Dietary intake of methyl donor nutrients in relation to metabolic health status, serum levels of brain-derived neurotrophic factor and adropin.

BACKGROUND AND AIMS: There is a lack of evidence on dietary intake of methyl donor nutrients with metabolic health status and related biomarkers. Thus, this study aimed to assess the relation between methyl donor nutrients intake and metabolic health status with regarding the interactive roles of brain-derived neurotrophic factor (BDNF) and adropin in Iranian adults. METHODS: This cross-sectional survey was conducted among 527 Iranian adults (45.7% female) selected by multistage cluster random-sampling method. A validated food frequency questionnaire was used to evaluate participants' dietary intake. Metabolic unhealthy status was defined by Wildman criteria as having ≥ 2 of hyperglycemia, hypertriglyceridemia, hypo-HDL-cholesterolemia, hypertension, chronic inflammation, and insulin resistance. Concentrations of metabolic parameters, BDNF and adropin were determined using fasting blood samples. RESULTS: An inverse association was found between methyl donor nutrients intake and metabolically unhealthy status in multivariable-adjusted model (ORT3 vs. T1 = 0.30; 95%CI: 0.12-0.75). This association was especially significant among overweight/obese adults and was stronger in women. Additionally, consumption of vitamin B6 and choline was separately related to reduced odds of metabolically unhealthy status. Methyl donor intake was not significantly related to low BDNF (ORT3 vs. T1 = 0.93; 95%CI: 0.60-1.44) and adropin (ORT3 vs. T1 = 0.71; 95%CI: 0.44-1.15). However, the interaction between high methyl donor nutrients intake and high BDNF was related to lower odds of metabolically unhealthy status in multivariable-adjusted model (ORMDNS∗BDNF = 0.27; 95%CI: 0.11-0.67). CONCLUSION: Higher intake of methyl donor nutrients, alone and in interaction with BDNF levels, was associated with decreased odds of metabolically unhealthy status in Iranian adults.

Dietary Phytochemical Index in Relation to Metabolic Health Status, Serum Adropin, and Brain-Derived Neurotrophic Factor Levels in Adults.

Background: Little is known about the relationship between dietary intake of phytochemicals with metabolic health status and underlying mechanisms. Objectives: Little is known about the relationship between dietary intake of phytochemicals with metabolic health status and underlying mechanisms. We hypothesized that dietary phytochemical index (DPI) improves metabolic health status by ameliorating serum concentrations of brain-derived neurotrophic factor (BDNF) and adropin. Methods: A cross-sectional study was performed in 527 adults (286 males and 241 females). The dietary intakes of participants were collected by a 168-item food frequency questionnaire, and DPI was estimated as a percentage of energy intake derived from phytochemical-rich foods. Anthropometric variables, blood pressure, glycemic and lipid profiles, and biochemical variables were assessed. The metabolically unhealthy (MU) phenotype was determined based on the definition presented by Wildman et al. Results: The MU phenotype was identified in 51.4% of male and 32.0% of female participants. Participants in the third tertile of DPI had 59% lower odds of MU than those in the first tertile (OR: 0.41; 95% CI: 0.19, 0.87) after considering potential confounders. Stratified analysis by sex and body mass index indicated that DPI was inversely related to MU phenotype in females (OR: 0.28; 95% CI: 0.08, 0.97) and normal-weight individuals (OR: 0.11; 95% CI: 0.02, 0.62). DPI was also inversely associated with hyperglycemia, hypertriglyceridemia, and chronic inflammation. Nonsignificant reduced odds of low BDNF (OR: 0.87; 95% CI: 0.42, 1.84) and adropin (OR: 0.75; 95% CI: 0.31, 1.79) were observed in individuals in the top tertile of DPI compared with those in the bottom tertile. Conclusions: This study showed that individuals with higher dietary intake of phytochemicals had lower odds of MU, particularly females and normal-weight individuals. No significant relationship was observed between serum BDNF and adropin with phytochemical intake.

Nutrient patterns in relation to metabolic health status and serum levels of brain-derived neurotrophic factor (BDNF) and adropin in adults.

