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.

Malnutrition-related conditions and interventions in US state/territorial Older Americans Act aging plans

Background

Factors that decrease independence and increase morbidity must be reduced to improve the nutrition, health, and other challenges confronting older adults. In the United States (US), the Older Americans Act (OAA) requires each state/territory develop multi-year aging plans for spending federal funds that foster healthy aging (including support of congregate/home delivered meals programs) and separately requires grant applications for nutrition service programs supporting older Native Americans. Malnutrition (particularly protein-energy undernutrition), sarcopenia, frailty, and obesity can all result in disability but are potentially changeable. The study goal was to collect baseline information on mentions of these malnutrition-related conditions and interventions that address them in US state/territorial OAA program multi-year aging plans.

Methods

OAA program multi-year aging plans available on the ADvancing States website in February 2021 (n = 52) were searched for number of mentions of defined nutrition terms including malnutrition, sarcopenia, frailty, obesity, and whether terms were included in plans’ goals/objectives, strategies/actions, or solely in the narrative.

Results

Malnutrition, sarcopenia, frailty, and obesity were mentioned infrequently in US state/territorial OAA program multi-year aging plans. 33% of plans mentioned malnutrition but only 8% as goals/objectives and 15% as strategies/actions. 62% mentioned frailty; 6% (goals/objectives), 15% (strategies/actions). None mentioned sarcopenia whereas in contrast, 21% mentioned obesity; 2% (goals/objectives), 2% (strategies/actions). Nutrition intervention mentions were nearly nil. There were no significant differences in frequency of term mentions by US region or by states with higher percentages of older adults or obese adults.

Conclusions

Clearly specifying definitions of malnutrition-related conditions and incorporating them into measurable goals/objectives, defined strategies/actions, and outcomes may help improve future state/territorial OAA program multi-year aging plans to better support healthy aging.

Trends in Overall and Micronutrient-Containing Dietary Supplement Use in US Adults and Children, NHANES 2007-2018

BACKGROUND

Dietary supplement (DS) use is widespread in the United States and contributes large amounts of micronutrients to users. Most studies have relied on data from 1 assessment method to characterize the prevalence of DS use. Combining multiple methods enhances the ability to capture nutrient exposures from DSs and examine trends over time.

OBJECTIVES

The objective of this study was to characterize DS use and examine trends in any DS as well as micronutrient-containing (MN) DS use in a nationally representative sample of the US population (≥1 y) from the 2007-2018 NHANES using a combined approach.

METHODS

NHANES obtains an in-home inventory with a frequency-based dietary supplement and prescription medicine questionnaire (DSMQ), and two 24-h dietary recalls (24HRs). Trends in the prevalence of use and selected types of products used were estimated for the population and by sex, age, race/Hispanic origin, family income [poverty-to-income ratio (PIR)], and household food security (food-secure vs. food-insecure) using the DSMQ or ≥ 1 24HR. Linear trends were tested using orthogonal polynomials (significance set at P < 0.05).

RESULTS

DS use increased from 50% in 2007 to 56% in 2018 (P = 0.001); use of MN products increased from 46% to 49% (P = 0.03), and single-nutrient DS (e.g., magnesium, vitamins B-12 and D) use also increased (all P < 0.001). In contrast, multivitamin-mineral use decreased (70% to 56%; P < 0.001). In adults (≥19 y), any (54% to 61%) and MN (49% to 54%) DS use increased, especially in men, non-Hispanic blacks and Hispanics, and low-income adults (PIR ≤130%). In children (1-18 y), any DS use remained stable (∼38%), as did MN use, except for food-insecure children, whose use increased from 24% to 31% over the decade (P = 0.03).

CONCLUSIONS

The prevalence of any and MN DS use increased over time in the United States. This may be partially attributed to increased use of single-nutrient products. Population subgroups differed in their DS use.

Do Multivitamin/Mineral Dietary Supplements for Young Children Fill Critical Nutrient Gaps?

BACKGROUND

Nearly a third of young US children take multivitamin/mineral (MVM) dietary supplements, yet it is unclear how formulations compare with requirements.

OBJECTIVE

Describe the number and amounts of micronutrients contained in MVMs for young children and compare suggested amounts on product labels to micronutrient requirements.

DESIGN

Cross-sectional.

SETTING

All 288 MVMs on the market in the United States in the National Institutes of Health's Dietary Supplement Label Database in 2018 labeled for children 1 to <4 years old.

MAIN OUTCOME MEASURES

Number of MVM products and amounts per day of micronutrients in each product suggested on labels compared with requirements represented by age-appropriate Daily Values (DV). Micronutrients of public health concern identified by the Dietary Guidelines for Americans (DGA) 2015-2020 (DGA 2015) and DGA 2020-2025 (DGA 2020) or those of concern for exceeding the upper tolerable intake levels.

STATISTICAL ANALYSES

Number of products and percent DV per day provided by each micronutrient in each product.

RESULTS

The 288 MVMs contained a mean of 10.1 ± 2.27 vitamins and 4.59 ± 2.27 minerals. The most common were, in rank order, vitamins C, A, D, E, B6, B12; zinc, biotin, pantothenic acid, iodine, and folic acid. For micronutrients denoted by the DGA 2015 and DGA 2020 of public health concern, 56% of the 281 products containing vitamin D, 4% of the 144 with calcium, and none of the 60 containing potassium provided at least half of the DV. The upper tolerable intake level was exceeded by 49% of 197 products with folic acid, 17% of 283 with vitamin A, and 14% of 264 with zinc. Most MVMs contained many of 16 other vitamins and minerals identified in national surveys as already abundant in children's diets.

CONCLUSIONS

A reexamination of the amounts and types of micronutrients in MVMs might consider formulations that better fill critical gaps in intakes and avoid excess.

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.

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 (<RDA, 0.8 g/kg BW), moderate (≥RDA, <1.2 g/kg BW), and high (≥1.2 g/kg BW)]. ALM was measured using DXA, and GSMAX was measured using handgrip dynamometer. "Low lean mass" and "weakness" were defined using NIH criteria for ALMBMI and GSMAXBMI, respectively. Linear and logistic regression models were performed.

