Major Gaps in Understanding Dietary Supplement Use in Health and Disease.

Precise dietary assessment is critical for accurate exposure classification in nutritional research, typically aimed at understanding how diet relates to health. Dietary supplement (DS) use is widespread and represents a considerable source of nutrients. However, few studies have compared the best methods to measure DSs. Our literature review on the relative validity and reproducibility of DS instruments in the United States [e.g., product inventories, questionnaires, and 24-h dietary recalls (24HR)] identified five studies that examined validity (n = 5) and/or reproducibility (n = 4). No gold standard reference method exists for validating DS use; thus, each study's investigators chose the reference instrument used to measure validity. Self-administered questionnaires agreed well with 24HR and inventory methods when comparing the prevalence of commonly used DSs. The inventory method captured nutrient amounts more accurately than the other methods. Reproducibility (over 3 months to 2.4 years) of prevalence of use estimates on the questionnaires was acceptable for common DSs. Given the limited body of research on measurement error in DS assessment, only tentative conclusions on these DS instruments can be drawn at present. Further research is critical to advancing knowledge in DS assessment for research and monitoring purposes.

Dietary Isoflavone Intake and Breast Cancer Prognosis: A Prospective Analysis and Meta-Analysis.

We aimed to examine the association between dietary isoflavone intake and the risk of breast cancer recurrence and summarize evidence on the role of dietary isoflavone intake in breast cancer prognosis. This prospective study included 592 breast cancer survivors who completed a dietary assessment. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models. Of the studies published until May 31, 2023, that were searched in PUBMED and EMBASE databases, 14 studies were selected. Adjusted HRs were combined using fixed- or random-effects models. During the median follow-up of 4.3 years, 47 recurrences were identified. The HR (95% CI) for recurrence comparing the highest versus the lowest tertile of isoflavones intake was 1.29 (0.60-2.78). In a meta-analysis of previously published data and ours, dietary isoflavone intake was associated with a better breast cancer prognosis. The combined HRs (95% CIs) comparing the extreme categories were 0.81 (0.67-0.98) for recurrence and 0.85 (0.76-0.96) for all-cause mortality. A nonlinear inverse association was observed between isoflavone intake and the risk of recurrence and all-cause mortality. Our study suggests that dietary isoflavone intake is associated with a favorable prognosis in breast cancer survivors and warrants further investigation.

Association between nut consumption and low muscle strength among Korean adults.

Nuts are an important component of a healthy diet, but little has been known about their effects on muscle health. Therefore, this study examined the association between nut consumption and low muscle strength among Korean adults. This cross-sectional analysis was conducted using single 24-h recall and handgrip strength data from 3962 younger adults 19-39 years, 6921 middle-aged adults 40-64 years and 3961 older adults ≥65 years participated in the seventh cycle (2016-2018) of the Korea National Health and Nutrition Examination Survey. Low muscle strength was defined as handgrip strength <28 kg for men and <18 kg for women. Sex-specific OR were obtained for younger, middle-aged and older adults using multivariable logistic regression analyses. About one in four Korean adults were consuming nuts (using a culinary definition) with peanut being the most frequently consumed type. After adjustment for age, BMI, total energy intake, household income, alcohol consumption, smoking, resistance exercise, medical history and dietary protein intake, nut consumption was associated with the lower risk of low muscle strength among older adults ≥65 years (men: OR 0·55, 95 % CI (0·38, 0·79); women: OR 0·69, 95 % CI (0·51, 0·93)); however, this association was not observed among younger adults 19-39 years or middle-aged adults 40-64 years. Our results suggest that consuming nuts might be beneficial in lowering the risk of low muscle strength among Korean older adults.

A narrative review of nutrient based indexes to assess diet quality and the proposed total nutrient index that reflects total dietary exposures.