The present study aimed to investigate the association of nutrient patterns (NPs) with metabolic health status and serum levels of brain-derived neurotrophic factor (BDNF) and adropin in Iranian adults. This cross-sectional survey was performed on 527 adults aged 20-60 years in Isfahan, Iran. To evaluate dietary intake, a validated 168-item semi-quantitative food frequency questionnaire (FFQ) was used. Participants were categorized as metabolically healthy (MH) and metabolically unhealthy (MU) according to their glycemic and lipid profile, insulin resistance (IR), and inflammation status. An overnight fasting blood sample was collected from each participant and serum levels of BDNF and adropin were assessed. A total of 42.50% of participants were recognized as MU. Three NPs were recognized by factor analysis that labeled as "high animal protein" (NP1), "high vegetable" (NP2), and "high carbohydrate" (NP3) patterns. Moderate adherence to NP2 was related to a lower risk of MU (ORT2 vs. T1 = 0.38, 95% CI: 0.18-0.76). Moreover, high adherence of NP2 (T3 vs. T1) was inversely associated with hypertriglyceridemia (OR = 0.27, 95% CI: 0.11-0.65; P-trend < 0.001) and high hs-CRP values (OR = 0.29, 95% CI: 0.09-1.00; P-trend = 0.03). No significant association was observed between adherence of NP1 and NP3 with MU in crude and adjusted models. However, negative associations were found between moderate adherence to NP3 and insulin resistance (IR) (OR = 0.23, 95% CI: 0.06-0.91) as well as high adherence to NP1 and hypertension (OR = 0.23, 95% CI: 0.09-0.61; P-trend < 0.001). NPs were not associated with serum BDNF and adropin values.

Adherence to Mediterranean-Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay Diet in Relation to Serum Brain-Derived Neurotrophic Factor Concentrations and Metabolic Health Status in Adults.

Background: There is a lack of data regarding the Mediterranean-Dietary Approaches to Stop Hypertension Intervention for Neurodegenerative Delay (MIND) diet and metabolic health. Objectives: This study assessed the relation between MIND diet and metabolic health status relative to serum brain-derived neurotrophic factor (BDNF) concentrations. Methods: This was a cross-sectional study of 527 adults (286 males and 241 females) recruited from 20 schools in 6 different educational districts of Isfahan, Iran. Dietary intakes of participants were collected by a validated 168-item food frequency questionnaire, and MIND diet score was estimated. Anthropometric indices, blood pressure, biochemical parameters, and BDNF concentrations were assessed for all participants. The metabolically unhealthy (MU) phenotype was determined based on blood pressure, glycemic and lipid profiles, chronic inflammation, and insulin resistance. Results: The frequency of MU phenotype among obese/overweight and normal-weight individuals was 79.5 % and 20.5 %, respectively. After adjustment for confounders, individuals in the top tertile of the MIND diet scores had 58 % lower odds of having the MU phenotype than individuals in the bottom tertile (odds ratios [ORs]: 0.42; 95 % confidence interval [CI]: 0.20, 0.90). In the fully adjusted model, females and normal-weight individuals had 81 % (OR: 0.19; 95 % CI: 0.04, 0.83) and 89 % (OR: 0.11; 95 % CI: 0.02, 0.69) lower chance of developing the MU phenotype, respectively. In addition, significant inverse associations between adherence to the MIND diet and high-blood pressure and hypertriglyceridemia were found. No significant association was found between adherence to MIND diet and odds of low BDNF concentrations. Conclusions: Adherence to MIND diet is inversely associated with odds of MU phenotype, especially among women and normal-weight individuals. BDNF concentration is not associated with MIND diet and MU status.

Diet in relation to Metabolic, sleep and psychological health Status (DiMetS): protocol for a cross-sectional study.

INTRODUCTION: Metabolic disturbances are of major health concerns in the world. In addition to their high prevalence, these disorders have substantial roles in developing other physical and mental diseases. Diet could have a considerable influence on managing the progression of these conditions and their consequent health-related effects. The aim of the 'Diet in relation to Metabolic, sleep and psychological health Status' Project is to explore the association of nutrition with metabolic, sleep and mental health, considering potential mediators including brain-derived neurotrophic factor (BDNF) and adropin. METHODS AND ANALYSIS: This cross-sectional study will be conducted on adults (20-65 years) working in schools of Isfahan, Iran. A multistage cluster random sampling method will be used to select participants. Anthropometric, body composition and biochemical values including fasting blood glucose, lipid profile, 25-hydroxy vitamin D, insulin, BDNF, adropin, malondialdehyde, superoxide dismutase, glutathione peroxidase, uric acid, creatinine and C reactive protein will be measured for each participant. National Cholesterol Education Program and Adult Treatment Panel III will be considered to define metabolic syndrome. Diet will be assessed through a validated Food Frequency Questionnaire. Furthermore, sleep status, mental health, quality of life, physical activity and demographic status of individuals will be assessed by validated questionnaires. The collected data will be analysed using appropriate statistical methods. ETHICS AND DISSEMINATION: The study protocol was approved by the local Ethics Committee of Isfahan University of Medical Sciences. All participants will provide written informed consent. Dissemination will be through conference presentations and publications in peer-reviewed journals.

