Adiposity Mediates the Association between the Dietary Inflammatory Index and Markers of Type 2 Diabetes Risk in Middle-Aged Black South African Women

The association between dietary inflammatory index (DII) scores and c-reactive protein (CRP) and nonalcoholic fatty liver disease (NAFLD) in a general population cohort

BACKGROUND AND AIMS

Although there is extensive literature showing the ability of the dietary inflammation index (DII®) to predict concentrations of plasma inflammatory markers, few studies are testing the association between DII scores and nonalcoholic fatty liver disease (NAFLD). Considering the high prevalence of NAFLD and its complications, we conducted a validation study of DII scores and examined its association with NAFLD in the general adult population of Iran.

METHODS

This cross-sectional study was conducted on 3110 adult participants in the Amol Cohort Study (AmolCS) who underwent abdominal ultrasonography to diagnose NAFLD. DII and energy-adjusted DII (E-DII™) scores were computed using data from a valid semi-quantitative 168-item food frequency questionnaire (FFQ). Multivariable logistic regression adjusting for socio-demographic, lifestyle, and health-related factors was used to assess association.

RESULTS

The EDII was associated with CRP inflammatory biomarker. Participants in the highest, i.e., most pro-inflammatory tertile had the highest odds of NAFLD by ultrasound in all models [fully adjusted model: OR (95 % CI) tertile3vs.1:1.54 (1.05-2.05); Ptrend = 0.04, and 1.63 (1.19-2.21); Ptrend = 0.03 in women and men, respectively]. The highest tertile had the highest OR for NAFLD by fatty liver index (FLI) only in men [fully adjusted model OR (95 % CI) tertile3vs.1: 1.77 (1.15-2.71); Ptrend = 0.01]. Similar results were also obtained for NAFLD by hepatic steatosis index (HSI) in women [fully adjusted model: OR (95 % CI) tertile3vs.1: 1.70 (1.12-2.58); Ptrend = 0.03]. The results of the fully adjusted multivariable model of liver markers and NAFLD status, stratified by gender and abdominal obesity, revealed that the highest tertiles had the highest OR for NAFLD by ultrasound and NAFLD by FLI only in men without abdominal obesity [fully adjusted model: OR (95 % CI) tertile3vs.1: 1.83 (1.17-2.84); Ptrend = 0.03, and, respectively]. NAFLD by FLI tended to increase strongly with tertile E-DII scores in men without abdominal obesity in crude and three adjusted models [full-adjusted model: OR (95 % CI) tertile3vs.1: 3.64 (1.56-8.46); Ptrend = 0.005]. By contrast, women with abdominal obesity in the highest tertile had the highest OR for NAFLD by ultrasound in all models [full-adjusted model: OR (95 % CI) tertile3vs.1: 1.67 (1.07-2.62); Ptrend = 0.02].

CONCLUSIONS

Our results suggest that diet plays a role in regulating inflammation. Additionally, we observed an inflammatory diet predicts the risk of NAFLD in Iranian adults. However, longitudinal studies are required in order to further substantiate the utility of the DII in the development of more effective dietary interventions among populations at risk of chronic disease.

Association of dietary and lifestyle inflammation score with type 2 diabetes mellitus and cardiometabolic risk factors in Iranian adults: Sabzevar Persian Cohort Study

Systemic inflammation may contribute to the initiation and progression of type 2 diabetes mellitus (T2DM) through diet and lifestyle. We examined the association of dietary inflammation score (DIS), lifestyle inflammation score (LIS) and dietary and lifestyle inflammation score (DLIS) with T2DM and cardiometabolic risk factors among Iranian adults. In this study, we identified and recruited 619 patients with T2DM and 2113 without T2DM from 35 to 75 years old men and women in the baseline phase of the Sabzevar Persian Cohort Study. Using a validated 115-item semi-quantitative FFQ, we calculated a 19-component DIS and a 3-component LIS weighted by circulating inflammation biomarkers. The DIS, LIS and DLIS associations with diabetes were assessed by multivariable logistic regression analysis. The average age of the participants was 48·29 (sd 8·53) (without T2DM: 47·66 (sd 8·42); with T2DM: 50·44 (sd 8·57)). Individuals in the highest compared with the lowest tertiles of DLIS (OR: 3·40; 95 % CI 2·65, 4·35; Ptrend < 0·001), DIS (OR: 3·41; 95 % CI 2·66, 4·38; Ptrend < 0·001) and LIS (OR: 1·15; 95 % CI 0·90, 1·46; Ptrend = 0·521) had an increased risk of T2DM. For those in the highest relative to the lowest joint DIS and LIS tertiles, the results were OR: 3·37; 95 % CI 2·13, 5·32; Pinteraction < 0·001. No significant associations were found between DLIS and cardiometabolic risk factors, including blood pressure, liver enzymes and glycaemic and lipid profiles, except for waist circumference (P < 0·001) and waist-to-hip ratio (P = 0·010). A higher DIS and DLIS score was associated with a higher risk of T2DM, while the LIS score was not associated with T2DM risk.

Dietary Inflammatory Index and diabetic retinopathy risk in US adults: findings from NHANES (2005-2008)

BACKGROUND

Inflammation is associated with the pathophysiology of diabetic retinopathy (DR). Within the framework of complete dietary patterns, the Dietary Inflammatory Index (DII) was formulated to evaluate the inflammatory properties inherent in a diet. The main purpose of the current study was to assess the relationship between DII and DR using National Health and Nutrition Examination Survey (NHANES).

METHODS

The original sample size included 1,148 diabetes patients out of 2005-2008 NHANES surveys. Twenty-four-hour dietary consumptions were used to calculate the DII scores. Demographic characteristics and retina examinations were collected for the comparison between DR and non-DR groups in diabetes patients. The relationship between DII and DR was analyzed by a logistic regression model.

