Research backing for synbiotic effects still a bit thin, experts say
According the FAO/WHO, probiotics are defined as "live microorganisms which when administered in adequate amounts confer a health benefit on the host" . Prebiotics are defined as “A substrate that is selectively utilized by host microorganisms conferring a health benefit” (ISAPP 2017). Synbiotics are a combination of the two.
Relationship key to product's benefits
Product formulators tout the ability of the prebiotics they use in their formulations to boost the growth and activity of the bacterial species they have selected. That relationship is the key to a successful synbiotic, said Dr Ralf Jäger, PhD, principal in the scientific consultancy Increnovo.
“Synbiotics are not simply a ‘mixture’ between probiotics and prebiotics, synbiotics are synergistic combinations of pro- and prebiotics. Synbiotics must have a superior effect, compared to the activity of the probiotic or prebiotic alone,” Jäger told NutraIngredients-USA.
“Simplified, there are three ways a prebiotic can help out its buddy probiotic. The prebiotic can 1) increase probiotic stability during storage and gastrointestinal passage, 2) act as the food therefore increase probiotic growth, or 3) indirectly promote growth, not by acting as food, but positively changing the microbiota allowing for better growth conditions,” he said.
Paucity of data
It’s a nice idea, said Dr Alex Schauss, PhD, principal in the consulting firm AIBMR. Schauss and his colleagues have taken dozens of ingredients through the GRAS and NDI processes, so he believes he has a good insight into what kind of data regulators might be looking for to support claims such as the synergistic boost a synbiotic pairing is supposed to provide.
“The data at the moment is very weak and it's not compelling,” Schauss said. “Most ‘synbiotics’ are just based on the definition of the noun—the interaction of two substances or organisms that are in close proximity to one another. There is a lot of speculation about these effects and they do seem reasonable to construe. But we are in a world of science and data takes precedence.”
Schauss makes a distinction between products marketed as synbiotics that are claiming mere additive effects to those that purport to have some multiplier activity. The first are just two ingredients that have gut health benefits offered together, much as B vitamins and caffeine might be paired together in an ‘energy’ beverage. The latter are synbiotic products that claim that special extra boost.
“If you are just basing the claims for your synbiotic on the additive effect—one plus one equals two, in other words—then I don’t think there’s much issue. But if you are going to three, or four, or five—that’s where you have to have the data,” he said.
Careful product development needed
Digestive Health Online Conference 2017
Prebiotics, probiotics and synbiotics will take center stage at the upcoming Digestive Health Online Conference, hosted by NutraIngredients-USA. This free-to-attend event will take place on November 15. For more information and to register, please click HERE.
Jäger said while the synergistic effects of properly formulated synbiotics are in his view undoubtedly real, they must be proven via a careful product development plan. You can’t just throw a prebiotic and a probiotic together and claim a synbiotic effect without potentially defrauding the consumer.
“The development of a synbiotic should start with growing the probiotic strain in vitro in the presence of various prebiotic carbohydrates and in comparison to glucose, in order to find the best suited combination candidate for a synbiotic product. You are basically putting your probiotic in front of an all-you-can-eat buffet to check what prebiotic it likes to eat, and as with human preferences, individual probiotic preferences differ. They like to eat different things,” he said.
“Take inulin for example, different sources of inulin, chicory or agave, have different carbohydrate structures. While L. acidophilus strains (DDS-1, LA-5 and LA-14) showed increased growth with chicory inulin, agave inulin has no beneficial effect. L. acidophilus strains (DDS-1, LA-5 and LA-14) grow on GOS, trans-GOS, sc-FOS; however, not on Arabinogalactan or maize dextrin (R. Jäger, M. Purpura, J. Kiers, M. Olson: Pro- and prebiotic in vitro screening to identify potential best-match synbiotics. Gastroenterology 2013, 144(5 Suppl 1):S-898).
“Once you have identified your lead combination or combinations in vitro, you would have to test the synbiotic in a human study, showing at least increased colonization of your probiotic. And the study must compare the symbiotic vs. the probiotic vs. the prebiotic. Even if you can show greater colonization, the question remains if greater colonization results in clinically meaningful benefits,” Jäger concluded.
Market opportunity for committed companies
Both Jäger and Schauss said they believe there is a continuing market opportunity for synbiotics, assuming that companies are willing to step up to the plate to do the research. Failing that, the category could founder on the shoals of products that don’t really deliver on the promises printed on their labels.
“I do think it’s an opportunity for a company to take some leadership and guide the category,” Schauss said.
“The overall concept of synbiotics has great potential and can easily be understood by consumers. More effective synbiotics can drive down costs of probiotic supplements and make them more affordable for consumers. However, the category has currently taken a little bit of a backseat to postbiotics (the metabolic byproduct of probiotics) and immunobiotics (dead ‘probiotics’) or even fermented foods like kefir, sauerkraut or kombucha. Synbiotics currently suffer from the lack of clear scientific evidence, showing superiority over the individual pro- and prebiotic,” Jäger said.