Metabolic health status and renal disorders: a cross-sectional study.

Previous surveys suggests that body mass index (BMI) may be positively related to development of chronic kidney disease (CKD). However, this association might be altered by metabolic syndrome. Therefore, we aimed to evaluate the association of metabolic health status with CKD. The present cross-sectional study was carried out on 3322 representative sample of Iranian adults. Metabolic syndrome was identified based on the National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) and BMI was assessed by anthropometric measurements. Estimated glomerular filtration rate (eGFR) was calculated by modification of diet in renal disease-Chronic Kidney Disease Epidemiology Collaboration (MDRD-EPI) formula. Subjects were categorized into four phenotypes: metabolically healthy normal weight (MHNW), metabolically healthy overweight and obesity (MHO), metabolically unhealthy normal weight (MUHNW), and metabolically unhealthy overweight and obesity (MUHO). Based on multivariate-adjusted models, the risk of CKD was significantly higher in MUHO compared with MHNW (OR: 1.48; p < 0.05). Although MUHNW and MUHO were associated with lower eGFR and albuminuria, the significant association was not observed in case of hematuria. Furthermore, subjects with kidney stones tended to be in MHO (OR: 1.42; p < 0.05) and MUHO phenotypes (OR: 1.64; p < 0.05), in comparison to the MHNW phenotype. The odds of kidney disorders were higher in adults with metabolic syndrome, regardless of BMI. However, this relationship might be strengthened by the concomitance of metabolic syndrome and obesity. To verify our findings, clarify the causality, and elucidate the underlying mechanisms, further research are warranted.

Association between dietary insulin index and load with brain derived neurotrophic factor, adropin and metabolic health status in Iranian adults.

The associations of high potential insulinogenic foods with metabolic health (MH) status and brain-derived neurotrophic factor (BDNF) and adropin were not investigated quite enough. We examined the relationship between dietary insulin load (DIL) and dietary insulin index (DII) with MH and serum levels of BDNF and adropin among Iranian adults. This cross-sectional investigation accomplished among 527 Iranian middle-aged adults (54.3% men). Dietary information was obtained by a validated food frequency questionnaire. Anthropometric indices and blood pressure were assessed. For measuring lipid and glycemic profile and serum levels of BDNF and adropin, blood samples were assembled after 12 h of fasting. MH was defined based on lipid and glycemic profile, high blood pressure, insulin resistance and chronic inflammation. After adjustments all confounders, participants in the highest tertile of DII compared to the lowest one had a 115% increased odds for metabolic unhealthy (MU) profile (ORT3 vs. T1 = 2.15, 95% CI 1.03-4.49). However, DIL was not related to MU. Higher DII was additionally associated with high blood pressure, in maximally-adjusted model (ORT3 vs. T1 = 3.57, 95% CI 1.61-7.92). Moreover, moderate DIL was significantly associated with hypertriglyceridemia (ORT2 vs. T1 = 2.56, 95% CI 1.01-6.45). Each tertile increase in DII or DIL was not significantly associated with serum BDNF or adropin values. Greater DII was associated with higher chance of MU and hypertension in Iranian adults; but no association was found between DIL and metabolic health. DIL or DII was not related to circulating BDNF or adropin. To confirm these findings, additional prospective investigations are required.

An Unhealthy Plant-Based Diet Increases Risk of Hypertension but not Framingham Risk Score in Adults.

Backgrounds: We investigated the relation of plant-based diets (PDs) with hypertension (HTN) and Framingham risk score (FRS) in Iranian adults. Objectives: We hypothesized that healthy PDs might have positive effects on blood pressure (BP) and FRS, whereas less-healthy plant-based foods might have negative effects. Methods: The current cross-sectional study was performed on 527 middle-aged adults (45.7% women), who were selected through a multistage cluster random-sampling method. The assessment of dietary intakes was performed by using a validated food-frequency questionnaire. Twelve-hour fasting blood samples were collected to evaluate total cholesterol and high-density lipoprotein concentrations. BP was measured through the standard method and HTN was defined as BP ≥130/80 mmHg. FRS was used to predict the 10-y risk for development of cardiovascular disease (CVD). Results: The prevalence of HTN and high FRS among study participants were, respectively, 62% and 15.6%. After adjustment for potential confounders, plant-based diet index (PDI) and healthy plant-based diet index (hPDI) were not significantly associated with HTN [odds ratio (OR): 0.99; 95% confidence interval (CI): 0.55, 1.79 and OR: 0.83; 95% CI: 0.45, 1.53, respectively)]. However, those in the highest tertile of unhealthy plant-based diet index (uPDI) in comparison with those in the bottom tertile had a 100% increased odds of HTN (OR: 2.00; 95% CI: 1.04, 3.88). Greater adherence to PDI, hPDI, and uPDI was not related to high FRS chance, in fully adjusted model (OR: 0.50; 95% CI: 0.15, 1.65; OR: 1.03; 95% CI: 0.26, 4.04; and OR: 2.05; 95% CI: 0.56, 7.52, respectively). Conclusions: This study demonstrated that less-healthy PDs would enhance the chance of HTN in Iranian adults, although PDIs were not significantly related to the 10-y risk of developing CVD.

