Reference Methods and Standards for Dietary Supplements

The integrity of the nation's food supply is a major component of public health and safety. The development of reference methods and standards for nutrients, contaminants, and adulterants in foods is essential to provide traceability for food-matrix measurements, and is especially relevant to international trade issues. Project components include measurement and standards issues related to nutrients in food products, contaminants and adulterants in food products, and to chemical composition of and contaminants in dietary supplements. Project priorities are determined in consultation with the AOAC, FDA, NIH, and the Food Products Association.

• SRMs with assigned values for active and/or marker compounds and priority contaminants are being provided for the dietary supplement industry and measurement communities that will lead to improved quality of dietary supplements, and ultimately reduce public health risks that could potentially be associated with these products. Potential health risks may result from contamination (e.g., pesticides, toxic elements), adulteration (presence of unlabeled foreign materials including pharmaceuticals), or variability in product composition (e.g., changes in levels of active constituents). These SRM suites will assist manufacturers of dietary supplements to characterize raw materials and to monitor final products for selected contaminants or adulterants. In addition, the SRMs will assist self-assessment of consistency and quality in finished products.
• The Analytical Chemistry Division is collaborating with the Food and Drug Administration (FDA) and the National Institutes of Health's Office of Dietary Supplements (NIH-ODS) in a multi-year program to develop SRMs and analytical methods for a number of dietary supplement materials, including botanical and botanical-containing matrices as well as a multivitamin/multielement material. Materials will be characterized for active or marker compounds, toxic elements (As, Cd, Hg, and Pb), and pesticides, as appropriate.

A suite of five ephedra-containing materials will be the first NIST-issued botanical dietary supplement SRMs:
SRM 3240 Ephedra sinica Stapf Aerial Parts
SRM 3241 Ephedra sinica Stapf Native Extract
SRM 3242 Ephedra sinica Stapf Commercial Extract
SRM 3243 Ephedra-Containing Solid Oral Dosage Form
SRM 3244 Ephedra-Containing Protein Powder

Ginkgo biloba SRM suite (under development; SRMs 3246-3248, plant, extract, tablet)

SRM 3280, Multivitamin/Multielement Tablets (under development; values for 18 elements, 15 vitamins, and 2 carotenoids are expected; completion scheduled for early 2006.)

• Continue six-year effort to develop SRMs for eight to ten different botanical dietary supplements. Under development are SRMs of saw palmetto, carrot extract, bitter orange, St. John's wort, and green tea. The next priorities for SRM development include: �-carotene (e.g., a mixture of �-carotene isomers), vitamin E (e.g., d-a-tocopheryl acetate/d,l-a-tocopheryl acetate and a mixture of the tocopherol and tocotrienol isomers), black cohosh, and a number of berry materials (e.g., cranberries and blueberries).