Adherence to Mediterranean dietary quality index and risk of breast cancer in adult women: a case-control study.

BACKGROUND: Breast cancer (BC) is the fifth most prevalent cause of cancer-related deaths in Iran. Given that the role of whole-diet on cancer risk is important, this study aimed to assess the association of MedDQI and breast cancer risk. METHODS: This hospital-based case-control study was performed on 150 women with pathologically confirmed breast cancer within the period of less than 3 months. Controls were 150 apparently healthy that were matched by age. Dietary data was collected using a validated questionnaire. To examine participants' adherence to MedDQI, the MedDQI was created according to foods and nutrients highlighted or minimized in the MedDQI construction. RESULTS: After adjusting for possible confounders, participants in the highest quartile of the MedDQI score had 55% lower odds of breast cancer than women in the bottom quartile (OR: 0.45, 95% CI: 0.21, 0.94, P trend: 0.02). Stratified analysis by menopausal status showed such association in postmenopausal women (OR: 0.24, 95% CI: 0.07, 0.8, P trend: 0.055) after controlling for age and energy intake. CONCLUSION: The results showed an inverse association between adherence to the MedDQI and risk of breast cancer among Iranian women. More prospective studies are needed to confirm our results.

Comparative effectiveness of single foods and food groups on body weight: a systematic review and network meta-analysis of 152 randomized controlled trials.

PURPOSE: This study aimed at quantifying and ranking the effects of different foods or food groups on weight loss. METHODS: We searched PubMed, Scopus, Cochrane Central Register of Controlled Trials, and Embase to April 2021. We included randomized trials evaluating the comparative effects of two or more food groups, or compared a food group against a control group (usual diet, no intervention) for weight loss in adults. We conducted random-effects network meta-analysis with Bayesian framework to estimate mean difference [MD] and 95% credible interval [CrI] of the effect of food groups on weight loss. RESULTS: 152 RCTs with 9669 participants were eligible. Increased consumption of fish (MD - 0.85 kg, 95% CrI - 1.66, - 0.02; GRADE = low), whole grains (MD - 0.44 kg, 95% CrI - 0.88, 0.0; GRADE = very low), and nuts (MD - 0.37 kg, 95% CI - 0.72, - 0.01; GRADE = low) demonstrated trivial weight loss, well below minimal clinically important threshold (3.9 kg), when compared with the control group. Interventions with other food groups led to no weight loss when compared with either the control group or other food groups. The certainty of the evidence was rated low to very low with the point estimates for all comparisons less than 1 kg. None of the food groups showed an important reduction in body weight when restricted to studies conducted in participants with overweight or obesity. CONCLUSIONS: Interventions with a single food or food group resulted in no or trivial weight loss, especially in  individuals with overweight or obesity. Further trials on single foods or food groups for weight loss should be highly discouraged.

Positive Association Between Nutrient Adequacy and Waist Circumference: Results of a Cross-Sectional Study.

Metabolic syndrome (MetS) is a multifactorial disease with its exact causes not completely clear. Micronutrients such as vitamin A, vitamin D, zinc, and magnesium have been associated with MetS components. Our objective was to investigate the association of nutrient adequacy (NA) with MetS components. The present cross-sectional study consisted of 850 adults between 18-59 years from Tehran, Iran. Dietary intake, socio-demographic data, medical history, and anthropometric indices were collected by trained personnel. NA was calculated as the mean intake ratio to the recommended amount of 16 micronutrients. MetS were defined by the consensus of National Cholesterol Education Program-Adult Treatment Panel III criteria. The association between NA and MetS was examined using linear regression analyses after controlling potential confounders. More participants in the highest quartile were obese in terms of general obesity (p = 0004) and abdominal obesity (p = 0.003) compared with subjects in the least quartile. A significant positive correlation was found between waist circumference (WC) and NA even after controlling for all potential confounders (p < 0.001). NA was positively associated with WC among adults living in Tehran.

Interaction of dietary acid load and general and central obesity with muscle strength and skeletal muscle mass.

