Dietary Supplement Laboratory Quality Assurance Program (DSQAP)

Summary

The National Institute of Standards and Technology (NIST), in collaboration with the National Institutes of Health (NIH) Office of Dietary Supplements (ODS), revitalized the Dietary Supplement Laboratory Quality Assurance Program (DSQAP) to support the measurement needs of the dietary supplements community. The DSQAP provides an opportunity for dietary supplements testing laboratories to improve comparability of their measurements, as well as for NIST to assess community needs for reference materials, workshops, and other measurement services.

Description

Credit: Canva stock

Approximately 75% of the U.S. population takes dietary supplements, including vitamins and mineral supplements, representing an annual expenditure of more than $20 billion. Regulations, driven by reported cases of inaccurate labeling, adulteration, contamination (with pesticides, heavy metals, or toxic botanicals), and drug interactions, are now in place that require manufacturers to evaluate the identity, purity, and composition of their ingredients and finished products. In 2007, a Dietary Supplement Laboratory Quality Assurance Program (DSQAP) was initiated to enable participants to improve the accuracy and precision of their measurements for nutrients, marker compounds, toxic elements, and/or pesticides in dietary supplement ingredients and finished products. From 2017 to 2021, the participants of the DSQAP were served by studies conducted as part of the Health Assessment Measurements QAP. As part of a revamp of the NIST QAPs in 2021, NIST and ODS revitalized the DSQAP, which conducted its sixteenth exercise in 2022.

Approximately twice a year, exercises offer participants the opportunity to measure concentrations of nutritional and toxic elements, fat- and water-soluble vitamins, fatty acids, active and/or marker compounds, and contaminants in samples distributed by NIST. Participant data is compiled at NIST and analyzed for accuracy, precision, and concordance within the community. Reports and certificates of completion are sent to participants. Workshops and other presentations will offer opportunities to discuss results, measurement challenges, and methodological advancements in the characterization of dietary supplements. The intercomparison exercises, data reports, and workshops are designed to provide participating laboratories with the tools to evaluate their dietary supplement analytical methodology. Information gained through participation may be used by the participants to demonstrate "appropriateness" of analytical methodology to regulatory agencies and to improve the quality of information associated with dietary supplement products through increased measurement capabilities.

Future DSQAP studies may address additional areas such as botanical authenticity, as needs are identified. Please send suggestions for future studies or requests for additional information regarding DSQAP and other NIST QAPs to QAPHUB [at] nist.gov (QAPHUB[at]nist[dot]gov).

Upcoming Exercises

Exercise 3 (In progress – registration closed)

Study	Measurands and Samples
Toxic Elements	As, Cd, Pb, and Hg in kava root and kava extract
Fat-Soluble Vitamins	Total retinol and retinyl acetate in multivitamin tablets
Water-Soluble Vitamins	Thiamin (B1) and riboflavin (B2) in yohimbe containing solid oral dosage form and multivitamin tablets
Botanicals	Kava lactones in kava root and kava extract

Exercise 3 Final Report is in progress.

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Exercise 2 (In progress – registration closed)

Study	Measurands and Samples
Toxic Elements	As, Cd, Pb, and Hg in eleuthero and ginger extracts
Fat-Soluble Vitamins	Total β-carotene in saw palmetto and multivitamin tablets
Botanicals I	Gingerols in ginger rhizome, extract, and ginger-containing supplements
Fatty Acids	Fatty acids in fish oils
Botanicals II	Triterpene glycosides in black cohosh rhizome and extract

Crossed out studies were offered but then cancelled due to low enrollment

Exercise 2 Final Report is coming soon.

Major Accomplishments

Exercise 1

Study	Measurands and Samples
Elements*	Ca, Cr, Mg, I, Na, K, As, Cd, Cu, Zn, Se, I, S, and Hg in kelp
Vitamins I*	Niacin and vitamin K1 in kelp
Vitamins II	Vitamins B1, B2, B3, B5, B6, B7, B9, & B12 in liquid and powdered drink mixes
Botanicals I*	Phenolic content in kelp and green tea
Botanicals II	Withanolides in ashwagandha
Proximates*	Ash, carbohydrates, fat, protein, solids, starch, total dietary fiber, and calories in kelp
Contaminants*	PFAS in kelp

*Study run in part as a collaboration with World Wildlife Fund (WWF)
Exercise 1 Final Report.

WORKSHOPS

NIST DSQAP Workshop (April 23, 2023): NIST and the University of Mississippi National Center for Products Research co-sponsored a half-day workshop that was held in conjunction with the 21st Oxford International Conference on the Science of Botanicals (ICSB). The workshop described recent updates to NIST QAP offerings, and focused on discussion of the analytical challenges in measuring nutrients, phytochemicals, or contaminants in dietary supplements, botanicals, and other natural products.

