancer, type 2 diabetes mellitus, and cardiovascular disease mortality, while dietary total iron intake could decrease the risk of colorectal adenoma, esophageal cancer, coronary heart disease, and depression. Iron supplementation was a protective factor against eight outcomes. However, it was associated with decreased length and weight gain. The quality of evidence for most outcomes was "low" or "very low" with the remaining eleven as "high" or "moderate". All outcomes were categorized as class III, IV, or NS based on evidence classification. Although high iron intake has been identified to be significantly associated with a range of outcomes, firm universal conclusions about its beneficial or negative effects cannot be drawn given the low quality of evidence for most outcomes.

Ultra-Processed Foods and Nutritional Dietary Profile: A Meta-Analysis of Nationally Representative Samples

Excessive consumption of ultra-processed foods (UPFs), as described by the NOVA classification system, represents a potential threat to human health. The nutritional composition of UPFs may explain their observed adverse effects. The present study aimed to provide a quantitative meta-analysis of nationally representative surveys on the consumption of UPFs and the dietary/nutrient composition of respondents' diets. A systematic search for relevant studies published prior to July 2021 was conducted via electronic databases. The studies that provided the dietary/nutrient composition of foods categorized according to the NOVA classification system were selected. The association between UPFs and other dietary variables was modelled using ordinary least squares linear regression based on aggregated data extracted from the selected articles. Consumption of UPFs represented up to 80% of total caloric intake in the US and Canada, with confectionery and sugar-sweetened beverages being the most consumed items. When considered in relation to other food groups, an inverse linear relation between UPFs and less-processed foods was evident. Increased UPF intake correlated with an increase in free sugars, total fats, and saturated fats, as well as a decrease in fiber, protein, potassium, zinc, and magnesium, and vitamins A, C, D, E, B12, and niacin. In conclusion, the data indicate that increased UPF consumption negatively affects the nutritional quality of diets.

Effect of Microgravity Environment on Gut Microbiome and Angiogenesis

Microgravity environments are known to cause a plethora of stressors to astronauts. Recently, it has become apparent that gut microbiome composition of astronauts is altered following space travel, and this is of significance given the important role of the gut microbiome in human health. Other changes observed in astronauts comprise reduced muscle strength and bone fragility, visual impairment, endothelial dysfunction, metabolic changes, behavior changes due to fatigue or stress and effects on mental well-being. However, the effects of microgravity on angiogenesis, as well as the connection with the gut microbiome are incompletely understood. Here, the potential association of angiogenesis with visual impairment, skeletal muscle and gut microbiome is proposed and explored. Furthermore, metabolites that are effectors of angiogenesis are deliberated upon along with their connection with gut bacterial metabolites. Targeting and modulating the gut microbiome may potentially have a profound influence on astronaut health, given its impact on overall human health, which is thus warranted given the likelihood of increased human activity in the solar system, and the determination to travel to Mars in future missions.

RNAi suppression of xylan synthase genes in wheat starchy endosperm

The xylan backbone of arabinoxylan (AX), the major cell wall polysaccharide in the wheat starchy endosperm, is synthesised by xylan synthase which is a complex of three subunits encoded by the GT43_1, GT43_2 and GT47_2 genes. RNAi knock-down of either GT43_1 or all three genes (triple lines) resulted in decreased AX measured by digestion with endoxylanase (to 33 and 34.9% of the controls) and by monosaccharide analysis (to 45.9% and 47.4% of the controls) with greater effects on the amount of water-extractable AX (to 20.6 and 19.9% of the controls). Both sets of RNAi lines also had greater decreases in the amounts of substituted oligosaccharides released by digestion of AX with endoxylanase than in fragments derived only from the xylan backbone. Although the GT43_1 and triple lines had similar effects on AX they did differ in their contents of soluble sugars (increased in triple only) and on grain size (decreased in triple only). Both sets of transgenic lines had decreased grain hardness, indicating effects on cell wall mechanics. These results, and previously published studies of RNAi suppression of GT43_2 and GT47_2 and of a triple mutant of GT43_2, are consistent with the model of xylan synthase comprising three subunits one of which (GT47_2) is responsible for catalysis with the other two subunits being required for correct functioning but indicate that separate xylan synthase complexes may be responsible for the synthesis of populations of AX which differ in their structure and solubility.