RESULTS

Among middle-aged adults, 15.6% of men and 13.4% of women had low lean mass and 3.5% of men and 2.3% of women exhibited weakness. Protein intakes per kilogram BW were positively associated with ALMBMI and GSMAXBMI among men and women after adjustment for age, race/Hispanic origin, physical activity, and self-rated health. Compared with the moderate protein group, the high protein group had a higher GSMAXBMI and the low protein group had a lower GSMAXBMI among men and women. The low protein group had a lower ALMBMI (women) and had a higher OR for low lean mass (men) compared with the moderate protein group.

CONCLUSIONS

Higher protein intakes were associated with greater ALMBMI and GSMAXBMI in this representative sample of US middle-aged adults. Our findings highlight the need for further research on dietary protein as a potential modifying factor of sarcopenia risk in middle age.

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.

Association of food insecurity with dietary intakes and nutritional biomarkers among US children, National Health and Nutrition Examination Survey (NHANES) 2011-2016

BACKGROUND

Food insecurity is associated with poorer nutrient intakes from food sources and lower dietary supplement use. However, its association with total usual nutrient intakes, inclusive of dietary supplements, and biomarkers of nutritional status among US children remains unknown.

OBJECTIVE

The objective was to assess total usual nutrient intakes, Healthy Eating Index-2015 (HEI-2015) scores, and nutritional biomarkers by food security status, sex, and age among US children.

METHODS

Cross-sectional data from 9147 children aged 1-18 y from the 2011-2016 NHANES were analyzed. Usual energy and total nutrient intakes and HEI-2015 scores were estimated using the National Cancer Institute method from 24-h dietary recalls.

RESULTS

Overall diet quality was poor, and intakes of sodium, added sugars, and saturated fat were higher than recommended limits, regardless of food security status. Food-insecure girls and boys were at higher risk of inadequate intakes for vitamin D and magnesium, and girls also had higher risk for inadequate calcium intakes compared with their food-secure counterparts, when total intakes were examined. Choline intakes of food-insecure children were less likely to meet the adequate intake than those of their food-secure peers. No differences by food security status were noted for folate, vitamin C, iron, zinc, potassium, and sodium intakes. Food-insecure adolescent girls aged 14-18 y were at higher risk of micronutrient inadequacies than any other subgroup, with 92.8% (SE: 3.6%) at risk of inadequate intakes for vitamin D. No differences in biomarkers for vitamin D, folate, iron, and zinc were observed by food security status. The prevalence of iron deficiency was 12.7% in food-secure and 12.0% in food-insecure adolescent girls.

CONCLUSIONS

Food insecurity was associated with compromised intake of some micronutrients, especially among adolescent girls. These results highlight a need for targeted interventions to improve children's overall diet quality, including the reduction of specific nutrient inadequacies, especially among food-insecure children. This study was registered at clinicaltrials.gov as NCT03400436.

Nonfood Prebiotic, Probiotic, and Synbiotic Use Has Increased in US Adults and Children From 1999 to 2018

BACKGROUND & AIMS

Public interest in pre-, pro-, and synbiotic products is increasing because of interactions between gut microbiota and human health. Our aim was to describe nonfood (from dietary supplements or medication) pre-, pro-, and synbiotic use by US adults and children and reported reasons.

METHODS

Using data from the National Health and Nutrition Examination Survey (NHANES), we text-mined dietary supplement and prescription medication labels and ingredients to identify pre-, pro-, and synbiotic products used in the past 30 days. We describe trends in use from 1999 to 2018 (n = 101,199) and prevalence in 2015-2016 and 2017-2018 (n = 19,215) by age groups, sex, ethnicity/race, education, income, self-reported diet and health quality, and prescription gastrointestinal medication use stratified by children (<19 years) and adults (19+ years).

RESULTS

Nonfood pre-, pro-, and synbiotic use increased up to 3-fold in recent cycles. Prevalence of use for all ages for prebiotics was 2.4% (95% confidence interval [CI], 2.0-2.9), for probiotics was 4.5% (95% CI, 3.5-5.6), and for synbiotics was 1.1% (95% CI, 0.8-1.5). Use was highest among older adults (8.8% [95% CI, 5.4-13.3] among those aged 60-69 years for probiotics), non-Hispanic Whites, those with higher educational attainment and income, those with more favorable self-reported diet or health quality, and those with concurrent prescription gastrointestinal medication use. The top reasons for use were for digestive health and to promote/maintain general health. Less than 30% reported using these products based on a health care provider's recommendation.

CONCLUSIONS

One in 20 US adults or children use nonfood pre-, pro-, or synbiotic products, and use has sharply increased in recent years. Most individuals voluntarily take these products for general digestive or overall health reasons.

Supplemental Vitamin D Increased Serum Total 25-Hydroxyvitamin D in the US Adult Population During 2007-2014

BACKGROUND

Data from the 2007-2010 NHANES suggested that vitamin D supplements contributed to increased serum concentrations of 25-hydroxyvitamin D [25(OH)D] in the US population.

OBJECTIVES

We sought to determine whether 25(OH)D continued to increase during NHANES 2011-2014 and whether associations of 25(OH)D with preselected covariates differed across time periods.

METHODS

For this study, 25(OH)D was measured in adults (≥20 y) using LC-MS/MS. Descriptive and regression analyses were stratified by survey period to investigate the effects of age, race-Hispanic origin, sex, season, BMI, dietary vitamin D, and vitamin D-containing supplements. A multiple linear regression model was used to assess 25(OH)D changes between two 4-y survey periods, namely 2007-2010 and 2011-2014.

RESULTS

We observed several significant concomitant increases between 2007-2010 and 2011-2014: unadjusted mean 25(OH)D increased by 2.7 nmol/L (95% CI: 0, 5.4 nmol/L; P = 0.048), the percentage of persons taking any vitamin D-containing supplements increased 2.9% (95% CI: 0.03, 5.5%; P = 0.0314), and the percentage of persons taking high-dose (≥1000 IU/d) vitamin D-containing supplements increased 8.6% (95% CI: 6.9, 9.9%; P < 0.0001). With covariate adjustment, the increase in 25(OH)D from 2007-2010 to 2011-2014 was no longer statistically significant [1.4 nmol/L (95% CI: -3.0, 0.23 nmol/L; P = 0.09)]. After adjustments, several large differences in 25(OH)D remained, namely non-Hispanic blacks had 25(OH)D 22 nmol/L lower than that of non-Hispanic whites, and users of vitamin D-containing supplements ≥1000 IU/d had 25(OH)D 31 nmol/L higher than that of nonusers.

