Researchers identified seven studies, all of which demonstrated "significant improvements" in at least one of the outcomes measuring the effect taking pre/probiotics compared with placebo, no treatment, or baseline measurements. "Our review suggests utilizing pre/probiotic may be a potentially useful adjunctive treatment," Sanjay Noonan, Brighton and Sussex Medical School, and his research team wrote. "Furthermore, patients with certain co-morbidities, such as IBS, might experience greater benefits from such treatments, given that pre/probiotic are useful treatments for other conditions that were not the primary focus of this discourse."
Regarding depression, the researchers concluded that "purely from the information gathered in this review, it is valid to suggest that, for patients with clinically recognized depression: isolate, or adjuvant, prebiotic therapy is unlikely to affect an individual’s experience of their condition in a quantitatively evident way; and that isolate, or adjuvant, probiotic/combined prebiotic–probiotic therapy may offer a quantitatively measurable improvement in parameters relating to depression."
Results were less clear regarding anxiety. The research team concluded that there was "inadequate data to suggest anything meaningful to support or refute the use of either pre/probiotic agents (or a combination of both) in patients with clinically recognized anxiety disorders."
The researchers further noted that results are limited by several factors including sample sizes, short study durations and not enough information on long-term effects. The add that more research is needed to determine if the benefits can be replicated in larger, longer-term studies, and whether the effects are maintained with continued use of pre/probiotics.
Continued research in this area has been a focus of the natural products industry. InWholeFoodsMagazine's2020 Forecast,published in December 2019, experts identified the Microbiome and -biotics as a top focus for 2020. George Paraskevakos, Executive Director of the International Probiotics Association (IPA), toldWholeFoods: “A significant area where companies are working and researching is the other ‘biotic’ segments such as parabiotic, eubiotic, psychobiotic, etc. The research is starting to report interesting results. As a differentiator companies are also investing heavily into dose delivery research in a vast array of applications. With a different dose delivery and more targeted condition specific formulas companies are looking to introduce new and novel products.”