A priori dietary indices provide a standardized, reproducible way to evaluate adherence to dietary recommendations across different populations. Existing nutrient-based indices were developed to reflect food/beverage intake; however, given the high prevalence of dietary supplement (DS) use and its potentially large contribution to nutrient intakes for those that use them, exposure classification without accounting for DS is incomplete. The purpose of this article is to review existing nutrient-based indices and describe the development of the Total Nutrient Index (TNI), an index developed to capture usual intakes from all sources of under-consumed micronutrients among the U.S. population. The TNI assesses U.S. adults' total nutrient intakes relative to recommended nutrient standards for eight under-consumed micronutrients identified by the Dietary Guidelines for Americans: calcium, magnesium, potassium, choline, and vitamins A, C, D, E. The TNI is scored from 0 to 100 (truncated at 100). The mean TNI score of U.S. adults (≥19 y; n = 9,954) based on dietary data from NHANES 2011-2014, was 75.4; the mean score for the index ignoring DS contributions was only 69.0 (t-test; p < 0.001). The TNI extends existing measures of diet quality by including nutrient intakes from all sources and was developed for research, monitoring, and policy purposes.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.1967872.

The Total Nutrient Index is a Useful Measure for Assessing Total Micronutrient Exposures Among US Adults.

BACKGROUND: Most dietary indices reflect foods and beverages and do not include exposures from dietary supplements (DS) that provide substantial amounts of micronutrients. A nutrient-based approach that captures total intake inclusive of DS can strengthen exposure assessment. OBJECTIVES: We examined the construct and criterion validity of the Total Nutrient Index (TNI) among US adults (≥19 years; nonpregnant or lactating). METHODS: The TNI includes 8 underconsumed micronutrients identified by the Dietary Guidelines for Americans: calcium; magnesium; potassium; choline; and vitamins A, C, D, and E. The TNI is expressed as a percentage of the RDA or Adequate Intake to compute micronutrient component scores; the mean of the component scores yields the TNI score, ranging from 0-100. Data from exemplary menus and the 2003-2006 (≥19 years; n = 8861) and 2011-2014 NHANES (≥19 years; n = 9954) were employed. Exemplary menus were used to determine whether the TNI yielded high scores from dietary sources (women, 31-50 years; men ≥ 70 years). TNI scores were correlated with Healthy Eating Index (HEI) 2015 overall and component scores for dairy, fruits, and vegetables; TNI component scores for vitamins A, C, D, and E were correlated with respective biomarker data. TNI scores were compared between groups with known differences in nutrient intake based on the literature. RESULTS: The TNI yielded high scores on exemplary menus (84.8-93.3/100) and was moderately correlated (r = 0.48) with the HEI-2015. Mean TNI scores were significantly different for DS users (83.5) compared with nonusers (67.1); nonsmokers (76.8) compared with smokers (70.3); and those living with food security (76.6) compared with food insecurity (69.1). Correlations of TNI vitamin component scores with available biomarkers ranged from 0.12 (α-tocopherol) to 0.36 (serum 25-hydroxyvitamin D), and were significantly higher than correlations obtained from the diet alone. CONCLUSIONS: The evaluation of validity supports that the TNI is a useful construct to assess total micronutrient exposures of underconsumed micronutrients among US adults.

Diets high in glycemic index and glycemic load are associated with an increased risk of metabolic syndrome among Korean women.

BACKGROUND AND AIMS: Accurate estimation of the glycemic index (GI) and glycemic load (GL) of diets is essential when assessing health implications of dietary GI and GL. The present study aimed to estimate dietary GI and GL utilizing the updated GI tables with a large number of new, reliable GI values and assess their associations with metabolic syndrome among Korean adults. METHODS AND RESULTS: We analyzed data from 3317 men and 6191 women for this cross-sectional study. Dietary intake was assessed with a validated food frequency questionnaire. Metabolic syndrome and its components were defined based on the harmonized criteria with Korean-specific cutoffs for waist circumference. Multivariate logistic regression was used to estimate adjusted odds ratios (ORs) and 95% confidence intervals (CIs). Compared with women in the lowest quintiles of energy-adjusted dietary GI and GL, women in the highest quintiles had significantly greater risks of metabolic syndrome (GI, OR = 1.56, 95% CI = 1.18-2.06; GL, OR = 1.80, 95% CI = 1.27-2.57), elevated blood pressure, reduced high-density lipoprotein cholesterol (HDL-C, both GI and GL), elevated triglycerides (GI only), elevated waist circumference, and elevated fasting glucose (GL only). Among men, no significant association was noted except for a higher risk of reduced HDL-C (OR = 1.59, 95% CI = 1.01-2.29) in the highest quintile of energy-adjusted dietary GI than in the lowest quintile. CONCLUSION: Our findings suggest that dietary GI and GL are positively associated with metabolic syndrome risk among women, but not men, in Korea.