CONCLUSIONS

After adjusting for vitamin D supplement dose, the overall adjusted increase in 25(OH)D was no longer statistically significant, suggesting that changes in US adults' 25(OH)D concentrations between NHANES periods 2007-2010 and 2011-2014 may primarily be associated with changes in vitamin D supplementation.

Opportunities for Adding Undernutrition and Frailty Screening Measures in US National Surveys

Both undernutrition and frailty adversely affect the health and functional outcomes of the older adult population. Timely and accurate national data are necessary to assess those at risk of these debilitating but often preventable conditions, to correct them and support healthy aging. The objective was to identify relevant measures in undernutrition and frailty screening tools and determine if these measures are collected in recent protocols for US national surveys sampling older adults and which measures could be added to be able to better assess risk of undernutrition and frailty. Commonly used undernutrition and frailty screening tools were evaluated to identify measures that were unique or common to both. US national surveys were examined to determine whether they included older adults in their survey sample, collected health measures from participants, in what form, and whether they were functional indexes or survey questions. A comparative analysis of survey protocols was performed to determine which surveys collected data related to the measures of undernutrition and frailty. Of the 8 national surveys, only 3 provided ≥1 physical measurement (i.e., height/weight, grip strength, balance). Most surveys included self-reported data on height/weight, physical functioning/mobility, disability, and psychological components. Whereas 6 included questions on food security/food program participation, only 1 collected data on dietary intake. Currently national surveys include only limited health measures that can be used to identify undernutrition and frailty risk in older adults. Adding a few simple screening measures already included in popular screening tools, such as grip strength, unintentional weight loss, and loss of appetite, to national surveys which monitor older Americans would facilitate estimation of the prevalence of undernutrition and frailty risk, better estimate those at risk, provide an opportunity to set national goals to reduce their risk, and help implement strategies for improved health outcomes.

Screening Community-Living Older Adults for Protein Energy Malnutrition and Frailty: Update and Next Steps

Protein-energy malnutrition (PEM)/undernutrition and frailty are prevalent, overlapping conditions impacting on functional and health outcomes of older adults, but are frequently unidentified and untreated in community settings in the United States. Using the World Health Organization criteria for effective screening programs, we reviewed validity, reliability, and feasibility of data-driven screening tools for identifying PEM and frailty risk among community-dwelling older adults. The SCREEN II is recommended for PEM screening and the FRAIL scale is recommended as the most promising frailty screening tool, based on test characteristics, cost, and ease of use, but more research on both tools is needed, particularly on predictive validity of favorable outcomes after nutritional/physical activity interventions. The Malnutrition Screening Tool (MST) has been recommended by one expert group as a screening tool for all adults, regardless of age/care setting. However, it has not been tested in US community settings, likely yields large numbers of false positives (particularly in community settings), and its predictive validity of favorable outcomes after nutritional interventions is unknown. Community subgroups at highest priority for screening are those at increased risk due to prior illness, certain demographics and/or domiciliary characteristics, and those with BMI < 20 kg/m² or < 22 if > 70 years or recent unintentional weight loss > 10% (who are likely already malnourished). Community-based health professionals can better support healthy aging by increasing their awareness/use of PEM and frailty screening tools, prioritizing high-risk populations for systematic screening, following screening with more definitive diagnoses and appropriate interventions, and re-evaluating and revising screening protocols and measures as more data become available.

Dietary Supplement Use Among Adults: United States, 2017-2018

Dietary supplement use is common in the United States (1). The additional nutrients provided by dietary supplements can help meet recommended nutrient targets but can also potentially lead to excess intakes (2,3). This report describes recent prevalence estimates for dietary supplement use among U.S. adults, the distribution of the number of dietary supplements used, and the most common types of dietary supplements used. Trends in dietary supplement use from 2007-2008 through 2017-2018 are also reported.

High folic acid or folate combined with low vitamin B-12 status: potential but inconsistent association with cognitive function in a nationally representative cross-sectional sample of US older adults participating in the NHANES

BACKGROUND

Potential safety concerns relative to impaired cognitive function may exist when high folic acid exposures are combined with low vitamin B-12 status.

OBJECTIVES

We aimed to examine the relation of the coexistence of high folate and low vitamin B-12 status with cognitive function, utilizing various definitions of "high" folate status.

METHODS

Cross-sectional data from older adults (≥60 y; n = 2420) from the 2011-2014 NHANES were analyzed. High folate status was defined as unmetabolized serum folic acid (UMFA) > 1 nmol/L or serum total folate > 74.1 nmol/L, and low vitamin B-12 status as methylmalonic acid > 271 nmol/L or serum vitamin B-12 < 150 pmol/L. Logistic regression models estimated ORs of scoring low on 1 of 4 cognitive tests: the Digit Symbol Substitution Test (DSST), the Consortium to Establish a Registry for Alzheimer's Disease Delayed Recall (CERAD-DR) and Word Learning tests, and the Animal Fluency test (AF).

RESULTS

A significant interaction was observed relative to scoring low on the DSST (<34; UMFA; P-interaction = 0.0071) and AF (serum folate; P-interaction = 0.0078) for low vitamin B-12 and high folate status. Among those with low vitamin B-12, high UMFA or high serum total folate was associated with higher risk of scoring low on the DSST (OR: 2.16; 95% CI: 1.05, 4.47) and the AF (OR: 1.93; 95% CI: 1.08, 3.45). Among those with "normal" vitamin B-12, higher UMFA or serum total folate was protective on the CERAD-DR. In noninteraction models, when high folate and normal vitamin B-12 status was the reference group, low vitamin B-12 combined with high UMFA was associated with greater risk based on the DSST (<34, OR: 2.87; 95% CI: 1.85, 4.45; <40, OR: 2.22; 95% CI: 1.31, 3.75) and AF (OR: 1.97; 95% CI: 1.30, 2.97); but low vitamin B-12 and lower UMFA (OR: 1.69; 95% CI: 1.16, 2.47) was also significantly associated for DSST < 40 risk.

CONCLUSIONS

Low vitamin B-12 was associated with cognitive impairment both independently and in an interactive manner with high folate for certain cognitive performance tests among older adults.

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.

Demographic, Physiologic, and Lifestyle Characteristics Observed with Serum Total Folate Differ Among Folate Forms: Cross-Sectional Data from Fasting Samples in the NHANES 2011-2016

BACKGROUND

Serum folate forms were measured in the US population during recent NHANES to assess folate status.

