There is a lack of information from Middle Eastern countries regarding diet–disease associations. We examined dietary glycaemic and insulinemic potential in relation to risk of incident diabetes among a large group of Iranian adults. The present study was carried out using data from Yazd Health Study-Taghzieh Mardom Yazd, a prospective cohort study on adults aged 20–70 years in Yazd Greater Area, Iran. This study was initiated in 2014–2016 (baseline examination), and data are collected prospectively at one 5-year intervals. Data on demographic characteristics, dietary intakes and potential confounders were gathered by interview. During the follow-up phase of the study, diabetes incidence was confirmed by laboratory tests and physician diagnoses. This study included a total of 6178 participants in the cross-sectional analysis and 5105 subjects in the prospective phase. Examining the cross-sectional phase, we failed to find any significant association between dietary glycaemic index (GI) and glycaemic load (GL) as well as dietary insulin index (DII) or dietary insulin load (DIL) and prevalence of diabetes. No significant relationship was also seen between DII/DIL and risk of T2DM in the prospective phase; however, in the stratified analysis by BMI status, there was an inverse significant association between DII and risk of type 2 diabetes mellitus (hazard ratio for T3 v. T1: 0·19; 95 % CI: 0·04, 0·92; P = 0·03) in non-obese (BMI ≥ 25 kg/m2) and overweight (BMI < 25 kg/m2) participants. No significant association was found between dietary GI/ dietary GL/ DII/ or DIL with risk of T2DM. More research, particularly with a longer follow-up duration, is needed to confirm these findings.

Ulcerative colitis (UC) is a chronic inflammatory disease involving the colon and rectum. One of the most modifiable environmental factors affecting UC severity is the patient’s dietary pattern. Although the role of dietary patterns on UC aetiology has been investigated previously, its relationship with disease severity has not yet been elucidated. This study examined the association between UC patients’ dietary patterns and disease severity. This cross-sectional study was conducted in 340 UC patients. Using an FFQ, food patterns were assessed. Twenty-five food categories were categorised based on the similarity of the nutrient composition of the food using the factor analysis method. A simple clinical colitis activity index was used to determine disease severity. Three dietary patterns were identified based on the factor analysis: healthy, unhealthy and Western dietary pattern. After adjusting for potential confounding factors, patients who were in the highest tertile of healthy dietary pattern compared with the lowest tertile were 92 % less likely to have severe UC (OR: 0·08; 95 % CI: 0·03, 0·22). Also, those in the highest tertile of the Western dietary pattern were 3·86 times more likely to have severe UC than those in the lowest tertile (OR: 3·86; 95 % CI: 1·86, 8·00). Even after controlling for confounding variables, unhealthy dietary pattern did not increase the risk of severe UC. Our data indicate the beneficial role of healthy dietary pattern in amelioration of disease severity in UC patients. To confirm this association, more studies are needed, especially prospective cohort studies.

Findings on the effect of walnut consumption on cardiometabolic profiles in individuals with abnormal glucose homoeostasis are conflicting. We summarised earlier data in this regard. A systematic literature search of relevant reports published in Medline/PubMed, ISI web of Science, EMBASE, SCOPUS and Google Scholar up to October 2020 was conducted. Randomised trials that enrolled individuals with abnormal glucose homoeostasis in which the main intervention was walnut consumption were included. Abnormal glucose homoeostasis was defined as a spectrum of impaired glucose tolerance or pre-diabetic status that is associated with insulin resistance. Twelve studies were included in systematic review and eight in meta-analysis. No significant effect of walnut consumption on anthropometric measures, including weighted mean difference (WMD: −0·13; 95 % CI −0·64, 0·39 kg), BMI (–0·08; 95 % CI −0·47, 0·32 kg/m2) and waist circumference (0·01; 95 % CI −0·50, 0·52 cm) was observed. Although walnut intake did not influence on lipid profiles (including TAG, total- and HDL-cholesterol levels), individuals in the intervention group tended to have lower levels of LDL-cholesterol than those in the control group (–0·10; 95 % CI −0·20, 0·01 mmol/l; P = 0·06). Other cardiometabolic factors including markers of glycaemic control (fasting blood glucose and HbA1C levels), blood pressure and stimulus-adjusted response measure (a parameter of endothelial function) were not significantly affected. However, walnut consumption resulted in a significant increase in flow-mediated dilation (FMD) (0·93 %; 95 % CI 0·16, 1·71 %). Summarising earlier evidence, we found that walnut consumption might influence FMD and LDL-cholesterol levels in individuals with abnormal glucose homoeostasis. It did not affect other cardiometabolic profiles in these individuals.

