This study aimed to explore the combined effects of serum vitamin-D level and tobacco exposure on the risk of overweight and obesity in children. This cross-sectional study analysed the data of 11 636 children aged 2–17 years from the National Health and Nutrition Examination Surveys database between 2007 and 2018. Univariable and multivariate weighted logistic regression models were used to analyse the associations of serum vitamin-D or cotinine levels with overweight and obesity in children as well as the combined effects of serum vitamin-D and cotinine on the risk of overweight and obesity in children. Subgroup analysis was performed in terms of gender, age, race and household smokers. OR with corresponding 95 % CI was presented. The elevated risk of overweight and obesity in children was found in those with serum vitamin-D < 20 ng/ml (OR = 1·44, 95 % CI: 1·29, 1·61). Also, the odds of overweight and obesity in children was 1·14 (OR = 1·14, 95 % CI: 1·01, 1·29) in children with cotinine ≥ 0·05 ng/ml. Relative to participants with serum vitamin-D ≥ 20 ng/ml and cotinine < 0·05 ng/ml, increased risk of overweight and obesity was identified in those with serum vitamin-D < 20 ng/ml and cotinine < 0·05 ng/ml (OR = 1·45, 95 % CI: 1·26, 1·68) and serum vitamin-D < 20 ng/ml and cotinine ≥ 0·05 ng/ml (OR = 1·62, 95 % CI: 1·38, 1·91). Serum vitamin-D and cotinine exposure had combined effects on the risk of overweight and obesity in children.

The percentage of US adults following low-carbohydrate diets (LCD) doubled in the last decade. Some researchers observed this trend with concern and highlighted the potential for nutritional deficiencies and impaired overall diet quality with LCD. The present study investigated nutrient intake in a nationally representative sample of 307 US adults following an LCD. Using cross-sectional data from the National Health and Nutrition Examination Surveys, we compared nutrient intake profiles in said individuals with the daily nutritional goals specified in the current 2020–2025 Dietary Guidelines for Americans (DGA). Results were then compared with the general population consuming a standard American diet. Almost 57 % of low-carbohydrate dieters were female, and the mean age was 48·67 (1·35) years. Individuals consuming LCD exceeded the recommendations for saturated fat, total lipid and sodium intake (both sexes). An insufficient intake was observed for fibre, Mg, potassium and several other vitamins (vitamins A, E, D in both sexes as well as vitamin C in men and folate in women). Neither men nor women met the recommendations for fibre intake. A comparable picture was found for the general population. The potentially insufficient intake of several essential nutrients in LCD warrants consideration and a careful assessment with regard to the current DGA.

We aim to examine the relation of several folate forms (5-methyltetrahydrofolate (5-mTHF), unmetabolised folic acid (UMFA) and MeFox) with kidney function and albuminuria, which remained uncertain. The cross-sectional study was conducted in 18 757 participants from National Health and Nutrition Examination Survey 2011–2018. The kidney outcomes were reduced estimated glomerular filtration rate (eGFR) (<60 ml/min/1·73 m2), microalbuminuria (albumin:creatinine ratio (ACR) of 30–299 mg/g) and macroalbuminuria (ACR ≥ 300 mg/g). Overall, there were significant inverse associations between serum 5-mTHF and kidney outcomes with significant lower prevalence of reduced eGFR (OR, 0·71; 95 % CI: 0·57, 0·87) and macroalbuminuria (OR, 0·65; 95 % CI: 0·46, 0·91) in participants in quartiles 3–4 (v. quartiles 1–2; both Pfor trend across quartiles <0·05). In contrast, there were significant positive relationship between serum UMFA and kidney outcomes with significant higher prevalence of reduced eGFR in participants in quartiles 2–4 (v. quartile 1; OR, 2·12; 95 % CI: 1·45, 3·12; Pfor trend <0·001) and higher prevalence of macroalbuminuria in participants in quartile 4 (v. quartiles 1–3; OR, 1·46; 95 % CI: 1·06, 2·01; Pfor trend <0·001). However, there was no significant associations of 5-mTHF and UMFA with microalbuminuria. In addition, there were significant positive relationships of serum MeFox with reduced eGFR, microalbuminuria and macroalbuminuria (all Pfor trend <0·01). In conclusion, higher 5-mTHF level, along with lower UMFA and MeFox level, was associated with lower prevalence of kidney outcomes, which may help counsel future clinical trials and nutritional guidelines regarding the folate supplement.

We examined the association between plasma antioxidant levels and markers of inflammation, including C-reactive protein (CRP) and fibrinogen (FG) in US adults. National Health and Nutrition Examination Survey participants examined between 2001 and 2002 were included, if data on CRP or FG levels. Serum vitamins A and E, two retinyl esters, and six carotenoids were measured using HPLC with photodiode array detection. Multivariable-adjusted linear regression analyses accounted for the survey design and sample weights. A total of 784 eligible participants were included; 47·5 % (n 372) were men. In multivariable linear regression models, serum α-carotene, trans-β-carotene, cis-β-carotene, β-cryptoxanthin, combined lutein/zeaxanthin, trans-lycopene, retinyl palmitate, α-tocopherol, retinol and 25-hydroxy vitamin D were negatively associated with serum CRP (P<0·001 for all comparisons). Serum α-carotene, trans-β-carotene, cis-β-carotene, combined lutein/zeaxanthin, trans-lycopene, α-tocopherol, retinol and 25-hydroxy vitamin D were negatively associated with serum FG levels (P<0·001 for all comparisons). In the same model, the risk of CVD, defined as CRP levels >3 mg/l, decreased with increasing levels of antioxidants (α-carotene, trans-β-carotene, cis-β-carotene, vitamins A and E). Furthermore, we found a moderate impact of adiposity on the link between antioxidants and CRP. Our results suggest that the lower the antioxidants levels, the higher the inflammatory burden, based on CRP and FG levels. Adiposity moderately affects this association. Furthermore, an inverse relationship between CVD risk and antioxidant levels was observed. This finding suggests that reduced levels of vitamins with antioxidant properties may predispose to increased CVD risk.

The present cross-sectional study sought to determine the potential relationships between the intake of dairy foods (total dairy products, milk and cheese) and cognitive function through information garnered in the National Health and Nutrition Examination Surveys (1988–94 and 1999–2002). Cognitive measures of vasomotor speed, coding speed and immediate memory recall were assessed from a simple reaction time task (SRTT), symbol–digit substitution test (SDST) and serial digit learning task, respectively, in adults 20–59 years of age. A summation of the percentile rank scores on each of the three tests provided a measure of overall cognitive function. In adults 60 years of age and above, a story recall test and a digit–symbol substitution test (DSST) were utilised to determine cognitive function in an elderly population. The results indicated that cognitive scores for the SRTT were not different between consumers and non-consumers of dairy foods. However, there were associations observed between 20- and 59-year-old consumers of total dairy foods and a higher SDST percentile score (53·2 (se 1·3) to 49·4 (se 2·0)) and a calculated global cognitive percentile score (53·3 (se 1·1) to 50·2 (se 1·4)) compared with non-consumers. A similar significant association was observed with cheese consumers. In adults over 60 years of age, an association between total dairy product consumption and higher DSST percentile scores (51·5 (se 1·9) to 46·2 (se 3·0)) was also observed. These findings highlight the need for additional research on how dairy products may affect cognition and by what mechanisms, through its nutrients or other components.