On February 23, 2011, FDA denied OVOS Natural Health, Inc.’s New Dietary Ingredient (NDI) application, permitting the use of homotaurine as a dietary ingredient in dietary supplements. FDA explained that it denied the petition because homotaurine is not considered a dietary ingredient within the meaning of Section 201(ff)(1) of the Food, Drug & Cosmetic Act (FD&C Act).

The significance of this decision lies in the agency’s narrow interpretation of an “amino acid” as it applies to dietary supplements under the FD&C Act. According to FDA, for the purposes of Section 201(ff)(1)(D) of the FD&C Act, the term “amino acid” refers to an “alpha-amino carboxylic acid used as a constituent of proteins or peptides.” This means that if a substance is neither an alpha-amino carboxylic acid nor a constituent of proteins or peptides, then it cannot be contained in a dietary supplement as an amino acid.

As background, OVOS’ parent company previously instituted but discontinued an Investigational New Drug (IND) study of homotaurine in 2008 after completing a 78-week study. In 2009, the company decided to market homotaurine as an ingredient for use in dietary supplements. Under the FD&C Act, a dietary supplement may not include an article authorized for investigation as a new drug for which substantial clinical investigations have been instituted and existence of such investigation has been made public, unless it was marketed as a dietary supplement or as a food prior to such authorization. However, the FD&C Act does allow FDA to issue a regulation, after notice and comment, and waive this restriction with respect to a particular substance. It was reported on Nutraingredients.com—had the petition been granted—that OVOS would have become the first firm to have an ingredient switched from drug to dietary supplement status after its initial efforts to obtain drug approval for the ingredient were not satisfactory at the clinical trial stage.

Based on the legislative history of the Dietary Supplement Health and Education Act of 1994 (DSHEA), FDA concluded that nutrition science was the appropriate scientific context for analysis of what is an “amino acid” under Section 201(ff)(1)(D) and noted that amino acids recognized in nutrition science are alpha-amino carboxylic acids, which are constituents of proteins. FDA further stated that the “Amino Acids” Section of the Food and Nutrition Board of the Institute of Medicine (IOM) report discusses the 20 amino acids that are consistent with the agency’s definition and that these amino acids do not include homotaurine. FDA also noted that its food additive regulation for amino acids used as “nutrients added to foods” (21 C.F.R. § 172.320) lists the same 20 individual amino acids. According to FDA, more general definitions that include chemical or other non-nutritive properties are not appropriate for the purpose of defining the term “amino acid” in the context of the supplementation of the human diet. FDA thus concluded that homotaurine is not an “amino acid” under Section 201(ff)(1)(D) because it is a gamma-amino sulfonic acid, and not an alpha-amino carboxylic acid or a constituent of proteins.

Another significant issue relates to FDA’s determination that synthetic substances that are not already part of the food supply do not qualify as a “botanical” (or extract thereof) within the meaning of Section 201(ff)(1)(C). Specifically, FDA says that although homotaurine naturally occurs in some plants, including the seaweed dulse, OVOS’ homotaurine is not a botanical (or extract thereof) because it is made synthetically (i.e., it was not extracted from the seaweed dulse or any other botanical). As FDA noted, the agency conclusion is consistent with its previous determination that synthetic compounds are not botanicals under Section 201(ff)(1).

What Happens from Here?

FDA’s narrow interpretation of the term “amino acid” in the context of dietary supplement regulation goes beyond this particular petition and will likely apply to the entire dietary supplement industry in the future. Not only is FDA expected to apply this definition when reviewing NDI notifications, but it may also make the marketing of many dietary supplement products impermissible under the FD&C Act.    

References furnished upon request.