Relationship Between a Plant-Based Dietary Portfolio and Risk of Cardiovascular Disease: Findings From the Women's Health Initiative Prospective Cohort Study

Background The plant-based Dietary Portfolio combines established cholesterol-lowering foods (plant protein, nuts, viscous fiber, and phytosterols), plus monounsaturated fat, and has been shown to improve low-density lipoprotein cholesterol and other cardiovascular disease (CVD) risk factors. No studies have evaluated the relation of the Dietary Portfolio with incident CVD events. Methods and Results We followed 123 330 postmenopausal women initially free of CVD in the Women's Health Initiative from 1993 through 2017. We used Cox proportional-hazard models to estimate adjusted hazard ratios (HRs) and 95% CI of the association of adherence to a Portfolio Diet score with CVD outcomes. Primary outcomes were total CVD, coronary heart disease, and stroke. Secondary outcomes were heart failure and atrial fibrillation. Over a mean follow-up of 15.3 years, 13 365 total CVD, 5640 coronary heart disease, 4440 strokes, 1907 heart failure, and 929 atrial fibrillation events occurred. After multiple adjustments, adherence to the Portfolio Diet score was associated with lower risk of total CVD (HR, 0.89; 95% CI, 0.83-0.94), coronary heart disease (HR, 0.86; 95% CI, 0.78-0.95), and heart failure (HR, 0.83; 95% CI, 0.71-0.99), comparing the highest to lowest quartile of adherence. There was no association with stroke (HR, 0.97; 95% CI, 0.87-1.08) or atrial fibrillation (HR, 1.10; 95% CI, 0.87-1.38). These results remained statistically significant after several sensitivity analyses. Conclusions In this prospective cohort of postmenopausal women in the United States, higher adherence to the Portfolio Diet was associated with a reduction in incident cardiovascular and coronary events, as well as heart failure. These findings warrant further investigation in other populations.

Resilience and Equity in a Time of Crises: Investing in Public Urban Greenspace Is Now More Essential Than Ever in the US and Beyond

The intersecting negative effects of structural racism, COVID-19, climate change, and chronic diseases disproportionately affect racial and ethnic minorities in the US and around the world. Urban populations of color are concentrated in historically redlined, segregated, disinvested, and marginalized neighborhoods with inadequate quality housing and limited access to resources, including quality greenspaces designed to support natural ecosystems and healthy outdoor activities while mitigating urban environmental challenges such as air pollution, heat island effects, combined sewer overflows and poor water quality. Disinvested urban environments thus contribute to health inequity via physical and social environmental exposures, resulting in disparities across numerous health outcomes, including COVID-19 and chronic diseases such as cancer and cardiovascular diseases (CVD). In this paper, we build off an existing conceptual framework and propose another conceptual framework for the role of greenspace in contributing to resilience and health equity in the US and beyond. We argue that strategic investments in public greenspaces in urban neighborhoods impacted by long term economic disinvestment are critically needed to adapt and build resilience in communities of color, with urgency due to immediate health threats of climate change, COVID-19, and endemic disparities in chronic diseases. We suggest that equity-focused investments in public urban greenspaces are needed to reduce social inequalities, expand economic opportunities with diversity in workforce initiatives, build resilient urban ecosystems, and improve health equity. We recommend key strategies and considerations to guide this investment, drawing upon a robust compilation of scientific literature along with decades of community-based work, using strategic partnerships from multiple efforts in Milwaukee Wisconsin as examples of success.

Substituting Meat or Dairy Products with Plant-Based Substitutes Has Small and Heterogeneous Effects on Diet Quality and Nutrient Security: A Simulation Study in French Adults (INCA3)

BACKGROUND

Plant-based substitutes are designed to have the same use as animal-based foods in the diet and could therefore assist the transition toward more plant-based diets. However, their nutritional impact has not been characterized.

OBJECTIVES

We assessed and compared the effects of plant-based substitutes on the nutritional quality of the diet.

METHODS

We simulated separately the substitution of meat, milk, and dairy desserts with 96 plant-based substitutes in the diets of 2121 adults (18-79 y old) from the cross-sectional French Third Individual and National Study on Food Consumption Survey (INCA3; 2014-2015). The quality of initial individual diets and the 203,616 substituted diets was evaluated using the Probability of Adequate Nutrient Intake (PANDiet) scoring system, which assesses the probability of adequate (sufficient and not excessive) nutrient intake; also, nutrient security was evaluated using the SecDiet scoring system, which assesses the risk of overt deficiency.

