Higher dietary methyl donor micronutrient consumption is associated with higher muscle strength in adults: a cross-sectional study.

Methyl donor micronutrients might affect muscle strength via DNA methylation. We aimed to evaluate the combined relationship of dietary methyl donor micronutrients containing betaine, choline, methionine, vitamin B12, vitamin B6 and folate on muscle strength. This cross-sectional study was conducted on 267 subjects including 113 men and 154 women. Dietary intake of micronutrients was assessed utilising a validated 168-item semi-quantitative FFQ, and methyl donor micronutrient score (MDMS) was calculated. The muscle strength of the participants was measured using a digital handgrip dynamometer. The association was determined using linear regression analysis. The mean age of participants was 36·8 ± 13·2 years. After taking into account potential confounding variables, there was no significant association between dietary methyl donor micronutrient score (MDMS) and the mean left-hand muscle strength (ß: 0·07, se: 0·05, P = 0·07); however, the changes were significant in the mean right-hand muscle strength (ß: 0·09, se: 0·04, P = 0·03). There was also a significant positive relationship between mean muscle strength and methyl donors' intake after fully adjusting for potential confounders (ß: 0·08, se: 0·04, P = 0·04). In conclusion, our findings revealed that higher dietary methyl donor micronutrient consumption is associated with enhanced muscle strength. As a result, advice on a higher intake of methyl donor-rich foods including grains, nuts, dairy products and seafood might be recommended by dietitians as a general guideline to adhere to. Additional prospective studies are needed to confirm the findings.

Dose-response association of obesity and risk of mental health among tehranian residents: result of a cross-sectional study.

BACKGROUND: Obesity and mental health issues are two of the most prevalent global public health issues for a significant portion of people. The purpose of this study was to investigate the relationship between obesity indicators and mental health in Tehran-dwelling Iranian adults. METHODS: We conducted a cross-sectional study on healthy Iranian adults using a convenience sampling technique. The short form of the Depression Anxiety and Stress Scale (DASS-21) was used to measure the outcome, and independent variables included body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), body adiposity index (BAI), and a body shape index (ABSI). The relationship between obesity and mental health was investigated using a multivariate logistic regression model. The non-linear dose-response relationships were evaluated using restricted cubic splines (RCS) with three knots. The Benjamini-Hochberg procedure was used to adjust for multiple testing. RESULTS: In our study of 434 participants, females made up 52% of the participants, with a mean age of 38.57 years. In all, 54.6%, 53.9%, and 56.6% were classified as having anxiety, depression, and stress respectively. Logistic regression analysis showed that the odds of mental health components including anxiety, depression, or stress was not significantly different across the tertiles of the obesity indicators. We observed a significant dose-response relationship between BAI and ABSI and the risk of anxiety (PBenjamini-Hochberg 0.028 > Pdose-response 0.023) and stress (PBenjamini-Hochberg 0.028 > Pdose-response 0.003) but not depression (PBenjamini-Hochberg 0.014 < Pdose-response 0.018). The lowest risk for anxiety was observed in people with a BAI of 28% and ABSI equal to 0.079. The risk of stress seemed to increase beyond an ABSI of 0.086. CONCLUSION: Our findings showed no direct linear association between obesity indices and anxiety. However, a dose-response relationship was observed between BAI and ABSI and the risk of anxiety and stress, indicating the need for further investigation.

Association of meal-specific protein intake and cardiometabolic risk factors: a cross-sectional study.

