Location: Nutrient Data Laboratory2009 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
The Nutrient Data Laboratory (NDL) continues to work with the Office of Dietary Supplements (ODS) of the National Institutes of Health, to further develop and release the Dietary Supplement Ingredient Database (DSID) in response to needs expressed by the public health research community. A key goal of the DSID is to report analytical levels of nutrients and other bioactive components in dietary supplements (DS). DSID complements estimates of nutrient intake from supplements provided in databases which report only label values and is designed to support the estimation of total nutrient intake. The foundation of the DS database is analytical data, using an approach similar to that used in USDA food databases. A USDA statistician worked with NDL to optimize regression equations and estimates of variability, using data from over 115 products from the adult MVM study conducted in 2008-2009. Regression equations for each nutrient were developed for application to other dietary supplement products not chemically analyzed. Codes were developed for researchers’ use in linking statistical regression estimates to specific adult MVMs reported in national surveys. On April 20, 2009, this data was made available in the Dietary Supplement Ingredient Database, Release 1 (DSID-1) for use by researchers and the public. Based on input from federal stakeholders, dietary supplement ingredients in additional products have been prioritized for review and inclusion in future releases of the DSID. During this reporting period, 65 children’s MVM products were analyzed and data evaluation conducted to determine the relationship between label and analytical values for up to 22 nutrients labeled as present in these MVM products. Twenty commonly reported fish oil and flaxseed oil supplements were purchased and chemically analyzed for determination of omega-3 fatty acid content. Sampling plans were developed for purchase of over 50 representative omega-3 fatty acid products. A sampling plan was developed for prenatal MVMs, and over 60 products were purchased and analyzed. For all studies, statistical sampling plans were developed using national survey data and current market sources to identify representative products and major 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. NDL scientists communicated DSID progress in presentations at the Experimental Biology meeting and National Nutrient Databank Conference. Two presentations were given at a national supplement industry meeting to inform stakeholders about DSID research and data release plans.
5. Significant Activities that Support Special Target Populations
Dietary supplements are consumed by populations in various ethnic, socioeconomic, and other vulnerable groups. For example, DSID has initiated 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 sub-populations. The nationwide sampling program was designed to select sample units from all marketing channels (retail, grocery, drug, multi-level) and from a large selection of known or popular brands to assure that products purchased by diverse populations are covered.