Trends in Nutrient- and Non-Nutrient-Containing Dietary Supplement Use among US Children from 1999 to 2016.

OBJECTIVES: To characterize dietary supplement use among US children, including product type, motivations, user characteristics, and trends over time with a primary focus on non-vitamin/non-mineral dietary supplements (NVNM). STUDY DESIGN: Overall, NVNM, and vitamin and/or mineral dietary supplement only (VM-only) use; motivations for use; and trends in use over time were examined in children (≤19 years of age) using the National Health and Nutrition Examination Survey 1999-2016 data (n = 42 510). RESULTS: Between 1999 and 2016, overall dietary supplement and VM-only dietary supplement use among all children remained relatively stable at ∼30%; yet, NVNM dietary supplement use increased from 2.9% to 6.4%, mainly due to increased use of omega-3 polyunsaturated fatty acids. NVNM use was greater in boys than in girls (3.9% vs 3.3%), and greater in older children than in younger children (Ptrend < .0001), the opposite of what was observed with VM-only dietary supplement use. Although both user groups shared 2 primary motivations, both motivations were reported by a significantly greater percent of vitamin and/or mineral dietary supplement users vs NVNM users: to maintain health (38.7% vs 23.1%) and to improve health (33.1% vs 22.6%). NVNM users were much more likely to use dietary supplement for relaxation, stress, and sleep; for mental health; and for colon and bowel health. CONCLUSIONS: Although the prevalence of any dietary supplement and VM-only dietary supplement use among US children has both remained stable, the prevalence of NVNM use has increased substantially over time. Yet, NVNM use remains relatively low overall. NVNM use exhibited different patterns by sex, age, and motivations when compared with vitamin and/or mineral dietary supplement use. Despite increasing NVNM use, high-quality evidence supporting their use is lacking, especially in children.

Dietary Protein Intake Is Positively Associated with Appendicular Lean Mass and Handgrip Strength among Middle-Aged US Adults.

BACKGROUND: Sarcopenia, a progressive loss of skeletal muscle mass and strength, can begin in the 4th decade of life. Protein intake predicts skeletal muscle mass and strength among older adults, but knowledge of similar associations among middle-aged adults is lacking. OBJECTIVES: We aimed to assess associations between protein intake and skeletal muscle mass, characterized by appendicular lean mass adjusted for BMI [in kg/m2 (ALMBMI)], and muscle strength, represented by handgrip strength adjusted for BMI (GSMAXBMI), among middle-aged adults. METHODS: We analyzed cross-sectional data from 1209 men and 1208 women aged 40-59 y in the 2011-2014 NHANES. Protein intake per kilogram actual body weight (BW), assessed by two 24-h recalls, was examined as continuous and categorical parameters [low (

Comparison of 4 Methods to Assess the Prevalence of Use and Estimates of Nutrient Intakes from Dietary Supplements among US Adults.