We aimed to investigate the association of main meals' specific protein intake with cardiometabolic risk factors, including general and abdominal obesity, serum lipid profile, and blood pressure (BP). This cross-sectional study was conducted on 850 subjects aged 20-59 years. Dietary intakes were assessed by completing three 24-h recalls, and the protein intake of each meal was extracted. Anthropometric measures, lipid profile, fasting blood sugar and BP were measured. Multivariate logistic regression controlling for age, physical activity, sex, marital status, smoking status, BMI and energy intake was applied to obtain OR and CI. The mean age was 42 years, and the mean BMI of the participants was 27·2. The mean protein intake for breakfast, lunch and dinner was 12·5, 22·2 and 18·7 g/d, respectively. After adjustment for confounders, higher protein intake was not associated with any of the cardiometabolic risk factors, including LDL-cholesterol, HDL-cholesterol, total cholesterol (TC), TAG, body weight, BP and fasting plasma glucose, in any of the three main meals consumed within a day. Adherence to a higher protein intake at each meal was not associated with cardiometabolic risk factors in Iranian adults. Further prospective studies are needed to justify our findings.

Association of low-carbohydrate diet score and carbohydrate quality with visceral adiposity and lipid accumulation product.

The present study examined the association between low-carbohydrate diet (LCD) score, glycemic index (GI), and glycemic load (GL) with visceral fat level (VFL) and lipid accumulation product (LAP). This cross-sectional study was conducted on 270 adults (118 men and 152 women) aged between 18-45 living in Tehran, Iran, between February 2017 and December 2018. Dietary intake was assessed using a validated semi-quantitative food frequency questionnaire (FFQ). Body composition were also assessed. We used analyses of covariance and binary logistic regression to explore associations after controlling for age, energy intake (model 1), education, smoking status, physical activity, occupation, marriage and metabolic diseases. There were no significant differences between tertiles of GI, GL and LCD for means of anthropometric measures, LAP and VFL index in men, while women in the highest tertile of GI and GL had significantly higher mean LAP in the crude model (P = 0·02) and model 1(P = 0·04), which disappeared after controlling for other confounders (P = 0·12). Moreover, the OR and CIs for having high LAP and VFL was not associated with dietary GI, GL and LCD in crude and adjusted models. However, chance of high VFL reduced by 65% and 57% among women with high adherence to LCD score (OR = 0·35, 95% CI = 0·16-0·78, P = 0·01) and model 1 (OR = 0·43, 95% CI = 0·18-1, P = 0·05), respectively. However, this significant association disappeared after controlling for other confounders (P = 0·07). Overall, we found carbohydrate quality and LCD score are not associated with LAP and VFL index. However, gender-specific relationship should not be neglect and warrants further investigation.

The association of meal-specific food-based dietary inflammatory index with cardiovascular risk factors and inflammation in a sample of Iranian adults.

BACKGROUND: This study aimed to evaluate the association of meals-specific food-based dietary inflammatory index (FDII), with cardiovascular (CVD) risk factors and inflammation among Iranian adults. METHODS: In this cross-sectional study, we recruited 816 participants living in Tehran via two-staged cluster sampling. Three non-consecutive 24-h dietary recalls (two working days and one day off) were obtained from individuals to specify the main meals and meal-specific FDIIs. Anthropometric measures were done. Insulin and high-sensitivity c-reactive protein (hs-CRP) were measured. Multiple linear regressions were used to investigate the association of FDII with Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), hs-CRP, Triglyceride Glucose Index (TyG), and Lipid Accumulation Product Index (LAP). RESULTS: The range of FDIIs for breakfast, lunch, and dinner were (-2.47,1.98), (-2.66,3.23) and (-4.09,3.13) in order, and the mean age was 42.2 ± 10.5 years. We found that there was no significant association between FDII and hs-CRP level in the three meals (ß = -0.003; 95% CI: -0.030, 0.025 for breakfast,ß = -0.020; 95% CI: -0.041, 0.001 for lunch, and ß = 0.006; 95% CI: -0.016, 0.028 for dinner) after adjusting for age, sex, education, occupation, maritage, physical activity, smoking, morningness-eveningness score, energy, body mass index, and other FDIIs. Also, we found no significant association between breakfast, lunch, and dinner-specific FDII and HOMA-IR (ß = -0.368, -0.223, 0.122), TyG index (ß = -0.009, 0.060, -0.057) and LAP (ß = 2.320, -0.278, -0.297). CONCLUSIONS: We found no associations between meal-based FDII scores and CVD and inflammation. Further research of prospective nature is needed to confirm these findings.