RESULTS

227 subjects (110 non-DR and 117 DR) were selected in the analyses by using undersampling method to balance the sample size. Compared with non-DR group, DR group had higher DII values (1.14 ± 0.29 vs. 1.49 ± 0.21, p = 0.32), higher levels of HbA1c (6.8 ± 1.1% vs. 7.7 ± 2.6%, p < 0.001), longer duration of diabetes (6.52 ± 12 years vs. 14 ± 11 years, p < 0.001). The odds rate (OR) of DII for DR from the logistic regression was 1.38 (95%CI 1.06-1.81, p < 0.001). HbA1c, diabetes duration and obesity were important influencing factors, and their ORs were 1.81 (95% CI:1.31-2.50), 1.12 (95%CI:1.04-1.20), 4.01 (95%CI:1.12-14.32), respectively. In addition, the most important dietary indices for DR were different across males and females.

CONCLUSIONS

The current study demonstrates that a higher DII is associated with an increased risk of DR in US adults. Considering diet as a modifiable factor, limiting pro-inflammatory diets or encouraging an anti-inflammatory diet may be a promising and cost-effective method in the management of DR.

The dietary inflammatory index is positively associated with insulin resistance in underweight and healthy weight adults

The aim of this study was to explore the relationship between dietary inflammatory index (DII) and insulin resistance (IR) in underweight and healthy weight adults. This cross-sectional study involved 3205 participants from the National Health and Nutrition Examination Survey (NHANES) from 2005 to 2018. All dietary data used to calculate the DII were obtained based on the average of two 24-h dietary recall interviews. Participants were divided into an anti-inflammatory diet group and a pro-inflammatory diet group based on DII < 0 and DII ≥ 0, respectively. Fasting blood glucose and fasting insulin data used to calculate IR index (HOMA-IR) were from laboratory data in the NHANES database. According to the linear regression analysis results of DII and HOMA-IR, we found that there was a positive relationship between DII and IR. A positive association between DII and HOMA-IR was seen in the following groups after stratification: by age in 20-39-year olds, by sex in males, by race in Non-Hispanic Whites, by family history of diabetes in those without a family history of diabetes, by education level in those with high school education, by smoking status in current smokers and non-smokers, by hypertension in those with hypertension, by BMI in those with a BMI of 18.5-24.99, by hypertriglyceridemia (HTG) in those without HTG, by poverty impact ratio (PIR) in those with PIR ≤ 1.3 and >1.3, and by physical activity in those with moderate recreational activities. In conclusion, in underweight and healthy weight adults, DII was positively correlated with the risk of IR.

Energy-Adjusted Dietary Inflammatory Index and Diabetes Risk in Postmenopausal Hispanic Women

BACKGROUND

Type 2 diabetes is a major public health concern in the United States and worldwide. The dietary inflammatory index (DII) and the energy-adjusted DII (E-DII) are tools that assess dietary inflammation. Previous evidence suggests that obesity can modify the association between inflammation and disease.

OBJECTIVE

The aim of this study was to evaluate the association between the DII/E-DII and incident diabetes in self-identified Hispanic women from the Women's Health Initiative (WHI). The secondary aim was to evaluate whether obesity modifies the association between the DII/E-DII scores and incident diabetes.

DESIGN

Participants were from the WHI Observational Study and the Clinical Trial Components (except women from the treatment arm in the Dietary Modification Trial) conducted among postmenopausal women in the United States. DII/E-DII scores were calculated from a self-administered food frequency questionnaire at baseline that included 122 food items, of which 12 are representative of Hispanic eating patterns.

PARTICIPANTS/SETTINGS

Participants included 3,849 postmenopausal women who self-identified as Hispanic that were recruited for the WHI from 1993 to 1998 at 40 US clinical centers.

MAIN OUTCOME MEASURES

The outcome was incident diabetes.

STATISTICAL ANALYSIS PERFORMED

Cox regression models were used to assess the association between DII/E-DII and incident diabetes. Models were adjusted for age at baseline, lifestyle-related risk factors, known type 2 diabetes mellitus (T2DM) risk factors, and neighborhood socioeconomic status. Interaction was tested between the DII/E-DII scores and obesity.

RESULTS

The incidence of diabetes was 13.1% after a median follow-up of 13 years. Higher E-DII scores were associated with a higher risk of incident diabetes (hazard ratio [HR], 1.09; 95% confidence interval [CI], 1.04-1.14). There was no interaction between E-DII scores and obesity (P = 0.73).

CONCLUSIONS

Pro-inflammatory diets, as measured by higher E-DII scores, were associated with a higher risk of incident diabetes. Future research is needed for understanding how the inflammatory potential of diets can be decreased.

Cardiometabolic Care: Assessing Patients with Diabetes Mellitus with No Overt Cardiovascular Disease in the Light of Heart Failure Development Risk

The mechanisms leading to the development of heart failure (HF) in diabetes mellitus (DM) patients are multifactorial. Assessing the risk of HF development in patients with DM is valuable not only for the identification of a high-risk subgroup, but also equally important for defining low-risk subpopulations. Nowadays, DM and HF have been recognized as sharing similar metabolic pathways. Moreover, the clinical manifestation of HF can be independent of LVEF classification. Consequently, approaching HF should be through structural, hemodynamic and functional evaluation. Thus, both imaging parameters and biomarkers are important tools for the recognition of diabetic patients at risk of HF manifestation and HF phenotypes, and arrhythmogenic risk, and eventually for prognosis, aiming to improve patients' outcomes utilizing drugs and non-pharmaceutical cardioprotective tools such as diet modification.

Dietary inflammatory index and cardiovascular disease risk in Hispanic women from the Women's Health Initiative

BACKGROUND

To evaluate the association between the dietary inflammatory index (DII^®) and incident cardiovascular disease (CVD) in Hispanic women from the Women's Health Initiative (WHI), and to determine if body mass index (BMI) interacted with the DII scores.