RESULTS

Impacts on PANDiet depended on both the food substituted and the types of substitutes. Soy-based substitutes provided a slight improvement in diet quality (0.8% increase of the PANDiet score when substituting meat), whereas cereal-based substitutes resulted in a 1.1% decrease. Globally, substitutions led to better adequacies for fiber, linoleic acid, α-linolenic acid, vitamin E, folate, and SFAs, but lower adequacies regarding vitamin B-12 and riboflavin, as well as bioavailable zinc and iron when substituting meat, and calcium and iodine when substituting milk/dairy desserts. When they substituted dairy products, calcium-fortified substitutes allowed maintenance of calcium adequacy but there was a higher risk of iodine deficiency when substituting dairy, which may warrant iodine fortification. Substitutions modified the energy share of ultra-processed foods from 29% to 27%-40%, depending on the food substituted and the substitute used.

CONCLUSIONS

Plant-based substitutes had a small effect on overall diet quality and heterogeneous impacts on nutrient adequacy and security. Plant-based substitutes that include legumes appear more nutritionally adequate to substitute animal products than do other substitutes.

Validity of observational evidence on putative risk and protective factors: appraisal of 3744 meta-analyses on 57 topics

BACKGROUND

The validity of observational studies and their meta-analyses is contested. Here, we aimed to appraise thousands of meta-analyses of observational studies using a pre-specified set of quantitative criteria that assess the significance, amount, consistency, and bias of the evidence. We also aimed to compare results from meta-analyses of observational studies against meta-analyses of randomized controlled trials (RCTs) and Mendelian randomization (MR) studies.

METHODS

We retrieved from PubMed (last update, November 19, 2020) umbrella reviews including meta-analyses of observational studies assessing putative risk or protective factors, regardless of the nature of the exposure and health outcome. We extracted information on 7 quantitative criteria that reflect the level of statistical support, the amount of data, the consistency across different studies, and hints pointing to potential bias. These criteria were level of statistical significance (pre-categorized according to 10^-6, 0.001, and 0.05 p-value thresholds), sample size, statistical significance for the largest study, 95% prediction intervals, between-study heterogeneity, and the results of tests for small study effects and for excess significance.

RESULTS

3744 associations (in 57 umbrella reviews) assessed by a median number of 7 (interquartile range 4 to 11) observational studies were eligible. Most associations were statistically significant at P < 0.05 (61.1%, 2289/3744). Only 2.6% of associations had P < 10^-6, ≥1000 cases (or ≥20,000 participants for continuous factors), P < 0.05 in the largest study, 95% prediction interval excluding the null, and no large between-study heterogeneity, small study effects, or excess significance. Across the 57 topics, large heterogeneity was observed in the proportion of associations fulfilling various quantitative criteria. The quantitative criteria were mostly independent from one another. Across 62 associations assessed in both RCTs and in observational studies, 37.1% had effect estimates in opposite directions and 43.5% had effect estimates differing beyond chance in the two designs. Across 94 comparisons assessed in both MR and observational studies, such discrepancies occurred in 30.8% and 54.7%, respectively.

CONCLUSIONS

Acknowledging that no gold-standard exists to judge whether an observational association is genuine, statistically significant results are common in observational studies, but they are rarely convincing or corroborated by randomized evidence.

Metformin and health outcomes: An umbrella review of systematic reviews with meta-analyses

BACKGROUND

The objective was to capture the breadth of outcomes that have been associated with metformin use and to systematically assess the quality, strength and credibility of these associations using the umbrella review methodology.

METHODS

Four major databases were searched until 31 May 2020. Meta-analyses of observational studies and meta-analyses of randomized controlled trials (RCTs) (including active and placebo control arms) were included.

RESULTS

From 175 eligible publications, we identified 427 different meta-analyses, including 167 meta-analyses of observational studies, 147 meta-analyses of RCTs for metformin vs placebo/no treatment and 113 meta-analyses of RCTs for metformin vs active medications. There was no association classified as convincing or highly suggestive from meta-analyses of observational studies, but some suggestive/weak associations of metformin use with a lower mortality risk of CVD and cancer. In meta-analyses of RCTs, metformin was associated with a lower incidence of diabetes in people with prediabetes or no diabetes at baseline; lower ovarian hyperstimulation syndrome incidence (in women in controlled ovarian stimulation); higher success for clinical pregnancy rate in poly-cystic ovary syndrome (PCOS); and significant reduction in body mass index in people with type 1 diabetes mellitus, in women who have obesity/overweight with PCOS and in obese/overweight women. Of 175 publications, 166 scored as low or critically low quality per AMSTAR 2 criteria.