Supporting The Standardization of Seaweed Measurements Workshop (October 24, 2023): In support of the DSQAP Exercise 1 seaweed collaboration with World Wildlife Fund (WWF), NIST hosted a workshop to discuss the QAP results, observations, and technical recommendations, as well as provide opportunities for discussions on improving measurement capabilities. The workshop included presentations from both NIST staff and external experts, along with discussions between NIST staff and participants for more in-depth conversations. These discussions with the research and analytical laboratory communities included the importance of robust and validated analytical methods and the future role of NIST in supporting seaweed measurement standardization.

Historical Exercises

Past participants can access historical results at QAP HUB. Log in using your existing credentials, or enter your email address to request a new password.

Exercise A

Study	Measurands and Samples
Nutritional Elements	Ca, Fe, Mg, and Zn in multivitamin tablets
Toxic Elements	Pb in Ginkgo and Ephedra tablets
Water-Soluble Vitamins	Folic acid in multivitamin tablets and infant formula
Fat-Soluble Vitamins	Vitamins A & E in multivitamin tablets and infant formula
Fatty Acids	Fatty acids in vegetable oil blends
Botanicals	Caffeine in solid oral dosage forms

Exercise A Report

Exercise B

Study	Measurands and Samples
Toxic Elements	As in Ephedra
Water-Soluble Vitamins	Vitamins B1 & B2 in multivitamin tablets
Botanicals	Phytosterols in saw palmetto, flavonols in Ginkgo biloba synephrine in bitter orange

Exercise B Report

Exercise C

Study	Measurands and Samples
Nutritional Elements	Ca, Na, P, and Zn in protein drink mix and fortified milk powder
Toxic Elements	As and Cd in bitter orange
Water-Soluble Vitamins	Niacin and vitamin B6 in protein drink mix and fortified milk powder
Fat-Soluble Vitamins	Retinyl palmitate in fortified milk powder
Fatty Acids	Omega-3 and omega-6 fatty acids in botanical oils
Botanicals	Phytosterols in a neat solution and saw palmetto

Exercise C Report

Exercise D

Study	Measurands and Samples
Toxic Elements	Pb in Ginkgo
Water-Soluble Vitamins	Niacin in fortified milk powder
Fat-Soluble Vitamins	β-carotene in oils
Botanicals	Organic acids in berry extracts

Exercise D Report

Exercise E

Study	Measurands and Samples
Nutritional Elements	Ca, Fe, and Zn in fortified breakfast cereals
Water-Soluble Vitamins	Niacin in fortified breakfast cereals
Fat-Soluble Vitamins	β-carotene in oil and multivitamin tablet
Contaminants	Aflatoxins in peanut products
Botanicals	Catechins in green tea

Exercise E Report

Exercise F

Study	Measurands and Samples
Nutritional Elements	Na and Fe in chocolate, spinach, and blueberries
Toxic Elements	As, Cd, Pb, and Hg in green tea
Water-Soluble Vitamins	Vitamins B1, B3, B6, & B12 in milk powder, blueberries, and B-vitamin tablets
Fat-Soluble Vitamins	Vitamin D in infant formula and supplements
Fatty Acids	Fatty acids in botanical oils, fish oils, and fish tissue
Botanicals	Isoflavones in soy-containing products

Participants in DSQAP Exercise F can request a copy of the final report via email to QAPHUB [at] nist.gov (QAPHUB[at]nist[dot]gov).

Exercise G

Study	Measurands and Samples
Nutritional Elements	Na in tomato leaves and cranberry powder
Toxic Elements	Pb in multivitamin tablets and Ephedra-containing tablets
Water-Soluble Vitamins	Folate in breakfast cereal and fortified milk powder
Fat-Soluble Vitamins	β-carotene in ethanolic solutions and saw palmetto extract
Botanicals	Anthocyanins/anthocyanidins in cranberry and bilberry extracts

Exercise G Report

Exercise H

Study	Measurands and Samples
Nutritional Elements	Ca, Cu, and Mn in calcium supplement and oyster tissue
Water-Soluble Vitamins	Choline in soy flour and egg powder
Fat-Soluble Vitamins	Tocopherols in carrot oil and egg powder
Fatty Acids	Omega-3 and -6 fatty acids in saw palmetto extract and berries
Contaminants	PAHs in neat solution and green tea leaves
Botanicals	Phytosterols in flax and perilla oils

Exercise H Report

Exercise I

Study	Measurands and Samples
Nutritional Elements	Cr, Mo, and Se in egg powder and multivitamin tablets
Toxic Elements	Cd in breakfast cereal and calcium supplement
Water-Soluble Vitamins	Pantothenic acid soy flour and blueberries
Fat-Soluble Vitamins	Vitamin A in egg powder and breakfast cereal
Botanicals	Catechins in green tea leaves and extract