METHODS

Secondary analysis of baseline dietary data and long-term CVD outcomes among 3,469 postmenopausal women who self-identified as Hispanic enrolled in WHI. DII scores were calculated from self-administered food frequency questionnaires. The CVD outcomes included coronary heart disease (CHD) and stroke. Stratified Cox regression models were used to assess the relationship between DII scores and CVD in women with and without obesity. Models were adjusted for age, lifestyle risk factors, known risk factors, and neighborhood socioeconomic status.

RESULTS

The incidence of CHD was 3.4 and 2.8% for stroke after a median follow-up of 12.9 years. None of the DIIs were associated with CVD risk in this sample of Hispanic women. BMI interacted with the DII (p < 0.20) and stratified models showed that the associations between the DII and CVD were only significant in women with overweight (p < 0.05). In this group, higher DII scores were associated with a higher risk of CHD (HR 1.27; 95% CI: 1.08, 1.51) and a higher risk of stroke (HR 1.32; 95% CI: 1.07, 1.64).

CONCLUSION

Among postmenopausal Hispanic women with overweight, greater adherence to pro-inflammatory diets was associated with higher risk of CVD. Additional research is needed to understand how to promote long-term heart-healthy dietary habits to reduce inflammation and prevent CVD in at-risk Hispanic women.

A higher energy-adjusted Dietary Inflammatory Index is positively associated with total and visceral body fat in young male adults

BACKGROUND

The energy-adjusted Dietary Inflammatory Index (E-DII™) has been associated with a high body mass index and markers of chronic diseases. Also, pro-inflammatory diets with a high E-DII have been positively associated with metabolic disturbances such as glucose intolerance and type II diabetes mellitus. However, it is unclear whether E-DII scores are positively associated with body fat percentage and visceral fat per se. This cross-sectional study aimed to evaluate whether the E-DII is associated with body fat content and metabolic health indicators in lean and obese young men.

METHODS

The present study was conducted on 59 participants, without comorbidities, not using tobacco, medication and nutritional supplements. Dietary data were obtained by 3-day food records to calculate E-DII scores based on 28 food parameters. Body composition was assessed by dual X-ray absorptiometry (DXA). Blood samples were taken to measure fasting glucose, insulin, triacylglycerols, total cholesterol, and low- and high-density lipoprotein cholesterol. An oral glucose tolerance test also was performed. Associations were determined by mixed-effects linear regression.

RESULTS

E-DII scores ranged from -3.48 to +3.10. Energy intake was similar across E-DII tertiles. After adjusting for covariates, the highest E-DII tertile was associated with increased body fat, visceral adipose tissue and waist circumference. There was no association between E-DII scores and glycaemic parameters.

CONCLUSIONS

In young participants, a dietary pattern with a higher E-DII (i.e., pro-inflammatory) score was associated with high body fat and markers of central adiposity assessed by DXA, regardless of body mass.

The association between the dietary pattern in abdominal obesity based on visceral fat index and dyslipidaemia in the Henan Rural Cohort Study

The present study aimed to explore the association between dietary patterns in abdominal obesity obtained by reduced-rank regression (RRR) with visceral fat index (VFI) as a dependent variable and dyslipidemia in rural adults in Henan, China. A total of 29538 people aged 18-79 were selected from the Henan Rural Cohort Study. RRR analysis was used to identify dietary patterns; logistic regression analysis and restricted cubic spline regression models were applied to analyze the association between dietary patterns in abdominal obesity and dyslipidemia. VFI was used as a mediator to estimate the mediation effect. The dietary pattern in abdominal obesity was characterized by high carbohydrate and red meat intake and low consumption of fresh fruits, vegetables, milk, etc. After full adjustment, the highest quartile of dietary pattern scores was significantly associated with an increased risk of dyslipidemia (OR: 1·33, 95 % CI 1·23-1·44, P_trend < 0·001), there was a non-linear dose-response relationship between them (P_{overall-association} < 0·001, P_{non-lin-association} = 0·022). The result was similar in dose-response between the dietary pattern scores and VFI. The indirect effect partially mediated by VFI was significant (OR: 1·07, 95 % CI 1·06-1·08). VIF explained approximately 53·3 % of odds of dyslipidemia related to the dietary pattern. Abdominal obesity dietary pattern scores positively affected VFI and dyslipidemia; there was a dose-response in both relationships. Dyslipidemia progression increased with higher abdominal obesity dietary pattern scores. In addition, VFI played a partial mediating role in relationship between abdominal obesity dietary pattern and dyslipidemia.

Unpacking determinants and consequences of food insecurity for insulin resistance among people living with HIV: Conceptual framework and protocol for the NOURISH-OK study

Background:

Over the past four decades, advances in HIV treatment have contributed to a longer life expectancy for people living with HIV (PLWH). With these gains, the prevention and management of chronic co-morbidities, such as diabetes, are now central medical care goals for this population. In the United States, food insecurity disproportionately impacts PLWH and may play a role in the development of insulin resistance through direct and indirect pathways. The Nutrition to Optimize, Understand, and Restore Insulin Sensitivity in HIV for Oklahoma (NOURISH-OK) will use a novel, multi-level, integrated framework to explore how food insecurity contributes to insulin resistance among PLWH. Specifically, it will explore how food insecurity may operate as an intermediary risk factor for insulin resistance, including potential linkages between upstream determinants of health and downstream consequences of poor diet, other behavioral risk factors, and chronic inflammation.

Methods/design:

This paper summarizes the protocol for the first aim of the NOURISH-OK study, which involves purposeful cross-sectional sampling of PLWH (n=500) across four levels of food insecurity to test our conceptual framework. Developed in collaboration with community stakeholders, this initial phase involves the collection of anthropometrics, fasting blood samples, non-blood biomarkers, 24-hour food recall to estimate the Dietary Inflammatory Index (DII^®) score, and survey data. A 1-month, prospective observational sub-study (total n=100; n=25 for each food security group) involves weekly 24-hour food recalls and stool samples to identify temporal associations between food insecurity, diet, and gut microbiome composition. Using structural equation modeling, we will explore how upstream risk factors, including early life events, current discrimination, and community food access, may influence food insecurity and its potential downstream impacts, including diet, other lifestyle risk behaviors, and chronic inflammation, with insulin resistance as the ultimate outcome variable. Findings from these analyses of observational data will inform the subsequent study aims, which involve qualitative exploration of significant pathways, followed by development and testing of a low-DII^® food as medicine intervention to reverse insulin resistance among PLWH (ClinicalTrials.gov Identifier: NCT05208671).