OBJECTIVE

We describe post-folic acid-fortification concentrations of serum folate forms in the fasting US population ≥1 y from the NHANES 2011-2016.

METHODS

We measured 5 biologically active folates and 1 oxidation product (MeFox) of 5-methyltetrahydrofolate (5-methyl-THF). We calculated geometric means of 5-methyl-THF, unmetabolized folic acid (UMFA), nonmethyl folate (sum of tetrahydrofolate, 5-formyltetrahydrofolate, and 5,10-methenyltetrahydrofolate), total folate (sum of above biomarkers), and MeFox by demographic, physiologic, and lifestyle variables; estimated the magnitude of variables on biomarker concentrations after covariate adjustment; and determined the prevalence of UMFA >2 nmol/L.

RESULTS

After demographic adjustment, age, sex, and race-Hispanic origin were significantly associated with most folate forms. MeFox increased with age, while 5-methyl-THF, UMFA, and nonmethyl folate displayed U-shaped age patterns. Compared with non-Hispanic whites, non-Hispanic blacks had 23% lower predicted 5-methyl-THF but comparable UMFA; non-Hispanic Asians had comparable 5-methyl-THF but 28% lower UMFA; Hispanics, non-Hispanic Asians, and non-Hispanic blacks had ∼20% lower MeFox. After additional physiologic and lifestyle adjustment, predicted UMFA and MeFox concentrations were 43% and 112% higher, respectively, in adults with chronic kidney disease and 17% and 15% lower, respectively, in adults consuming daily 1-<2 alcoholic beverages; 5-methyl-THF concentrations were 20% lower in adult smokers. The prevalence of UMFA >2 nmol/L was highest in persons aged ≥70 y (9.01%) and lowest in those aged 12-19 y (1.14%). During 2011-2014, the prevalence was 10.6% in users and 2.22% in nonusers of folic acid-containing supplements.

CONCLUSIONS

In fasting persons ≥1 y, the demographic, physiologic, and lifestyle characteristics observed with serum total folate differed among folate forms, suggesting biological and/or genetic influences on folate metabolism. High UMFA was mostly observed in supplement users and older persons.

Dietary Supplement Use and Its Micronutrient Contribution During Pregnancy and Lactation in the United States

OBJECTIVE

To estimate the prevalence of use and the micronutrient contribution of dietary supplements among pregnant, lactating, and nonpregnant and nonlactating women in the United States.

METHODS

Cross-sectional data from 1,314 pregnant, 297 lactating, and 8,096 nonpregnant and nonlactating women (aged 20-44 years) in the 1999-2014 National Health and Nutrition Examination Survey were combined to produce statistically reliable, nationally representative estimates. Information about dietary supplements used in the past 30 days was collected through an interviewer-administered questionnaire and in-home inventory. The prevalence of nutrient-specific supplement use, mean daily nutrient intakes from supplements among users, and motivations for supplement use were assessed. Differences by age, income, and trimester within pregnant women were also tested.

RESULTS

Seventy-seven percent of pregnant women and 70% of lactating women used one or more dietary supplements, whereas 45% of nonpregnant and nonlactating women used supplements. In particular, 64% of pregnant and 54% of lactating women used prenatal supplements. Mean intakes of thiamin, riboflavin, niacin, folic acid, vitamins B6, B12, and C, iron, and zinc from supplements alone were at or above their respective recommended dietary allowances (RDAs) among pregnant and lactating supplement users. About half of pregnant and 40% of lactating women took supplements based on the recommendation of a health care provider. Among pregnant women, those in their first trimester, aged 20-34 years, or in a lower-income family were less likely to use supplements compared with their counterparts.

CONCLUSION

The majority of pregnant and lactating women used dietary supplements, which contributed many nutrients in doses above the RDAs. Although inadequate Intakes of folate and iron are of concern among pregnant women who are not using supplements, supplement users often consumed high doses, suggesting a potential need of health care providers to discuss dietary supplement use and the recommended doses of nutrients during pregnancy and lactation.

Folate status in the US population 20 y after the introduction of folic acid fortification

BACKGROUND

Enriched cereal-grain products have been fortified in the United States for >20 y to improve folate status in women of reproductive age and reduce the risk of folic acid-responsive neural tube birth defects (NTDs).

OBJECTIVES

Our objectives were to assess postfortification changes in folate status in the overall US population and in women aged 12-49 y and to characterize recent folate status by demographic group and use of folic acid-containing supplements.

METHODS

We examined cross-sectional serum and RBC folate data from the NHANES 1999-2016.

RESULTS

Serum folate geometric means increased from 2007-2010 to 2011-2016 in persons aged ≥1 y (38.7 compared with 40.6 nmol/L) and in women (35.3 compared with 37.0 nmol/L), whereas RBC folate showed no significant change. Younger age groups, men, and Hispanic persons showed increased serum and RBC folate concentrations, whereas non-Hispanic black persons and supplement nonusers showed increased serum folate concentrations. The folate insufficiency prevalence (RBC folate <748 nmol/L; NTD risk) in women decreased from 2007-2010 (23.2%) to 2011-2016 (18.6%) overall and in some subgroups (e.g., women aged 20-39 y, Hispanic and non-Hispanic black women, and supplement nonusers). After covariate adjustment, RBC folate was significantly lower in all age groups (by ∼10-20%) compared with persons aged ≥60 y and in Hispanic (by 8.2%), non-Hispanic Asian (by 12.1%), and non-Hispanic black (by 20.5%) compared with non-Hispanic white women (2011-2016). The 90th percentile for serum (∼70 nmol/L) and RBC (∼1800 nmol/L) folate in supplement nonusers aged ≥60 y was similar to the geometric mean in users (2011-2014).

CONCLUSIONS

Blood folate concentrations in the US population overall and in women have not decreased recently, and folate insufficiency rates are ∼20%. Continued monitoring of all age groups is advisable given the high folate status particularly in older supplement users.

Vitamin D status in the United States, 2011-2014

BACKGROUND

Vitamin D is important for bone health; in 2014 it was the fifth most commonly ordered laboratory test among Medicare Part B payments.

OBJECTIVES

The aim of this study was to describe vitamin D status in the US population in 2011-2014 and trends from 2003 to 2014.

METHODS

We used serum 25-hydroxyvitamin D data from NHANES 2011-2014 (n = 16,180), and estimated the prevalence at risk of deficiency (<30 nmol/L) or prevalence at risk of inadequacy (30-49 nmol/L) by age, sex, race and Hispanic origin, and dietary intake of vitamin D. We also present trends between 2003 and 2014.