Legumes and nuts intake in relation to metabolic health status, serum brain derived neurotrophic factor and adropin levels in adults.

There is controversial evidence about the relationship between consumption of legumes and nuts with metabolic disturbances. The present study was undertaken to explore the association of legumes and nuts intake with metabolic health status among Iranian adults. This cross-sectional study was conducted on 527 adults (45.7% female, aged 20-65 years) chosen through a multistage cluster random-sampling approach. Dietary intakes of individuals were assessed using a validated food frequency questionnaire. Fasting blood samples were gathered to evaluate biochemical parameters. Metabolic health status of subjects was determined according to the criteria defined by Wildman. Data of covariates were collected using pre-tested procedures. The overall prevalence of metabolic unhealthy (MU) phenotype was 42.5%. After controlling all confounders, participants with highest intake of legumes and nuts had lower odds of MU status, compared with the lowest intake (OR 0.35; 95% CI 0.18-0.71). This association was stronger in normal-weight rather than overweight/obese adults and also in women rather than men. Higher consumption of legumes and nuts was additionally related to decreased odds of hyperglycemia, hypertriglyceridemia, and hypertension. A marginally inverse association was observed between legumes and nuts intake with low brain-derived neurotrophic factor (BDNF) levels, in fully-adjusted model (ORT3 vs. T1 0.50; 95% CI 0.25-1.01). Each tertile increase in legumes and nuts intake was marginally related to higher adropin levels ([Formula: see text] = 4.06; P = 0.07). In conclusion, this study demonstrated that higher intake of legumes and nuts is associated with lower chance of MU both in normal weight and overweight/obese adults. The association may be facilitated through serum BDNF and adropin.

The effect of a low versus high sodium diet on blood pressure in diabetic patients: A systematic review and meta-analysis of clinical trials.

There have been numerous clinical trials that have investigated the effect of sodium intake on blood pressure in diabetic patients. The purpose of this systematic review and meta-analysis was to evaluate the clinical trial studies performed on the effect of low sodium diet (LSD) versus high sodium diet (HSD) on blood pressure in diabetic patients. PubMed, Scopus, and Web of Science were systematically searched from database inception to July 10, 2021. Both type 1 and 2 diabetes was considered. Overall, there were 15 studies included in this meta-analysis. The weighted (WMD) mean difference with 95% confidence interval (CI) was calculated using a random-effects model. Risk of bias in the studies was assessed based on the Cochrane collaboration tool and the quality of all the studies was considered as good. Overall, LSD significantly reduced SBP (systolic blood pressure) (WMD: -3.79 mmHg, 95% CI: -6.02, -1.56) and DBP (diastolic blood pressure) (WMD: -1.62 mmHg, 95% CI: -2.84, -0.40), in comparison with HSD, in diabetics. However, LSD had no significant effect on MAP (mean arterial pressure) in comparison with HSD (WMD: -1.81, 95%CI: -5.49, 1.87). Although subgroup analysis could not attenuate heterogeneity in SBP, subgroup analysis in DBP based on duration (≤1 week: WMD: -2.35, 95%CI: -3.69, -1.00, I 2  = 48.9%, p = 0.081, >1 week: WMD: -1.04, 95% CI: -2.83, 0.76, I 2  = 74.7%, p = 0.003) and study design (cross-over: WMD: -1.94, 95% CI: -2.71, -1.17, I 2  = 32.1%, p = 0.183, parallel: WMD: -2.17, 95% CI: -6.48, 2.13, I 2  = 82.4%, p = 0.001) successfully detected sources of heterogeneity. LSD significantly reduced SBP and DBP, however, had no effect on MAP, in comparison with HSD.

Association of plant-based diets with adropin, atherogenic index of plasma, and metabolic syndrome and its components: A cross-sectional study on adults.