Discussion:

The NOURISH-OK study will address important research gaps to inform the development of food as medicine interventions to support healthy aging for PLWH.

Anti-inflammatory diets reduce the risk of excessive gestational weight gain in urban South Africans from the Soweto First 1000-Day Study (S1000)

Purpose

To (i): examine whether maternal dietary inflammation assessed using the dietary inflammatory index (DII) is associated with gestational weight gain (GWG) and delivery outcomes in urban South African women from the Soweto First 1000-Day Study (S1000); and (ii): explore whether serum high-sensitivity c-reactive protein (hs-CRP) levels mediate these associations.

Methods

Energy-adjusted-DII (E-DII™) scores were calculated for 478 pregnant women using a quantitative food frequency questionnaire. GWG (kg/week) was assessed via anthropometry and hs-CRP concentrations were assessed in a sub-sample at < 14 (n = 263) and at 24–28 (n = 270) weeks gestational age. Multivariable linear and logistic regression models were used to examine associations between maternal E-DII scores, GWG, hs-CRP concentrations, and delivery outcomes.

Results

Positive vs. negative E-DII scores were associated with an increased odds of excessive weight gain (OR (95% CI): 2.23 (1.20; 4.14); P = 0.01) during pregnancy. Higher hs-CRP concentrations in the first trimester were associated with lower weight-for-length z-score (β (95% CI): −0.06 (−0.11; −0.01) per 1 mg/l hs-CRP; P = 0.02) and a reduction in odds of a large-for-gestational age delivery (OR (95% CI): 0.66 (0.47; 0.94); P = 0.02). Higher hs-CRP concentrations in the second trimester were associated with an increased odds of delivering preterm (OR (95% CI): 1.16 (1.01; 1.32); P = 0.03).

Conclusions

Consumption of an anti-inflammatory diet during pregnancy reduced the risk of excessive GWG in a rapidly urbanising setting (Soweto, South Africa), where obesity prevalence rates are high. Further research is needed to better understand how maternal diet may ameliorate the effects of maternal adiposity on inflammatory milieu and fetal programming.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00394-022-02931-x.

Role of C-Reactive Protein in Diabetic Inflammation

Even though type 2 diabetes mellitus (T2DM) represents a worldwide chronic health issue that affects about 462 million people, specific underlying determinants of insulin resistance (IR) and impaired insulin secretion are still unknown. There is growing evidence that chronic subclinical inflammation is a triggering factor in the origin of T2DM. Increased C-reactive protein (CRP) levels have been linked to excess body weight since adipocytes produce tumor necrosis factor α (TNF-α) and interleukin 6 (IL-6), which are pivotal factors for CRP stimulation. Furthermore, it is known that hepatocytes produce relatively low rates of CRP in physiological conditions compared to T2DM patients, in which elevated levels of inflammatory markers are reported, including CRP. CRP also participates in endothelial dysfunction, the production of vasodilators, and vascular remodeling, and increased CRP level is closely associated with vascular system pathology and metabolic syndrome. In addition, insulin-based therapies may alter CRP levels in T2DM. Therefore, determining and clarifying the underlying CRP mechanism of T2DM is imperative for novel preventive and diagnostic procedures. Overall, CRP is one of the possible targets for T2DM progression and understanding the connection between insulin and inflammation may be helpful in clinical treatment and prevention approaches.

Relationship Between Socioeconomic Status and Win-Win Values: Mediating Roles of Childhood Neglect and Self-Continuity

The family plays a key role on the development of children. One with low socioeconomic status was more likely to suffer childhood neglect, which might impact on development of self-continuity and win-win values. Using cross-sectional data from 489 participants, this study conducted a mediation model to examine the roles of childhood neglect and self-continuity between socioeconomic status and win-win values. Our results showed that childhood neglect and self-continuity fully mediated the effect of socioeconomic status on win-win values. Specifically, socioeconomic status might affect win-win values through three roles: the individual mediating role of childhood neglect, the individual mediating role of self-continuity, and the multiple mediation roles of childhood neglect and self-continuity.

Associations of Dietary Inflammatory Index With Prediabetes and Insulin Resistance

BACKGROUND AND AIMS

Previous studies suggested that dietary inflammatory index (DII) was associated with a variety of adverse health conditions. However, less is known about the role of DII in prediabetes and insulin resistance (IR). Therefore, this study aimed to investigate whether DII is associated with prediabetes and IR in American adults.

METHOD AND RESULTS

DII scores were calculated using the average of two 24-hour dietary recalls. Linear regression models were performed to evaluate the associations of DII with markers of Type 2 diabetes (T2D) risk, and the associations of DII with prediabetes and IR were estimated using logistic regression model. The diet of the participants showed an anti-inflammatory potential, with a mean DII score of -0.14 (range: -5.83 to +5.32). After controlling for multiple potential confounders, DII scores were positively associated with fasting plasma glucose (FPG) (β: 0.009; 95%CI: 0.005 to 0.012), fasting serum insulin (FSI) (β: 0.083; 95%CI: 0.067 to 0.099) and homeostatic model assessment of insulin resistance (HOMA-IR) (β: 0.092; 95%CI: 0.075 to 0.109). Participants in the highest tertile of DII score have increased odds of prediabetes (OR: 1.40; 95%CI: 1.17 to 1.69; P for trend <0.001) and IR (OR: 1.79; 95%CI: 1.49 to 2.14; P for trend <0.001) compared with those in the first tertile of DII score.

