Debra R. Keast

Foods, Fortificants, and Supplements: Where Do Americans Get Their Nutrients?

Limited data are available on the source of usual nutrient intakes in the United States. This analysis aimed to assess contributions of micronutrients to usual intakes derived from all sources (naturally occurring, fortified and enriched, and dietary supplements) and to compare usual intakes to the Dietary Reference Intake for U.S. residents aged ≥2 y according to NHANES 2003–2006 (n = 16,110). We used the National Cancer Institute method to assess usual intakes of 19 micronutrients by source. Only a small percentage of the population had total usual intakes (from dietary intakes and supplements) below the estimated average requirement (EAR) for the following: vitamin B-6 (8%), folate (8%), zinc (8%), thiamin, riboflavin, niacin, vitamin B-12, phosphorus, iron, copper, and selenium (<6% for all). However, more of the population had total usual intakes below the EAR for vitamins A, C, D, and E (34, 25, 70, and 60%, respectively), calcium (38%), and magnesium (45%). Only 3 and 35% had total usual intakes of potassium and vitamin K, respectively, greater than the adequate intake. Enrichment and/or fortification largely contributed to intakes of vitamins A, C, and D, thiamin, iron, and folate. Dietary supplements further reduced the percentage of the population consuming less than the EAR for all nutrients. The percentage of the population with total intakes greater than the tolerable upper intake level (UL) was very low for most nutrients, whereas 10.3 and 8.4% of the population had intakes greater than the UL for niacin and zinc, respectively. Without enrichment and/or fortification and supplementation, many Americans did not achieve the recommended micronutrient intake levels set forth in the Dietary Reference Intake.

Development and Validation of the Nutrient-Rich Foods Index: A Tool to Measure Nutritional Quality of Foods

Ranking and/or classifying foods based on their nutrient composition is known as nutrient profiling. Nutrition quality indices need to be tested and validated against quality of the total diet. A family of nutrient-rich foods (NRF) indices were validated against the Healthy Eating Index (HEI), an accepted measure of diet quality. All foods consumed by participants in NHANES 1999-2002 studies were scored using NRFn.3 (where n = 6-15) indices based on unweighted sums, means, and ratios of percent daily values (DV) for nutrients to encourage (n) and for nutrients to limit (LIM) (3). Individual food scores were calculated based on 100 kcal (418 kJ) and FDA serving sizes [reference amounts customarily consumed (RACC)]. Energy-weighted food-based scores per person were then regressed against HEI, adjusting for gender, age, and ethnicity. The measure of index performance was the percentage of variation in HEI (R2) explained by each NRF score. NRF indices based on both nutrients to encourage and LIM performed better than indices based on LIM only. Maximum variance in HEI was explained using 6 or 9 nutrients to encourage; index performance actually declined with the inclusion of additional vitamins and minerals. NRF indices based on 100 kcal (418 kJ) performed similarly to indices based on RACC. Algorithms based on sums or means of nutrient DV performed better than ratio-based scores. The NRF9.3 index, based on 9 nutrients to encourage and 3 LIM per RACC and per 100 kcal, explained the highest percentage of variation from HEI and could be readily expected to rank foods based on nutrient density.

Food Sources of Energy and Nutrients among Adults in the US: NHANES 2003–2006

Identification of current food sources of energy and nutrients among US adults is needed to help with public health efforts to implement feasible and appropriate dietary recommendations. To determine the food sources of energy and 26 nutrients consumed by US adults the 2003–2006 National Health and Nutrition Examination Survey (NHANES) 24-h recall (Day 1) dietary intake data from a nationally representative sample of adults 19+ years of age (y) (n = 9490) were analyzed. An updated USDA Dietary Source Nutrient Database was developed for NHANES 2003–2006 using current food composition databases. Food grouping included ingredients from disaggregated mixtures. Mean energy and nutrient intakes from food sources were sample-weighted. Percentages of total dietary intake contributed from food sources were ranked. The highest ranked sources of energy and nutrients among adults more than 19 years old were: energy—yeast bread/rolls (7.2%) and cake/cookies/quick bread/pastry/pie (7.2%); protein—poultry (14.4%) and beef (14.0%); total fat—other fats and oils (9.8%); saturated fatty acids—cheese (16.5%) and beef (9.1%); carbohydrate—soft drinks/soda (11.4%) and yeast breads/rolls (10.9%); dietary fiber—yeast breads/rolls (10.9%) and fruit (10.2%); calcium—milk (22.5%) and cheese (21.6%); vitamin D—milk (45.1%) and fish/shellfish (14.4%); and potassium—milk (9.6%) and coffee/tea/other non-alcoholic beverages (8.4%). Knowledge of primary food sources of energy and nutrients can help health professionals design effective strategies to reduce excess energy consumed by US adults and increase the nutrient adequacy of their diets.