The relationship between adherence to the Mediterranean dietary pattern during early pregnancy and behavioral, mood and cognitive development in children under 1 year of age: a prospective cohort study.

PURPOSE: To investigate the potential relationship between diet quality, represented by the Mediterranean diet score, during early pregnancy and behavioral, mood, and cognitive development in children under 1 year of age in a prospective cohort study in Iran. METHODS: 658 Iranian pregnant women and their infants participated in this prospective birth cohort study. The Mediterranean diet score was calculated by using data from a food frequency questionnaire during the first trimester of pregnancy. We assessed the children's development using the Ages and Stages Questionnaire (ASQ) at 6-month age. We used Cox proportional hazard model to calculate the hazard ratio (HR) and 95% confidence interval (CI) of ASQ domains across categories of the Mediterranean diet score. RESULTS: The mean age of the mothers was 28.8 ± 5.08 years old, and the average follow-up duration was 90 weeks. The mean BMI of the mothers before pregnancy was 25.1 ± 4.43 kg/m2. In the multivariable-adjusted model, those infants whose mothers were in the second (HR: 0.44; 95% CI: 0.19, 1.04; P = 0.06) and third (HR: 0.39; 95% CI: 0.17, 0.89; P = 0.03) tertiles of the Mediterranean diet score had a lower risk of communication impairment compared to those who were at the first tertile. There was no association between maternal adherence to the Mediterranean diet during early pregnancy and other domains of the ASQ. CONCLUSIONS: Greater adherence to the Mediterranean dietary pattern during the first trimester of pregnancy may be favorably associated with communication abilities at 6-month aged infants. More large-scale cohort studies are needed to confirm our findings.

The association between self-reported nocturnal sleep duration, irregularity in daily energy intake and diet quality in a sample of Iranian adults.

OBJECTIVE: Evidence on the relationship between sleep duration and irregularity in daily energy intake with diet quality in Iranian adults is scarce. We aimed to evaluate the association of sleep duration with diet quality and irregularity in daily energy intake. DESIGN: This is a cross-sectional study. SETTING: The study was performed in healthcare centres in Tehran. PARTICIPANTS: 739 adults aged 20-59 years were recruited. Dietary intake was assessed by a FFQ and three 24-h dietary recalls. Diet quality was assessed using the Healthy Eating Index-2015 (HEI-2015). An irregularity score of daily energy intake was calculated based on the deviation from the 3-d mean energy intake. Sleep duration was estimated using self-reported nocturnal sleep duration by each person. RESULTS: The mean age of the study participants was 44·4 ± 10·7 years; 70 % were women. The mean nocturnal sleep duration, HEI score and irregularity score were 6·7 ± 1·22 h/d, 52·5 ± 8·55 and 22·9 + 19, respectively. After adjusting for potential confounders, sleep duration was not associated with adherence to HEI-2015 (OR: 1·16; 95 % CI 0·77, 1·74). Longer sleep duration was marginally associated with a lower odd of irregularity in daily energy intake. However, after adjustment for various confounders, this association was not significant (OR: 0·82; 95 % CI 0·50, 1·33; Ptrend = 0·45). No significant interaction was observed between sleep duration and irregularity in daily energy intake in relation to adherence to HEI-2015 (Pinteraction = 0·48). CONCLUSIONS: We found that sleep duration was not associated with adherence to HEI-2015 and irregularity in daily energy intake. Further prospective studies are warranted.

The Effects of L-Carnitine Supplementation on Weight Loss, Glycemic Control, and Cardiovascular Risk Factors in Patients With Type 2 Diabetes: A Systematic Review and Dose-response Meta-Analysis of Randomized Controlled Trials.