Background: Little is known about the association of plant-based diet indices with metabolic syndrome (MetS) and its novel predictive biomarkers, including the atherogenic index of plasma (AIP) and adropin. We aimed to investigate the association of plant-based diets with adropin, atherogenic index of plasma, and MetS and its components in adults. Methods: The present population-based cross-sectional study was conducted on a representative sample of adults aged 20-60 years in Isfahan, Iran. Dietary intake was obtained through a validated 168-item semi-quantitative food frequency questionnaire (FFQ). Peripheral blood was obtained after an overnight fast of at least 12 h from each participant. MetS was identified based on the Joint Interim Statement (JIS). AIP was calculated as a logarithmically transformed ratio of triglyceride (TG)/high-density lipoprotein cholesterol (HDL-c), and serum levels of adropin were measured by an ELISA kit. Results: A total of 28.7% of subjects had MetS. No significant association was found between the overall plant-based diet index (PDI) and the healthful plant-based diet index (hPDI) with MetS. However, a non-linear association was observed between hPDI and MetS. Subjects in the third quartile of the unhealthful plant-based diet index (uPDI) had higher odds of MetS compared to the first quartile (OR: 2.39; 95% CI: 1.01, 5.66). The highest quartile of PDI (OR: 0.46; 95% CI: 0.21, 0.97) and the third quartile of hPDI (OR: 0.40; 95% CI: 0.18, 0.89) were associated with decreased odds of having high-risk AIP compared to the first quartile, after adjusting for potential confounders. No linear association was found between quartiles of plant-based diet indices and serum levels of adropin. Conclusion: Plant-based diet index (PDI) and hPDI were not associated with the prevalence of MetS in adults, while moderate adherence to uPDI increased the prevalence of MetS. In addition, high adherence to PDI and moderate adherence to hPDI were associated with decreased odds of high-risk AIP. No significant association was found between plant-based diet indices and serum adropin levels. To confirm these findings, further studies with prospective designs are warranted.

The influential role of parents' socioeconomic status and diet quality on their children's dietary behavior: results from the LIPOKAP study among the Iranian population.

PURPOSE: There is a paucity of evidence regarding the influential factors on Iranian children's diet quality. To assess this issue, we explore the relationship between parental diet quality, socioeconomic status (SES), and nutritional knowledge with their children's diet quality using a cross-sectional sample of the Iranian population. METHODS: In this study, paired parents along with one of their children (aged 6-18 years old) who lived with them were included. Dietary intake was assessed using a food frequency questionnaire (FFQ) and diet quality was determined using an Alternative Healthy Eating Index-2010 (AHEI). Nutritional knowledge and SES were also explored using validated questionnaires. Multiple linear regression analysis was used and beta (ß) and corresponding 95% confidence interval (CI) were reported. RESULTS: After controlling for potential confounders, the parents' AHEI was significantly associated with their children's diet quality (ß = 12.34, 95% CI: 10.75, 13.93; P < 0.001). The nutritional knowledge of parents was significantly associated with children's AHEI after controlling for potential confounders (ß = 1.63, 95% CI: 0.14, 3.11; P = 0.032). Moreover, the parents' SES was inversely associated with the AHEI of children (ß=-3.76, 95% CI: -5.40, -2.11; P < 0.001); however, further adjustment for confounders attenuated this relationship (Model 3: ß = 0.87, 95% CI: -0.76, 2.34; P = 0.269). CONCLUSIONS: We found that the children's diet quality could be influenced by their parents' SES, nutritional knowledge, and diet quality. Our findings suggest that improving the nutritional knowledge of parents not only may improve the healthy eating pattern of parents but also could influence their children's diet quality.

Association between short sleep duration and intake of sugar and sugar-sweetened beverages: A systematic review and meta-analysis of observational studies.