RESULTS

In 2011-2014, the percentage aged ≥1 y at risk of vitamin D deficiency or inadequacy was 5.0% (95% CI: 4.1%, 6.2%) and 18.3% (95% CI: 16.2%, 20.6%). The prevalence of at risk of deficiency was lowest among children aged 1-5 y (0.5%; 95% CI: 0.3%, 1.1%), peaked among adults aged 20-39 y (7.6%; 95% CI: 6.0%, 9.6%), and fell to 2.9% (95% CI: 2.0%, 4.0%) among adults aged ≥60 y; the prevalence of at risk of inadequacy was similar. The prevalence of at risk of deficiency was higher among non-Hispanic black (17.5%; 95% CI: 15.2%, 20.0%) than among non-Hispanic Asian (7.6%; 95% CI: 5.9%, 9.9%), non-Hispanic white (2.1%; 95% CI: 1.5%, 2.7%), and Hispanic (5.9%; 95% CI: 4.4%, 7.8%) persons; the prevalence of at risk of inadequacy was similar. Persons with higher vitamin D dietary intake or who used supplements had lower prevalences of at risk of deficiency or inadequacy. From 2003 to 2014 there was no change in the risk of vitamin D deficiency; the risk of inadequacy declined from 21.0% (95% CI: 17.9%, 24.5%) to 17.7% (95% CI: 16.0%, 19.7%).

CONCLUSION

The prevalence of at risk of vitamin D deficiency in the United States remained stable from 2003 to 2014; at risk of inadequacy declined. Differences in vitamin D status by race and Hispanic origin warrant additional investigation.

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.

Dietary Supplement Use among Infants and Toddlers Aged <24 Months in the United States, NHANES 2007-2014

BACKGROUND

Limited nationally representative data are available on dietary supplement (DS) use and resulting nutrient exposures among infants and toddlers.

OBJECTIVE

This study evaluated DS use among US infants and toddlers to characterize DS use, estimate nutrient intake from DSs, and assess trends in DS use over time.

METHODS

Using nationally representative data from NHANES (2007-2014) and trends over time (1999-2014), we estimated prevalence of DS use and types of products used for US infants and toddlers aged <2 y (n = 2823). We estimated median daily intakes of vitamins and minerals consumed via DSs for all participants aged <2 y, by age groups (0-11.9 mo and 12.0-23.9 mo), and by feeding practices for infants 0-5.9 mo.

RESULTS

Overall, 18.2% (95% CI: 16.2%, 20.3%) of infants and toddlers used ≥1 DS in the past 30 d. Use was lower among infants (0-5.9 mo: 14.6%; 95% CI: 11.5%, 18.1%; 6-11.9 mo: 11.6%; 95% CI: 8.8%, 15.0%) than among toddlers (12-23.9 mo: 23.3%; 95% CI: 20.4%, 26.3%). The most commonly reported DSs were vitamin D and multivitamin infant drops for those <12 mo, and chewable multivitamin products for toddlers (12-23.9 mo). The nutrients most frequently consumed from DSs were vitamins D, A, C, and E for those <2 y; for infants <6 mo, a higher percentage of those fed breast milk than those fed formula consumed these nutrients via DSs. DS use remained steady for infants (6-11.9 mo) and toddlers from 1999-2002 to 2011-2014, but increased from 7% to 20% for infants aged 0-5.9 mo.

CONCLUSIONS

One in 5 infants and toddlers aged <2 y use ≥1 DS. Future studies should examine total nutrient intake from foods, beverages, and DSs to evaluate nutrient adequacy overall and by nutrient source.

Dietary Supplement Use Differs by Socioeconomic and Health-Related Characteristics among U.S. Adults, NHANES 2011⁻2014

The objective of this study was to estimate the prevalence of use and types of dietary supplements (DS) used by U.S. adults (≥19 years) by sociodemographic characteristics: family income-to-poverty ratio (PIR), food security status, and Supplemental Nutrition Assistance Program (SNAP) participation using NHANES 2011⁻2014 data (n = 11,024). DS use was ascertained via a home inventory and a retrospective 30-day questionnaire. Demographic and socioeconomic differences related to DS use were evaluated using a univariate t statistic. Half of U.S. adults (52%) took at least one DS during a 30-day period; multivitamin-mineral (MVM) products were the most commonly used (31%). DS and MVM use was significantly higher among those with a household income of ≥ 350% of the poverty level, those who were food secure, and SNAP income-ineligible nonparticipants across all sex, age, and race/ethnic groups. Among women, prevalence of use significantly differed between SNAP participants (39%) and SNAP income-eligible nonparticipants (54%). Older adults (71+ years) remained the highest consumers of DS, specifically among the highest income group (82%), while younger adults (19⁻30 years), predominantly in the lowest income group (28%), were the lowest consumers. Among U.S. adults, DS use and the types of products consumed varied with income, food security, and SNAP participation.

The Dietary Supplement Label Database: Recent Developments and Applications

Objective

To describe the history, key features, recent enhancements, and common applications of the Dietary Supplement Label Database (DSLD).

Background and History

Although many Americans use dietary supplements, databases of dietary supplements sold in the United States have not been widely available. The DSLD, an easily accessible public-use database was created in 2008 to provide information on dietary supplement composition for use by researchers and consumers.

Rationale

Accessing current information easily and quickly is crucial for documenting exposures to dietary supplements because they contain nutrients and other bioactive ingredients that may have beneficial or adverse effects on human health. This manuscript details recent developments with the DSLD to achieve this goal and provides examples of how the DSLD has been used.

Recent Developments

With periodic updates to track changes in product composition and capture new products entering the market, the DSLD currently contains more than 71,000 dietary supplement labels. Following usability testing with consumer and researcher user groups completed in 2016, improvements to the DSLD interface were made. As of 2017, both a desktop and mobile device version are now available. Since its inception in 2008, the use of the DSLD has included research, exposure monitoring, and other purposes by users in the public and private sectors.

Future Directions

Further refinement of the user interface and search features to facilitate ease of use for stakeholders is planned.

Conclusions

The DSLD can be used to track changes in product composition and capture new products entering the market. With over 71,000 DS labels it is a unique resource that policymakers, researchers, clinicians, and consumers may find valuable for multiple applications.

