Structure/function claim: a statement on the label of a food or dietary supplement about how that product might affect the human body’s structure (“helps enhance muscle tone”) or function (“strengthens your immune system”)—the type of statement that critics fear is being used by some manufacturers to make unsubstantiated health claims.

What’s the difference between the statements “calcium builds strong bones” and “calcium reduces the risk of osteoporosis”? According to the Food and Drug Administration, the former is a structure/function claim, which does not require FDA approval, whereas the latter is a health claim, and so must be approved because it describes a relationship between an ingredient and a reduced risk of a health condition. Yet in a 2001 AARP Public Policy Institute survey, 38% of respondents made no distinction between the two statements.

Some reform advocates say that the FDA should treat structure/function claims like health claims or do away with them. The Center for Science in the Public Interest calls such claims “a long-standing problem that the FDA has largely ignored,” while Marion Nestle, a nutrition expert at new York University, noted the irony that a letter the FDA sent to the Nestlé company regarding its Juicy Juice Brain Development Fruit Juice stated that the claim “no sugar added” violated a nutrient-claim rule, but it didn’t address the statement “helps support brain development” because it is a structure/function claim.

Still, those pushing for tougher labeling rules hope the FDA will soon scrutinize structure/function claims. The agency recently requested input from consumers on how they use and understand labels.