CONCLUSIONS

This study indicates that DII was positively associated with FPG, FSI, and HOMA-IR, and a more pro-inflammatory diet was related to increased odds of insulin resistant and prediabetes.

Dietary Inflammatory Index in relation to Type 2 Diabetes: A Meta-Analysis

BACKGROUND AND AIMS

Epidemiologic studies show a strong association between chronic inflammation and type 2 diabetes (T2D). Diet may also affect the risk of T2D by modulating inflammation. This meta-analysis aimed to assess the relation of dietary inflammatory index (DII) and risk of T2D.

METHODS

PubMed and Scopus were systematically searched from their inception to September 2020 to identify relevant studies. Relative risks, hazard ratios, or odds ratios (OR), with their corresponding 95% confidence intervals (95% CI), were calculated and pooled using a random-effects model.

RESULTS

A total of 48 different studies, with a total sample size of 1,687,424 participants, were eligible to be included in this meta-analysis. In the overall analysis, no significant association was observed between DII and risk of T2D (OR = 1.03, 95% CI: 0.91 to 1.15), with significant evidence for heterogeneity (I ²  = 96.5%, P < 0.001); however, higher DII was identified as being significantly related to increased risk of T2D in high quality studies (OR = 1.58, 95% CI: 1.15 to 2.17). In the stratified analysis by the dietary assessment tool, background disease, and sex of participants, DII showed no significant association with T2D.

CONCLUSIONS

Higher DII might be associated with an increased risk of T2D. Additional well-designed studies are required to confirm this finding.

The dietary inflammatory index, obesity, type 2 diabetes, and cardiovascular risk factors and diseases

An unhealthy diet is a recognized risk factor in the pathophysiology of numerous chronic noncommunicable diseases (NCD), including obesity, type 2 diabetes (T2DM), and cardiovascular diseases (CVD). This is, at least in part, due to unhealthy diets causing chronic low-grade inflammation in the gut and systemically. To characterize the inflammatory potential of diet, we developed the Dietary Inflammatory Index (DII®). Following this development, around 500 papers have been published, which examined the association between the DII, energy-adjusted DII (E-DII™), and the children's DII (C-DII™) and many chronic NCDs including obesity and cardiometabolic diseases. Although a previous narrative review published in 2019 briefly summarized the evidence in this area, there was a significant increase in papers on this topic since 2020. Therefore, the purpose of this narrative review is to provide an in-depth updated review by including all papers until July 2021 on DII and its relationship with obesity, T2DM, and CVD. Furthermore, we aim to identify potential gaps in the literature and provide future directions for research. Most studies found that DII was associated with an increased risk of obesity, T2DM, and CVD with some relationships being sex-specific. However, we identified the paucity of papers describing associations between dietary inflammation and T2DM and its risk factors. Few studies used gold-standard measures of cardiometabolic risk factors. We also identified the lack of interventional studies designed to change the inflammatory potential of diets and study its effect on cardiometabolic risk factors and diseases. We recommend that such interventional studies are needed to assess if changes in DII, representing the inflammatory potential of diet, independently of changes in body composition can modulate cardiometabolic risk factors and diseases.

Sex Differences in the Associations of Nutrient Patterns with Total and Regional Adiposity: A Study of Middle-Aged Black South African Men and Women

The study evaluated the association between nutrient patterns with body fat and regional adiposity in middle-aged black South African (SA) men and women and determined if this differed by sex. Body fat and regional adiposity (dual-energy x-ray absorptiometry), and dietary intake (7-day quantified food frequency questionnaire) were measured in black SA men (n = 414) and women (n = 346). Using principal component analysis, nutrient patterns were computed from 25 nutrients in the combined sample. Four nutrient patterns were extracted, explaining 67% of the variance in nutrient intake. Animal and fat, as well as the vitamin C, sugar, and potassium driven patterns, were positively associated with total adiposity. In contrast, the retinol and vitamin B12 pattern was associated with the centralisation of fat. Notably, the strength of the association between the animal-driven nutrient pattern and BMI was greater in men (1.14 kg/m², 95% CI (0.63–1.66)) than in women (0.81 kg/m², 95% CI (0.25–1.36)) (P_int = 0.017). In contrast, the plant-driven pattern was associated with higher abdominal subcutaneous adipose tissue (SAT) in women (44 cm², 95% CI (22–67)) but not men (P_int = 1.54 × 10⁻⁴). These differences suggest that although men and women have similar nutrient patterns, their associations with the whole body and regional body fat are different.

Diet scores and prediction of general and abdominal obesity in the Melbourne collaborative cohort study

OBJECTIVE

To ascertain which of the Alternative Healthy Eating Index (AHEI) 2010, Dietary Inflammatory Index (DII®) and Mediterranean Diet Score (MDS) best predicted BMI and waist-to-hip circumference ratio (WHR).

DESIGN

Body size was measured at baseline (1990-1994) and in 2003-2007. Diet was assessed at baseline using a FFQ, along with age, sex, socio-economic status, smoking, alcohol drinking, physical activity and country of birth. Regression coefficients and 95 % CI for the association of baseline dietary scores with follow-up BMI and WHR were generated using multivariable linear regression, adjusting for baseline body size, confounders and energy intake.

SETTING

Population-based cohort in Melbourne, Australia.

PARTICIPANTS

Included were data from 11 030 men and 16 774 women aged 40-69 years at baseline.

RESULTS

Median (IQR) follow-up was 11·6 (10·7-12·8) years. BMI and WHR at follow-up were associated with baseline DII® (Q5 v. Q1 (BMI 0·41, 95 % CI 0·21, 0·61) and WHR 0·009, 95 % CI 0·006, 0·013)) and AHEI (Q5 v. Q1 (BMI -0·51, 95 % CI -0·68, -0·35) and WHR -0·011, 95 % CI -0·013, -0·008)). WHR, but not BMI, at follow-up was associated with baseline MDS (Group 3 most Mediterranean v. G1 (BMI -0·05, 95 % CI -0·23, 0·13) and WHR -0·004, 95 % CI -0·007, -0·001)). Based on Akaike's Information Criterion and Bayesian Information Criterion statistics, AHEI was a stronger predictor of body size than the other diet scores.

