Consumers often misinterpret commonly used language on nutritional supplements, with researchers finding that people who viewed labels of either fish oil or a hypothetical supplement were more likely to believe it prevented or treated neurologic- or cardiac-related conditions if the label mentioned brain health, cognitive function, or heart health.
Those words were interpreted to imply that the supplement prevented or treated specific diseases, including heart attack, heart failure and dementia, wrote Ann Marie Navar, MD, PhD, MSc, of University of Texas Southwestern Medical Centre in Dallas, and co-authors in JAMA Network Open.
“Multiple large randomised clinical trials have found that fish oil supplements do not prevent cardiovascular events and are not recommended for primary or secondary prevention of atherosclerotic cardiovascular disease (ASCVD),” Navar and colleagues noted.
“But despite this, nearly 20% of adults in the United States with ASCVD take a fish oil supplement, most of whom do so for heart health.”
Likewise, no supplements have consistently been proven to preserve brain health, said Dylan Wint, MD, Director of Cleveland Clinic’s Lou Ruvo Centre for Brain Health in Las Vegas, who wasn’t involved with the research.
“In a study of the effects of multivitamins, age-related cognitive decline was slower in individuals taking the multivitamin versus those taking placebo,” Wint told MedPage Today. “There are inconsistent results from studies of omega fatty acids and B vitamins.”
An association between a nutrient-rich diet and brain health “does not mean that supplementing with that nutrient will necessarily preserve or promote brain health”, Wint pointed out.
“Currently, there is far more evidence supporting a brain-healthy diet than any supplement.”
FDA regulations allow three types of label claims for food and dietary supplements – nutrient content claims, health claims, and structure/function claims. Nutrient claims refer to the quantity of an ingredient, like “200 mg of sodium”.
Health claims are rare: they refer to a statement that associates a supplement ingredient with treating or preventing a specific disease based on an FDA evidence review.
“Structure/function claims are intended to refer to the role of an ingredient in the supplement affecting normal function of the human body, such as ‘calcium builds strong bones’,” Navar and colleagues wrote.
“These claims are not intended to describe that taking the supplement itself will prevent or treat a disease. Nevertheless, the language used in structure/function claims is often ambiguous, such as ‘heart health’ or ‘supports cognitive function’.”
In 2012, the Office of Inspector General reported that many dietary supplements’ structure/function claims failed to meet federal requirements.
To determine how US consumers currently perceive these claims, Navar and colleagues conducted two online surveys using the SurveyMonkey Audience platform. The sample was drawn from a panel used in an FDA study of qualified health claims about olive oil, omega-3 fatty acids, and green tea.
One survey was for a fish oil supplement, the other was for a hypothetical supplement called Viadin H. For each survey, participants were randomised to one of four labels that had different health-related statements, such as “supports heart health”, or “supports cognitive function”, then were asked about the supplement’s benefits.
Overall, 2 239 participants completed the fish oil survey and 2 164 completed the Viadin H survey. In the fish oil study, 52.6% were women and 21.5% were 45-54-years-old. In the Viadin H study, 51.2% were women and 23.7% were aged 45-54.
Respondents shown a fish oil label that said “supports cognitive function” were more likely to say that fish oil prevents dementia (47.4% vs 39.6%, P=0.009) and improves memory in dementia (48.0% vs 40.5%, P=0.01) than those shown no-claim labels. Those shown a “supports heart health” fish oil claim were more likely to say it prevents heart attacks (62.5% vs 53.9%, P=0.003) and heart failure (59.0% vs 50.7%, P=0.005).
Less than a quarter of respondents shown a Viadin H label with the words “brain health” or “supports cognitive function” said the supplement prevented dementia or improved memory (20.2% for brain health claim; 23.3% for the cognitive function claim).
Those who saw a Viadin H label stating “heart health” or “supports heart function”, however, were much more likely to say the supplement prevents heart attack or heart failure (40.0% for the heart health claim; 40.5% for the heart function claim).
In the fish oil survey, respondents not taking fish oil had greater differences in reported health benefits between label groups than those taking fish oil, the researchers said.
Respondents did not know the survey topic when they agreed to take the survey, Navar and colleagues noted. Nonetheless, about 80% reported using at least one dietary supplement, higher than the 56% reported in the general adult population. Participants also had higher education levels than the national average, with more than 55% reporting they had at least a college degree.
Study details
Label Statements and Perceived Health Benefits of Dietary Supplements
Joanna Nicole Assadourian, Eric Peterson, Ann Marie Navar.
Published in JAMA Network Open on 22 September 2025
Abstract
Importance
Dietary supplement use is widespread, and their labels often contain structure/function claims (eg, supports heart or brain health), which legally are not intended to imply the supplement prevents or treats a disease. How structure/function statements are interpreted by consumers, however, is unknown.
Objectives
To evaluate how commonly used structure/function claims are associated with consumer beliefs regarding the health benefits of supplements.
Design, Setting, and Participants
We conducted two online survey studies of US adults participating in the SurveyMonkey Audience platform, one for a fish oil supplement and one for a hypothetical supplement called Viadin H. For each survey, participants were randomised to one of four labels that were otherwise identical but had different health-related label statements (eg, supports heart health, cognitive function) and then asked about the supplement’s health benefits.
Main Outcomes and Measures
The percentage of participants who reported that the supplement was somewhat likely or very likely to prevent or treat a list of diseases.
Results
Overall, 2239 participants completed the fish oil survey (473 [21.5%] aged 45-54 years; 1142 [52.6%] women), and 2164 completed the Viadin H survey (510 [23.7%] aged 45-54 years; 1085 [51.2%] women). Respondents shown the fish oil label that said “Supports Heart Health” were more likely than those shown a no-claim control to report that it prevents heart attacks (370 of 592 [62.5%] vs 306 of 568 [53.9%]; P = .003) and heart failure (349 [59.0%] vs 288 [50.7%]; P = .005). Those shown the “Supports Cognitive Function” label claim were more likely to report that fish oil prevents dementia (255 of 538 [47.4%] vs 225 [39.6%]; P = .009) and improves memory in dementia (258 [48.0%] vs 230 [40.5%]; P = .01) compared with those shown no-claim labels. For Viadin H, those shown a label stating “Heart Health” or “Supports Heart Function” were more likely to report the supplement prevents heart attack or heart failure, while those shown a label stating “Brain Health” or “Supports Cognitive Function” were more likely to report the supplement prevented dementia or improved memory (eg, lower risk of heart attack: “Heart Health” label, 209 of 525 [40.0%]; “Supports Heart Function” label, 225 of 556 [40.5%]; “Brain Health” label, 113 of 556 [20.2%]; and “Supports Cognitive Function” label, 124 of 536 [23.3%]; P < .001).
Conclusions and Relevance
In this survey study, commonly used structure/function claims on supplement labels were often misinterpreted by consumers to imply a disease-specific benefit, contrary to their regulatory intent. Improved regulations for supplement labelling may be needed to minimise consumer misunderstanding.
FDA study of qualified health claims
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