Location: Methods and Application of Food Composition Laboratory
Project Number: 8040-10700-004-018-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 15, 2023
End Date: Jun 30, 2025
Objective:
The Dietary Supplement Ingredient Database (DSID) (http://dsid.usda.nih.gov; (U.S. Department of Agriculture, 2012) currently provides nationally representative supplement composition data for adult and children’s MVM, based on chemical analysis. All other dietary supplement databases contain label information only. In addition to the evaluation of vitamin and mineral levels in dietary supplements, the DSID has expanded to include supplements with other ingredients of interest, including omega-3 (n-3) fatty acids in fish and plant oil supplements, and catechins, caffeine, turmeric and proanthocyanidins in botanical supplements. New studies are evaluating proanthocyanidins in cranberry DS and measuring the levels of L-5-methyltetrahydrofolate in prenatal, child and adult dietary supplements.
Approach:
Several types of studies are planned, including ongoing national studies and studies evaluating the performance quality of DS dosage forms. Over the period of performance, DSID research will include:
1. Proanthocyanidin (PAC) content of cranberry DS: The quality of products containing cranberry powders and extracts is largely unknown for this popular DS category. This research has two objectives: evaluate popular cranberry DSs for their total PAC content, as analyzed by DMAC (4-di-methylaminocinnamaldehyde), a colorimetric assay that is the industry standard for voluntary label claims for total PAC content; and evaluate new developments in methodology for testing of PAC content by high performance liquid chromatography (HPLC) and high resolution mass spectrometry (MS), focusing on separating and quantifying A-type and B-type PAC content. We are evaluating a thiolysis method for quantifying total PACs and are testing all products for disintegration of the various dosage forms.
2. Content of L-5-methyltetrahydrofolate (L-5-MTHF), other folates and folic acid in DS: L-5-MTHF (MTHF) is the primary biologically active isomer of folic acid and the primary form of folate in serum. MTHF is starting to replace folic acid in some types of DS, especially prenatal MVM. It is marketed as a more bioavailable form of folic acid, and the percentage of DS products in the US market with MTHF appears to be increasing. There have been concerns about the stability of MTHF and the label integrity of products listing this ingredient since is much more expensive than folic acid. This study began in the summer of 2023, with the purchase and initial testing of dietary supplements claiming L-5-MTHF content. Both disintegration and dissolution testing will be completed for all products. In addition, all products will be tested for their ratio of L- (active form) to D-5-MTHF (inactive form) to identify any products that may contain a racemic mixture of the stereoisomers.
