Protein versus probiotics: How extreme intake limits the effects of beneficial bacteria in bodybuilders – 60-day trial

They discovered that probiotic intake had no effect on the gut microbiome and short chain fatty acids (SCFAs) produced in bodybuilders who have consumed high amounts of protein. 

The 60-day trial, conducted by researchers from Kyunghee University, ChunLab, and IIdong Pharmaceutical, published its findings in the journal Nutrients.​

In the trial, 15 bodybuilders who were on an extremely high protein and low-carbohydrate diet were randomly assigned to the intervention group (8) or the placebo group (7).

The intervention group took a capsule consisting of 1tr CFU of each of these four strains: L. acidophilus, L. casei, L. helveticus,​ and Bifidobacterium bifidum, ​while the placebo group took a capsule containing corn starch. The capsules were provided by IIdong Pharma.

Faecal samples were taken from the subjects before and after the supplement intake, and the types of short-chain fatty acids (SCFA) found in their faecal samples were analysed.

However, the supplement intake did not lead to a positive effect on their gut microbial environment or the concentration of SCFAs.

For instance, both the intervention and placebo groups saw a decrease in the amount of SCFAs acetic acid and propionic acid after the trial.

This showed that the probiotic supplementation did not work and the researchers believe this was due to the high protein diet.

“Sixty days of probiotic intake had no demonstrable effect on the gut microbiome and SCFAs of bodybuilders who were continuously exposed to exercise stimulation and consumed a highly nutritional diet,” ​the researchers said.

Part two ​

To clarify if diet indeed play a role on the impact of probiotic supplementation, the researchers conducted a second round of studies.

This time round, they included data from a previous trial conducted by Jang et al​ that studied 1) bodybuilders who consumed varying amounts of protein and 2) individuals who led a sedentary lifestyle.

With the newly added data, the researchers compared the gut microbiota of 28 bodybuilders and 15 individuals leading a sedentary lifestyle but did not take probiotics.

Amongst the bodybuilders, some took 1) high protein and meagre dietary fibre, or 2) high protein and proper dietary fibre, or 3) proper protein and meagre dietary fibre.

Analysis showed that bodybuilders with high protein and meagre dietary fibre did not have significant differences in their gut microbiota when compared to those leading a sedentary lifestyle.

This showed that the high protein diet had offset the exercise induced microbiota change.

However, when the bodybuilders took in protein or dietary fibre that is within the Korean recommended dietary allowance (KRDA), they had a more diverse gut microbiota than individuals leading a sedentary lifestyle. [GS1]​ 

Start from good nutrition ​

In conclusion, the researchers suggested that a balanced nutrition is required for exercise-induced or probiotic-induced microbiota change to take place.

“​Overall, based on gut microbiome analysis according to nutritional intake, we can conclude that probiotic supplementation without improvements in nutritional intake does not significantly affect the gut microbiome of bodybuilders.​

“Therefore, to use probiotics as ergogenic aids, it is necessary to develop customized probiotics considering differences in gut microbiome according to exercise type based on nutritional intake,”​ the researchers said.  

This study was supported by the Ministry of Education of the Korea and the National Research Foundation of Korea.

Source: Nutrients​

The Effect of Athletes’ Probiotic Intake May Depend on Protein and Dietary Fiber Intake​

https://doi.org/10.3390/nu12102947​​

Authors: Hyon Park, et al