CONCLUSIONS

Poor quality or pro-inflammatory diets predicted overall and central obesity. The AHEI may provide the best way to assess the obesogenic potential of diet.

Dietary inflammatory index and its relationship with gut microbiota in individuals with intestinal constipation: a cross-sectional study

OBJECTIVE

To determine whether there is an association between the inflammatory potential of the diet, measured by the dietary inflammatory index (DII®), and the composition of intestinal microbiota in adults with functional constipation (FC).

METHODS

A cross-sectional study was carried out with 68 adults with FC. Energy-adjusted DII (E-DII) was calculated from data obtained from food surveys, serum inflammation markers were measured and the composition of the intestinal microbiota was evaluated using the 16S rRNA gene sequencing method. Participants were assigned into two groups: anti-inflammatory diet (AD: E-DII < 0) and pro-inflammatory diet (PD: E-DII ≥ 0). Associations of E-DII scores with microbial diversity and composition were examined using differences between the E-DII groups and linear and hierarchical regression.

RESULTS

E- DII was inversely correlated with relative abundance of Hungatella spp. and Bacteroides fragilis and positively correlated with Bacteroides thetaiotaomicron and Bacteroides caccae (p < 0.05). B. fragilis was positively correlated with IL-10. The AD group had higher relative abundances for the genus Blautia and Hungatella, lower abundances of Bacteroides thetaiotamicron and Bacteroides spp. (p < 0.05), as well as higher frequency of evacuation (p = 0.02) and lower use of laxatives (p = 0.05). The AD group showed a reduction in the abundance of Desulfovibrio spp. and Butyrivibrio, Butyrivibrio crossotus, Bacteroides clarus, Bacteroides coprophilus and Bacteroides intestinalis (all p < 0.05). The greater abundance of Bacteroides clarus increased the individual's chance of performing a manual evacuation maneuver.

CONCLUSION

Therefore, the results of this study demonstrated that the inflammatory potential of the diet is associated with the gut microbiota in individuals with FC.

The Association Between Dietary Inflammatory Potential and Sex Hormones in Male Children and Adolescents Aged 6-19 Years

Aims

This study aimed to assess the relationship between dietary inflammatory index (DII) and sex hormones in male children and adolescents aged 6-19 years.

Methods

We obtained data from the 2013-2016 National Health and Nutrition Examination Survey (NHANES). Male participants aged 6-19 years old with the complete data of DII and sex hormones were included. Weighted multiple regression analysis and subgroup analysis were preformed to estimate the independent relationship between DII and sex hormones.

Results

A total of 1717 male participants with the average age of 13.02 ± 3.82 years were enrolled, of whom 41.3% (n=713) were children and 58.47% (n=1004) were adolescents. In children, mean DII was 0.18 ± 1.67, with scores ranging from -4.53 to 4.08. As for adolescents, the mean DII was 0.36 ± 1.98, mean total testosterone (TT) was 376.94 ± 206.69 ng/dl overall. A negative association between DII with TT and estradiol (E2) was observed (TT: β=-11.97, P=0.0006; E2: β=-0.45, P=0.0108) in male adolescent. Subgroup analysis and interaction test results indicated that this association was similar in male adolescents with different body mass index. No statistically significant association was observed in children.

Conclusions

Pro-inflammatory diet was associated with lower TT and E2 level in male adolescent, while no association with statistical significance between them was observed in male children. However, more studies are still needed to validate the causal relationship between DII and sex hormones.

Association between Dietary Inflammatory Index and Type 2 diabetes mellitus in Xinjiang Uyghur autonomous region, China

Background

Diet and inflammation have both been studied in relation to type 2 diabetes mellitus (T2DM). The aim of this cross-sectional study was to examine the association between the Dietary Inflammatory Index (DII®) and T2DM.

Methods

Subjects were adults enrolled in the baseline study of the Xinjiang multi-ethnic natural population cohort and health follow-up study from January to May 2019. The study involved 5,105 subjects (58.7% men) between 35 and 74 years of age. The DII score was calculated from a data obtained via a food frequency questionnaire consisting of 127 food items.

Results

Logistic regression analyses were used to estimate the odds ratios (ORs) and 95% confidence intervals (95% CIs) of DII in relation to T2DM. After adjusting for potential confounders, compared to subjects in the 1st DII quintile, subjects in the 5th quintile (i.e., with the most pro-inflammatory diet) had higher odds of T2DM (OR = 3.27, 95%CI:2.38,4.50; p < 0.001).

Conclusions

Our results suggest that a pro-inflammatory diet is associated with a higher risk of T2DM in this population of Chinese adults.

Association between inflammatory potential of the diet and sarcopenia/its components in community-dwelling older Japanese men

PURPOSE

Chronic inflammation is a pathophysiological cause of age-related diseases including sarcopenia. However, limited data are available on the association between the diet-derived inflammation and sarcopenia. Here, using the Dietary Inflammatory Index (DII), we examined the associations between inflammatory potentials of the diet, sarcopenia/its components, and serum inflammatory markers.

MATERIALS AND METHODS

This cross-sectional study was performed in 2014 among 1,254 community-dwelling older adults. Energy-adjusted DII score (E-adjusted DII) was calculated using a self-administered diet history questionnaire. Sarcopenia/its components was determined according to the Asian Working Group for Sarcopenia. Serum interleukin (IL)-1β, IL-4, IL-6, IL-10, tumor necrosis factor (TNF)α, and high-sensitivity C-reactive protein (hsCRP) were measured.

