Cross sectional determinants of VO2 max in free living Iranians: Potential role of metabolic syndrome components and vitamin D status.

BACKGROUND AND AIMS: The purpose of the study was to evaluate the determinants of cardiorespiratory fitness (CRF) in Iranian adults and the potential contribution of vitamin D status. METHODS: In this cross-sectional study 264 cases (116 men and 147 women aged 18-70 years old were participated. Maximal oxygen consumption (VO2 max) was measured by the Bruce protocol utilizing treadmill exercise testing. Anthropometric data, body composition and fasting blood glucose and lipid concentrations were measured. Serum levels of 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D) were assessed using enzyme-linked immunosorbent assay. Stepwise linear regression analysis was applied to determine significant predictors of VO2 peak. We tested non-linear (quadratic and cubic terms) versus linear association of adjusted (for determinants) VO2 max and vitamin D levels. RESULTS: Multiple regression results showed that fat free mass, HDL-C and physical activity, waist circumference, age and sex were determinants of VO2 peak. All of these explained the 65.3% of VO2 peak. There was a non-linear cubic association (R2 = 0.03, p = 0.046) between serum 25(OH)D and adjusted VO2 peak in which 25(OH)D in people with a high 25(OH)D levels (>60 nmol/L), had better fitness and those with serum 25(OH) less than 20 nmol/L. We found no linear and non-linear associations between serum 1,25(OH)2 D and adjusted VO2 max. CONCLUSIONS: Our results showed that waist circumference and HDL-C, as components of metabolic syndrome, contribute ∼2% to the variance in VO2 max. Moreover, high concentrations of 25(OH)D but not 1,25(OH)2 D may make additional contributions to CRF.

Association of health literacy and nutritional literacy with sun exposure in adults using structural equation modelling.

BACKGROUND: Inadequate health and nutritional literacy is a common problem among adults, associated with poor health outcomes. Therefore, this study aimed to investigate the relationship between health literacy and nutritional literacy to sun exposure behaviour. METHODS: We conducted a cross-sectional study on 261 adults (18-65 years) in Iran. Data was collected on knowledge, motivation, health literacy, nutritional literacy, and sun exposure behaviour using an interview-assisted questionnaire. Using the information-motivation-behavioural skills model and structural equation modeling, we tested whether health and nutritional literacy were associated with the relationships between knowledge of vitamin D, attitudes toward sun exposure, and sun exposure behaviour. Different models using structural equation modeling were performed to analyze the data. RESULTS: The finding showed that health literacy (ß = 0.29, p < 0.001) and nutritional literacy (ß = 0.14, p = 0.02) was directly associated with sunlight exposure. Indirect relationships also existed between knowledge and sunlight exposure through health literacy (ß = 0.33, p < 0.001) and nutritional literacy (ß = 0.22, p = 0.01). The model had good fit (x2/df = 1.422; RMSEA = 0.040; CFI = 0.851; NFI = 0.657). There was no significant relationship between health literacy and motivation (ß = 0.11, p = 0.16), nutritional literacy and motivation (ß = 0.06, p = 0.42) and motivation and sun exposure (ß = 0.01, p = 0.91). CONCLUSIONS: The findings showed that individuals with sufficient health literacy and nutritional literacy were more likely to have exposure to sunlight. Health and nutritional literacy should be considered when educating adults about vitamin D supplements and sunlight exposure.

The association between lunch composition and obesity in Iranian adults.

We aimed to assess the dietary composition of lunch meal using a posteriori-derived dietary patterns and to determine the association of lunch composition with obesity in a sample of Iranian adults. This cross-sectional study was conducted on 850 men and women in Tehran (aged 20-59 years). Dietary intakes were assessed using three 24-h dietary recalls, and dietary patterns were identified via principal component factor analysis. For each identified pattern, scores were calculated for each participant and then classified into tertiles. Central obesity was defined WHO criteria. General obesity was defined as a BMI of more than 30 kg/m2. Three major dietary patterns were identified at lunch meal using twelve food groups: 'Bread, grains and fat', 'Western' and 'Potato and eggs'. After adjustment for potential confounders, participants at the top tertile of the 'Bread, grains and fat' dietary pattern had greater odds for a higher waist-to-hip ratio (WHR), compared with those in the lowest tertile (OR: 1·44, 95 % CI 1·01, 2·07). However, we found no association between 'Western' or 'potato and eggs' patterns and WHR (OR: 0·89, 95 % CI 0·62, 1·28 and OR: 1·16, 95 % CI 0·69, 1·42, respectively). None of the identified dietary patterns was associated when defining obesity with waist circumference or BMI. In conclusion, participants had a greater chance of central obesity defined based on WHR following a lunchtime pattern with a higher and positive loading factor for 'Bread, grains and fat'.