CONCLUSIONS

Observational evidence on metformin seems largely unreliable. Randomized evidence shows benefits for preventing diabetes and in some gynaecological and obstetrical settings. However, almost all meta-analyses are of low or critically low quality according to AMSTAR 2 criteria.

Risk factors for eating disorders: an umbrella review of published meta-analyses

Objective:

To grade the evidence about risk factors for eating disorders (anorexia nervosa, bulimia nervosa, and binge eating disorder) with an umbrella review approach.

Methods:

This was a systematic review of observational studies on risk factors for eating disorders published in PubMed/PsycInfo/Embase until December 11th, 2019. We recalculated random-effect meta-analyses, heterogeneity, small-study effect, excess significance bias and 95% prediction intervals, grading significant evidence (p < 0.05) from convincing to weak according to established criteria. Quality was assessed with the Assessment of Multiple Systematic Reviews 2 (AMSTAR-2) tool.

Results:

Of 2,197 meta-analyses, nine were included, providing evidence on 50 risk factors, 29,272 subjects with eating disorders, and 1,679,385 controls. Although no association was supported by convincing evidence, highly suggestive evidence supported the association between childhood sexual abuse and bulimia nervosa (k = 29, 1,103 cases with eating disorders, 8,496 controls, OR, 2.73, 95%CI 1.96-3.79, p = 2.1 x 10-9, AMSTAR-2 moderate quality) and between appearance-related teasing victimization and any eating disorder (k = 10, 1,341 cases with eating disorders, 3,295 controls, OR 2.91, 95%CI 2.05-4.12, p = 1.8x10-9, AMSTAR-2 moderate quality). Suggestive, weak, or no evidence supported 11, 29, and 8 associations, respectively.

Conclusions:

The most credible evidence indicates that early traumatic and stressful events are risk factors for eating disorders. Larger collaborative prospective cohort studies are needed to identify risk factors for eating disorders, particularly anorexia nervosa.

Dietary Fiber-Tethered Gold Nanoparticles: An Innovative Analytical Tool for Probing Interactions

Epidemiological studies have recognized that daily consumption of dietary fiber-containing foods reduces the incidence of developing many chronic diseases, for example, by interacting with nutritionally relevant compounds. The low affinity nature that some of these interactions can have make the development of an analytical detection system for their study particularly difficult. Therefore, the mechanism of action of binding compounds, by which a dietary fiber exerts its potential health benefits, remains largely unknown. Here, a novel method based on glyco-nanotechnology is proposed for studying the interaction between galactomannan and target molecules. Starting from a bottom-up approach, gold nanoparticles and thiolated galactomannans of two different sizes were synthesized separately, and then mixed for auto-assembly of the two glyconanoparticle materials. In addition, a preliminary interaction study between the prepared glyconanoparticles and Concanavalin A was carried out using transmission electron microscopy (TEM) from which it could be deduced that the molecular weight and ligand density on the gold core play an important role in the interaction. Therefore, dietary fiber-tethered gold nanoparticles are a valuable tool to elucidate key parameters underlying dietary fiber interactions.

Nutritional, Cardiovascular Health and Lifestyle Status of 'Health Conscious' Adult Vegans and Non-Vegans from Slovenia: A Cross-Sectional Self-Reported Survey

The study aim was to investigate differences in nutritional, cardiovascular and lifestyle status of ‘health conscious’ subjects. In a partial ‘lock-down’ during the COVID-19 pandemic period, we performed a web-based, cross-sectional study. We compared 80 self-selected subjects (51 vegans, 67% females, and 29 non-vegans, 55% females, p = 0.344). Nutritional status was assessed by bio-electrical impedance and standardized food frequency questionnaires (i.e., contribution of nutrients from foods and supplementation, combined and separate). Serum lipid concentrations and blood pressure (BP) were assessed from annual or initial examination reports, while sociodemographic, economic, and lifestyle statuses were obtained by standardized questionnaires. Finally, a multivariate linear regression model was used to estimate the relationship between total fiber and saturated fatty acid (SFA) intake and low-density lipoprotein cholesterol (LDL cholesterol) values. The vegans had a significantly lower body mass index (22.8 ± 2.4 vs. 26.6 ± 3.6 kg/m², p < 0.001) and body fat % (19.3 ± 7.3 vs. 25.8 ± 8.2%, p < 0.001) than the non-vegans. There were significant differences between vegans and non-vegans in energy intake, and most macronutrient (10/12) and micronutrient (15/23) intakes in units/day. Both diets were well designed, with high fiber and low SFA and free sugar intake but remained insufficient in n-3 long chain polyunsaturated fatty acids (for vegans), vitamin D, calcium, sodium (for vegans) and iodine. Vegans also had a significantly lower lipid profile and BP than non-vegans, except for high-density lipoprotein cholesterol. However, both groups met targeted recommendations. Furthermore, fiber and SFA intake and age explained 47% of the variance in LDL cholesterol. In conclusion, ‘health conscious’ vegans and non-vegans with comparable lifestyle statuses had significant differences in dietary intake, body composition and cardiovascular health status.

