Bailey RL, Gahche JJ, Lentino CV, et al. Dietary supplement use in the United States, 2003-2006. J Nutr. 2011;141(2):261-266.

The use of dietary supplements by US adults has been tracked by the National Health and Nutrition Examination Survey (NHANES) since 1971. In the 1990s, the survey was expanded to include infants, children, and adolescents, and the frequency of data collection was increased from every 4 years to every 2 years. This paper reports on the most recent estimates of supplement usage using data from the 2003-2006 NHANES.

NHANES is a nationally representative, cross-sectional survey of US residents in which the participants are asked to complete an in-person household interview and a health examination by way of a Mobile Examination Center. All data used in this report were from the in-person interviews. Data from two survey cycles (2003-2004, n=10,122 and 2005-2006, n=10,348) were combined, excluding data for subjects less than 1 year old (1003), pregnant women (674), and those with missing or incomplete data (35). The final total population included was 18,758.

Data on age, gender, race/ethnicity, weight, and height were collected via personal interview and questionnaire. Use of dietary supplements was surveyed using the Dietary Supplement Questionnaire, which recorded use of vitamins, minerals, herbals, and other supplements over the past 30 days. Detailed information about type, consumption frequency, duration, and amount taken was collected for each supplement used. The major classes of supplements were placed in 3 categories: multivitamin/multi-mineral (MVMM), botanicals, and amino acids. Data from adults were analyzed separately from that of children.

Dietary supplement use was reported by 49% (44% of males, 53% of females) of the population aged 1 year and older. In general, supplement use increased with age. The majority of users (79%) reported taking them every day within the last 30 days, 12% reported use between 20 and 29 days, 9% between 10–19 days, and 9% reported use for less than10 days. Across the 3 major categories of supplements, MVMM use was highest (33%), followed by botanical supplements (14%) and amino acids (4%). Use of botanical supplements was more common in older than in younger age groups.

Among adults, 54% reported dietary supplement use. Obese individuals took fewer dietary supplements (48%) than overweight (57%) or normal-weight individuals (56%). Use was highest in those with more than a high school education (61%) and lowest in those with less than a high school education (37%). Non-Hispanic whites had a higher use of dietary supplements (59%) than non-Hispanic blacks (36%) or Mexican-Americans (34%).

Between 28-31% of the population took supplements containing 1 or more of the following vitamins: B-6, B-12, C, A, and E. Vitamins B-6, B-12, C, and K were most commonly used by those over 51 years. Vitamin B-6 and B-12 use was also high in those over 8 years, while vitamin C was high in 4-8-year-olds. Vitamins A and E were most used by those over 71 years old and children over 8 and 4-8 years old, respectively. The lowest prevalence of use of vitamin supplements was among adolescents (14-18-year-olds), with the exception of vitamin K. Overall, 17% of the population took supplements containing vitamin K.

The use of selected minerals ranged from 18-27% in the population, with the most used being magnesium. Iron use was highest in 4-8-year-olds, and lowest in males 14-18 years old. Among females, the highest iron use was in 19-30-year-olds (23%) and 31-50-year-olds (26%). [Note: Recall that pregnant women were excluded from the study.] Use of zinc, magnesium, selenium, and chromium was highest in those older than 51 years.

Over half of all participants used dietary supplements (54%), an increase of ~10% since NHANES 1988-1994 data and 2% since NHANES 1999-2000 data. Most participants reported taking only 1 dietary supplement, but ~10% took over 5. Use of MVMM is high and has increased over time and with age. 20% of adults used a supplement with at least 1 herbal ingredient (use of botanicals has been reported since NHANES 1988-1994). Very little change in supplement use among children occurred since NHANES 1999-2002, with the exception of a 5-7% decrease in iron use among various childhood ages. More than one-third of children reported using supplements containing vitamins B-6, B-12, C, A, and E. Overall, the data show a high prevalence of dietary supplement use in the US.