Exercise I Report

Exercise J

Study	Measurands and Samples
Nutritional Elements	Ca, Mg, and Z in natural and enhanced waters
Toxic Elements	As in St. John's wort
Water-Soluble Vitamins	Vitamins B1, B3, and B6 in multivitamin tablets and enhanced water
Fat-Soluble Vitamins	Vitamin E in multivitamin tablets and enhanced water
Fatty Acids	Omega-3 and -6 fatty acids in plant and fish oils
Contaminants	Aflatoxins in peanut products
Botanicals	Isoflavones in soy protein isolate and soy flour
Identity	Pure and adulterated Ginkgo biloba. **Consensus-based only, no quantitative results required

Exercise J Report

Exercise K

Study	Measurands and Samples
Nutritional Elements	P and Fe in cranberry and blueberry
Toxic Elements	Hg in Ephedra and Ginkgo
Water-Soluble Vitamins	Vitamins B1, B2, and B3 in multivitamin tablets and protein powder
Fat-Soluble Vitamins	Vitamin K1 in multivitamin tablets and protein powder
Contaminants	Acrylamide in chocolate and coffee
Botanicals	Phytosterols in saw palmetto

Exercise K Report

Exercise L

Study	Measurands and Samples
Nutritional Elements	Iodine in cat food and multivitamin tablets
Toxic Elements	As and Pb in St. John’s wort
Water-Soluble Vitamins	Biotin in cat food and multivitamin tablets
Fat-Soluble Vitamins	Lutein and zeaxanthin in spinach and multivitamin tablets
Fatty Acids	Omega-3 and -6 in fish oils
Botanicals	Chlorogenic acid, flavonoids, and naphthodianthrones in St. John’s wort

Exercise L Report

Exercise M

Study	Measurands and Samples
Nutritional Elements	K and Zn in spinach and spirulina
Toxic Elements	As and Pb in ginger and ginseng
Water-Soluble Vitamins	Vitamins B1 and B2 in spirulina and multivitamin tablets
Fat-Soluble Vitamins	Vitamin K1 in basil and kelp
Botanicals	Curcuminoids in turmeric
Identity	Chondroitin sulfate

Exercise M Report

Exercise N

Study	Measurands and Samples
Nutritional Elements	Cr in a chromium supplement and multivitamin tablets
Toxic Elements	As, Cd, and Pb in calcium supplement and ginkgo supplement
Water-Soluble Vitamins	Folic acid in cereal and multivitamin tablets
Fat-Soluble Vitamins	vitamin D in protein powder, calcium supplement, and multivitamin tablets
Fatty Acids	Omega-3 and -6 in saw palmetto berries and botanical oil
Botanicals	Ginsenosides in ginseng

Exercise N Report

Exercise O

Study	Measurands and Samples
Toxic Elements	AS, Cd, Pb, and Hg in black cohosh and turmeric
Natural Products	Curcuminoids in turmeric; Chondroitin sulfate in supplements
Botanicals	Botanical ID: Ginkgo biloba

Exercise O Report

Related Standard Reference Materials

As part of a multi-year interagency agreement among the NIST, the NIH/ODS, the Food and Drug Administration (FDA) Center for Food Safety and Applied Nutrition (CFSAN), and the FDA Center for Drug Evaluation and Research (CDER), NIST is developing Reference Materials (RMs) and Standard Reference Materials (SRMs) for botanical dietary supplements. RMs and SRMs with assigned values for concentrations of active and/or marker compounds, pesticides, and toxic elements are being produced to assist in the verification of manufacturers' label claims and for use in quality control during the manufacturing process in support of the Good Manufacturing Practices released by the FDA in 2007. 

For the most up-to-date information about available RMs and SRMs, visit the NIST Store.

Associated Publications

If you or your institution subscribe to a journal cited below, clicking on the link should take you to a page from which you can access the reference.

• Mudge, E.M., Brown, P.N., Rimmer, C.A., Phillips, M.M. (2020) Determination of Curcuminoids in Turmeric Dietary Supplements by HPLC-DAD: Multi-laboratory Study Through the NIH-ODS/NIST Quality Assurance Program, J. AOAC Int. 103(6), 1625-1632.
• Wood, L.J., Lippa, K.A., Phillips, M.M., Rimmer, C.A., Heckert, N.A., Leigh, S.D., Moors, A.J., Pugh, R.S. (2013) Breakfast Cereal Sampling Study for Nutritional Elements, Anal. Bioanal. Chem. 405, 4569-4578.
• Phillips, M.M., Rimmer, C.A., Wood, L.J., Lippa, K.A., Sharpless, K.E., Duewer, D.L., Sander, L.C., Betz, J.M. (2011) Dietary Supplement Laboratory Quality Assurance Program: The First Five Exercises, J. AOAC Int. 94(3), 803-814.