Dietary supplement use is associated with higher intakes of minerals from food sources

BACKGROUND Dietary supplement use is extensive in US adults. Some reports suggested that supplement users had higher nutrient intakes from the diet than did nonusers, but to our knowledge this finding has not been examined in nationally representative survey data. OBJECTIVE In this analysis, we examined mineral intakes from the diet by supplement-use categories and how these supplements contributed to meeting or exceeding Dietary Reference Intakes for selected minerals. DESIGN Data from adults (≥19 y of age; n = 8860) who participated in NHANES 2003-2006, a nationally representative, cross-sectional survey, were examined. Supplement use was defined as the participants self-reported use of a supplement that contained one or more selected minerals. RESULTS Dietary intakes of minerals from food sources were higher for magnesium, copper, potassium, and selenium in male supplement users than in nonusers. For women, dietary intakes of minerals from food sources were higher for users than for nonusers for each mineral examined except for selenium. In women, users of calcium-containing dietary supplements were much more likely to meet the Estimated Average Requirement (EAR) than were nonusers. Even after consideration of supplement use, >14% of adults had inadequate intakes for calcium and magnesium on the basis of the percentage of adults with usual intakes less than the EAR. The prevalence of adults who exceeded the tolerable upper intake level (UL) for calcium, zinc, iron, and magnesium was higher in users than in nonusers. CONCLUSIONS Individuals who used mineral-containing dietary supplements had higher mineral intakes from food sources in the diet than did nonusers. For all minerals examined, and particularly for calcium and magnesium in men and women and iron in women, supplement use decreased the prevalence of intake inadequacy for each respective mineral; however, supplements contributed to risk of potentially excessive intakes for calcium, iron, zinc, and magnesium.

Examination of Vitamin Intakes among US Adults by Dietary Supplement Use

BACKGROUND More than half of US adults use dietary supplements. Some reports suggest that supplement users have higher vitamin intakes from foods than nonusers, but this observation has not been examined using nationally representative survey data. OBJECTIVE The purpose of this analysis was to examine vitamin intakes from foods by supplement use and how dietary supplements contribute to meeting or exceeding the Dietary Reference Intakes for selected vitamins using data from the National Health and Nutrition Examination Survey among adults (aged ≥19 years) in 2003-2006 (n=8,860). RESULTS Among male users, mean intakes of folate and vitamins A, E, and K from food sources were significantly higher than among nonusers. Among women, mean intakes of folate and vitamins A, C, D, and E from foods were higher among users than nonusers. Total intakes (food and supplements) were higher for every vitamin we examined among users than the dietary vitamin intakes of nonusers. Supplement use helped lower the prevalence of intakes below the Estimated Average Requirement for every vitamin we examined, but for folic acid and vitamins A, B-6, and C, supplement use increased the likelihood of intakes above the Tolerable Upper Intake Level. CONCLUSIONS Supplement use was associated with higher mean intakes of some vitamins from foods among users than nonusers, but it was not associated with the prevalence of intakes less than the Estimated Average Requirement from foods. Those who do not use vitamin supplements had significantly higher prevalence of inadequate vitamin intakes; however, the use of supplements can contribute to excess intake for some vitamins.