BACKGROUND: We aimed to examine the combined association of dietary acid load and obesity with muscle strength. METHODS: This cross-sectional study was conducted on 270 adults (118 men and 152 women), aged 18-70 y. Dietary data were collected using a validated 168-item semi-quantitative food frequency questionnaire. Potential renal acid load (PRAL), net endogenous acid production (NEAP), and dietary acid load (DAL) were calculated. General obesity was defined as a body mass index (BMI) ≥30 kg/m2 and abdominal obesity was defined as a waist circumference (WC) ≥102 cm for men and ≥88 cm for women. Muscle strength was measured by a digital handgrip dynamometer. RESULTS: The mean of muscle strength was higher in participants classified as high-PRAL/BMI≥30 (P = 0.01), high-PRAL/WC < 102 (men) or 88 (women) (P = 0.002), high-NEAP/BMI≥30 (P = 0.002), high-NEAP/WC < 102 (men) or 88 (women) (P < 0.001) and also high-DAL/BMI≥30 (P = 0.01) and high-DAL/WC < 102 (men) or 88 (women) (P = 0.001) compare to other classifications in the crude model. Both for obese and non-obese people PRAL, NEAP, and DAL were associated with higher muscle strength, which is opposite to the acid hypothesis. These associations were not significant after adjustment for confounders. Also, the mean of skeletal muscle mass was higher in participants that were classified as high-PRAL/BMI≥30 and high-PRAL/WC < 102 (men)-or-88 (women), high-NEAP/BMI≥30, and high-NEAP/WC < 102 (men)-or-88 (women), high-DAL/BMI≥30 and high-DAL/WC < 102 (men)-or-88 (women) (Ptrend<0.001 for all). These significant associations remained significant after controlling for confounders. CONCLUSIONS: We found that the interaction of dietary acid load and general and central obesity could be associated with skeletal muscle mass but not muscle strength. All findings of association indicated higher muscle strength and skeletal muscle mass with higher acid diet measures, contrary to the acid hypothesis.

The low-carbohydrate-diet score is associated with resting metabolic rate: an epidemiologic study among Iranian adults.

PURPOSE: Low-carbohydrate diet (LCD) has been used for weight loss and preventing obesity, but the association of adherence to LCD and resting metabolic rate (RMR) has not been investigated. This study aimed to investigate the association between the low-carbohydrate-diet score (LCDS) and RMR among Iranian adults. METHODS: This cross-sectional study was conducted on 270 Iranian adults 18-70 y of age. To assess dietary intakes, participants completed a validated food frequency questionnaire. The LCDS was calculated based on carbohydrate, protein and fat intake, expressed as a percentage of energy. The higher score indicates the lower carbohydrate and the higher protein and fat intake. RMR was measured by indirect calorimetry after an overnight fast. RESULTS: Multivariate-adjusted means showed that RMR significantly increased across tertiles (p = 0.041). However, there were no significant differences in the mean of fat mass (FM) and fat-free mass (FFM) across tertiles of LCDS (p = 0.986 and p = 0.621, respectively). Also LCDS and RMR (r = 0.14, p = 0.021) were found to be correlated, but LCDS and FFM (r = 0.06, p = 0.323), FM (r = -0.05, p = 0.412), had no statistically significant correlation. RMR had a significant positive association with LCDs in the crude model (ß = 18.81, 95% CI: 2.55, 35.07, P = 0.024). Moreover, after controlling for covariates this association changed to non-significant (ß = -0.14, 95% CI: -7.05, 19.25, P = 0.03). CONCLUSION: Adherence to diets lower in carbohydrates and higher in fat and protein were associated with higher RMR. Further studies with a larger sample size are needed to confirm these findings.

Administration of dietary antioxidants for patients with inflammatory bowel disease: A systematic review and meta-analysis of randomized controlled clinical trials.

