A scrutiny of labels on various dietary supplements often reveals an array of health claims, with manufacturers asserting support for specific bodily functions or organs such as brain health or the immune system.
However, a recent study published in JAMA Cardiology on August 23 sheds light on the questionable validity of such claims, particularly in the realm of fish oil supplements. Examining over 2,800 unique fish oil products, the study discovered that the majority of these supplements imply health benefits for various bodily structures and functions without substantial scientific trial data to substantiate their efficacy.
Cardiologist and epidemiologist at UT Southwestern Medical Center in Dallas and co-author of the study, Ann Marie Navar, MD, PhD, said, “I worry as a cardiologist that patients may read a statement like ‘promotes heart health’ and wrongly infer that the supplement has been shown to prevent heart disease. I wouldn’t call any specific claim that we found ‘misinformation’ per se, but I think there is a lot of room for confusion.”
Scientific Evidence Doesn’t Necessarily Support Majority of Health Claims in Supplements
The U.S. Food and Drug Administration (FDA) refrains from officially endorsing dietary supplements for any purpose, and these products cannot assert that they prevent, treat, or cure diseases. Health claims for supplements are typically categorized by the FDA as either “qualified” or “structure/function” claims.
Qualified claims indicate support from scientific evidence, with specific language addressing any lack of consensus.
In the case of fish oil supplements, the study revealed that nearly three-quarters (73.9 percent) of the investigated products made health claims, yet only a small fraction (19.2 percent) utilized FDA-qualified claims, while the majority (80.8 percent) relied on structure/function claims.
An example of a qualified health claim is: “Supportive but not conclusive research shows that consumption of EPA and DHA omega-3 fatty acids may reduce the risk of coronary heart disease.”
According to agency standards, structure and function claims, on the other hand, describe the role of a nutrient or ingredient on the structure or function of the human body — such as “promotes heart health,” “supports cognitive health,” and “promotes joint comfort and mobility.”
Fish Oil Supplements Make Various Health Claims
According to the most recent report in JAMA Cardiology, Dr. Navar and his team found that nearly three-quarters (73.9 percent) of the 2,819 unique fish oil supplements they examined included at least one health claim. Among these, only 399 (19.2 percent) utilized FDA-qualified claims, with the remaining majority (80.8 percent) relying solely on structure/function claims.
Dr. Marilyn Tan, an endocrinologist and clinical associate professor of medicine at Stanford University, urges caution regarding these health assertions, emphasizing the lack of robust clinical studies to validate the efficacy and safety of dietary supplements. Although some limited evidence suggests benefits of fish oil supplements for conditions like depression and ADHD, the study highlights the variability in the amounts of essential omega-3 fatty acids (EPA and DHA) across different products.
“Many of the claims are very vague, alluding to key terms that catch people’s attention, such as ‘aging,’ ‘vitality,’ ‘immune support,’ and ‘cellular support. Claims related to structure/function should not be taken as a proven effect in vivo [in the living human body]. Many structural and functional claims do not pan out in real world or clinical settings,” says Dr. Tan, who was not involved in the new research.
Variation in Omega-3 Fatty Acid Levels Across Different Supplements
According to the American Heart Association (AHA), fish oil contains ‘two omega-3 fatty acids that play an important role in heart and brain health.’
However, the latest research revealed significant variations in the levels of these fatty acids – EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) – across various fish oil supplements.
Researchers observed that achieving a minimum daily dose of 2 grams (g) of EPA and DHA could potentially contribute to lowering triglycerides, a type of fat in the bloodstream.
Out of the 255 evaluated fish oil supplements in terms of EPA and DHA content, only 24 (9.4 percent) met or exceeded this recommended minimum level.
Dr. Navar said, “As a cardiologist, I sometimes recommend fish oil supplements for people with high triglycerides. But at this [2 g] dose, the risk of atrial fibrillation may be increased, so fish oil is not what I consider first-line for high triglycerides. We have other, better, and safer medications available.”
Always Speak to Your Doctor Before Taking Supplements
Dr. Tan advises patients to exercise caution when considering supplements, emphasizing that misleading claims can lead to potential harmful outcomes.
She stresses the importance of increased regulation in the supplement industry. Dr. Navar, a contributor to the study, goes further, suggesting that, in many cases, patients might be better off abstaining from supplements altogether.
“It’s important to review all supplements and their contents with your healthcare providers, and it’s critical not to use a supplement to replace a medication prescribed by your healthcare provider,” she says.
“Based on my clinical experience, a lot of people are spending money and effort to take pills that they think are helping them but that really are not,” she says.
As the debate on the efficacy and safety of dietary supplements continues, the study serves as a reminder of the importance of evidence-based decision-making and consulting with the healthcare professionals before incorporating supplements into one’s routine.
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