Prebiotics, Probiotics, and Postbiotics - The Confusing Regulatory Landscape

Posted on Behalf of  Amanda Buerger, Haley Divis, Tony Cappello

A March, 2021 national survey indicated that few Americans (35%) were aware of the role oral postbiotics play in gut health, and even fewer were aware of their connection with overall immunity (28%). Consumer interest in boosting immunity has soared during the COVID-19 pandemic, and sales of oral probiotics have substantially grown in the last 18 months. Although public understanding of pre-, pro-, and postbiotics is increasing, a need still exists for the United States scientific community and supplement industry to align their existing definitions, regulations, and health claims regarding probiotics across markets.

The following are consensus definitions of pre-, pro-, and postbiotics:

  • Prebiotics - substrates that are selectively utilized by host microorganisms conferring a health benefit
    • The NIH uses a slightly more specific definition for prebiotics, which is also used by the International Scientific Association for Probiotics and Prebiotics (ISAPP): "Complex carbohydrates (such as inulin and other fructo-oligosaccharides) that microorganisms in the gastrointestinal tract use as metabolic fuel”
  • Probiotics - live microorganisms that, when administered in adequate amounts, confer a health benefit on the host
  • Postbiotics - functional bioactive compounds, generated in a matrix during fermentation, which may be used to promote heath

National Institutes of Health (NIH)

The NIH published a probiotics in food products fact sheet for health professionals (NIH, 2020). The NIH emphasizes that not all products labeled “probiotic” have scientifically proven health benefits (NIH, 2020). NIH details identification, mechanisms of action, and sources of probiotics, as well as health benefits associated with probiotics (NIH, 2020). Although the NIH provides a fact sheet with information for health professionals, there is little guidance regarding specific label definitions.

Food and Drug Administration (FDA)

The regulatory constraints that the FDA applies to an oral probiotic depends on its intended use (Venugopalan et al., 2010). For instance, if a probiotic is “intended to diagnose, cure, mitigate, treat or prevent a human disease,” then it must be subjected to the rigorous new drug therapy regulations (FDA, 2019a). Alternatively, if a probiotic is intended as a dietary supplement, it is regulated as a food product by the FDA’s Center for Food Safety and Applied Nutrition (FDA, 2019b). Unlike for probiotics used to diagnose, prevent, or treat diseases, FDA approval is not required before dietary supplements are marketed (FDA, 2019b). In this case, the manufacturer is responsible for the ultimate safety of the dietary supplement and is accountable for the “adequate evidence” behind any claims (Venugopalan et al., 2010). Overall, the FDA does not require evidence from manufacturers regarding the safety or benefit claims being made for dietary supplements before or after marketing (Venugopalan et al., 2010).

Similarly,  FDA approval is not required for dietary supplements that claim to maintain normal body functioning (FDA, 2019b). However, specific health claims do warrant FDA approval, including clinical data and clinical studies that support the health claim. According to the FDA, “health claims describe a relationship between a food, food component, or dietary supplement ingredient, and reducing risk of a disease or health-related condition” (Venugopalan et al., 2010).


With emerging popularity of pre-, pro-, and postbiotics, uncertainty has surrounded the meaning of these words and the associated consumer product claims.  Although the NIH provides little label regulation guidance, the FDA imparts different regulatory restrictions based on the product claim type. The World Health Organization has suggested that probiotic health claims and food labeling should be permitted, given that there is “sufficient scientific evidence” available to support the claim (WHO, 2002). The FDA, however, does not require such evidence be submitted for dietary supplements, only for probiotics as drugs. Because pre-, post-, and probiotics can influence the health of a person’s microbiome and their overall health, scientific review and FDA regulation of these products should be universally aligned and more clearly defined. Only after such changes will consumers have a transparent view as to what these products offer.

Cardno ChemRisk scientists have extensive experience performing risk assessments and providing regulatory support to various industries, including food and pharmaceutical entities. Our team applies multidisciplinary approaches to understand and solve complex toxicological and public health issues related to microbial contamination and microbial risk assessments. For more information on Cardno ChemRisk’s capabilities in these areas, please contact Dr. Tony Cappello.