Health claims of fish oil supplements often vague and lack backing by trial data: JAMA

USA: A recent cross-sectional study has shown that the majority of fish oil supplement labels make health claims, usually in the form of function/structure claims implying a health benefit across a variety of organ systems despite a lack of trial data showing efficacy.

The study findings published in JAMA Cardiology by researchers at UT Southwestern Medical Center, suggest the need for additional regulation of the claims made on fish oil supplement labels to prevent consumer misinformation. 

"Your daily dose of omega-3s may not be doing what you think it is. Most fish oil supplements on the market today have labels boasting health benefits that aren’t supported by clinical data," the researchers wrote. 

“About 1 in 5 Americans over the age of 60 take fish oil supplements, often because they think it is helping their heart,” said Ann Marie Navar, M.D., Ph.D., Associate Professor of Internal Medicine in the Division of Cardiology and a member of the Peter O’Donnell Jr. School of Public Health at UT Southwestern, who led the study. “But extensive research has shown that for most people, there is no cardiovascular benefit in taking over-the-counter fish oil supplements, and at high doses, they can even increase the risk of atrial fibrillation.”

Researchers analyzed data from fish oil supplement labels obtained from the National Institutes of Health Dietary Supplement Label Database. Of the 2,819 labels studied, 2,082 (73.9%) made at least one health-related claim.

The majority of supplements with a label making a health claim (80.3%) used what is called a structure/function claim, which is intended to describe in broad terms the effect of the nutrient on a body system.

“Structure/function claims are allowed by the FDA, but they can be vague and misleading,” said Dr. Navar, a board-certified cardiologist. “And they are being made for fish oil for a broad number of organ systems, including for the heart, brain, joints, eyes, and immune system. Structure/function claims can include statements like ‘supports cognitive health’ or ‘supports healthy joints.’ Technically, these cannot be used to claim that the supplement treats or prevents disease, but we feel that this type of language can be very confusing to consumers who may be unaware these statements do not require support from randomized trials.”

Reference:

Assadourian JN, Peterson ED, McDonald SA, Gupta A, Navar AM. Health Claims and Doses of Fish Oil Supplements in the US. JAMA Cardiol. Published online August 23, 2023. doi:10.1001/jamacardio.2023.2424.