Do dietary supplements improve micronutrient sufficiency in children and adolescents

OBJECTIVE To examine if children use supplements to fill gaps in nutritionally inadequate diets or whether supplements contribute to already adequate or excessive micronutrient intakes from foods. STUDY DESIGN Data were analyzed for children (2-18 years) from the National Health and Nutrition Examination Survey 2003-2006, a nationally representative, cross-sectional survey (n = 7250). Diet was assessed using two 24-hour recalls, and dietary supplement use was assessed with a 30-day questionnaire. RESULTS Prevalence of supplements use was 21% (<2 years) and 42% (2-8 years). Supplement users had higher micronutrient intakes than nonusers. Calcium and vitamin D intakes were low for all children. Inadequate intakes of phosphorus, copper, selenium, folate, and vitamins B-6 and B-12 were minimal from foods alone among 2-8 year olds. However, among 9-18 year olds, a higher prevalence of inadequate intakes of magnesium, phosphorus, and vitamins A, C, and E were observed. Supplement use increased the likelihood of intakes above the upper tolerable intake level for iron, zinc, copper, selenium, folic acid, and vitamins A and C. CONCLUSIONS Even with the use of supplements, more than a one-third of children failed to meet calcium and vitamin D recommendations. Children 2-8 years old had nutritionally adequate diets regardless of supplement use. However, in children older than 8 years, dietary supplements added micronutrients to diets that would have otherwise been inadequate for magnesium, phosphorus, vitamins A, C, and E. Supplement use contributed to the potential for excess intakes of some nutrients. These findings may have implications for reformulating dietary supplements for children.

Out-of-hand nut consumption is associated with improved nutrient intake and health risk markers in US children and adults: National Health and Nutrition Examination Survey 1999-2004

The purpose of this study was to determine the association of out-of-hand nut (OOHN) consumption with nutrient intake, diet quality, and the prevalence of risk factors for cardiovascular disease and metabolic syndrome. Data from 24-hour recalls from individuals aged 2+ years (n = 24,385) participating in the 1999-2004 National Health and Nutrition Examination Survey were used. The population was divided into children aged 2 to 11, 12 to 18, and adults 19+ years, and each group was dichotomized into OOHN consumers and nonconsumers. Out-of-hand nut consumers were defined as those individuals consuming ¼ oz of nuts or more per d. Means, standard errors, and covariate-adjusted analyses of variance were determined using appropriate sample weights. Diet quality was determined using the Healthy Eating Index-2005. Significance was set at P < .05. The percent of OOHN consumers increased with age: 2.1% ± 0.3%, 2.6% ± 0.3%, 6.5% ± 0.5%, and 9.6% ± 0.5% those aged 2 to 11, 12 to 18, 19 to 50, and 51+ years, respectively. The 2 latter groups were combined into a single group of consumers aged 19+ years for subsequent analyses. Consumers of OOHN from all age groups had higher intakes of energy, monounsaturated and polyunsaturated fatty acids, dietary fiber, copper, and magnesium and lower intakes of carbohydrates, cholesterol, and sodium than did nonconsumers. Diet quality was higher in OOHN consumers of all age groups. In children aged 2 to 11 years, consumers had a higher prevalence of overweight/obesity. In those aged 12 to 18 years, weight and percent overweight were lower in consumers. Adult consumers had higher high-density lipoprotein cholesterol, red blood cell folate, and serum folate levels and lower insulin, glycohemoglobin, and C-reactive protein levels than did nonconsumers. Adult consumers also had a 19% decreased risk of hypertension and a 21% decreased risk of low high-density lipoprotein cholesterol levels. Data suggested that OOHN consumption was associated with improved nutrient intake, diet quality, and, in adults, a lower prevalence of 2 risk factors for metabolic syndrome. Consumption of OOHN, as part of a healthy diet, should be encouraged by health professionals.

Fortified foods are major contributors to nutrient intakes in diets of US children and adolescents.

