New paper discusses the rationale for proprietary blends in supplements and the potential pitfalls of how they are regulated

A recent paper published in The Journal of Nutrition, and co-authored by the The Consumer Healthcare Products Association's (CHPA; Washington, D.C.) senior vice president of dietary supplements, Duffy MacKay, summarizes the rationale for using proprietary blends in dietary supplements, how they are regulated and labeled, as well as the challenges this presents for researchers.

“While proprietary blends of non-nutritive ingredients are permitted under current law, the issue is not without controversy, as manufacturers are not required to disclose the exact amounts of each ingredient used in the blend,” explained MacKay, in a press release. “This raises transparency issues and challenges for both researchers and consumers when it comes to understanding exposure levels. For example, researchers needing to calculate exposures in assessments of intakes or determine doses in clinical trials must use alternative ways to arrive at amounts. From a consumer standpoint, this creates obstacles to informed decision making, as it’s challenging to understand if the product will provide the intended benefits if they are unable to determine the amount of each ingredient included in the blend.”

The lack of transparency also raises safety concerns, notes MacKay. While FDA does have access to the specific amounts of each ingredient in a proprietary blend through a Master Manufacturing Record, “this is very much seen as ‘reactive regulating,’” said MacKay. “To that point, it’s equally important to consider the potential benefits of proactive regulating, especially considering the attention supplement modernization has received in Congress.”

The paper's lead author is Leila G. Saldanha, PhD, RD, FAND, senior nutrition scientist at the National Institutes of Health’s (NIH) Office of Dietary Supplements (ODS). Other co-authors included ODS Senior nutrition scientist Johanna T. Dwyer, DSc, RD and Constance J. Hardy, interdisciplinary scientist at FDA’s Center for Food Safety and Applied Nutrition (CFSAN).