OBJECTIVE: Accumulating evidence has been reported regarding the effect of dietary antioxidants on clinical variables in IBD patients, however, findings are controversial. This systematic review and meta-analysis aimed to investigate effect of dietary antioxidants on clinical variables in patients with IBD or its subtypes. METHODS: We searched PubMed, Scopus, and ISI Web of Science from inception to January 2021 using relevant keywords. Data were pooled by using the random-effect model. All statistical analyses were done using STATA version 14. RESULTS: Our meta-analysis was exclusively done on studies about the effect of curcumin on IBD patients, because limited studies were done on other antioxidants. Curcumin administration resulted in significant increment of clinical remission in patients with IBD (SMD: 0.86%, 95% CI: 0.16, 1.56, p = 0.016), significant remission in clinical symptoms (SMD: -0.96 score, 95% CI: -1.34, -0.57, p < 0.001), and significant increment in endoscopic remission in IBD patients (SMD: 0.51%, 95% CI: 0.16, 0.85, p = 0.004), comparing to control group. Curcumin supplementation also made better clinical response than control group (SMD: 0.74%, 95% CI: 0.22, 1.26, p = 0.005) and also resulted in significant improvement in quality of life of patients with IBD, as compared to control group (SMD: 1.23 score, 95% CI: 0.72, 1.74, p < 0.001). CONCLUSIONS: Our meta-analysis showed that curcumin significantly improved clinical and endoscopic remissions in IBD patients. This supplementation also caused significant reduction in clinical symptoms of IBD patients along with better clinical response and the increased quality of life. Further researches with larger sample size and longer period of intervention are required to evaluate efficacy of dietary antioxidants on clinical variables in patients with IBD.

The interaction of aging with serum 25(OH)D and 1,25(OH)2 D status on muscle strength.

BACKGROUND: To investigate the combination relationship of age with serum 25-hydroxyvitamin D (25(OH) D) and 1,25-(OH)2D3 levels on muscle strength. METHODS: We performed a cross-sectional study on 270 subjects containing 115 men and 155 women. Serum concentration of 25(OH) D and 1,25-(OH)2D3 were assessed. Hand grip strength (HGS) was measured using a digital dynamometer. RESULTS: There was no significant difference in mean of HGS among tertiles of 25(OH)D (P = .350) and 1,25(OH)2 D (P = .467) before and after controlling for potential confounding factors. A significant difference in HGS was found between age categories in both crude (P < .001) and adjusted models (P = .018), where mean grip strength increased in the three first age categories, but decreased in the last group (48-69 years old). There was also a significant interaction between age and 25(OH) D (P = .049) and 1,25-(OH)2D3 (P = .047) on HGS, in which the combination effect increased the mean of muscle strength up to middle age after adjusting for confounders. CONCLUSIONS: Serum 25(OH)D and 1,25(OH)2 D were not related to muscle strength. However, age, and combination of age with both 25(OH)D and 1,25(OH)2 D, significantly resulted in improving in muscle strength up to middle age.

Higher health literacy score is associated with better healthy eating index in Iranian adults.

OBJECTIVE: Although there is some evidence for the importance of health literacy (HL), many health complications and nutrition knowledges such as portion size assessment, knowing the food labels, and choosing the nutrition sources affecting diet quality, data about HL and healthy eating index (HEI) are limited and controversial. The aim of this study was to evaluate the associations between HL and HEI in adults. METHODS: This cross-sectional study included 261 adults 18 to 65 y of age from five districts of Tehran, Iran. HL was estimated using the Health Literacy for Iranian Adult (HELIA) questionnaire. Dietary intake, sociodemographic data, physical activity, and anthropometric measurements were collected using validated questionnaires. Diet quality was assessed based on HEI-2015 scores using data from a food frequency questionnaire. RESULTS: Despite components of HEI-2015, the association between HEI-2015 and HL tertiles was significant (P of crude model = 0.007) even after adjustment for possible confounders. Multivariate regression showed a positive relationship between HL and HEI-2015 that was significant before (ß = 0.12, P = 0.04) and after controlling for the confounding effect in model 1 (ß = 0.14, P = 0.03). Additionally, a positive association between physical activity and HL was shown (ß = 0.12, P = 0.03) and finally among the HEI components, only saturated fats were significantly related to HL (ß = -0.11, P = 0.01). CONCLUSION: Findings from the present study confirmed a considerable association between HL and HEI and shows HL levels have an important role in adherence to the Iranian Dietary Guidelines.

Higher dietary insulin load and index are not associated with the risk of metabolic syndrome and obesity in Iranian adults.