Federal Monitoring of Dietary Supplement Use in the Resident, Civilian, Noninstitutionalized US Population, National Health and Nutrition Examination Survey.. J Nutr 2018;148:1436S-1444S. [PMID: 31105335 PMCID: PMC6516064 DOI: 10.1093/jn/nxy093]

Objective

This review summarizes the current and previous data on dietary supplement (DS) use collected from participants in the National Health and Nutrition Examination Survey (NHANES), describes the NHANES dietary supplement database used to compute nutrient intakes from DSs, discussed recent developments and future direction, and describes many examples to demonstrate the utility of these data in informing nutrition research and policy.

Background and History

Since 1971, NHANES, has been collecting information on the use of DSs from participants. These data are critical to national nutrition surveillance and have been used to characterize usage patterns, examine trends over time, assess the percentage of the population meeting or exceeding nutrient recommendations, and to help elucidate the sources contributing nutrients to the diet of the US population.

Rationale

Over half of adults and about one-third of children in the United States use at least one dietary supplement in the past 30 days. Dietary supplements contribute to the dietary intake of nutrients and bioactive compounds in the US and therefore need to be assessed when monitoring nutritional status of the population and when studying diet-health associations.

Recent Developments

With the recent development and availability of the Dietary Supplement Label Database (DSLD), a comprehensive DS database that will eventually contain labels for all products marketed in the US, NHANES DS data will be more easily linked to product information to estimate nutrient intake from DS.

Future Directions

Over time, NHANES has both expanded and improved collection methods. The continued understanding of sources of error in collection methods will continue to be explored and is critical to improved accuracy.

Conclusions

NHANES provides a rich source of nationally representative data on the usage of dietary supplements in the US.

Dietary Supplement Use Was Very High among Older Adults in the United States in 2011-2014

Background: Dietary supplements (DSs) have the potential to be both beneficial and harmful to health, especially in adults aged ≥60 y, and therefore it is important to monitor the patterns of their use.Objective: This study evaluated DS use by adults aged ≥60 y to characterize the use of DSs, determine the motivations for use, and examine the associations between the use of DSs and selected demographic, lifestyle, and health characteristics.Methods: Data from 3469 older adults aged ≥60 y from the 2011-2014 NHANES were analyzed. DSs used in the past 30 d were ascertained via an interviewer-administered questionnaire in participants' homes. The prevalence of overall DS use and specific types of DSs were estimated. The number of DSs reported and the frequency, duration, and motivation(s) for use were assessed. Logistic regression models were constructed to examine the association between DS use and selected characteristics.Results: Seventy percent of older adults in the United States reported using ≥1 DS in the past 30 d; 54% of users took 1 or 2 products, and 29% reported taking ≥4 products. The most frequently reported products were multivitamin or mineral (MVM) (39%), vitamin D only (26%), and omega-3 fatty acids (22%). Women used DSs almost twice as often as men [adjusted OR (aOR), 1.8; 95% CI: 1.5, 2.3). Those not reporting prescription medications were less likely to take a DS than those reporting ≥3 prescription medications (aOR, 0.4; 95% CI: 0.3, 0.6). The most frequently reported motivation for DS use was to improve overall health (41%).Conclusions: Use of DSs among older adults continues to be high in the United States, with 29% of users regularly taking ≥4 DSs, and there is a high concurrent usage of them with prescription medications.

B-vitamin status and bone mineral density and risk of lumbar osteoporosis in older females in the United States

BACKGROUND

Previous data suggest that elevated serum total homocysteine (tHcy) may be a risk factor for bone fracture and osteoporosis. Nutritional causes of elevated tHcy are suboptimal B-vitamin status. To our knowledge, this is the first nationally representative report on the relation of B vitamins and bone health from a population with folic acid fortification.

OBJECTIVE

The purpose of this analysis was to examine the relation between B-vitamin status biomarkers and bone mineral density (BMD), risk of osteoporosis, and biomarkers of bone turnover.

DESIGN

We examined the relation of tHcy, methylmalonic acid (MMA), and serum/red blood cell folate and total-body and lumbar spine BMD in women aged ≥50 y participating in the NHANES 1999-2004 (n = 2806), a nationally representative cross-sectional survey. These are the only years with concurrent measurement of tHcy and whole-body dual-energy X-ray absorptiometry. We also examined B-vitamin biomarkers relative to bone turnover markers, bone alkaline phosphatase, and urinary N-terminal cross-linked telopeptide of type I collagen in a 1999-2002 subset with available data (n = 1813).

RESULTS

In comparison with optimal concentrations, women with elevated tHcy were older with lower serum vitamin B-12, red blood cell folate, and dietary micronutrient intakes and had significantly higher mean ± SE markers of bone turnover (bone alkaline phosphatase: 15.8 ± 0.59 compared with 14.0 ± 0.25 μg/L; urinary N-terminal cross-linked telopeptide of type I collagen: 48.2 ± 2.9 compared with 38.9 ± 0.90 nmol bone collagen equivalents per mmol creatinine/L). Elevated MMA (OR: 1.88; 95% CI: 1.10, 3.18) and tHcy (OR: 2.17; 95% CI: 1.14, 4.15) were related to increased risk of lumbar osteoporosis. When examined as a continuous variable, tHcy was negatively associated, serum folates were positively associated, and MMA and vitamin B-12 were not significantly associated with lumbar and total-body BMD.

CONCLUSION

In this nationally representative population of older US women with high exposure to B vitamins through food fortification and dietary supplements, only elevated tHcy and MMA were independently associated with risk of lumbar spine osteoporosis.

Estimating caffeine intake from energy drinks and dietary supplements in the United States

No consistent definition exists for energy products in the United States. These products have been marketed and sold as beverages (conventional foods), energy shots (dietary supplements), and in pill or tablet form. Recently, the number of available products has surged, and formulations have changed to include caffeine. To help characterize the use of caffeine-containing energy products in the United States, three sources of data were analyzed: sales data, data from federal sources, and reports from the Drug Abuse Warning Network. These data indicate that sales of caffeine-containing energy products and emergency room visits involving their consumption appear to be increasing over time. Data from the National Health and Nutrition Examination Survey (NHANES) 2007-2010 indicate that 2.7% [standard error (SE) 0.2%] of the US population ≥1 year of age used a caffeine-containing energy product, providing approximately 150-200 mg/day of caffeine per day in addition to caffeine from traditional sources like coffee, tea, and colas. The highest usage of these products was among males between the ages of 19 and 30 years (7.6%, SE 1.0). Although the prevalence of caffeine-containing energy product use remains low overall in the US population, certain subgroups appear to be using these products in larger amounts. Several challenges remain in determining the level of caffeine exposure from and accurate usage patterns of caffeine-containing energy products.