RESULTS

The mean of E-adjusted DII was 0.13±2.1 (-4.92~5.29) in participants (74.6±5.5 y). After adjustment of confounders, men in the highest tertile of the E-adjusted DII showed a 2.89-times (95% CI: 1.04-8.04) higher risk of sarcopenia than those in the lowest tertile. Regarding its components (low muscle mass/strength/function), men in the highest tertile did not have significantly greater odds, respectively. Intriguingly, when the E-adjusted DII was calculated only based on anti-inflammatory food parameters, men who did not consume food with anti-inflammatory properties scored high E-adjusted DII and were significantly associated with sarcopenia in the highest tertile (OR: 2.96; 95% CI: 1.06-8.93). Higher serum hsCRP levels were seen in sarcopenic men with the highest E-adjusted DII (p=0.036).

CONCLUSIONS

These results suggest that a diet with pro-inflammatory potential is associated with the risk of sarcopenia. Further investigations whether anti-inflammatory diet could reduce its risk are needed.

Dietary and lifestyle inflammatory scores and risk of incident diabetes: a prospective cohort among participants of Tehran lipid and glucose study

Background

Inflammation is a precursor of chronic disease, which is affected by lifestyle and dietary habits. Recently empirical dietary inflammatory patterns (EDIP), dietary inflammation scores (DIS), and lifestyle inflammation scores (LIS) were developed to indicate lifestyle and dietary contributions in systemic inflammation. The current study aimed to investigate the associations between these indices and the incidence of diabetes among Tehranian adults.

Methods

A total of 4624 individuals, aged 20–75 years, who were free of diabetes at baseline (2008–2011), were followed for 5.71 years (2014–2017) to ascertain incident diabetes. Dietary intakes were collected at baseline using the food frequency questionnaire. The hazard ratio (HR) of diabetes was calculated by Cox proportional hazards regression across quartiles of EDIP, DIS, and LIS, adjusted for potential confounders.

Results

The mean ± SD for the age and BMI of the study population (45.1% male) were 40.8 ± 12.7 years and 27.1 ± 4.1 Kg.m2, respectively. At the end of the follow-up, 329 (7.1%) diabetes cases were identified. In the multivariable-adjusted model, individuals in the highest compared to the lowest quartile of EDIP (HR = 0.83; 95%CI:0.59–1.15, p for trend = 0.286), and LIS (HR = 2.41; 95%CI:1.61–3.60, P for trend < 0.001) had increased risk of diabetes. However, no significant associations were found between the score of DIS and diabetes incidents (HR = 0.83; 95%CI:0.59–1.15, p for trend = 0.286).

Conclusion

Greater adherence to EDIP and LIS scores was associated with a higher risk of diabetes, while no significant association was found between the DIS score and diabetes incident.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-021-11327-1.

Dietary inflammatory index score, glucose control and cardiovascular risk factors profile in people with type 2 diabetes

We examined the relationships between the dietary inflammatory index (DII^®), dietary habits and cardiovascular risk factor profiles in people with type 2 diabetes mellitus (T2DM). Energy-adjusted DII (E-DII™) scores were calculated from a Food Frequency Questionnaire in 2568 T2DM patients from different parts of Italy. Analyses were conducted according to quartiles of sex-specific E-DII scores. Higher, more pro-inflammatory, (quartile 4) E-DII scores were associated with overall poor quality of the diet characterised by higher content of refined carbohydrates, added sugars, saturated fat and cholesterol and lower unsaturated fat, fibre and polyphenols compared to quartile 1. Higher E-DII scores also were associated with higher waist circumference (105.4 vs. 103.5 cm; p = 0.002), triglycerides (154.6 vs. 146.1 mg/dL; p = 0.005), diastolic blood pressure (80.05 vs. 78.6 mmHg; p = 0.04) and lower HDL-cholesterol (45.3 vs. 47.4 mg/dL; p = 0.04). In conclusion, E-DII is a potent marker of overall quality of the diet and is associated with an unfavourable cardiovascular risk factor profile.

Long-term anti-inflammatory diet in relation to improved breast cancer prognosis: a prospective cohort study

Inflammation-modulating nutrients and inflammatory markers are established cancer risk factors, however, evidence regarding the association between post-diagnosis diet-associated inflammation and breast cancer survival is relatively sparse. We aimed to examine the association between post-diagnosis dietary inflammatory index (DII®) and risks of all-cause and breast cancer-specific mortality. A total of 1064 female breast cancer survivors in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening (PLCO) Trial prospective cohort, were included in this analysis if they had completed the diet history questionnaire (DHQ). Energy-adjusted DII (E-DIITM) scores were calculated based on food and supplement intake. Cox regression and competing risk models were used to estimate multivariable-adjusted hazards ratios (HRs) and 95% confidence intervals (95% CIs) by E-DII tertile (T) for all-cause and breast cancer-specific mortality. With median follow-up of 14.6 years, there were 296 (27.8%) deaths from all causes and 100 (9.4%) breast cancer-specific death. The E-DII was associated with all-cause mortality (HR T3 vs T1, 1.34; 95% CI, 1.01-1.81; P trend, 0.049, Table 2) and breast cancer mortality (HR T3 vs T1, 1.47; 95% CI, 0.89-2.43; P trend, 0.13; multivariable-adjusted HR for 1-unit increment: 1.10; 95% CI: 1.00-1.22). Non-linear positive dose-response associations with mortality from all causes were identified for E-DII scores (P non-linearity < 0.05). The post-diagnosis E-DII was statistically significantly associated with mortality risk among breast cancer survivors. Long-term anti-inflammatory diet might be a means of improving survival of breast cancer survivors.