PURPOSE: L-carnitine supplementation has been recommended to improve cardiometabolic health markers in diabetic patients. Our purpose was to assess the dose-dependent effects of l-carnitine supplementation on cardiometabolic risk factors in patients with type 2 diabetes. METHODS: PubMed/Medline, Scopus, and Web of Science were searched until May 2022 for randomized controlled trials that examined the impact of l-carnitine supplementation on cardiometabolic risk factors in adults with type 2 diabetes. The mean difference (MD) and its 95% confidence interval (CI) were estimated utilizing a random-effects model. Nonlinear dose-response associations were modeled with restricted cubic splines. The certainty of evidence was rated using the GRADE approach. FINDINGS: Twenty-one randomized trials with 2041 patients with type 2 diabetes were included. We found that every 1 g/d supplementation with l-carnitine significantly reduced body mass index (MD: -0.37 kg/m2, 95% CI: -0.59, -0.15; I2 =93%, n=13, GRADE=low), HbA1c (MD: -0.16%, 95% CI: -0.32, -0.01; I2 = 94%, n = 18, GRADE = moderate), and low-density lipoprotein cholesterol (MD: -0.11 mmol/L, 95% CI: -0.16, -0.05; I2 = 91%, n = 11, GRADE = high). There were also reductions in serum triglycerides (MD: 0.07 mmol/L), total cholesterol (MD: -0.13 mmol/L), and fasting plasma glucose (MD: -0.17 mmol/L). A U-shaped effect was demonstrated for body mass index, with the largest reduction at 2 g/d. A linear reduction was seen for serum triglycerides, total cholesterol, and fasting plasma glucose up to l-carnitine supplementation of 4 g/d. IMPLICATIONS: L-carnitine supplementation resulted in a small reduction in serum lipids and plasma glucose in patients with type 2 diabetes. However, due to high statistical heterogeneity, the results should be interpreted very cautiously.

Comparative efficacy and safety of probiotics, prebiotics, and synbiotics for type 2 diabetes management: A systematic review and network meta-analysis.

AIMS: To compare the effects of probiotics, prebiotics, and synbiotics for type 2 diabetes (T2D) management. METHODS: We searched PubMed, Scopus, CENTRAL, and grey literature sources to December 2022 for randomized trials of the impacts of probiotics, prebiotics, or synbiotics in patients with T2D. We performed network meta-analyses with a Bayesian framework to calculate mean difference [MD] and 95 % credible interval [CrI] and rated the certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. RESULTS: 68 randomised trials were included. All results are presented in comparison to the placebo. Supplementation with probiotics (MD: -0.25 %, 95%CrI: -0.42, -0.08; GRADE = moderate) and synbiotics (MD: -0.31 %, 95%CrI: -0.61, -0.04; GRADE = very low) resulted in a trivial/unimportant decrease in glycated hemoglobin. Supplementation with probiotics (MD: -0.69 mmol/L, 95%CrI: -0.98, -0.40; GRADE = very low) and synbiotics (MD: -0.82 mmol/L, 95%CrI: -1.22, -0.43; GRADE = very low) resulted in a trivial/unimportant decrease in fasting plasma glucose. Supplementation with probiotics resulted in a small but important decrease in low-density lipoprotein cholesterol (MD: -0.19 mmol/L; 95%CrI: -0.34, -0.05; GRADE = very low). Supplementations had moderate effects on serum triglyceride (GRADE = low). CONCLUSIONS: Existing evidence is uncertain and does not support supplementation with probiotics, prebiotics, and synbiotics for T2D management.

Total and different dietary fiber subtypes and the risk of all-cause, cardiovascular, and cancer mortality: a dose-response meta-analysis of prospective cohort studies.

