Location: Nutrient Data Laboratory2010 Annual Report
1a. Objectives (from AD-416)
Our long-term objective is to provide reliable estimates for the composition of dietary supplement (DS) products due to their increasing prevalence of use. An analytically based composition database of representative values of nutrients and other ingredients in dietary supplement products consumed by the U.S. population is being developed. This database will improve accuracy in estimating the contribution of dietary supplements to total dietary intakes of nutrients and thus will result in a better evaluation of the nutritional status of Americans. Over the next 5 years we will focus on the following objectives: Objective 1: Determine and monitor the nutrient and other ingredient composition of dietary supplements commonly consumed by Americans. Compile, maintain, and disseminate electronic dietary supplement composition databases utilizing standardized approaches according to specified timelines. Objective 2: Evaluate and update methods for the acquisition, evaluation, compilation and dissemination of dietary supplement composition data utilizing new, robust computerized systems. Objective 3: Investigate the variability of dietary supplement composition data attributable to inherent supplement differences, analytical methodology, and other contributing factors.
1b. Approach (from AD-416)
Objective 1: NDL will develop estimates of the nutrient and other ingredient content of high priority dietary supplement (DS) products and disseminate dietary supplement databases on a bi-annual basis. This research will include the identification of high priority dietary supplement products and ingredients according to prevalence of consumption, public health interest in specific ingredients, and the availability of reliable analytical methods for specific compounds. Studies of dietary supplements composition for various product types including user groups by age and/or gender will be conducted. Samples will be analyzed by qualified laboratories which demonstrate expertise in the analysis of dietary supplement components and matrices. Scientists will review and evaluate laboratory data for accuracy and precision and will apply appropriate statistical techniques to final data for estimation of dietary supplement component amounts. Objective 2: NDL will develop and validate methods for data acquisition (e.g., USDA analytical data, industry data), including statistical sampling, sample handling, laboratory methodology, and data quality evaluation, to ensure representative and accurate dietary supplement ingredient estimates. For analytical studies managed by NDL, statistical sampling plans for the analysis of dietary supplements will continue to be developed based upon market share and ingredient label information. NDL will include available Standard Reference Materials (SRMs) when sending batches of samples to the laboratory for analysis. NIST recommendations for the analysis of ingredients in SRMs, including stability information and extraction and homogenization procedures will be used in the development and evaluation of NDL laboratory protocols for contracted labs. Objective 3: NDL will investigate the variability of dietary supplement composition data attributable to inherent supplement differences, analytical methodology, and other contributing factors. The magnitude of variability attributable to the measurement process will vary for each ingredient or ingredient group (i.e., minerals analyzed by inductively-coupled plasma spectroscopy (ICP)) and can confound the results for variability inherent in a product. In addition, the assessment of individual ingredient variability will be a factor in determining sample sizes for future analytical studies.
3. Progress Report
NDL continues to collaborate with the Office of Dietary Supplements, National Institutes of Health, to develop the Dietary Supplement Ingredient Database (DSID) in response to needs expressed by the public health research community. A key goal is to report analytical levels of nutrients and other bioactive components in dietary supplements. Initial studies on adult multivitamin/mineral (MVM) products determined levels of 18 vitamins and minerals in adult MVMs. These data were made available in the Dietary Supplement Ingredient Database, Release 1 (www.dietarysupplementdatabase.usda.nih.gov) for use by researchers and the public. In 2010, NDL made research progress in three new studies: 1. Children’s MVMs: analytical data for a representative group of 65 children’s products were evaluated and summarized to determine the relationship between label and analytical values for up to 20 nutrients; 2. Prenatal MVMs: analytical nutrient data were evaluated for 40 retail and 20 direct sales prenatal MVMs; and 3. Omega-3 supplements: over 50 supplements representing the lower market share were chemically analyzed and data were evaluated for omega-3 fatty acid content. For all studies, statistical sampling plans have been developed using national survey data and current market sources to identify representative products and market channels. Up to 6 lots per product were purchased nationwide. Qualified laboratories analyzed nutrient components. Quality control was monitored using validated laboratory methods, reference materials, and duplicate analysis. In FY2010 NDL collaborated with a specialized laboratory to develop methodology for analysis of vitamin D in dietary supplements. An optimized method was determined to be acceptable after reviewing results for standard reference materials (SRMs), other control materials, and a variety of MVM matrices. Using this method, selected adult MVM products and all products from the children’s and prenatal studies were analyzed. Results are being evaluated. Final data will be statistically analyzed to establish estimates for vitamin D in children’s and prenatal MVMs reported in national surveys. NDL scientists worked with developers to begin designing a database model for the Dietary Supplement Ingredient System (DSIS), to incorporate system requirements defined by NDL in a needs assessment. The DSIS will facilitate acquisition, evaluation, analysis, and dissemination of dietary supplement data. NDL scientists communicated DSID progress in scientific reports at annual meetings of Experimental Biology, American Dietetic Association, AOAC, and National Nutrient Databank Conference.
5. Significant Activities that Support Special Target Populations
Dietary supplements are consumed by populations in various ethnic, socioeconomic, and other vulnerable groups. For example, NDL staff have begun studies of prenatal multivitamin/mineral (MVM) and children’s MVM supplements. Data acquired through DSID studies will be used to monitor total dietary intake and health status of various vulnerable population groups. The nationwide sampling program was designed to select sample units of dietary supplements from all marketing channels (retail, drug stores, multi-level, Internet) and from a large selection of known or popular brands to assure that products purchased by diverse populations are included.