BACKGROUND: Accurate and reliable methods to assess prevalence of use of and nutrient intakes from dietary supplements (DSs) are critical for research, clinical practice, and public health monitoring. NHANES has been the primary source of DS usage patterns using an in-home inventory with a frequency-based DS and Prescription Medicine Questionnaire (DSMQ), but little is known regarding DS information obtained from 24-h dietary recalls (24HRs). METHODS: The objectives of this analysis were to compare results from 4 different methods for measuring DS use constructed from two data collection instruments (i.e., DSMQ and 24HR) and to determine the most comprehensive method for measuring the prevalence of use and estimating nutrient intakes from DS for selected nutrients. NHANES 2011-2014 data from US adults (aged ≥19 y; n = 11,451) were used to examine the 4 combinations of methods constructed for measuring the prevalence of use of and amount of selected nutrients from DSs (i.e., riboflavin, vitamin D, folate, magnesium, calcium): 1) DSMQ, 2) 24HR day 1, 3) two 24HRs (i.e., mean), and 4) DSMQ or at least one 24HR. RESULTS: Half of US adults reported DS use on the DSMQ (52%) and on two 24HRs (mean of 49%), as compared with a lower prevalence of DS use when using a single 24HR (43%) and a higher (57%) prevalence when combining the DSMQ with at least one 24HR. Mean nutrient intake estimates were highest using 24HR day 1. Mean supplemental calcium from the DSMQ or at least one 24HR was 372 mg/d, but 464 mg/d on the 24HR only. For vitamin D, the estimated intakes per consumption day were higher on the DSMQ (46 µg) and the DSMQ or at least one 24HR (44 µg) than those on the 24HR day 1 (32 µg) or the mean 24HR (31 µg). Fewer products were also classed as a default or reasonable match on the DSMQ than on the 24HR. CONCLUSIONS: A higher prevalence of use of DSs is obtained using frequency-based methods, whereas higher amounts of nutrients are reported from a 24HR. The home inventory results in greater accuracy for products reported. Collectively, these findings suggest that combining the DSMQ with at least one 24HR (i.e., DSMQ or at least one 24HR) is the most comprehensive method for assessing the prevalence of and estimating usual intake from DSs in US adults.This trial was registered at clinicaltrials.gov as NCT03400436.

Older adults with obesity have higher risks of some micronutrient inadequacies and lower overall dietary quality compared to peers with a healthy weight, National Health and Nutrition Examination Surveys (NHANES), 2011-2014.

OBJECTIVE: To evaluate total usual intakes and biomarkers of micronutrients, overall dietary quality and related health characteristics of US older adults who were overweight or obese compared with a healthy weight. DESIGN: Cross-sectional study. SETTING: Two 24-h dietary recalls, nutritional biomarkers and objective and subjective health characteristic data were analysed from the National Health and Nutrition Examination Survey 2011-2014. We used the National Cancer Institute method to estimate distributions of total usual intakes from foods and dietary supplements for eleven micronutrients of potential concern and the Healthy Eating Index (HEI)-2015 score. PARTICIPANTS: Older adults aged ≥60 years (n 2969) were categorised by sex and body weight status, using standard BMI categories. Underweight individuals (n 47) were excluded due to small sample size. RESULTS: A greater percentage of obese older adults compared with their healthy-weight counterparts was at risk of inadequate Mg (both sexes), Ca, vitamin B6 and vitamin D (women only) intakes. The proportion of those with serum 25-hydroxyvitamin D < 40 nmol/l was higher in obese (12 %) than in healthy-weight older women (6 %). Mean overall HEI-2015 scores were 8·6 (men) and 7·1 (women) points lower in obese than in healthy-weight older adults. In addition, compared with healthy-weight counterparts, obese older adults were more likely to self-report fair/poor health, use ≥ 5 medications and have limitations in activities of daily living and cardio-metabolic risk factors; and obese older women were more likely to be food-insecure and have depression. CONCLUSIONS: Our findings suggest that obesity may coexist with micronutrient inadequacy in older adults, especially among women.

Best Practices for Dietary Supplement Assessment and Estimation of Total Usual Nutrient Intakes in Population-Level Research and Monitoring.

The use of dietary supplements (DS) is pervasive and can provide substantial amounts of micronutrients to those who use them. Therefore when characterizing dietary intakes, describing the prevalence of inadequacy or excess, or assessing relations between nutrients and health outcomes, it is critical to incorporate DS intakes to improve exposure estimates. Unfortunately, little is known about the best methods to assess DS, and the structure of measurement error in DS reporting. Several characteristics of nutrients from DS are salient to understand when comparing to those in foods. First, DS can be consumed daily or episodically, in bolus form and can deliver discrete and often very high doses of nutrients that are not limited by energy intakes. These characteristics contribute to bimodal distributions and distributions severely skewed to the right. Labels on DS often provide nutrient forms that differ from those found in conventional foods, and underestimate analytically derived values. Finally, the bioavailability of many nutrient-containing DS is not known and it may not be the same as the nutrients in a food matrix. Current methods to estimate usual intakes are not designed specifically to handle DS. Two temporal procedures are described to refer to the order that nutrient intakes are combined relative to usual intake procedures, referred to as a "shrinking" the distribution to remove random error. The "shrink then add" approach is preferable to the "add then shrink" approach when users and nonusers are combined for most research questions. Stratifying by DS before usual intake methods is another defensible option. This review describes how to incorporate nutrient intakes from DS to usual intakes from foods, and describes the available methods and fit-for-purpose of different analytical strategies to address research questions where total usual intakes are of interest at the group level for use in nutrition research and to inform policy decisions. Clinical Trial Registry: NCT03400436.