Effect of dark chocolate on flow-mediated dilatation: Systematic review, meta-analysis, and dose-response analysis of randomized controlled trials.

BACKGROUND & AIMS: We aimed to investigate the effect of dark chocolate on flow-mediated dilatation (FMD) using randomized clinical trials. METHODS: In order to find relevant papers, PubMed and Scopus were searched up to November 2018. Mean differences of eligible trials were pooled using random-effects models (the Der Simonian-Laird estimator). Subgroup analysis was conducted to assess the potential source of heterogeneity. Fractional polynomial modeling was used to explore dose-response relationships. RESULTS: Seventeen studies involving 615 participants assessed the effect of dark chocolate and six included studies involving 179 participants investigated the effect of flavonoids on FMD. Chronic consumption of dark chocolate and flavan-3-ols both increased FMD (0.69, 95% CI 0.22-1.16, p < 0.001, 1.16, 95% CI 0.52-1.80 p = 0.001, respectively). Pooling chronic consumption of dark chocolate and flavonoids improved FMD (p < 0.001) with significant heterogeneity among studies (p < 0.001; I2 = 64.2%). Type of intervention (flavonoid or cocoa, p = 0.230-dark chocolate, p < 0.001) was a source of heterogeneity. Also, we found that acute consumption of dark chocolate (p < 0.001) and both dark chocolate and flavonoids (p < 0.001) had beneficial effects on FMD. Consumption of flavonoids more than 40 g/day increases FMD with the highest mean of FMD in doses around 40-60 g/day. A non-linear dose-response has been also found after the chronic consumption of dark chocolate on FMD with a greater reduction in doses lower than 20 g/day. CONCLUSION: Current evidence indicated the beneficial effect of acute and chronic consumption of dark chocolate and flavonoids on FMD. Non-linear associations should be considered when investigating the effects of dietary intakes on FMD.

Fermented foods and inflammation: A systematic review and meta-analysis of randomized controlled trials.

OBJECTIVE: The effect of fermented foods consumption on inflammation has been investigated in several studies, but findings are inconsistent. Therefore we conducted a meta-analysis to examine the effect of fermented foods on inflammatory biomarkers including C-reactive protein (CRP), interleukin (IL)-6 and tumor necrosis factor (TNF)-α in the general adult population. DESIGN: systematic review and meta-analysis. METHODS: In this systematic review and meta-analysis, randomized controlled trials in the general adult population comparing fermented foods with a control product were searched from two literature databases (PubMed and Scopus) up to June 4, 2019. Trials with mean difference (MD) of 95% confidence interval (CI) were pooled using random effect model. Heterogeneity was assessed using Cochran's Q and I2 tests. Subgroup analysis was applied to define possible sources of heterogeneity. RESULTS: The search strategy identified 3293 documents. Overall, 26 publications with 1461 people met the inclusion criteria. Our results indicated that intake of fermented foods could reduce serum TNF-α levels ((WMD = -8.26, 95% CI: -14.61, -1.91, p = 0.01; I2 = 99.9%, p < 0.001)). However, no change was observed in serum levels of CRP ((WMD = -0.21, 95% CI: -0.47, 0.05, p = 0.11), I2 = 93.8%, p < 0.001) and IL-6 ((WMD = 0.31, 95% CI:-3.79, 4.43, p = 0.88), I2 = 99.3%, p < 0.001). CONCLUSION: Our findings showed that intake of fermented foods did not improve serum CRP and IL-6. We observed a reduction in pooled effect of TNF-α following intake of fermented foods.