Multivitamin-mineral use is associated with reduced risk of cardiovascular disease mortality among women in the United States

BACKGROUND

Multivitamin-mineral (MVM) products are the most commonly used supplements in the United States, followed by multivitamin (MV) products. Two randomized clinical trials (RCTs) did not show an effect of MVMs or MVs on cardiovascular disease (CVD) mortality; however, no clinical trial data are available for women with MVM supplement use and CVD mortality.

OBJECTIVE

The objective of this research was to examine the association between MVM and MV use and CVD-specific mortality among US adults without CVD.

METHODS

A nationally representative sample of adults from the restricted data NHANES III (1988-1994; n = 8678; age ≥40 y) were matched with mortality data reported by the National Death Index through 2011 to examine associations between MVM and MV use and CVD mortality by using Cox proportional hazards models, adjusting for multiple potential confounders.

RESULTS

We observed no significant association between CVD mortality and users of MVMs or MVs compared with nonusers; however, when users were classified by the reported length of time products were used, a significant association was found with MVM use of >3 y compared with nonusers (HR: 0.65; 95% CI: 0.49, 0.85). This finding was largely driven by the significant association among women (HR: 0.56; 95% CI: 0.37, 0.85) but not men (HR: 0.79; 95% CI: 0.44, 1.42). No significant association was observed for MV products and CVD mortality in fully adjusted models.

CONCLUSIONS

In this nationally representative data set with detailed information on supplement use and CVD mortality data ∼20 y later, we found an association between MVM use of >3 y and reduced CVD mortality risk for women when models controlled for age, race, education, body mass index, alcohol, aspirin use, serum lipids, blood pressure, and blood glucose/glycated hemoglobin. Our results are consistent with the 1 available RCT in men, indicating no relation with MVM use and CVD mortality.

The prevalence of using iodine-containing supplements is low among reproductive-age women, NHANES 1999-2006

During pregnancy, the iodine requirement rises to meet demands for neurological development and fetal growth. If these requirements are not met, irreversible pathological cognitive and behavioral changes to the fetus may ensue. This study estimated the prevalence of iodine-containing dietary supplement (DS) use and intakes of iodine from DSs among pregnant women and nonpregnant women of reproductive age (15-39 y) who were interviewed and examined in NHANES 1999-2006 (n = 6404). Although 77.5% of pregnant women reported taking one or more DSs in the past 30 d, only 22.3% consumed an iodine-containing supplement. Most pregnant women reported using one DS and reported taking this product daily. The vast majority of iodine-containing DSs reported by pregnant women claimed an iodine content of 150 μg iodine/serving on the label. Pregnant women using at least one DS containing iodine had a mean daily iodine intake of 122 μg/d from supplements; the median value was 144 μg/d. Median urinary iodine concentrations (UICs) were similar for pregnant and nonpregnant women in the population aged 15-39 y. The median UIC was 148 μg/L for pregnant women and 133 μg/L for nonpregnant women. The WHO has established a cutoff for insufficient iodine intake at <150 μg/L for pregnant women and <100 mg/L for those who are not pregnant. This suggests that as a population, we may not be meeting adequate intakes of iodine for pregnant women. More research is needed on the iodine intakes of pregnant women and women of reproductive age on their total iodine intake from all sources, not just DSs.

Why US adults use dietary supplements

BACKGROUND

Dietary supplements are used by more than half of adults, although to our knowledge, the reasons motivating use have not been previously examined in US adults using nationally representative data. The purpose of this analysis was to examine motivations for dietary supplement use, characterize the types of products used for the most commonly reported motivations, and to examine the role of physicians and health care practitioners in guiding choices about dietary supplements.

METHODS

Data from adults (≥20 years; n = 11 956) were examined in the 2007-2010 National Health and Nutrition Examination Survey, a nationally representative, cross-sectional, population-based survey.

RESULTS

The most commonly reported reasons for using supplements were to "improve" (45%) or "maintain" (33%) overall health. Women used calcium products for "bone health" (36%), whereas men were more likely to report supplement use for "heart health or to lower cholesterol" (18%). Older adults (≥60 years) were more likely than younger individuals to report motivations related to site-specific reasons like heart, bone and joint, and eye health. Only 23% of products were used based on recommendations of a health care provider. Multivitamin-mineral products were the most frequently reported type of supplement taken, followed by calcium and ω-3 or fish oil supplements. Supplement users are more likely to report very good or excellent health, have health insurance, use alcohol moderately, eschew cigarette smoking, and exercise more frequently than nonusers.

CONCLUSIONS

Supplement users reported motivations related to overall health more commonly than for supplementing nutrients from food intakes. Use of supplements was related to more favorable health and lifestyle choices. Less than a quarter of supplements used by adults were recommended by a physician or health care provider.

Dietary supplement use in the United States, 2003-2006

Dietary supplement use has steadily increased over time since the 1970s; however, no current data exist for the U.S. population. Therefore, the purpose of this analysis was to estimate dietary supplement use using the NHANES 2003-2006, a nationally representative, cross-sectional survey. Dietary supplement use was analyzed for the U.S. population (≥1 y of age) by the DRI age groupings. Supplement use was measured through a questionnaire and was reported by 49% of the U.S. population (44% of males, 53% of females). Multivitamin-multimineral use was the most frequently reported dietary supplement (33%). The majority of people reported taking only 1 dietary supplement and did so on a daily basis. Dietary supplement use was lowest in obese adults and highest among non-Hispanic whites, older adults, and those with more than a high-school education. Between 28 and 30% reported using dietary supplements containing vitamins B-6, B-12, C, A, and E; 18-19% reported using iron, selenium, and chromium; and 26-27% reported using zinc- and magnesium-containing supplements. Botanical supplement use was more common in older than in younger age groups and was lowest in those aged 1-13 y but was reported by ~20% of adults. About one-half of the U.S. population and 70% of adults ≥ 71 y use dietary supplements; one-third use multivitamin-multimineral dietary supplements. Given the widespread use of supplements, data should be included with nutrient intakes from foods to correctly determine total nutrient exposure.