Usual Nutrient Intakes from the Diets of US Children by WIC Participation and Income: Findings from the Feeding Infants and Toddlers Study (FITS) 2016.

Background: A recent report of the National Academies of Sciences, Engineering, and Medicine (NASEM) outlined priority nutrients for infants and children participating in the Special Supplemental Nutrition Program for Women, Infants, and Children (WIC). Objective: The objective of this study was to assess usual nutrient intakes from foods and beverages (not supplements) among US children aged <4 y by WIC participation status. Methods: A national random sample of children aged <4 y (n = 3,235) from the Feeding Infants and Toddlers Study (FITS) 2016 was categorized by WIC participation status (participants, lower-income nonparticipants, or higher-income nonparticipants) and age (younger infants aged 0-5.9 mo, older infants aged 6-11.9 mo, toddlers aged 12-23.9 mo, or preschoolers aged 24-47.9 mo). All participants contributed one 24-h dietary recall, with a second recall from a representative subsample (n = 799). Usual intakes and compliance with federal dietary recommendations were estimated by using the National Cancer Institute method. Differences between WIC participants and either lower-income nonparticipants or higher-income nonparticipants were tested using t tests. Results: The diets of infants (aged <12 mo) were nutritionally adequate in general. Older infants participating in WIC had higher compliance with iron and vitamin D guidelines than either group of nonparticipants and greater compliance with calcium, zinc, and potassium guidelines than higher-income nonparticipants. WIC toddlers had a higher risk of inadequate calcium and excessive sodium intakes than higher-income nonparticipants. Eight percent of WIC toddlers exceeded added sugar guidelines compared with either nonparticipant group (∼2%). WIC toddlers and preschoolers had a lower risk of inadequate vitamin D intake than lower-income nonparticipants, but inadequacy was >75% across all subgroups. WIC preschoolers had higher compliance with saturated fat guidelines but lower compliance with sodium and added sugar guidelines than higher-income nonparticipants. Conclusions: WIC participants had better intakes of iron (ages 6-23.9 mo), zinc and potassium (ages 6-11.9 mo), saturated fat (ages 24-47.9 mo), and vitamin D (all ages). Regardless of WIC participation status, most infants and children met the calcium and zinc guidelines, but large proportions had intakes not meeting the recommendations for iron (ages 6-11.9 mo), vitamin D, potassium, fiber, saturated fat, and sodium.

Total Usual Nutrient Intakes of US Children (Under 48 Months): Findings from the Feeding Infants and Toddlers Study (FITS) 2016.

Background: The US Dietary Guidelines will expand in 2020 to include infants and toddlers. Understanding current dietary intakes is critical to inform policy. Objective: The purpose of this analysis was to examine the usual total nutrient intakes from diet and supplements among US children. Methods: The Feeding Infants and Toddlers Study 2016 is a national cross-sectional study of children aged <48 mo (n = 3235): younger infants (birth to 5.9 mo), older infants (6-11.9 mo), toddlers (12-23.9 mo), younger preschoolers (24-36.9 mo), and older preschoolers (36-47.9 mo) based on the use of a 24-h dietary recall. A second 24-h recall was collected from a representative subsample (n = 799). Energy, total nutrient intake distributions, and compliance with Dietary Reference Intakes were estimated with the use of the National Cancer Institute method. Results: Dietary supplement use was 15-23% among infants and toddlers and 35-45% among preschoolers. Dietary intakes of infants were adequate, with mean intakes exceeding Adequate Intake for all nutrients except vitamins D and E. Iron intakes fell below the Estimated Average Requirement for older infants (18%). We found that 31-33% of children aged 12-47.9 mo had low percentage of energy from total fat, and >60% of children aged 24-47.9 mo exceeded the saturated fat guidelines. The likelihood of nutrient inadequacy for many nutrients was higher for toddlers: 3.2% and 2.5% greater than the Adequate Intake for fiber and potassium and 76% and 52% less than the Estimated Average Requirement for vitamins D and E, respectively. These patterns continued through older ages. Intakes exceeded the Tolerable Upper Intake Level of sodium, retinol, and zinc across most age groups. Conclusions: Dietary intakes of US infants are largely nutritionally adequate; concern exists over iron intakes in those aged 6-11.9 mo. For toddlers and preschoolers, high intake of sodium and low intakes of potassium, fiber, and vitamin D and, for preschoolers, excess saturated fat are of concern. Excess retinol, zinc, and folic acid was noted across most ages, especially among supplement users.