BACKGROUND: Findings of previous investigations that evaluated the relationship between sleep duration and sugar or sugar-sweetened beverages (SSBs) intake have been inconsistent. We aimed to summarize extant research that assessed the relation between short sleep duration and sugar and SSB intake. METHODS: A comprehensive search of PubMed, ISI Web of Sciences, Scopus, Science Direct, Embase, and Google Scholar was conducted. All observational studies that reported sleep duration as the exposure and intake of sugar or sugary drinks as the outcome were included. The quality of included studies was evaluated using the Newcastle-Ottawa Scale. The body of evidence was assessed using the GRADE approach. Random and fixed effects models were used to estimate pooled OR and 95% confidence intervals. RESULTS: Twenty-two studies in children and twelve in adults were included in the systematic review. Only 10 studies in children and 3 investigations in adults provided odds ratios (95% confidence intervals) for this association and could be included in the meta-analysis. All studies had a cross-sectional design and found a negative association between sleep duration and sugar in children, but not in adults. SSB intake was lower in those with sufficient sleep in all populations. Compared with those with sufficient sleep, children with short sleep duration had 16% (significant) higher odds of consuming sugar (OR: 1.16; 95% CI: 1.10, 1.21), 21% higher odds of soda intake (OR: 1.21; 95% CI: 1.16, 1.26), and 92% higher odds of consuming energy drink intake (OR: 1.92; 95% CI: 1.66, 2.22). However, sleep duration was not significantly associated with soft drink intake in children (OR: 1.17; 95% CI: 0.93, 1.48). In adults, the odds of drinking soda in those with short sleep duration was 1.2 times more than in those with sufficient sleep (OR: 1.20; 95% CI: 1.12, 1.28). Also, low vs. optimal sleep duration in adults was associated with a 58% increased intake of energy drinks (OR: 1.58; 95% CI: 1.31, 1.90). Of note, these findings in the adult population resulted from only 2 included investigations, due to the limited number of studies. CONCLUSION: The evidence reviewed supports a significant association between shorter sleep duration and higher SSBs intake in both children and adults, while such association with higher total sugar intake was significant in children but not in adults. Further research with more accurate measurements, sex-specific, and prospective designs should be carried out to clarify the causality and underlying mechanisms.

Dietary insulin index and insulin load in relation to hypertriglyceridemic waist phenotype and low brain derived neurotrophic factor in adults.

Background: The evidence about the relation of the insulinemic potential of food with visceral obesity and brain-derived neurotrophic factor (BDNF) was limited. We aimed to investigate the relation of dietary insulin index (DII) and dietary insulin load (DIL) with hypertriglyceridemic waist phenotype (HTGW) and serum BDNF in Iranian adults. Methods: This cross-sectional study included 528 middle-aged adults (45.6% women), using a multistage cluster random-sampling method. Dietary intakes were assessed using a validated semi-quantitative 168-item food frequency questionnaire. Blood samples were collected after 12 h of fasting for assessing the serum BDNF and triglyceride concentrations. HTGW was defined as triacylglycerol ≥ 150 mg/dL plus enlarged waist circumference. The values less than the first decile of serum BDNF were considered as the low level. Results: Individuals in the top tertile of DIL, in comparison to those in the bottom tertile, had higher odds of HTGW in both crude (OR = 1.96, 95% CI: 1.14-3.37) and fully adjusted model (OR = 6.10, 95% CI: 1.58-23.53). However, the relation between DII and odds of HTGW was statistically insignificant in crude (OR = 1.30, 95% CI: 0.78-2.16) and maximally adjusted model (OR = 1.25, 95% CI: 0.65-2.40). After considering confounders, participants in the top tertile of DIL had marginally higher odds of having low BDNF values (OR = 2.00, 95% CI: 0.95-4.21). Nevertheless, the association between DII and odds of low BDNF values was statistically insignificant. Conclusion: This population-based study demonstrated that adults with higher DIL had significantly higher chance of HTGW phenotype and slightly higher chance for low BDNF level. DII was not associated with HTGW phenotype or BDNF values.

The Effect of Saffron (Crocus sativus L.) Supplementation on Renal Function: A Systematic Review and Meta-Analysis of Randomized Controlled Clinical Trials.

Background: The present systematic review and meta-analysis of randomized controlled trials (RCTs) aimed at determining the effect of saffron supplementation on renal function. Methods: Electronic databases were searched up to February 2021. The risk of bias in individual studies was assessed using the Cochrane Collaboration tool. The overall weighted mean difference (WMD) and their 95% confidence intervals (CIs) were calculated using random-effect models. P < 0.05 was considered statistically significant. Results: A total of 11 trials were included in this study. Saffron had beneficial effect on BUN (WMD = -0.69 mg/dl; 95% CI, -1.36 to -0.01; P=0.046) compared to placebo, with significant heterogeneity (I 2 = 49.6%, P=0.037). However, it had no significant effect on serum Cr (WMD = 0.04 mg/dl; 95% CI: -0.01 to 0.09; P=0.127). Conclusion: It seems that saffron supplementation had no significant effect on Cr as a renal function factor. However, BUN reduction was significant in the saffron group compared to placebo.

Zinc nutritional status, mood states and quality of life in diarrhea-predominant irritable bowel syndrome: a case-control study.

