Medically reviewed by Onikepe Adegbola, MD, PhD
Probiotics have been an important topic of discussion in the field of nutrition. They have shown many health benefits over the decades. These probiotics are the microorganisms that improve your gut microbiota. But there has been a debate on whether a healthy person should take a probiotic.
Dr. John Damianos published his research in Supplement to the AEProbio Professional Discovery Review, which mentioned the effect of probiotics on gut microbiota for a healthy individual. There were two types of studies performed using probiotics. In the first study, they administered a single-strain probiotic to healthy individuals for 30 days. The second study focused on the athletic performance of patients with a monitored diet.
First Study to Analyze Changes in Composition
The first trial consisted of 30 individuals. 15 healthy individuals received 1 * 109 Bifidobacterium infantis and 15 healthy individuals received placebo gelatin capsules. They collected the patient’s stool samples before the intervention, during the intervention, and 30 days after the intervention.
To determine whether the probiotic affected the microbiota, they performed 16S rRNA sequencing from these samples.
Effects of Probiotics on the Gut Microbiota Of Healthy Individual
Probiotics do not alter the microbiome composition. Researchers observed that probiotics may not affect the composition and diversity of a healthy gut microbiome functionally. According to this study, probiotics do not alter the composition of the microbiome in healthy people.
They concluded that probiotics may have benefited only in states of dysbiosis, where the microbiota is disrupted, and not in healthy individuals with healthy microbiota.
However, this study comes with several limitations. Since the sample size was very small, the results may not be generalizable. Additionally, probiotics may not have to affect microbiome composition for them to exert their beneficial effects. Most probiotics do not colonize the gut, so the effects of probiotic supplementation cease once the supplementation is stopped.
Second Study To Analyze The Functional Effect
Scientists wanted to observe the effect of Bacillus coagulans Unique IS-2 supplementation on muscle strength in resistance-trained males. They combined the administration of probiotics with whey protein.
This study assessed the effects of probiotic supplementation on athletic performance in healthy individuals. The study involved 35 healthy males who took 2 billion CFU Bacillus coagulans Unique IS-2 mixed with 20 g of whey protein every day for 60 days. The control group consisted of 35 healthy males (age 18–25) who received 20 g of whey protein mixed with lactose. All the participants underwent specific resistance exercises with a full-body workout.
Effects of Probiotics on Athletic Performance
Despite its small size, this study was well designed and used an appropriate placebo. They found that in spite of intensive dietary counseling and structured exercise, the probiotic group performed better than the control group, possibly due to the increased protein absorption.
Unlike the first study, this one focused on functional outcomes instead of microbiome composition. Hence, they concluded that probiotics may be beneficial to healthy individuals since they improve athletic performance. But it is still unknown whether the microbiota was altered by B. coagulans or not. However, the benefits can be seen in the results.
To better understand how this probiotic works, larger trials are needed to evaluate the microbiome response. Future trials should recruit a more diverse cohort to determine the external validity of this study.
Treatments for some gut microbiota diseases are still being investigated. Probiotics might unveil new treatments in the future.
We need larger, better-powered trials involving specific single- and multi-strain probiotics to clarify this issue.
Dr. J. Damianos (2022). Supplementation of a single species probiotic does not affect the diversity and composition of the healthy adult gastrointestinal microbiome. Supplement to the AEProbio Professional Discovery Review, 4(1), 1-3