BACKGROUND: Data about the relation between dietary insulin load (DIL) and dietary insulin index (DII) with metabolic syndrome (MetS) and obesity are scarce. Therefore, the present study aimed to examine the association of the insulinemic potential of the diet with MetS and obesity amongst Iranian adults. METHODS: This cross-sectional study was conducted amongst 850 adults aged 20-59 years. Dietary data were collected using a 168-item food frequency questionnaire. DIL was calculated using a standard formula and DII was obtained by dividing DIL by the total energy intake of each participant. The guidelines of the International Diabetes Federation were used to define MetS. General obesity was considered as body mass index ≥ 30 kg/m2 , and abdominal obesity as waist circumference ≥ 94 cm for men and ≥ 80 cm for women. RESULTS: Mean DIL and DII values were 101 684 ± 54 802 and 49.4 ± 33.4, respectively. The mean age of participants was 44.9 ± 10.7 years and 36.8%, 28.5% and 48.8% of participants were suffering from MetS, general and abdominal obesity, respectively. In contrast with DIL (P = .73), participants in the last quartile of DII (P = .62) had lower odds of MetS than the first quartile. There were non-significant inverse associations between DIL (P = .91, P = .85) and DII (P = .59, P = .53) with odds of general and abdominal obesity before and after the adjustment of confounders, respectively. CONCLUSIONS: We did not observe any significant association of DIL and DII with the risk of MetS and obesity amongst the Iranian population. Further prospective studies are needed to confirm the findings of this study.

A negative association of dietary advanced glycation end products with obesity and body composition in Iranian adults.

Obesity caused by excessive deposited fat is generally classified as BMI ≥ 30 kg/m2. Research regarding the association between dietary advanced glycation end products (dAGE) and obesity is limited. The aim of the present study was to investigate the association between dAGE and obesity and body composition in Iranian adults. This cross-sectional study included 265 adults aged 18-75 years from Tehran, Iran. dAGE were estimated using a validated semi-quantitative FFQ, according to the published food carboxymethyl lysine-AGE database for 549 routinely consumed food items for the Northeastern American multiethnic urban population, and were reported by dividing total energy intake. Dietary intake, sociodemographic data and physical activity status were collected using validated questionnaires, and anthropometric characteristics were measured. Body composition was assessed by bioelectrical impedance analysis, and obesity was defined based on WHO guidelines. The intake of fat and meat was significantly increased in higher tertiles, compared with the first tertile of dAGE (P < 0·001). No association between dAGE and body composition measures and obesity was observed; however, there was a significant negative association between dAGE and BMI (BMI; P = 0·01), waist circumference (P = 0·01), waist:hip ratio (P = 0·03), fat-free mass (P = 0·02) and muscle mass index (P = 0·01) in non-linear models. In conclusion, higher consumption of dAGE was associated with increased intake of fat and meat and was negatively related to changes in body composition measurements. Therefore, dAGE may connect obesity to diet by energy imbalance.

Associations between adherence to MIND diet and metabolic syndrome and general and abdominal obesity: a cross-sectional study.

BACKGROUND: There is a lack of studies examining the association between Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) and metabolic syndrome (MetS) and obesity. Thus, this study aimed to investigate the association of adherence to the MIND diet with MetS and general and abdominal obesity. METHODS: This cross-sectional study was performed on 836 Iranian adults, 18-75 years old. A 167-item food frequency questionnaire (FFQ) was used to assess dietary intakes of participants. Anthropometric measurements, blood pressure, fasting blood glucose and lipid profile of each participant were recorded. The guidelines of the National Cholesterol Education Program Adult Treatment Panel III (ATP III) was used to define MetS. RESULTS: Mean age of study participants was 47.7 ± 10.7 years. The prevalence of MetS was 36.1% and mean body mass index (BMI) and waist circumference (WC) was 27.7 ± 4.69 kg/m2 and 92.0 ± 12.4 cm respectively. Those who were in the third tertile of the MIND diet score compared to the first tertile had 12% lower odds of having the MetS (ORs: 0.88; 95% CI 0.62-1.24) but the association was not significant (P = 0.77). There was a significant inverse association between the MIND diet score and odds of reduced high-density lipoprotein cholesterol (HDL-C) (ORs: 0.59; 95% CI 0.41-0.85; P = 0.008) and general obesity (ORs: 1.190.80-1.78; 95% CI 0.80-1.78; P = 0.02) in crude model and after controlling for confounders. CONCLUSIONS: We found that the MIND diet score is inversely associated with odds of reduced HDL and general obesity in Iranian adults.

Effects of melatonin supplementation on oxidative stress: a systematic review and meta-analysis of randomized controlled trials.

