New in Gut Health: Synbiotics

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Wellness practitioners are no strangers to the concept of pre- and probiotics, supplements that support and deliver good microbes for better gut health. But it's time for the next wave: synbiotics, a combination of pre- and probiotics. To keep research and development on the right track, an expert panel recently redefined the term and developed guidelines for scientific investigation in a consensus report published in Nature Reviews: Gastroenterology & Hepatology (August 21, 2020). The report is designed to be the definitive reference in the development of new synbiotic products.

"Synbiotics are starting to gain traction in the marketplace, but there's a lot of confusion around the term, even among scientists," says Kelly Swanson, consensus panel chair and professor in the Department of Animal Sciences at the University of Illinois. "The panel's main goal was to clarify what synbiotics are and provide guidance for future research and innovation."

The general idea of synbiotics was first proposed in 1995 at the same time prebiotics were defined. But because the U.S. Food and Drug Administration (FDA) regulates supplements so loosely, companies can sell products that may or may not provide health benefits.

"This consensus statement provides guidance for different stakeholders, including scientists in academia and industry, consumers and even journalists. We want to remind each group that these terms should be used consistently, avoiding sensationalizing or overstating health claims," says Hannah Holscher, panel member and assistant professor in the Department of Food Science and Human Nutrition at the University of Illinois.

The updated definition for synbiotics is: "A mixture comprising live microorganisms and substrate(s) selectively utilized by host microorganisms that confers a health benefit on the host." The authors noted that including pre- and probiotics in the definition may restrict formulators' ability to innovate, so this new definition allows for the use of microorganisms or other ingredients that may not necessarily fall under the pre- and probiotics umbrella.

Pre- and probiotics can still be included under the new definition ifs they're tested together and shown to provide positive results. For example, a prebiotic that aids digestion can be combined with a probiotic that boosts immunity, and as long as they continue to deliver those benefits together, they can be considered "complementary synbiotics." Another category is "synergistic synbiotics," in which the ingredients work together to deliver a single, targeted health benefit. 

"The key there is testing. Even if the pre- and probiotics work separately, there could be some antagonism when put together," says Swanson. "We don't want companies just randomly throwing things together." The consensus panel put together testing protocols for both cases, considering humans and animals, and encouraging researchers to consider age, health status, sex and other factors.

With better guiding documentation, they predict that the market for synbiotics will grow. "Just because there's a pre-, pro- or synbiotic on the market, that doesn't mean they'll work across the board from infants to adults to geriatrics, from heart disease to gastrointestinal health. They're all really there for a specific purpose," cautions Swanson.

Adds Holscher: "The question is not whether you should take a pre-, pro- or synbiotic. The question is, 'What do you need those products to do?' We know a lot about the specific health outcomes of these products, so it's a matter of finding what you need rather than thinking of them as a blanket cure-all."

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