We aimed to conduct a comprehensive review of the association between dietary fiber and the risk of mortality. We did a systematic search in PubMed, Scopus, and Web of Science up to November 2022 to find prospective cohort studies of the relationship between total and subtypes of dietary fiber and the risk of all-cause, cardiovascular (CVD), and cancer mortality in the general population. The hazard ratios (HRs) and 95% CIs were calculated using a random-effects model. A total of 28 studies with 1 613 885 participants were included. Higher intake of total and subtypes of dietary fiber including cereal, vegetable, legume, soluble, and insoluble fiber, but not fruit fiber, was associated with a lower risk of all-cause mortality, with HRs ranging from 0.77 for insoluble fiber to 0.93 for legume fiber. Similar findings were observed for CVD mortality, where higher intake of total and all subtypes of dietary fiber was each associated with a lower risk. Higher intake of total, cereal, vegetable, and insoluble fiber was also associated with a lower risk of cancer mortality. No association was found between the intake of fruit, legume, and soluble fiber and cancer mortality. Dose-response meta-analyses suggested an inverse association between total fiber intake and the risk of all-cause, CVD, and cancer mortality. The certainty of evidence was rated moderate for the association of total fiber with all-cause, CVD, and cancer mortality. In conclusion, our findings highlight the potential advantages of consuming a wide range of dietary fiber subtypes against all-cause, CVD, and cancer mortality. Registry and registry number: PROSPERO (CRD42021226816).

Association between diabetes risk reduction diet score and risk of breast cancer: A case-control study.

PURPOSE: To assess the association between the diabetes risk reduction diet score (DRRD) and the odds of breast cancer (BC). METHODS: During this hospital-based case-control study we included 149 newly diagnosed cases of BC and 150 controls matched by age. All cases were patients with pathologically confirmed BC, with no history of any form of other cancers. The controls were randomly selected from visitors and families of non-cancer patients in other wards of the same hospital who had no health issues including BC. The dietary intakes were evaluated by a validated 147-item semi-quantitative FFQ. DRRD score was calculated from 9 dietary components published before, with a better score resembling a higher adherence to DRRD. RESULTS: A negative association was found between the chances of BC and DRRD after adjusting for potential confounders, but it was not statistically significant (OR, 0.47; 95%CI, 0.11-2.08; P = 0.531). Also, there were no significant associations between DRRD and therefore the odds of BC in the crude model and also in post-menopausal (OR, 0.45; 95%CI, 0.10-1.99; P = 0.505) and pre-menopausal women (OR, 0.52; 95%CI, 0.18-1.40; P = 0.097) in our study, after adjusting for potential confounders. CONCLUSION: Adherence to a diet with a high DRRD score was not associated with the reduced risk of BC in Iranian adults.

Association of main meal quality index with the odds of metabolic syndrome in Iranian adults: a cross-sectional study.

BACKGROUND: Metabolic syndrome (MetS) is a common global issue linked to the quality of one's eating occasions. The current cross-sectional study evaluates the association between a novel index, the Main Meal Quality Index (MMQI), and MetS among Iranian adults. METHODS: A total of 824 men and women were recruited, and a 24-hour dietary recall assessed the dietary intake of the participants. Lunch was selected as the main meal based on energy density. The MMQI score was calculated based on ten components of dietary intake, with a higher score indicating more adherence to the index, with the final scores ranging from 0 to 100 points. The associations were assessed using binary logistic regression. RESULTS: The mean age was 42.2 years and the range of the calculated MMQI was 22 to 86 (mean in total participants: 56.62, mean in women: 56.82, mean in men: 55.64). The total prevalence of MetS in the sample was 34%. After adjustments for potential confounders, the participants at the top quartile of MMQI had a lower odds ratio for hypertriglyceridemia and low high-density lipoprotein (HDL) level, and a higher odds ratio for hypertension, hyperglycemia, abdominal obesity, and MetS. The sex-specific analysis also did not show any significant associations between adherence to MMQI and MetS and its components. CONCLUSION: Overall, MMQI is not associated with MetS and its components in a sample of Iranian men and women. More research is needed to examine MMQI and its possible association with current health-related problems including MetS.

