Dietary Supplement Laboratory Quality Assurance Program

Summary

The National Institute of Standards and Technology (NIST) established a Dietary Supplement Laboratory Quality Assurance Program (DSQAP) in collaboration with the National Institutes of Health (NIH) Office of Dietary Supplements (ODS). Participants measured concentrations of active and/or marker compounds and nutritional and toxic elements in samples distributed by NIST. Data were compiled at NIST where they were analyzed for accuracy, precision, and concordance within the community. Reports and certificates of completion were sent to participants, and workshops were held to discuss results as well as methodological advancements in the characterization of dietary supplements. The DSQAP concluded in 2018, and parts of the DSQAP community will now be served through the HAMQAP .

Description

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 Supplements 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. Approximately two intercomparison exercises were planned each year, with five to seven sample sets distributed in each exercise. Samples prepared and distributed by NIST were commercial samples with values assigned by NIST, or Standard Reference Materials available from NIST.

The intercomparison exercises, data reports, and workshops were 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.

For participants to access historical results, log in using your existing credentials at HAMQAP.

Major Accomplishments

Exercise A

• Nutritional elements: calcium, iron, magnesium, and zinc in multivitamin tablets
• Toxic elements: lead in Ginkgo and Ephedra tablets
• Water-soluble vitamins: folic acid in multivitamin tablets and infant formula
• Fat-soluble vitamins: vitamins A and E in multivitamin tablets and infant formula
• Fatty acids: fatty acids in vegetable oil blends
• Contaminants: none
• Botanical marker compounds: caffeine in solid oral dosage forms

Exercise A Report

Exercise B

• Nutritional elements: none
• Toxic elements: arsenic in Ephedra
• Water-soluble vitamins: vitamins B₁ and B₂ in multivitamin tablets
• Fat-soluble vitamins: none
• Fatty acids: none
• Contaminants: none
• Botanical marker compounds: phytosterols in saw palmetto, flavonols in Ginkgo biloba synephrine in bitter orange

Exercise B Report

Exercise C

• Nutritional elements: calcium, sodium, phosphorous, and zinc in protein drink mix and fortified milk powder
• Toxic elements: arsenic and cadmium 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
• Contaminants: none
• Botanical marker compounds: phytosterols in a neat solution and saw palmetto

Exercise C Report

Exercise D

• Nutritional elements: none
• Toxic elements: lead in Ginkgo
• Water-soluble vitamins: niacin in fortified milk powder
• Fat-soluble vitamins: β-carotene in oils
• Fatty acids: none
• Contaminants: none
• Botanical marker compounds: organic acids in berry extracts

Exercise D Report

Exercise E

• Nutritional elements: calcium, iron, and zinc in fortified breakfast cereals
• Toxic elements: none
• Water-soluble vitamins: niacin in fortified breakfast cereal
• Fat-soluble vitamins: β-carotene in oil and multivitamin tablet
• Fatty acids: none
• Contaminants: aflatoxins in peanut products
• Botanical marker compounds: catechins in green tea

Exercise E Report

Exercise F

• Nutritional elements: sodium and iron in chocolate, spinach, and blueberries
• Toxic elements: arsenic, cadmium, lead, and mercury in green tea
• Water-soluble vitamins: vitamins B₁, B₃, B₆, and BB₁₂ 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
• Contaminants: none
• Botanical marker compounds: isoflavones in soy-containing products

Participants in Exercise F report can obtain the final report by logging in to the QA portal (https://qa.nist.gov/hamqap/) and navigating to the Data Entry menu. 

Exercise G

• Nutritional elements: Sodium in tomato leaves and cranberry powder
• Toxic elements: lead 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
• Fatty acids: none
• Contaminants: none
• Botanical marker compounds: anthocyanins/anthocyanidins in cranberry and bilberry extracts

Participants in Exercise G report can obtain the final report by logging in to the QA portal (https://qa.nist.gov/hamqap/) and navigating to the Data Entry menu. 

Exercise H

• Nutritional elements: calcium, copper, and manganese in calcium supplement and oyster tissue
• Toxic elements: none
• 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
• Botanical marker compounds: phytosterols in flax and perilla oils

Exercise H Report

Exercise I

• Nutritional elements: chromium, molybdenum, and selenium in egg powder and multivitamin tablets
• Toxic elements: cadmium 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
• Fatty acids: none
• Contaminants: none
• Botanical marker compounds: catechins in green tea leaves and extract

Exercise I Report

Exercise J

• Nutritional elements: Calcium, magnesium, and zinc in natural and enhanced waters
• Toxic elements: arsenic 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
• Botanical marker compounds: isoflavones in soy protein isolate and soy flour
• Botanical ID: pure and adulterated Ginkgo biloba. **Consensus-based only, no quantitative results required

Exercise J Report

Exercise K

• Nutritional elements: phosphorus and iron in cranberry and blueberry
• Toxic elements: mercury 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
• Fatty acids: none
• Contaminants: acrylamide in chocolate and coffee
• Botanical marker compounds: phytosterols in saw palmetto
• Botanical ID: none

Exercise K Report

Exercise L

• Nutritional elements: iodine in cat food and multivitamin tablets
• Toxic elements: arsenic and lead 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
• Contaminants: none
• Botanical marker compounds: chlorogenic acid, flavonoids, and naphthodianthrones in St. John’s wort
• Botanical ID: none

Exercise L Report

Exercise M

• Nutritional elements: potassium and zinc in spinach and spirulina
• Toxic elements: arsenic and lead 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
• Fatty acids: none
• Contaminants: none
• Botanical marker compounds: curcuminoids in turmeric
• Identity: chondroitin sulfate

Exercise M Report

Exercise N

• Nutritional elements: chromium in a chromium supplement and multivitamin tablets
• Toxic elements: arsenic, cadmium, and lead 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
• Contaminants: none
• Botanical marker compounds: ginsenosides in ginseng
• Botanical ID: none

Exercise N Report

Exercise O

• Nutritional elements: none
• Toxic elements: arsenic, cadmium, lead, and mercury in black cohosh and turmeric
• Water-soluble vitamins: none
• Fat-soluble vitamins: none
• Fatty acids: none
• Contaminants: none
• Marker compounds: curcuminoids in turmeric; chondroitin sulfate in supplements
• Botanical ID: Ginkgo biloba

Exercise O Report

RELATED STANDARD REFERENCE MATERIALS

We recommend that laboratories use Standard Reference Materials (SRMs) to validate methodology and to value-assign in-house control materials. SRMs for dietary supplements may be purchased from the Standard Reference Materials Program at NIST (301-975-2200; fax: [phone]; or e-mail: srminfo [at] nist.gov).

Bioscience, Chemistry, Analytical chemistry, Food and nutrition, Metrology, Standards, Accreditation, Conformity assessment and Reference materials