OBJECTIVES: Previous studies showed that melatonin supplementation may suppress oxidative stress, however, the results have not been consistent. So, we conducted this meta-analysis to assess the precise relationship between melatonin supplementation and oxidative stress. METHODS: PubMed and Scopus were searched for randomized controlled trials that investigated the effect of melatonin supplementation on oxidative stress up to March 2020. Heterogeneity was assessed by Cochran's Q test and I-square (I 2) statistic. Data were pooled using the random effect model and standardized mean difference (SMD) was considered as the summary effect size. Also, standard methods were used for assessment of sensitivity analysis and publication bias. RESULTS: We included 15 related articles and our findings indicated that melatonin supplementation significantly increased total antioxidant capacity (TAC) level (SMD: 1.03, 95% CI: 0.24, 1.81, p=0.011) and reduced protein carbonyl (PCO) (SMD: -1.78, 95% CI: -2.97, -0.58, p=0.004) and malondialdehyde (MDA) levels (SMD: -0.94, 95% CI: -1.48, -0.40, p=0.001). Additionally, there was considerable effect on TAC level by using ≥20 mg/d melatonin and in people under 35 years old. MDA level also decreased using dosage of below 20 mg/d and in people ≥35 years old. CONCLUSIONS: The present study showed a promising effect of melatonin administration for reducing MDA, PCO, and increasing TAC levels. However, further studies especially with more attention to PCO level assessment are needed to confirm the findings of the present study in larger samples on different populations.

Dietary Total Antioxidant Capacity and Its Association with Renal Function and Progression of Chronic Kidney Disease in Older Adults: a Report from a Developing Country.

While evidence exists for an association between the dietary total antioxidant capacity (DTAC), mortality, metabolic syndrome, and cardiovascular diseases, data about DTAC and renal function, and progression of chronic kidney disease (CKD) are scarce. This study aimed to determine the associations between DTAC, renal function, and progression of CKD in older adults. The present cross-sectional study consisted of 226 older adults aged ≥ 60 years old from five districts of Tehran, Iran. DTAC was estimated using the oxygen radical absorbance capacity (ORAC) method. Dietary intake, socio-demographic data, medical history, and anthropometric measurements were collected using a validated questionnaire. The estimated glomerular filtration rate (eGFR) was assessed from serum creatinine. Albumin to creatinine ratio (ACR) was calculated by dividing albumin concentration by creatinine concentration and reported as mg/g. The DTAC ranged from 112.8 to 2,553.9. Analyses indicated that DTAC was not associated with eGFR (p = 0.35) and ACR (p = 0.91) even after controlling for confounding variables. Additionally, in logistic regression, no association between eGFR < 60 mL/min/1.73 m2 (p = 0.32) and ACR ≥ 30 mg/g (p = 0.32) with DTAC was observed, which was independent of confounding variables. We observed that more compliance with DTAC is not associated with renal function and CKD progression. Further studies are needed to confirm the findings of the present study in larger samples on different populations.

Breakfast-Based Dietary Patterns and Obesity in Tehranian Adults.

BACKGROUND: Breakfast is an important meal of the day that contributes to an overall healthy dietary pattern, better nutrient intake, and diet quality. This study sought to investigate the relationship between breakfast patterns and general and central obesity among middle-aged adults. METHODS: In this cross-sectional study of 840 apparently healthy women and men, aged 20-59 years, we assessed usual dietary intake by means of three 24-hour dietary recalls and we took anthropometric measurements. Dietary patterns were subsequently identified by factor analysis. To assess the association between breakfast composition and central and general obesity, logistic regression analysis was performed. RESULTS: We identified three major dietary patterns by factor analysis: the "bread and grains, meat products, and coffee" dietary pattern, the "sweets, tea and coffee" dietary pattern, and the "fruits, vegetables, and eggs" dietary pattern. Those people in the third tertile of the "sweets, tea and coffee" dietary category had a greater chance of having central obesity (odds ratio, 1.80; 95% confidence interval, 1.25-2.59; P=0.001). Moreover, higher adherence to the "bread and grains, meat products, and coffee" pattern increased the chance of central obesity (odds ratio, 1.67; 95% confidence interval, 1.47-1.97; P=0.03). CONCLUSION: Overall, our results suggest that specific breakfast dietary patterns are associated with increased odds of central obesity in Iranian adults.