Zinc is an important trace element for structure, and regulation in the central nervous system, as well as the gut homeostasis. There are several mental disorders associated with zinc deficiency. The relationship between zinc nutritional status with mood states and quality of life (QoL) in diarrhea-predominant irritable bowel syndrome (IBS-D) has not been studied yet. This case-control study aimed to investigate the association between zinc nutritional status with mood states and QoL in IBS-D patients. Sixty-one newly diagnosed patients with IBS-D and 61 matched healthy controls were enrolled. Dietary zinc intakes and serum zinc levels were measured. Mood states and QoL were evaluated by validated questionnaires. Logistic regression was used to estimate the odds of IBS-D in relation to zinc deficiency. Decreased serum zinc levels were observed in the IBS-D group than in the controls (p = 0.001). There were higher scores of depression (p = 0.014), anxiety (p = 0.005), and stress (p = 0.001) among IBS-D patients. Moreover, overall QoL, physical and psychological health were lower in IBS-D patients compared to the controls (p < 0.001). "Food avoidance" had the lowest, while the "relationship" had the highest score among the patients (51.09 ± 26.80 and 78.14 ± 23.30, respectively). Dietary zinc intake was positively correlated with psychological health in the controls (r = 0.295, p = 0.022) and with body image in the patients (r = 0.266, p = 0.044). According to the logistic regression, zinc deficiency was not significantly associated with odds of IBS-D. Findings show that zinc deficiency may be associated with some parameters of IBS-D. Further clinical studies are needed to explore the causal relationship between zinc status and IBS pathogenesis.

Serum vitamin D levels in relation to metabolic syndrome: A systematic review and dose-response meta-analysis of epidemiologic studies.

Several epidemiological studies examined the association of serum vitamin D with metabolic syndrome (MetS), but the findings were inconsistent. We conducted a systematic review and dose-response meta-analysis to quantify the association between blood vitamin D levels and MetS in adults. A systematic search up to December 2020 was conducted in MEDLINE (PubMed), ISI (Web of Science), Scopus, and Google Scholar databases for epidemiological studies that assessed the relation of serum 25-hydroxyvitamin D (as the exposure) and MetS (as the outcome) in adults. Eligible cross-sectional studies were restricted to those with representative populations. Finally, 43 studies were included in the analysis (38 cross-sectional, one nested case-control, and four cohorts studies). Combining 41 effect sizes from 38 cross-sectional studies included 298,187 general adult population revealed that the highest level of serum vitamin D, compared with the lowest level, was significantly related to a 43% decreased odds of MetS in developed countries (odds ratio [OR]: 0.57; 95% confidence interval [CI]: 0.49-0.65) and 40% in developing countries (OR: 0.60; 95% CI: 0.52-0.70). Linear dose-response analysis (including 222,175 healthy individuals and 39,308 MetS patients) revealed that each 25 nmol/L increase in serum vitamin D level was significantly associated with a 15% decreased odds of MetS (OR: 0.85; 95% CI: 0.80-0.91); however, we found no significant nonlinear association. Meta-analysis of five prospective studies with 11,019 participants revealed no significant relation (relative risk [RR]: 0.70; 95% CI: 0.37-1.32). This meta-analysis indicated an inverse association between serum vitamin D concentrations and risk of MetS in general adult populations in cross-sectional studies in a dose-response manner. However, no significant association was found in a small number of cohorts. More prospective studies are needed to confirm the causality of this relationship.

Effect of synbiotics and probiotics supplementation on autoimmune diseases: A systematic review and meta-analysis of clinical trials.

BACKGROUND & AIMS: Today synbiotics are considered as immunomodulatory agents. The current systematic review and meta-analysis investigated the effect of synbiotics and probiotics on inflammatory and oxidative stress markers in autoimmune disease. MATERIALS & METHODS: The English literature search was performed using PubMed, Scopus, Web of Science, and the Central Cochrane Library through March 2020. Random effects models and generic inverse variance methods were used to synthesize quantitative data by STATA14. RESULTS: From a total of 623 entries identified via searches, ten RCTs (n = 440; 216 as intervention, 224 as controls) were included. An additional eleven studies with same intervention and different markers were also explained systematically. The pooled effect size showed that Interleukin (IL)-6 (WMD = -7.79 pg/ml; 95% CI = -13.81, -1.77, P = 0.011), Tumor Necrosis Factor (TNF)-α (WMD = -1.05 pg/ml; 95% CI = -2.01, -0.10, P = 0.030), high sensitivity C-Reactive Protein (hs-CRP) (SMD = -0.58; 95% CI = -0.79, -0.37, P < 0.001), Malondialdehyde (MDA) (SMD = -0.36; 95% CI = -0.68, -0.04; P = 0.026), Homeostasis Model of Assessment-estimated Insulin Resistance (HOMA-IR) (WMD = -0.71; 95% CI = -1.05, -0.37, P < 0.001), and beta cell function (HOMA-ß) (WMD = -15.18; 95% CI = -22.08, -8.28, P < 0.001) changed following probiotics (or synbiotics) supplementation. Also supplementation with doses more than 2 billion CFU could reduce IL-10 concentrations (WMD = -1.84; 95% CI = -2.23, 1.87; P < 0.001). Glutathione (GSH) and Total Antioxidant Capacity (TAC) levels did not influence by synbiotics and probiotics; insignificancy was remained after subgrouping for participants' age, study duration, and disease duration. CONCLUSION: Our findings revealed that synbiotics and probiotics supplementation has significant effect on some inflammatory and oxidative stress markers; although, the number of trials was too small to powerful conclusion and further investigations may be needed.

