top of page

The Difference between “Food” and “Functional Food” and the Substantiation of Associated Claims

“Food” can be loosely defined as any substance that people or animals eat or drink, in order to maintain life and growth, satisfy hunger, or simply in response to hedonistic impulses. On the other hand, functional foods (or ingredients) have been defined as those foods or ingredients that supply a benefit beyond that of the traditional (i.e., mainstream) nutritive value. A prime example of a functional food ingredient can be seen in probiotics – the definition of probiotics by the World Health Organization (WHO) in 2001 is “live micro-organisms which, when administered in adequate amounts, confer a health benefit on the host.”[1]Therefore, application of the term “functional” beyond that of traditional nutritive value is an expressed (not implied) claim. That is, the seller is offering a product that will affect the structure or function of the body, otherwise it would not be “functional” and no one would purchase the product. It follows then, that the seller must substantiate his claim, proving the functionality through clinical trials – the type and rigor of which has increasingly become the subject of controversy and confusion between the two controlling Federal agencies, the Food and Drug Administration (FDA) and Federal Trade Commission (FTC).

As stated above, a functional food provides physiological benefits beyond that of traditional nutritive value. But the type of “benefit” defines the types of data needed to prove that the food is actually “functional.” If the food (or food ingredient) is functional by affecting the normal structure or function of the body, then FDA would look upon the claim associated with the functional food as a structure/function claim (SFC). The claim may characterize the means by which a nutrient or dietary ingredient acts to maintain such structure or function, for example, “fiber maintains bowel regularity,” or “antioxidants maintain cell integrity.” However, inconsistencies arise when functional food ingredients are added to dietary supplements or to conventional foods. Structure/function claims for conventional foods must focus on effects derived from nutritive value of the ingredient, but if the ingredient has no nutritive value such as the polyphenols in cranberry juice, the claim must be based on the nutritive value of the food – the cranberry juice and its effect on urinary tract health.  In contrast, structure/function claims for dietary supplements may focus on non-nutritive or nutritive effects – for exampl