BACKGROUND Even in an era of obesity and dietary excess, numerous shortfall micronutrients have been identified in the diets of US children and adolescents. To help tailor strategies for meeting recommendations, it is important to know what foods contribute greatly to micronutrient intakes. Data are lacking on specific contributions made by added nutrients. OBJECTIVE Our aims were to examine the impact of fortification on nutrient adequacy and excess among US children and adolescents and to rank food sources of added nutrient intake and compare rankings with those based on total nutrient intake from foods. DESIGN AND STATISTICAL ANALYSES Data were from 7,250 respondents 2 to 18 years old in the National Health and Nutrition Examination Survey 2003-2006. Datasets were developed that distinguished nutrient sources: intrinsic nutrients in foods; added nutrients in foods; foods (intrinsic plus added nutrients); and total diet (foods plus supplements). The National Cancer Institute method was used to determine usual intakes of micronutrients by source. The impact of fortification on the percentages of children having intakes less than the Estimated Average Requirement and more than the Upper Tolerable Intake Level was assessed by comparing intakes from intrinsic nutrients to intakes from intrinsic plus added nutrients. Specific food sources of micronutrients were determined as sample-weighted mean intakes of total and added nutrients contributed from 56 food groupings. The percentage of intake from each grouping was determined separately for total and added nutrients. RESULTS Without added nutrients, a high percentage of all children/adolescents had inadequate intakes of numerous micronutrients, with the greatest inadequacy among older girls. Fortification reduced the percentage less than the Estimated Average Requirement for many, although not all, micronutrients without resulting in excessive intakes. Data demonstrated the powerful influence of fortification on food-source rankings. CONCLUSIONS Knowledge about nutrient intakes and sources can help put dietary advice into a practical context. Continued monitoring of top food sources of nutrients and nutrient contributions from fortification will be important.

Contribution of beef consumption to nutrient intake, diet quality, and food patterns in the diets of the US population

This study examined the association between the nutrient contribution of beef, in its lowest and highest fat forms, and diet quality and food patterns in individuals 4+years of age. Beef consumers were categorized into three groups (lowest lean/highest fat [LLHF]; middle lean/middle fat content; and highest lean/lowest fat [HLLF]) based on the lean and fat content of beef consumed. Compared to non-beef consumers, HLLF consumers had higher intakes of vitamins B(6) and B(12), iron, zinc, and potassium. Non-beef consumers had higher intakes of thiamin, folate, calcium, and magnesium than HLLF beef consumers. The HLLF group had significantly higher intakes of vitamins A, C, B(6), and B(12); niacin; phosphorus; magnesium; iron; zinc; and potassium, protein and lower intakes of total energy; total fat; SFA; MUFA; total carbohydrates. There was no difference in diet quality between HLLF beef consumers and non-beef consumers. Moderate consumption of lean beef contributes to intakes of selected nutrients and diet quality was similar to non-beef consumers.

Energy and Nutrient Intakes from Processed Foods Differ by Sex, Income Status, and Race/Ethnicity of US Adults

BACKGROUND The 2010 Dietary Guidelines for Americans (DGA) recommends nutrients to increase and to decrease for US adults. The contributions processed foods make to the US intake of nutrients to increase and decrease may vary by the level of processing and by population subgroup. OBJECTIVE The hypotheses that the intakes of nutrients to increase or decrease, as specified by the DGA, are contributed exclusively from certain processed food categories and consumed differentially by population subgroups by sex, poverty-income ratio (ratio of household income to poverty threshold), and race/ethnicity was tested along with the hypothesis that specific processed food categories are responsible for nutrient intake differences between the population subgroups. DESIGN The 24-hour dietary recall data from the cross-sectional 2003-2008 National Health and Nutrition Examination Survey was used to determine population subgroup energy and nutrient intake differences among processed food categories defined by the International Food Information Council Foundation Continuum of Processed Foods. PARTICIPANTS/SETTING Fifteen thousand fifty-three US adults aged ≥19 years. STATISTICAL ANALYSES PERFORMED The mean daily intake of energy and nutrients from processed food categories reported by population subgroups were compared using regression analysis to determine covariate-adjusted least square means. RESULTS Processed food categories that contributed to energy and nutrient intake differences within subgroups did not uniformly or exclusively contribute nutrients to increase or decrease per DGA recommendations. The between-group differences in mean daily intake of both nutrients to increase and decrease contributed by the various processed food categories were diverse and were not contributed exclusively from specific processed food categories. CONCLUSIONS Recommendations for a diet adhering to the DGA should continue to focus on the energy and nutrient content, frequency of consumption, and serving size of individual foods rather than the level of processing.