What Are Functional Foods?
What functional foods are: definitions from dietetic and regulatory sources, how they differ from supplements, fortified foods and the marketing word superfood.
Content last updated . This page has not been medically reviewed.
Safety first. Supplements can cause side effects and interact with medicines. Read mushroom safety and interactions before you use any mushroom product.
A working definition
"Functional food" has no single legal definition in the United States. A 2009 trade-press summary reports that FDA gives no specific definition and that how a product is regulated depends on how it is marketed. [1] The American Dietetic Association position paper describes functional foods as including whole foods and fortified, enriched or enhanced foods that have a potentially beneficial effect on health when eaten as part of a varied diet on a regular basis, at effective levels. [2] We use the term for foods studied for health effects beyond basic nutrition, and we say which ones have trial evidence and which have only observational studies.What functional foods are not
| Term | What it means here |
|---|---|
| Dietary supplement | A pill, capsule, powder or liquid product with its own rules. Food results do not carry over to supplements, or the reverse. See Vitamins & Supplements. |
| Fortified food | A food with nutrients added. See Fortified foods. [3] |
| Superfood | A marketing word, not a scientific or regulatory category. See Claim checks. |
| Probiotic | A live microorganism with a shown benefit; a fermented food is not automatically one. [4][5] |
| Medicine | Foods do not treat disease on their own. |
How we judge a food
- Which kind of evidence? Randomized trials show what a food changed in a study. Observational studies show an association, and people who eat a food often differ in other ways.
- What was measured? Most trials measure markers such as LDL cholesterol or blood pressure, not heart attacks.
- What exactly was eaten? Juice, powder, extract and whole food are different.
- Where evidence is missing, we say "proper evidence not found" instead of filling the gap.
Where to go next
Explore foods · By wellness goal · Research and evidenceFrequently asked questions
Are functional foods regulated?
There is no single definition in U.S. regulation; rules depend on the product type and its claims. [1]
Is a superfood a functional food?
"Superfood" is a marketing term. See Claim checks.
References
- NutraIngredients. FDA still reviewing functional food regulatory requirements. 2009 trade-press summary that FDA has no regulatory definition of functional foods; check for newer FDA guidance.
- American Dietetic Association. Position of the American Dietetic Association: functional foods. J Am Diet Assoc 2009;109:735-46. Cited through a bibliographic record; the later Academy of Nutrition and Dietetics edition should be checked.
- U.S. Food and Drug Administration. Food Fortification Policy guidance (21 CFR 104.20). Summarized from the guidance; read the original for exact wording.
- Hill C et al. Expert consensus document. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol 2014. PMID 24912386.
- Marco ML et al. The International Scientific Association for Probiotics and Prebiotics (ISAPP) consensus statement on fermented foods. Nat Rev Gastroenterol Hepatol 2021. PMID 33398112.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.