Estimation of dietary total antioxidant capacity of Korean adults.

PURPOSE: Dietary total antioxidant capacity (TAC) has been reported to be inversely associated with the risk of chronic diseases. However, little is known about dietary TAC among the Korean population. Therefore, we aimed to estimate the dietary TAC of Korean adults and to document the major food sources. METHODS: We studied 33,581 Korean adults aged ≥19 years who participated in the Korea National Health and Nutrition Examination Survey 2007-2012. Dietary TAC was estimated from 1-day 24-h dietary recall data using a TAC database comprising antioxidant capacities of 42 dietary antioxidants, developed for common Korean foods. RESULTS: The average dietary TAC of Korean adults was 384.7 mg VCE/d, and the major contributors were flavonoids, followed by vitamin C and E. The energy-adjusted daily TAC level was higher in women, middle-aged adults, non-regular alcohol consumers, current non-smokers, supplement users, and in those with a higher income and education level than in their counterparts (P < 0.001). Fruits (47.3%), vegetables (28.4%), beverages and alcohols (11.2%), and legumes and legume products (5.5%), in particular, grapes, persimmons, mandarins, apples, and green tea, were major food sources of dietary TAC. In addition, the consumption of nutrient-dense foods, such as fruits and vegetables, increased, whereas the intake of energy and fat decreased across quartiles of energy-adjusted dietary TAC. CONCLUSIONS: The present study documented the baseline dietary TAC of Korean adults and the major food sources thereof using nationally representative data. Further research on the health effects of dietary TAC among Korean adults is warranted.

Associations of Dietary Antioxidants and Risk of Type 2 Diabetes: Data from the 2007-2012 Korea National Health and Nutrition Examination Survey.

Antioxidants are suggested to decrease risk of type 2 diabetes (T2D) by preventing progressive impairment of pancreatic ß-cell and endothelial function. This study was aimed to investigate the association between dietary antioxidants and risk of T2D in Korean adults based on a national representative data. A total of 24,377 adults (19-74 years) who completed one-day 24 h dietary recall and health examination were included. Dietary antioxidant intakes including α-carotene (p < 0.0001), lycopene (p = 0.0107), flavan-3-ols (p < 0.0001), and proanthocyanidins (p = 0.0075) were significantly higher in non-diabetic subjects than in diabetic subjects. After adjusting for confounding variables, the highest quartile group of α-carotene intake was associated with a 48% reduced risk of T2D in men (OR: 0.52, 95% CI: 0.34-0.80, p for trend = 0.0037) and a 39% reduced risk in women (OR: 0.61, 95% CI: 0.38-0.996, p for trend = 0.0377) compared to the lowest quartile group. Men in the highest quartile of ß-carotene intake showed lower risk of T2D (OR: 0.64, 95% CI: 0.42-0.97), but no significant decreasing trend. However, the intakes of total carotenoids and other antioxidants showed no significant association with the risk of T2D. These findings suggest that a further comprehensive approach which considers overall dietary pattern is required.

Estimation of dietary flavonoid intake and major food sources of Korean adults.

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.

Dietary intake and cancer incidence in Korean adults: a systematic review and meta-analysis of observational studies.