No association between dietary magnesium intake and body composition among Iranian adults: a cross-sectional study.

PURPOSE: Obesity is becoming more prevalent worldwide. Magnesium (Mg) intake may play a role in the regulation of energy metabolism and body weight. Therefore, in this cross-sectional study, we aimed to investigate the association between dietary Mg intake and body composition among healthy adults. METHODS: A total of 778 adult men and women aged 18-59 years who attended health care centers in Tehran, Iran, entered the final analysis. Dietary intake was assessed with a validated and reliable food frequency questionnaire with 168 items and the dietary Mg intake was estimated using Nutritionist IV software. Anthropometric measurements and blood samples were collected and body composition was evaluated employing the Body Mass Index (BMI), A Body Shape Index (ABSI), Body Adiposity Index (BAI), Body Roundness Index (BRI), Visceral Adiposity Index (VAI), Lipid Accumulation Index (LAP), and Triglyceride-Glucose index (TyG). Multiple linear regression analysis was used to determine the association of the dietary Mg intake with body composition indices. RESULTS: The mean daily dietary Mg intake was 294 ± 140 mg in men and 262 ± 112 mg in women. Unadjusted linear regression showed that dietary magnesium intake is significantly associated with a waist to hip ratio (WHR) and total cholesterol (TC) in men, and hip circumference (HC) in women. After adjusting for potential confounders including age, education, marriage, occupation and smoking, total energy intake, and activity score, there remained no significant association between dietary Mg intake and any of the body composition indices including BMI, ABSI, BAI, BRI, VAI, LAP, and TyG neither in men nor women. CONCLUSION: Higher Mg intake was not associated with anthropometric indices in Iranian adults, according to our findings. Additional observational studies would be beneficial in clarifying the existing findings.

Dose-dependent effect of carbohydrate restriction for type 2 diabetes management: a systematic review and dose-response meta-analysis of randomized controlled trials.

BACKGROUND: Carbohydrate restriction is effective for type 2 diabetes management. OBJECTIVES: We aimed to evaluate the dose-dependent effect of carbohydrate restriction in patients with type 2 diabetes. METHODS: We systematically searched PubMed, Scopus, and Web of Science to May 2021 for randomized controlled trials evaluating the effect of a carbohydrate-restricted diet (≤45% total calories) in patients with type 2 diabetes. The primary outcome was glycated hemoglobin (HbA1c). Secondary outcomes included fasting plasma glucose (FPG); body weight; serum total, LDL, and HDL cholesterol; triglyceride (TG); and systolic blood pressure (SBP). We performed random-effects dose-response meta-analyses to estimate mean differences (MDs) for a 10% decrease in carbohydrate intake. RESULTS: Fifty trials with 4291 patients were identified. At 6 months, compared with a carbohydrate intake between 55%-65% and through a maximum reduction down to 10%, each 10% reduction in carbohydrate intake reduced HbA1c (MD, -0.20%; 95% CI, -0.27% to -0.13%), FPG (MD, -0.34 mmol/L; 95% CI, -0.56 to -0.12 mmol/L), and body weight (MD, -1.44 kg; 95% CI, -1.82 to -1.06 kg). There were also reductions in total cholesterol, LDL cholesterol, TG, and SBP. Levels of HbA1c, FPG, body weight, TG, and SBP decreased linearly with the decrease in carbohydrate intake from 65% to 10%. A U-shaped effect was seen for total cholesterol and LDL cholesterol, with the greatest reduction at 40%. At 12 months, a linear reduction was seen for HbA1c and TG. A U-shaped effect was seen for body weight, with the greatest reduction at 35%. CONCLUSIONS: Carbohydrate restriction can exert a significant and important reduction on levels of cardiometabolic risk factors in patients with type 2 diabetes. Levels of most cardiometabolic outcomes decreased linearly with the decrease in carbohydrate intake. U-shaped effects were seen for total cholesterol and LDL cholesterol at 6 months and for body weight at 12 months.