GPA releases updated prebiotic definitions to drive innovation and research

The Global Prebiotic Association (GPA) has released updated definitions of prebiotics and prebiotic effects that integrate advancements in gut biology, metagenomics and prebiotic research. The association hopes these definitions enhance prebiotic research, consumer awareness and product innovations, such as novel and emerging prebiotics. 

The definitions may also help businesses meet regional guidelines and substantiation requirements for classification while assisting regulators in drafting standards. 

The GPA adds that the industry is interested in a unified definition, as it clarifies what is expected of companies regarding product quality, safety and efficacy. 

Moreover, the characterization of the prebiotic effect may support prebiotic compliance through standardized procedures in clinical research, design and regulatory oversight. 

The updated 2017 prebiotic definition is: “a compound or ingredient that is utilized by the microbiota producing a health or performance benefit.” This terminology no longer includes “selectivity” as an identifier of prebiotics. The GPA notes that the term is unclear and irrelevant with scientific advancements, hindering efforts to reach a consensus on the definition. 

With the updated definition, the GPA also includes new prebiotic ingredients, such as non-carbohydrates, various formulations (e.g., topical) and non-gastrointestinal microbiomes like the skin or urogenital microbiome. 

In addition, the organization introduces concepts of performance benefits and prebiotic effect: “a health or performance benefit that arises from alteration of the composition and/or activity of the microbiota, as a direct or indirect result of the utilization of a specific and well-defined compound or ingredient by microorganisms.”

“The GPA’s mission is to steward responsible growth of the prebiotic category globally. It is also to recognize established and emerging benefits, and the prebiotic definition and the discussion of prebiotic effect represent a huge milestone,” says Len Monheit, executive director at GPA.

The selectivity concept

The previous prebiotic definition was established by a panel of experts in microbiology, nutrition and clinical research convened by the International Scientific Association for Probiotics and Prebiotics (ISAPP) in 2016. This included substrates “selectively utilized by host microorganisms” to confer a health benefit. 

According to the paper published in Advances in Nutrition, ISAPP defines selectivity as the “selective utilization of a prebiotic candidate by a few resident taxa and not all.” 

The new definition is based on a GPA-led review of current scientific literature and discussion with industry and academic experts.However, the authors found this concept does not have criteria, such as how many taxa would use the prebiotic and to what extent.

They refer to earlier research establishing galactooligosaccharides (GOS) and inulin as the “only prebiotic ingredients that satisfy the selectivity definition.” Commonly classified as traditional prebiotics, these are selectively fermented by beneficial bacteria, mainly Bifidobacterium and Lactobacillus species. However, their impact on pathogenic microorganisms is limited. 

In addition, the authors argue that the selectivity concept does not differentiate between “good” and “bad” bacteria in the microbiome. There is also increasing evidence that a diverse microbiome is essential for intestinal balance and overall health. Research also shows that prebiotics can affect a broader range of bacteria, such as Akkermansia muciniphila. 

Therefore, the GPA concludes that selectivity “limits market growth potential and is outdated in light of modern research findings and technological advancements.” 

Novel and emerging prebiotics

Prebiotics improve the microbiome in three general ways: they support and feed microbiota, increase and influence by contributing to metabolite and microbe production and optimize and balance the environment and bacteria levels. 

The GPA considers several prebiotic classification criteria established by the UN Food and Agriculture Organization and other researchers. Prebiotics are resistant to host digestive processes, are utilized by the microbiota and confer a health benefit through their microbiome-modulation effect. Moreover, research must substantiate the effect of prebiotic candidates. 

Novel and emerging prebiotics are key for the future of prebiotics, such as fruit polyphenols and omega-3 fatty acids.Santa Al Antwan, Regulatory Affairs associate at SGS Nutrasource and co-author of the paper, says: “The value of this paper lies in its presentation of insights from key stakeholders — prebiotic industry professionals and scientists — who frequently engage with the public and recognize the importance of clear, precise terminology in definitions.”

Based on available evidence, the authors classify a prebiotic as established (extensively studied for its prebiotic effect), novel (increasing evidence) or emerging (research is underway for its potential). 

These criteria allow for a wider group of prebiotics than the current ISAPP definition. For example, acacia gum and resistant starch are established candidates under GPA’s definition but are not formally recognized as prebiotics by ISAPP. 

The researchers note that the future of prebiotics “will likely involve novel and emerging sources,” which target specific microbial niches and satisfy demands on sustainability, cost and scalability. 

With its member scientists and industry representatives, the GPA is developing Standards of Evidence to classify prebiotics, including existing and upcoming candidates. 

Prebiotic effect

The authors say defining a prebiotic effect in terms of health and wellness promotion is key to distinguishing prebiotics from fibers. Historically, this effect has been referenced to changes in the gut microbiome composition and effects in experimental and human intervention studies. However, the paper notes: “There has been no formal recognition of the term.” 

The new definition of prebiotic effect is aims to help maintain product integrity, efficacy and transparency.The GPA says that a distinct definition of this effect is fundamental to maintaining product integrity, efficacy and transparency. It defines a prebiotic effect as “a health or performance benefit that arises from alteration of the composition and/or activity of the microbiota, as a direct or indirect result of the utilization of a specific and well-defined compound or ingredient by microorganisms.”

“While prebiotics can be leveraged to promote health, a lot of confusion remains among consumers and other stakeholders around the term prebiotic and what exactly is a prebiotic effect,” says lead author Edward Deehan, Ph.D., assistant professor at the University of Nebraska-Lincoln, US.

“This position paper is a significant achievement for the prebiotic category and GPA, as it provides a sound regulatory and scientific perspective that will help bring clarity to and advance the category.”

The paper’s authors note that the definition can help distinguish between ingredients as prebiotics and those with a prebiotic effect, which is essential in product labeling. In the EU, prebiotics are not authorized as a health claim. Last month, scientists outlined a strategic roadmap for prebiotic health claims to gain regulatory recognition in the region.

The GPA stresses that prebiotics for human use must be characterized using substantiating evidence from human clinical trials linking physiologic effects to gut microbiome alterations, while animal studies could provide mechanistic and causal insights into prebiotic actions in humans. 

According to the paper authors, the definition may eliminate current trends of products carrying scientifically weak claims, which result from gaps in human data availability and challenges in translating results from animals to humans.