Epidemiological studies have suggested that flavonoids exhibit preventive effects on degenerative diseases. However, lack of sufficient data on flavonoid intake has limited evaluating the proposed effects in populations. Therefore, we aimed to estimate the total and individual flavonoid intakes among Korean adults and determine the major dietary sources of these flavonoids. We constructed a flavonoid database of common Korean foods, based on the food list reported in the 24-h recall of the Korea National Health and Nutrition Examination Survey (KNHANES) 2007-2012, using data from the Korea Functional Food Composition Table, US Department of Agriculture flavonoid database, Phenol-Explorer database and other analytical studies. This database, which covers 49 % of food items and 76 % of food intake, was linked with the 24-h recall data of 33 581 subjects aged ≥19 years in the KNHANES 2007-2012. The mean daily intake of total flavonoids in Korean adults was 318·0 mg/d, from proanthocyanidins (22·3 %), flavonols (20·3 %), isoflavones (18·1 %), flavan-3-ols (16·2 %), anthocyanidins (11·6 %), flavanones (11·3 %) and flavones (0·3 %). The major contributing food groups to the flavonoid intake were fruits (54·4 %), vegetables (20·5 %), legumes and legume products (16·2 %) and beverages and alcohols (3·1 %), and the major contributing food items were apples (21·9 %), mandarins (12·5 %), tofu (11·5 %), onions (9·6 %) and grapes (9·0 %). In the regression analysis, the consumption of legumes and legume products, vegetables and fruits predicted total flavonoid intake the most. The findings of this study could facilitate further investigation on the health benefits of flavonoids and provide the basic information for establishing recommended flavonoid intakes for Koreans.

BackgroundBoth short and long sleep duration have been consistently studied as a risk factor for obesity, hyperglycemia and hypertension. In this cross-sectional study, we provide an updated analysis of the Health Examinees (HEXA) study on the association between sleep duration and metabolic syndrome (MetS) occurrence among Koreans age 40–69 year olds.MethodsA total of 133,608 subjects (44,930 men, 88,678 women) were enrolled in the HEXA study 2004–2013. Sleep duration was categorized into 4 sleep categories (< 6 h, 6 to < 8 h, 8 to < 10 h, ≥10 h). MetS criterion was based on the National Cholesterol Education Program, Adult Treatment Panel III. Logistic regression was used to calculate adjusted odds ratios (ORs) and 95% confidence intervals (CIs).ResultsCompared with individuals sleeping 6 to < 8 h per day, less than 6 h of sleep was associated with MetS (multivariable adjusted OR: 1.12, 95% CI: 1.05–1.19) and elevated waist circumference (1.15, 1.08–1.23) among men; with elevated waist circumference (1.09, 1.04–1.14) among women. Greater than 10 h of sleep was associated with MetS (1.28, 1.08–1.50) and elevated triglycerides (1.33, 1.14–1.56) among men; with MetS (1.40, 1.24–1.58), elevated waist circumference (1.14, 1.02–1.27), elevated triglycerides (1.41, 1.25–1.58), reduced high-density lipoprotein cholesterol (HDL-C) (1.24, 1.12–1.38), and elevated fasting glucose (1.39, 1.23–1.57) among women.ConclusionsLess than 6 h of sleep is associated with elevated waist circumference among both men and women and with MetS among men only. Greater than 10 h of sleep is associated with MetS and elevated triglycerides among both men and women and with elevated waist circumference, reduced HDL-C, and elevated fasting glucose among women only.Electronic supplementary materialThe online version of this article (10.1186/s12889-018-5557-8) contains supplementary material, which is available to authorized users.

The aim of the present study was to identify the association of dietary patterns with osteoporosis in Korean postmenopausal women from the Korean Health and Nutrition Examination Survey 2008 -10. The present cross-sectional analysis included 3735 postmenopausal women who completed a health interview, nutrition survey and a health examination including bone mineral density (BMD) measurements. The general characteristics and dietary intakes of the participants were obtained using a standardised questionnaire and a 24 h recall method, respectively. The BMD of the femoral neck and lumbar spine was measured using dual-energy X-ray absorptiometry; osteoporosis was defined based on the WHO T-score criteria. Overall, we identified four dietary patterns using factor analysis as follows: 'meat, alcohol and sugar', 'vegetables and soya sauce', 'white rice, kimchi and seaweed' and 'dairy and fruit', which accounted for 30·9 % of the total variance in food intake (11·3, 7·7, 6·0 and 5·9 %, respectively). The subjects in the highest quintile of the 'dairy and fruit' pattern showed a decreased risk of osteoporosis of the lumbar spine (53 %) compared with those in the lowest quintile, after adjusting for covariates (OR 0·47, 95 % CI 0·35, 0·65, P for trend,0·0001). In contrast, the 'white rice, kimchi and seaweed' dietary pattern was negatively associated with bone health (OR 1·40, 95 % CI 1·03, 1·90, P for trend¼0·0479). The present results suggest that an increased intake of dairy foods and fruits in the traditional Korean diet, based on white rice and vegetables, may decrease the risk of osteoporosis in Korean postmenopausal women.

Our results suggest that a dietary pattern with high intake of dairy products, fruits and whole grains may contribute positively to bone health in a Korean adult population, and dietary pattern-based strategies could have potential in promoting bone health.

Higher SES leads to lower prevalence of anemia and IDA in Korean adolescent girls. This may be due to the fact that higher SES individuals consume more iron and vitamin C.