Serum vitamin D levels in relation to abdominal obesity: A systematic review and dose-response meta-analysis of epidemiologic studies.

Although several observational studies have investigated the relationship between vitamin D deficiency and risk of central obesity, the results were inconsistent. We performed a dose-response meta-analysis on epidemiologic studies that evaluated the association of vitamin D status and abdominal obesity in adults. A systematic search was carried out of all published articles, up to May 2020, in five electronic databases, including MEDLINE (Pubmed), EMBASE, Institute for Scientific Information (ISI) (Web of science), Scopus and Google scholar. Forty-one observational studies reported odds ratios (ORs) or relative risks (RRs) with 95% confidence intervals (CIs) for abdominal obesity in relation to serum vitamin D levels in adults were included in the analysis. Using a random effects model, the overall effect size was calculated. Combining 44 effect sizes from 36 cross-sectional studies with 257,699 participants revealed that the highest versus the lowest serum vitamin D level was significantly associated with a 23% decreased odds of abdominal obesity (OR: 0.77; 95% CI [0.71, 0.83]). This inverse association was significant in almost all subgroups based on different covariates. Dose-response analysis showed that each 25 nmol/L increase in serum vitamin D was related to 8% reduced risk of abdominal obesity (OR: 0.92; 95% CI [0.85, 0.99]). When we confined the analysis to 23 effect sizes from 17 studies with representative population (242,135 participants), the same results were obtained (OR: 0.79; 95% CI [0.71, 0.87]). Dose-response analysis indicated that each 25 nmol/L increase in blood vitamin D levels was linked to 10% decreased central adiposity risk in representative populations (OR: 0.90; 95% CI [0.82, 0.99]). This meta-analysis of epidemiologic studies revealed that serum vitamin D level was inversely associated with risk of abdominal obesity in adults, in a dose-response manner. The same findings were obtained in representative populations. Further prospective studies are required to examine the causal association between serum vitamin D levels and abdominal obesity.

Effects of Phytosterols supplementation on blood glucose, glycosylated hemoglobin (HbA1c) and insulin levels in humans: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: In the literature, there are still controversies regarding the effect of phytosterol(PS) supplementation on fasting blood sugar (FBS), insulin levels and glycosylated hemoglobin (HbA1c) in humans. We aimed to assess the impact of PS supplementation on FBS, HbA1c and insulin levels by conducting a systematic review and meta-analysis of the available randomized controlled trials (RCTs). METHODS: A comprehensive search was conducted to identify all RCTs published up to May 2019 in the following databases: PubMed-MEDLINE, Web of Science, Cochrane Library and Scopus. The mean difference with 95% confidence intervals (CIs) was pooled using a random-effects model (DerSimonian-Laird method). RESULTS: Twenty-six arms from 20 RCTs were included in the present meta-analysis. Our findings show that PS supplementation decreases insulin levels (mean difference [MD]: -6.426 µU/ml, 95% CI: -7.187, -5.665, P- value = 0.000). However, PS supplementation did not have significant effects on FBS and HbA1c levels. Following PS supplementation, significant changes in FBS (mean difference [MD]: -1.942 mg/dl, 95% CI: -3.637, -0.246, P- value = 0.025) and HbA1c (mean difference [MD]: -0.059%, 95% CI: -0.114, -0.004, P- value = 0.035) based on PS dosage (mg/d) were recorded. CONCLUSIONS: In patients with a baseline BMI <25 kg/m2, PS consumption significantly increased FBS levels. Patients who consumed 1-2 g/day of PS had a lower FBS and lower HbA1c levels.