Cancer is a major health burden in Korea, and dietary factors have been suggested as putative risk factors for cancer development at various sites. This study systematically reviewed the published literature investigating the associations between dietary factors and cancer incidence among Korean adults, following the Preferred Reporting Items for Systematic Reviews and Meta- Analyses guidelines. We focused on the 5 most studied cancer sites (stomach, colorectum, breast, thyroid, and cervix) as outcomes and dietary exposures with evidence levels greater than limited-suggestive according to the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) panel's judgment for any of the cancer sites. This resulted in the inclusion of 72 studies. Pooled estimates of the impact of dietary factors on cancer risk suggested protective associations of fruits and vegetables with risks for gastric cancer (GC), colorectal cancer (CRC), and breast cancer (BC) and dietary vitamin C with the risk of GC, as well as a harmful association between fermented soy products and the risk of GC. Despite the limited number of studies, we observed consistent protective associations of dietary fiber with GC and dietary fiber, coffee, and calcium with CRC. These findings are largely consistent with the WCRF/AICR expert report. However, pooled estimates for the associations of other salt-preserved foods with GC, meat with CRC, and dietary carotenoids and dairy products with BC did not reach statistical significance. Further studies with prospective designs, larger sample sizes, and diverse types of dietary factors and cancer sites are necessary.

Usual nutrient intakes and diet quality among United States older adults participating in the Supplemental Nutrition Assistance Program compared with income-eligible nonparticipants.

BACKGROUND: The proportion of older adults with food insecurity at 8% has increased faster than that of the general United States population from 2001 to 2017. Many low-income food-insecure older adults rely on food-assistance programs, such as the Supplemental Nutrition Assistance Program (SNAP), for meeting energy and nutrient needs, whereas others are eligible but do not participate. Neither updated nutrient intake estimates nor potential differences in meeting the Dietary Reference Intakes from foods alone and with dietary supplements (DS) among low-income older adults using or eligible for SNAP are known. OBJECTIVES: This study assessed and compared national estimates of usual nutrient adequacy and dietary quality of United States older adults using SNAP and income-eligible nonparticipants. METHODS: Usual dietary intake was estimated among older adults (≥60 y; n = 2582) in the 2007-2016 NHANES cross-sectional national survey. Data on food-assistance participation and eligibility (poverty-income-ratio ≤130%), DS use, and ≥24-h dietary recalls were used. The NCI method (Markov Chain Monte Carlo approach) was applied to estimate mean usual nutrient intakes, proportion of inadequate nutrient intake, and dietary quality using the 2015 Healthy Eating Index. RESULTS: Neither usual nutrient intake from dietary and total sources nor dietary quality differed between older adult SNAP participants and eligible nonparticipants. Low dietary quality and high percentage of inadequate intake for several nutrients were apparent among both groups, especially from food sources alone, including vitamins A (56%), C (55%), D (97%), E (99%), calcium (73%), and magnesium (74%), but rates were attenuated when DS were also considered (i.e., 36% reduced risk for vitamin D inadequacy). CONCLUSIONS: Diet quality and usual nutrient intake among older adult SNAP participants and eligible nonparticipants were poor, but DS lowered the risk of nutrient inadequacy. Future policies and programs should focus on improving the intake of vitamins A, C, D, E, calcium, and magnesium and dietary quality for all older adults.

Interaction between vitamin E intake and a COMT gene variant on colorectal cancer risk among Korean adults: a case-control study.

OBJECTIVES: Previous human trials have not supported the anticarcinogenic effect of vitamin E despite biological plausibility and considerable epidemiological evidence. A possible explanation for this inconsistency is the interactive effect of the catechol-O-methyltransferase (COMT) gene and supplemental vitamin E on cancer. We examined whether a COMT gene variant modulates the effect of dietary vitamin E intake on colorectal cancer (CRC) risk. METHODS: In this case-control study of Korean adults (975 cases and 975 age- and sex-matched controls), dietary vitamin E density (mg/1,000 kcal) was measured using a semiquantitative food frequency questionnaire, COMT single nucleotide polymorphism (SNP) rs740603 (A>G) was genotyped, and CRC was verified histologically. We estimated odds ratios (ORs) and 95% confidence intervals (CIs) using unconditional logistic regression models with adjustments for potential confounders. RESULTS: Higher vitamin E density was associated with a lower risk of CRC (highest vs. lowest quartiles: OR, 0.72; 95% CI, 0.55 to 0.96; p-for-trend=0.002). When stratified by COMT SNP rs740603 genotype, the inverse association between vitamin E density and CRC risk was confined to those with at least 1 A allele (≥median vs.