Scientists have characterised the results of the ketogenic Mediterranean eating regimen with phytoextracts on gut microbiota composition in athletes. The study by researchers in Italy and Spain is published within the journal Frontiers in Nutrition. 

Study: Effect of 30 days of ketogenic Mediterranean eating regimen with phytoextracts on athletes’ gut microbiome composition. Image Credit: Alesia.Bierliezova / Shutterstock

Background

Human gut microbiota is a set of trillions of microorganisms living naturally within the gastrointestinal tract (GI). Interactions between these microorganisms play a vital role in regulating metabolic and immunological processes.

The compositional and variety of gut microbiota may be influenced by aspects resembling age, genetic background, birth delivery route, breastfeeding, antibiotic use, eating regimen, and physical activity. Amongst these aspects, eating regimen and physical activity are the first modulators.

Diet plays an important role in sports nutrition, helping athletes maximize their fitness and performance. As well as, eating regimen can influence athletes’ overall health and performance levels by modulating gut microbiota. Amongst various eating regimen patterns, the ketogenic eating regimen, which is high in fat and protein and low in carbohydrates, is taken into account effective in maintaining body composition in athletes.

In the present study, scientists have investigated the results of a ketogenic Mediterranean eating regimen with phytoextracts on the gut microbiota composition in semi-professional soccer players.

Study design

The study was conducted on 16 semi-professional soccer players undergoing their regular training schedule (8 hours/week). The participants were randomly categorized into two groups, the keto eating regimen group, and the western eating regimen group.

The dietary interventions were continued for 30 days. Each diets contained the identical amount of protein. Furthermore, each participant was given three herbal extracts throughout the study period. The western eating regimen provided to the participants differed from the typically high-fat, high-carbohydrate western eating regimen.   

DNA extracted from participant-derived fecal samples was analyzed for gut microbiota composition by 16S rRNA amplicon sequencing.

Dietary intake

The dietary evaluation conducted before intervention revealed no difference in dietary nutrient intake between the study groups. As well as, the evaluation of eating regimen records revealed complete adherence of the participants to the dietary interventions.

Detailed list of food provided.

Through the intervention period, a big difference in dietary nutrient intake was noticed between the study groups. While carbohydrate intake was significantly higher within the western eating regimen group, fat intake was significantly higher within the keto eating regimen group.

Gut microbiota composition

The alpha diversity as a measure of gut microbiota composition was determined in each groups before and 30 days after the interventions. The findings revealed no significant difference in alpha diversity between the groups at each time points.

The evaluation of taxonomic effects revealed a significantly increased abundance of Actinobacteriota (a phylum of mostly Gram-positive bacteria) within the western eating regimen group and a significantly reduced abundance within the keto eating regimen group. 

The reduced abundance of Actinobacteriota within the keto eating regimen group may very well be as a consequence of a discount of Bifidobacteria, which in turn may very well be attributed to the relatively lower carbohydrate and fiber intake within the keto eating regimen group.

Further evaluation on the post-intervention time point revealed a significantly higher abundance of Bifidobacterium, Butyricicoccus, and Acidaminococcus within the western eating regimen group and a significantly higher abundance of Clostridia UCG-014, Butyricimonas, Odoribacterter, and Ruminococcus within the keto eating regimen group.

Impact of macronutrient intake

The impact of eating regimen macronutrient intake on microbial abundance and anthropometric and performance measures was analyzed within the study. The findings revealed a big positive correlation between carbohydrate intake and respiratory exchange ratio.

The participants within the keto eating regimen group who received lower amounts of carbohydrates showed a better respiratory exchange ratio reduction, indicating an increased reliance on oxidative metabolism. Furthermore, a big inverse association was observed between carbohydrate intake and Odoribacter abundance.

A major inverse association was observed between fat intake and respiratory exchange ratio, visceral adipose tissue, extracellular water, and Fusicatenibacter abundance. Body weight reduction showed a positive association with Ruminococcus torques and Lachnospira abundance and a negative association with Parabacteroides abundance.    

Study significance

The study reveals that a 30-day ketogenic eating regimen regimen with herbal extracts doesn’t alter the general alpha diversity of gut microbiota in athletes. Nonetheless, the eating regimen can considerably influence gut microbiota composition on the phylum and genus levels.

As mentioned by the scientists, an increased Bacteroidetes abundance and reduced Firmicutes abundance within the keto eating regimen group may very well be attributed to the upper fat mass and visceral adipose tissue reduction on this group.

Overall, the study indicates that the keto eating regimen could be used instead and protected intervention to keep up gut microbiota composition in athletes.