Should the lack of safety data in microbiome research ring alarm bells?

19 Jul 2018 --- A recent review notes that only two percent of trials in the widening research space around probiotics, prebiotics and synbiotics publish full safety data, highlighting the need for more comprehensive adverse risk reporting. Due to this, researchers warn that they cannot broadly conclude that these interventions are safe. However, industry players have refuted the “allegations” that the ingredients should be seen as “unsafe” due to the lack of safety data published.

Interventions aimed at modifying microbiota are increasingly popular. Innova Market Insights data notes that nearly 96 percent of global launches in the 12 months to the end of June 2017 were positioned on a health platform of some kind. Of this, almost 56 percent of introductions featured a digestive health and/or probiotic claim, with the Lactobacillus and Bifidobacterium strains proving the most common strains in probiotic products.

In light of the surge in use, researchers from the Centre of Research in Epidemiology and Statistics Sorbonne University and Columbia University studied 384 published randomized controlled trials involving probiotics, prebiotics, or synbiotics to examine how harms (adverse-effects) were reported. 

The findings, published in the Annals of Internal Medicine, showed that harms reporting for these interventions were almost always missing, insufficient or inadequate. One-third of the trials studied gave no information on harms, and only two percent adequately reported key safety components. 

According to the researchers, the inadequacy in reporting harms-related results may lead to an inaccurate safety profile and erroneous decision-making, with “major consequences” for patients, especially when used in treating severe diseases or are used by high-risk patients (such as preterm infants or critically ill persons).”

“A broad general conclusion that probiotics, prebiotics, and synbiotics are safe cannot be made without discussing safety and toxicology data,” the researchers conclude.

Misguided to call the ingredients “unsafe”?
The Council for Responsible Nutrition (CRN), a trade association for the dietary supplement and functional food industry, has responded to the review stating that “the only conclusion that can be drawn from the review is that reporting of harms-related information in clinical trials of these products is lacking.”

Therefore, the CRN also notes the need for increased harms reporting in studies but adds that its absence “does not signify the presence of safety concerns, it simply means we need to be better at reporting this crucial information.”

Importantly, probiotics and prebiotics used in products do undergo rigorous safety checks, the CRN explains, and “the safety of these ingredients is well-supported through their extensive history of use. Further, new probiotic and prebiotic dietary supplement ingredients are subject to pre-market evaluation of safety by FDA.” 

The CRN concludes that they agree with the “authors’ premise that members of the research community must commit to fully evaluating and reporting the safety of any intervention to ensure clinicians can confidently understand the safety of probiotics in the clinical setting.” In this way, positive contributions to scientific innovation can be made.

Harms-reporting
Harms-reporting is a term used to describe adverse side-effects, Dr. Megan Rossi, Consultant Dietitian and Nutritionist at the Department of Nutritional Sciences, Kings College London, tells NutritionInsight. During the process of gaining ethnical approval “the researchers must state how they will collect data and report adverse events. It is a clear process internally, but externally in the public eye it may appear ambiguous.” 

Some journals enforce strict word limits which mean that adverse effects are left out, Rossi continues, some journals, however, do mandate a section for adverse effects and it may be useful for more journals to do this.

However, Rossi advocates for the safety of probiotics, prebiotics and synbiotics in line with CRN: due to the extensive investigations into their safety. Groups such as immunocompromised people do have “a slightly increased risk of an adverse effect,” she says, “but researchers are currently looking to determine whether the benefits [of the ingredients] outweigh this [risk].”

Therefore, despite market growth and promising results in clinical trials, this review could raise questions over the safety of probiotic, prebiotic and synbiotic interventions due to a lack of safety information.

By Laxmi Haigh