Previous investigations have mostly studied an individual methyl donor nutrient in relation to psychological disorders and the findings were inconsistent. We investigated the association of methyl donor micronutrients (folate, B6, B12, choline, betaine and methionine) with psychological disorders in Iranian adults. In this cross-sectional study, dietary intakes of 3299 adults were collected using a validated food frequency questionnaire. Methyl donor micronutrient score (MDMS) was calculated based on energy-adjusted deciles of each nutrient. Hospital Anxiety and Depression Scale (HADS) and General Health Questionnaire (GHQ), validated for Iranians, have been applied to assess depression, anxiety and psychological distress. Participants had a mean age of 36·3 ± 7·9 years, of whom 58·5 % were women. After considering potential confounders, adults in the top quartile of MDMS, compared to the bottom one, had decreased odds of anxiety (OR: 0·53, 95 % CI: 0·37, 0·75), depression (OR: 0·75, 95 % CI: 0·58, 0·97) and psychological distress (OR: 0·61, 95 % CI: 0·46, 0·80). Among women, the top quartile of MDMS was protectively associated with anxiety (OR: 0·60, 95 % CI: 0·40, 0·90), depression (OR: 0·68, 95 % CI: 0·50, 0·93) and psychological distress (OR: 0·53, 95 % CI: 0·38, 0·74). Overweight and obese subjects in the highest quartile of MDMS had a 67 %, 35 % and 53 % lower odds of anxiety (95 % CI: 0·20, 0·56), depression (95 % CI: 0·44, 0·94) and psychological distress (95 % CI: 0·31, 0·70), respectively. We found that high consumption of methyl donor micronutrients was related to a reduced odds of psychological disorders, especially in women and overweight or obese individuals.

The authors investigate the association of breakfast skipping and its interaction with a dietary inflammatory index (DII) with the severity of psychological disorders. A total of 2876 Iranian general adults were enrolled in this cross-sectional study. Psychological problems profile score was calculated using the regression method in the framework of factor analysis based on depression, anxiety and psychological distress. The higher scores indicate more severity of mental problem. The frequency of breakfast eating in a week was assessed. Dietary intakes were assessed using a food-frequency questionnaire and twenty-seven items were included in the calculation of DII. In the crude model, individuals who ate breakfast seldom had the highest odds for having worse psychological problems profile (OR 3⋅59; 95 % CI 2⋅52, 5⋅11). Adjustment for various confounders did not change the associations (OR 3⋅35; 95 % CI 2⋅11, 5⋅32). In the adjusted multinomial logistic regression model, participants with high DII (>median) who skipped breakfast had highest risk of being in the higher tertiles of psychological problems profile compared with those who had low DII (<median) and ate breakfast (OR 6⋅67; 95 % CI 3⋅45, 12⋅90). Similar results were observed in women and men regarding the impact of breakfast skipping alone and interaction with DII on scores of psychological problems profile. Breakfast skipping is associated with higher risk of psychological problems. Similar findings were obtained in the stratified analysis by sex. Our findings confirmed that the DII and breakfast skipping are associated with mental health, interactionally. Further longitudinal studies are needed to confirm the true link between breakfast skipping and psychological problems.

Whole-grain foods have been reported to affect body weight and satiety. However, we are aware of no study in this regard among children. The present study aimed to determine the effects of whole grain consumption on anthropometric measures in overweight or obese children. In this randomised crossover clinical trial, forty-four overweight or obese girls participated. After a 2-week run-in period, subjects were randomly assigned to either intervention (n 44) or non-intervention (n 44) groups. Subjects in the intervention group were given a list of whole-grain foods and were asked to obtain half of their grain servings from these foods each day for 6 weeks. Individuals in the non-intervention group were asked not to consume any of these foods. A 4-week washout period was applied. Then, participants were crossed over to the alternate arm. The measurements were done before and after each phase. Mean age, weight and BMI of participants were 11·2 (sd 1·49) years, 51·2 (sd 10·2) kg and 23·5 (sd 2·5) kg/m2, respectively. Despite the slight reduction in weight and BMI, there were no significant differences in changes in these anthropometric measures. We found a significant effect of whole grain intake on waist circumference (−2·7 v. 0·3 cm, P = 0·04). No significant changes in hip circumference were observed. Changes in the prevalence of overweight, obesity and abdominal obesity were not significantly different. This study indicated a beneficial effect of whole-grain foods on waist circumference in overweight children; however, these foods did not influence weight and BMI.

This systematic review and meta-analysis was done to review earlier publications on the association between dietary acrylamide intake and risk of breast, endometrial and ovarian cancers. We performed a systematic search in the online databases of PubMed, ISI Web of Science and Scopus for relevant publications up to August 2020. Prospective cohort studies that considered dietary acrylamide as the exposure variable and breast, endometrial or ovarian cancer as the main outcome variable or as one of the outcome variables were included in this systematic review and meta-analysis. A total of fourteen cohort studies were included in the meta-analysis. We found no significant association between dietary acrylamide intake and the risk of breast (relative risk (RR) 0·95; 95 % CI 0·90, 1·01), endometrial (RR 1·03; 95 % CI 0·89, 1·19) and ovarian cancers (RR 1·02; 95 % CI 0·84, 1·24). In addition, we observed no significant association between dietary acrylamide intake and the risk of breast, endometrial and ovarian cancers in different subgroup analyses by smoking status, menopausal status, BMI status and different types of breast cancer. In conclusion, no significant association was found between dietary acrylamide intake and the risk of breast, endometrial and ovarian cancers.

