2011 Annual Report
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.
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.
Studies are underway for ingredient analysis in children’s MVMs, over-the-counter prenatal MVMs, and omega-3 fatty acid supplements. Statistical sampling plans were developed for all studies, identifying representative products and market channels. Up to 6 lots per product were purchased nationwide. Nutrient components were analyzed by qualified laboratories using validated methods, reference materials, and duplicates to monitor precision and accuracy.
In 2011, NDL made research progress on four studies: Children’s MVMs: Analytical data for 19 nutrients in multiple lots of 65 products were statistically evaluated to estimate the relationship between label and analytical values and to assess variability in children’s MVMs. The data will be linked to NHANES and released in FY 2012.
Prenatal MVMs: Analytical laboratory data for 22 nutrients were obtained for multiple lots of 48 retail and 23 direct sales products, to examine the relationship between label and analytical values and to assess variability in over-the-counter prenatal MVMs.
Omega-3 supplements: Analytical data were obtained for omega-3 fatty acid supplements representing the lower market share. Statistical analysis was initiated to assess omega-3 levels in multiple lots of over 80 supplement products.
Adult MVMs, 2nd study: A statistically based sampling plan was developed using DSID-1 results to determine statistical parameters for selecting representative adult MVM products in mass market, natural/health, and direct sales market channels. Nationwide product purchase began. Vitamin D, vitamin A, iodine, and chromium are being emphasized due to public health interest. NDL scientists worked with IT consultants to finalize database system requirements and develop a modular design for the Dietary Supplement Ingredient System (DSIS). NDL scientists reported DSID progress in reports at meetings of Experimental Biology, the American Dietetic Association, and an ODS-sponsored iodine seminar.