Total folate and folic acid intakes from foods and dietary supplements of US children aged 1-13 y

BACKGROUND

Total folate intake includes naturally occurring food folate and folic acid from fortified foods and dietary supplements. Recent reports have focused on total folate intakes of persons aged > or =14 y. Information on total folate intakes of young children, however, is limited.

OBJECTIVE

The objective was to compute total folate and total folic acid intakes of US children aged 1-13 y by using a statistical method that adjusts for within-person variability and to compare these intakes with the Dietary Reference Intake guidelines for adequacy and excess.

DESIGN

Data from the 2003-2006 National Health and Nutrition Examination Survey, a nationally representative cross-sectional survey, were analyzed. Total folate intakes were derived by combining intakes of food folate (naturally occurring and folic acid from fortified foods) on the basis of 24-h dietary recall results and folic acid intakes from dietary supplements on the basis of a 30-d questionnaire.

RESULTS

More than 95% of US children consumed at least the Estimated Average Requirement (EAR) for folate from foods alone. More than one-third (35%) of US children aged 1-13 y used dietary supplements, and 28% used dietary supplements containing folic acid. Supplement users had significantly higher total folate and folic acid intakes than did nonusers. More than half (53%) of dietary supplement users exceeded the Tolerable Upper Intake Level (UL) for total folic acid (fortified food + supplements) as compared with 5% of nonusers.

CONCLUSIONS

Total folate intakes of most US children aged 1-13 y meet the EAR. Children who used dietary supplements had significantly higher total folate intakes and exceeded the UL by >50%.

Unmetabolized serum folic acid and its relation to folic acid intake from diet and supplements in a nationally representative sample of adults aged > or =60 y in the United States

BACKGROUND

Unmetabolized serum folic acid (UMFA) has been detected in adults. Previous research indicates that high folic acid intakes may be associated with risk of cancer.

OBJECTIVE

The objective was to examine UMFA concentrations in relation to dietary and supplemental folate and status biomarkers in the US population aged > or =60 y.

DESIGN

Surplus sera were analyzed with the use of data from the National Health and Nutrition Examination Survey (NHANES) 2001-2002, a cross-sectional, nationally representative survey (n = 1121).

RESULTS

UMFA was detected in 38% of the population, with a mean concentration of 4.4 +/- 0.6 nmol/L (median: 1.2+/- 0.2 nmol/L). The group with UMFA (UMFA+) had a significantly higher proportion of folic acid supplement users than did the group without UMFA (60% compared with 41%). UMFA+ men and women also had higher supplemental and total (food + supplements) folic acid intakes than did their counterparts without UMFA. Forty percent of the UMFA+ group was in the highest quartile of total folic acid intake, but total folic acid intake was only moderately related to UMFA concentrations (r(2) = 0.07). Serum folate concentrations were significantly higher in the UMFA+ group and were predictive of UMFA concentrations (r(2) = 0.15). Serum 5-methyltetrahydrofolate and vitamin B-12 concentrations were higher in the UMFA+ group, whereas there was no difference between the 2 UMFA groups in red blood cell folate, serum homocysteine, or methylmalonic acid concentrations.

CONCLUSIONS

Approximately 40% of older adults in the United States have UMFA that persists after a fast, and the presence of UMFA is not easily explained in NHANES by folic acid intakes alone. Given the possibility that excessive folic acid exposure may relate to cancer risk, monitoring of UMFA may be warranted.

Estimation of total usual calcium and vitamin D intakes in the United States

Our objective in this study was to estimate calcium intakes from food, water, dietary supplements, and antacids for U.S. citizens aged >or=1 y using NHANES 2003-2006 data and the Dietary Reference Intake panel age groupings. Similar estimates were calculated for vitamin D intake from food and dietary supplements using NHANES 2005-2006. Diet was assessed with 2 24-h recalls; dietary supplement and antacid use were determined by questionnaire. The National Cancer Institute method was used to estimate usual nutrient intake from dietary sources. The mean daily nutrient intake from supplemental sources was added to the adjusted dietary intake estimates to produce total usual nutrient intakes for calcium and vitamin D. A total of 53% of the U.S. population reported using any dietary supplement (2003-2006), 43% used calcium (2003-2006), and 37% used vitamin D (2005-2006). For users, dietary supplements provided the adequate intake (AI) recommendation for calcium intake for approximately 12% of those >or=71 y. Males and females aged 1-3 y had the highest prevalence of meeting the AI from dietary and total calcium intakes. For total vitamin D intake, males and females >or=71, and females 14-18 y had the lowest prevalence of meeting the AI. Dietary supplement use is associated with higher prevalence of groups meeting the AI for calcium and vitamin D. Monitoring usual total nutrient intake is necessary to adequately characterize and evaluate the population's nutritional status and adherence to recommendations for nutrient intake.

Total folate and folic acid intake from foods and dietary supplements in the United States: 2003-2006

BACKGROUND

The term total folate intake is used to represent folate that occurs naturally in food as well as folic acid from fortified foods and dietary supplements. Folic acid has been referred to as a double-edged sword because of its beneficial role in the prevention of neural tube defects and yet possible deleterious effects on certain cancers and cognitive function. Previous monitoring efforts did not include folic acid from dietary supplements and are therefore not complete.

OBJECTIVE

Our objective was to combine data on dietary folate (as measured by two 24-h recalls) and folic acid from dietary supplements (collected with a 30-d frequency questionnaire) with the use of the bias-corrected best power method to adjust for within-person variability.

DESIGN

The National Health and Nutrition Examination Survey (NHANES) is a nationally representative, cross-sectional survey. Linear contrasts were constructed to determine differences in dietary and total folate intake for age and racial-ethnic groups by sex; prevalence of inadequate and excessive intakes is presented.

RESULTS

In 2003-2006, 53% of the US population used dietary supplements; 34.5% used dietary supplements that contained folic acid. Total folate intake (in dietary folate equivalents) was higher for men (813 +/- 14) than for women (724 +/- 16) and higher for non-Hispanic whites (827 +/- 19) than for Mexican Americans (615 +/- 11) and non-Hispanic blacks (597 +/- 12); 29% of non-Hispanic black women had inadequate intakes. Total folate and folic acid intakes are highest for those aged > or =50 y, and 5% exceed the Tolerable Upper Intake Level.

CONCLUSIONS

Improved total folate intake is warranted in targeted subgroups, which include women of childbearing age and non-Hispanic black women, whereas other population groups are at risk of excessive intake.