A new study reveals that much of the confidence people have in the health benefits of supplements might not come from science, but from clever wording on labels. Phrases like “boosts brain function” are enough to make consumers believe that a supplement can prevent serious conditions like dementia.
According to a 2023 survey, three-quarters (74%) of Americans report taking dietary supplements, with a staggering 92% of users saying that they’re essential to maintaining their health. But how essential are they, really? And how convincing?
A new study led by the University of Texas Southwestern Medical Center has examined how commonly made claims, such as “supports heart health” or “supports brain health,” affect our beliefs regarding the health benefits of dietary supplements.
Under US Food and Drug Administration (FDA) regulations, three types of label claims are allowed on dietary supplements: nutrient claims, health claims, and structure/function claims. Nutrient claims refer to how much of an ingredient is in a supplement (e.g., “only 200 mg of sodium”). Health claims refer to any statement associating a supplement ingredient with the treatment or prevention of a specific disease. They’re based on evidence reviewed by the FDA and are relatively rare. Structure/function claims are meant to highlight the effect of a supplement ingredient on normal body function (e.g., “calcium builds strong bones”). The problem is, though, that these sorts of claims can use language that’s ambiguous, including phrases like “heart health” or “brain health”.
The researchers ran two online surveys of US adults. Survey one gauged 2,239 participants’ beliefs in relation to fish oil supplements, a real and widely used product. For survey two, the researchers created a completely made-up supplement – they called it “Viadin H” – to see whether labeling affected the preexisting beliefs of 2,164 participants. Each participant was randomly shown one of four labels for the supplement, which varied only in the type of health-related claim: “Supports Heart Health”, “Supports Cognitive Function”, “Brain Health”, or no claim at all. After viewing the label, participants answered whether they thought the supplement could prevent or treat diseases like heart attack, heart failure, stroke, dementia, osteoporosis, or cancer.
For the fish oil supplement, people shown the “Supports Heart Health” label were more likely than those shown a label with no claims to say the supplement prevented heart attacks (62.5% vs 53.9%) or heart failure (59.0% vs 50.7%). Those shown the “Supports Cognitive Function” label claim were more likely to report that fish oil prevents dementia (47.4% vs 39.6%) and improves memory in people with dementia (48.0% vs 40.5%).
For the hypothetical Viadin H, the labels had an even bigger effect, since participants couldn’t have had any prior beliefs about health benefits. Those shown a label that read “Heart Health” or “Supports Heart Function” were more likely to report that the supplement prevents heart attack or heart failure: 40.0% and 40.5% for each respective label. In contrast, those shown brain health-related labels and more likely to report that the supplement prevents dementia or improves memory were lower: 20.2% for the “Brain Health” label, and 23.3% for “Supports Cognitive Function”. For the control conditions of osteoporosis and cancer, labels didn’t significantly change perceptions for unrelated conditions.
The study has limitations. Principally, it was a survey about people’s perceptions, not whether they actually bought or used the supplements differently. There is the potential for issues using self-reporting because participants can choose answers at random or give responses they think are “expected.”
Regardless, the findings raise some interesting – and important – issues. By law, structure/function claims, such as “Supports Heart Health”, aren’t supposed to imply disease prevention or treatment. Yet, the study shows that many consumers interpret them that way. The study authors argue that these statements should be reclassified as health claims, which would require scientific evidence and FDA review. They said this would reduce consumer misunderstanding.
The study was published in the journal JAMA Network Open.