Diet Quality Is Associated with Cardiometabolic Outcomes in Survivors of Childhood Leukemia

There is little information about how diet influences the health of childhood acute lymphoblastic leukemia (cALL) survivors. This study explores the associations between diet quality indices, cardiometabolic health indicators and inflammatory biomarkers among cALL survivors. Participants were part of the PETALE study (n = 241, median age: 21.7 years). Adherence to 6 dietary scores and caloric intake from ultra-processed foods were calculated. Multivariate logistirac regressions, Student t-tests and Mann-Whitney tests were performed. We found that 88% of adults and 46% of children adhered poorly to the Mediterranean diet, 36.9% had poor adherence to the World Health Organisation (WHO) recommendations and 76.3% had a diet to be improved according to the HEI-2015 score. On average, ultra-processed foods accounted for 51% of total energy intake. Low HDL-C was associated with a more inflammatory diet (E-DIITM score) and higher intake of ultra-processed foods. A greater E-DII score was associated with elevated insulin resistance (HOMA-IR), and consumption of ultra-processed foods was correlated with high triglycerides. Circulating levels of TNF-α, adiponectin and IL-6 were influenced by diet quality indices, while CRP and leptin were not. In conclusion, survivors of cALL have poor adherence to dietary recommendations, adversely affecting their cardiometabolic health.

Dietary inflammatory potential, cardiometabolic risk and inflammation in children and adolescents: a systematic review

The Dietary Inflammatory Index (DII^®) is a tool developed for quantifying the dietary inflammatory potential of individuals' diets, with the goal of assessing the effect of diet-associated inflammation on health outcomes. With most studies focusing on adults, little is known about the consequences for health of a more proinflammatory diet early in life. Hence, this study analyzed the available evidence on the association between the DII or the children's C-DII (C-DII^TM) and cardiometabolic risk and inflammatory biomarkers in children and adolescents. This systematic review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The search was performed at the LILACS, ScienceDirect, Cochrane and PubMed databases, without any restriction regarding the dates of the publications. A total of six observational studies qualified; including three cross-sectional and three longitudinal studies focused on children and adolescents between 3 and 18 years of age representing both sexes. All papers found a positive association between the DII or C-DII with cardiometabolic markers. These included adiposity (i.e., BMI, waist and hip circumference, waist-to-height ratio and fat mass index), and/or to inflammatory biomarkers (interleukins 1, 2 and 6, tumor necrosis factor-alpha, interferon gamma, and soluble vascular cell adhesion molecule-1). In conclusion, findings currently available in the literature indicate that a proinflammatory diet is associated with a higher risk of early development of cardiometabolic and inflammatory changes during childhood. Also, the findings show the applicability of the DII and C-DII in epidemiological studies and underscore the need for strategies to encourage healthy, anti-inflammatory diets to prevent chronical illnesses. Systematic Review Registration Number (PROSPERO: CRD42019123939).

The association between dietary inflammatory index and risk of central obesity in adults: An updated systematic review and meta-analysis

Backgrounds: Central obesity, as a pivotal component of metabolic syndrome is associated with numerous co-morbidities. Dietary factors influence central obesity by increased inflammatory status. However, recent studies didn't evaluate the association between central obesity and dietary inflammation index (DII^®) that give score to dietary factors according to their inflammatory potential. In the current systematic review and meta-analysis, we summarized the studies that investigated the association between DII^® with central obesity indices in the general populations. Methods: In a systematic search from PubMed, SCOPUS, Web of Sciences and Cochrane electronic databases, we collected relevant studies written in English and published until 30 October 2019. The population of included studies were apparently healthy subjects or individuals with obesity or obesity-related diseases. Observational studies that evaluated the association between DII^® and indices of central obesity including WC or WHR were included. Results: Totally thirty-two studies were included; thirty studies were cross-sectional and two were cohort studies with 103071 participants. Meta-analysis of observational studies showed that higher DII^® scores were associated with 1.81 cm increase in WC (Pooled weighted mean difference (WMD) = 1.813; CI: 0.785-2.841; p = 0.001). Also, a non-significant increase in the odds of having higher WC (OR = 1.162; CI: 0.95-1.43; p = 0.154) in the highest DII category was also observed. In subgroup analysis, the continent, dietary assessment tool and gender were the heterogeneity sources. Conclusion: The findings proposed that adherence to diets with high DII^® scores was associated with increased WC. Further studies with interventional designs are necessary to elucidate the causality inference between DII^® and central obesity indices.

Dietary anti-inflammatory index, metabolic syndrome and transition in metabolic status; a gender-specific analysis of ATTICA prospective study

AIMS

To examine the association between dietary anti-inflammatory index (D-AII) and metabolic syndrome (MetS)prevalence, 10-year (2002-2012) diabetes, hypertension, hypercholesterolaemia incidence and 10-year transition from healthy (absence of all MetS traits, excluding waist circumference) to unhealthy metabolic status.

METHODS

In 2001-2002, n = 1514 men and n = 1528 women (>18 years old) in Athens, Greece, free of cardiovascular disease were recruited. MetS was defined according to the revised NCEP ATP III (2005) or the IDF criteria or the harmonized criteria. The validated D-AII was calculated using a standardized procedure (range 10-77).

RESULTS

Inverse associations were observed between D-AII and transition from healthy to unhealthy metabolic status (Odds Ratio (OR)_{3rd vs. 1st tertile} = 0.88 95% Confidence Interval (95%CI)(0.73, 0.98)) and diabetes (OR_{3rd vs. 1st tertile} = 0.55, 95%CI(0.29, 0.77)). In women, D-AII was inversely associated with transition from healthy to unhealthy metabolic status (OR_{3rd vs. 1st tertile} = 0.55, 95%CI(0.26, 0.90), diabetes (OR_{3rd vs. 1st tertile} = 0.41, 95%CI(0.18, 0.64) and hypertension (OR_{3rd vs. 1st tertile} = 0.75, 95%CI(0.20, 0.95), yet only with diabetes incidence in men (OR_{3rd vs. 1st tertile} = 0.62, 95%CI(0.38, 0.93).

CONCLUSIONS

Diet with high anti-inflammatory load seems an effective preventive measure to retain a metabolically benign status, principally in terms of glycemic control.