Data on the effect of grape seed extract (GSE) on lipid profiles are inconclusive. We undertook a systematic review and meta-analysis of randomised controlled clinical trials on the effect of GSE on serum lipid profiles. The online databases of PubMed, ISI Web of Science, Scopus, ProQuest, Science Direct and Embase were searched for relevant publications until March 2019, using MeSH and non-MeSH keywords. Study selection, data extraction and quality assessment were completed independently by two investigators. Meta-regression and subgroup analyses were performed to identify the source of heterogeneity. Assessment of study quality was conducted using the Jadad scale. Eleven randomised clinical trials involving 536 participants were included in the present meta-analysis. Combining effect sizes from earlier studies, we found that GSE supplementation significantly decreased serum levels of LDL-cholesterol (−0·17 mmol/l; 95 % CI −0·34, −0·01) and TAG (−0·11 mmol/l; 95 % CI −0·18, −0·05). Although no overall significant effect of GSE supplementation on circulating total- and HDL-cholesterol levels was observed, there were significant reductions in these lipids in studies with <10 weeks of intervention and those that had administered the dosages of <300 mg/d of GSE. In conclusion, GSE supplementation seems to favourably affect serum levels of LDL and TAG concentrations, but it did not affect total- and HDL-cholesterol concentrations.

Little information is known about the influence of altitude on child growth in Ethiopia, where most people live in highlands. We investigated the relation of residential altitude with growth faltering (stunting) of infants and young children in Ethiopia. We also examined whether the altitude–growth relationship was independent of the influence of the dietary and non-dietary determinants of growth. We used the data of 26 976 under-5-year-old children included in the Ethiopian Demographic and Health Surveys, conducted from 2005 to 2016. The samples were recruited following a two-stage cluster sampling strategy. Stunting was defined by height-for-age <−2 z-scores. The relationship between residential altitude and stunting was examined by running multiple logistic regression analysis, controlling the effect of covariate dietary and non-dietary variables. The residential altitude of the study participants ranged from −116 to 4500 m above sea level (masl). There was a significant and progressive increase in the prevalence and odds of stunting with increasing altitude (P < 0·001), irrespective of the dietary and non-dietary predictors of stunting. The prevalence of stunting was lowest in lowlands (39 %) and highest in highlands (47 %). Compared with altitude <1000 masl, the odds of stunting was 1·41 times higher at altitude ≥2500 masl (OR 1·41, 95 % CI 1·16, 1·71) and 1·29 times higher at altitude 2000–2499 masl (OR 1·29, 95 % CI 1·11, 1·49). Children living in highlands might be at a higher risk of poor growth. Further studies are warranted to understand the mechanism behind the observed altitude–stunting link and identify strategies to compensate for the growth-faltering effect of living in highlands.

The present study was carried out to determine whether the dietary insulin index (DII) and dietary insulin load (DIL) are related to psychological disorders in a cross-sectional study among adults. A total of 3172 Iranian adults (age range of 18–55 years) were included. Data on dietary intakes were collected using a validated dish-based 106-item semi-quantitative FFQ. DII and DIL were calculated using food insulin index values published earlier. To assess depression and anxiety, an Iranian validated version of the Hospital Anxiety and Depression Scale was used. Furthermore, psychological distress was examined using the General Health Questionnaire. Among women, a significant positive association was seen; such that women in the highest quartile of DIL had higher odds of depression than those in the lowest quartile (OR 1·84; 95 % CI 1·14, 2·96). In terms of DII, in the fully adjusted model, women in the top quartile of DII were more likely to be depressed compared with those in the bottom quartile (OR 1·65; 95 % CI 1·05, 2·58). In conclusion, we found a significant positive association between DIL and DII and odds of depression among women, but not in men. However, such findings were not seen for anxiety and psychological distress.

No study is available that has assessed the association of dietary diversity score (DDS) and alternative healthy eating index (AHEI) with glioma. The present study aimed to assess this association in Iranian adults. Overall, 128 pathologically confirmed cases of glioma were enrolled from hospitals and 256 age- and sex-matched controls were recruited from other wards of the hospital between 2009 and 2011. Dietary assessment was done using a validated block-format 123-item semi-quantitative FFQ. Dietary indices including DDS and AHEI-2010 were constructed according to standard methods. After controlling for potential confounders, a significant inverse association was found between DDS and risk of glioma (OR 0·42, 95 % CI 0·19, 0·94). Such finding was also seen when further adjustment was made for BMI; such that participants in the highest quartile of DDS were 56 % less likely to have glioma compared with those in the lowest quartile (OR 0·44, 95 % CI, 0·20, 0·97). In addition, a significant inverse association was found between adherence to AHEI and glioma; such that in the fully adjusted model, participants in the fourth quartile of AHEI had 74 % lower risk of glioma compared with those in the first quartile (OR 0·26, 95 % CI 0·12, 0·56). In conclusion, we found that greater adherence to the healthy, as measured by AHEI, and diverse, as measured by DDS, diets was associated with decreased odds of glioma.