Fruit and vegetable consumption in relation to primary headaches: the MEPHASOUS study

BACKGROUND

Fruit and vegetable consumption may beneficially affect the odds of primary headaches due to their antioxidant contents. However, no study has examined the association between fruit and vegetable consumption and primary headaches among university students.

AIM

To assess the relation between fruit and vegetable intakes and primary headaches among Iranian university students.

METHODS

Overall, 83,214 university students with an age range of ≥ 18 years participated in the present study. Dietary intakes and also data on confounding variables were collected using validated questionnaires. Data on dietary intakes were collected using a validated dietary habits questionnaire. We used the International Classification of Headache Disorders-3 (ICHD-3) criteria to define primary headaches.

RESULTS

Fruit consumption was negatively associated with primary headaches; such that after controlling for potential confounders, greater intake of fruits was associated with 30% lower odds of primary headaches (OR: 0.70, 95% CI 0.58-0.84). Such an inverse association was also found for vegetable consumption. In the fully adjusted model, students in the top category of vegetable consumption were 16% less likely to have primary headaches compared with those in the bottom category (OR: 0.84, 95% CI 0.74-0.95). Subgroup analysis revealed that fruit consumption was inversely associated with primary headaches in females, unlike males, and vegetable consumption was inversely associated with these headaches in males, as opposed to females. Moreover, fruit and vegetable consumption was related to lower odds of primary headaches in normal-weight students.

CONCLUSION

Fruit and vegetable intakes were associated with reduced odds of primary headaches.

LEVEL OF EVIDENCE

Level III, cross-sectional analytic studies.

Gut microbiome variation modulates the effects of dietary fiber on host metabolism

BACKGROUND

There is general consensus that consumption of dietary fermentable fiber improves cardiometabolic health, in part by promoting mutualistic microbes and by increasing production of beneficial metabolites in the distal gut. However, human studies have reported variations in the observed benefits among individuals consuming the same fiber. Several factors likely contribute to this variation, including host genetic and gut microbial differences. We hypothesized that gut microbial metabolism of dietary fiber represents an important and differential factor that modulates how dietary fiber impacts the host.

RESULTS

We examined genetically identical gnotobiotic mice harboring two distinct complex gut microbial communities and exposed to four isocaloric diets, each containing different fibers: (i) cellulose, (ii) inulin, (iii) pectin, (iv) a mix of 5 fermentable fibers (assorted fiber). Gut microbiome analysis showed that each transplanted community preserved a core of common taxa across diets that differentiated it from the other community, but there were variations in richness and bacterial taxa abundance within each community among the different diet treatments. Host epigenetic, transcriptional, and metabolomic analyses revealed diet-directed differences between animals colonized with the two communities, including variation in amino acids and lipid pathways that were associated with divergent health outcomes.

CONCLUSION

This study demonstrates that interindividual variation in the gut microbiome is causally linked to differential effects of dietary fiber on host metabolic phenotypes and suggests that a one-fits-all fiber supplementation approach to promote health is unlikely to elicit consistent effects across individuals. Overall, the presented results underscore the importance of microbe-diet interactions on host metabolism and suggest that gut microbes modulate dietary fiber efficacy. Video abstract.

Nutrition in Physical Therapist Practice: Setting the Stage for Taking Action

Diet and nutrition are critical components of health, recovery from disease and illness, performance, and normal growth across the lifespan. Thus, it is important for physical therapists to be knowledgeable about nutrition and to have competency in providing information and guidance to patients/clients. Yet, there is an overwhelming amount of diet and nutrition information available from numerous sources, which makes it difficult to reach conclusions and determine the importance and relevance to patient care. The purpose of this perspective paper is to increase the knowledge and skills of physical therapists by providing guidelines for healthy eating and outlining diet and nutrition information most relevant for physical therapist practice and to clarify professional scope of practice related to diet and nutrition, including boundaries created by law, and the connection between healthy eating and health outcomes, muscle strength, bone health, and wound healing.