KANSAS CITY, MO. — The food industry has focused on the microbiome’s role in the gut-brain axis for several years. Now research is exploring the gut-muscle axis, too.

Whey protein, prebiotic fibers and probiotics all may assist formulators in creating products that benefit the gut-muscle axis.

“The gut has often been referred to as the ‘second brain’ because of how much it’s thought to control our mood and mental well-being, but there’s a growing body of evidence indicating that the gut microbiome can have wide-reaching effects beyond digestion, including benefits for immunity, brain health, the lungs — and even muscles,” said Sophie Zillinger Molenaar, global marketing lead Biotis at FrieslandCampina Ingredients and based in South Holland, The Netherlands. “This complex link between the gut microbiota, muscle function, body composition and athletic performance is known as the gut-muscle axis, and evidence suggests the gut microbiome can impact muscle mass and function, muscle recovery and athletic performance.”

Research has shown exercise may influence gut microbiota positively, leading to improved carbohydrate and amino acid metabolism, but extensive exercise, stress and dietary habits associated with heavy training may cause imbalances in the gut, Zillinger Molenaar said. Such imbalances may lead to issues such as bloating, abdominal pain, diarrhea and constipation. As many as 86% of athletes suffer with gastrointestinal problems associated with heavy exercise.

The gastrointestinal tract is important for endurance athletes, who have specific performance requirements, said Denisse Colindres, manager of nutrition communication for Beneo, which has a US office in Parsippany, NJ.

“Considerable amounts of nutrients need to be delivered just in time for performance and reloading or during training,” she said. “Also, the metabolism needs to be regulated according to the athletes’ needs.”

Whey protein and prebiotics

FrieslandCampina Ingredients recently launched Biotis fermentis. The ingredient combines whey protein, Biotis galacto-oligosaccharide (GOS) prebiotic fiber and probiotics.

“The true power of Biotis fermentis lies in how these three efficacious components are enhanced by fermentation and complement each other to activate the gut-muscle axis,” Zillinger Molenaar said. “Looking at each of these star players on their own, whey protein is the gold standard in sports nutrition and has long been a firm favorite of both athletes and active consumers alike for its muscle growth and recovery benefits.”

Whey protein is highly bioavailable and contains branched-chain amino acids (BCAAs) like leucine to enable a high level of muscle protein synthesis. Probiotic cultures support the gut, and Biotis GOS has been shown to impact gut microbiota composition positively, producing beneficial effects on gut health and mental well-being, Zillinger Molen said.

Two powder concepts fit into athletic routines. Biotis fermentis powder sticks may be consumed on-the-go and during training. The second concept is a powder for protein shakes. Biotis fermentis has a clean sensory profile with a mild acidic taste, according to FrieslandCampina. It may be mixed into water or juice without forming clumps, she said.

Supporting gut microbiota through prebiotics like chicory root fibers helps athletes in various ways, including digestive well-being, immune system boost, enhanced nutrient absorption and recovery, Colindres said, adding chicory root fiber intake at 3 grams per day has been shown to promote significant growth of Bifidobacteria in the gut microbiome in all age groups.

Dehydration and electrolyte imbalances may contribute to constipation, she said. Chicory root fibers balance the gut microbiota and keep pathogens away.

Beneo’s chicory root fiber inulin has an authorized health claim in the European Union concerning digestive health and regulatory support. In the United States, several function claims are possible.

Chicory root fibers work in applications such as dairy, cereal, baked foods and confectionery items, Colindres said. Chicory root fiber may appear on the ingredient lists of products as chicory root fiber, chicory fiber, chicory root extract, inulin, oligofructose or fructo-oligosaccharide (FOS).

Clasado Biosciences Ltd., Reading, United Kingdom, collaborated with Nottingham Trent University in England on a study investigating how prebiotics potentially may support sport and athletic health. The study measured the effects of a prebiotic intervention on markers of immunity and upper respiratory systems and gastrointestinal symptoms in rugby players. The study showed 24 weeks of prebiotic supplementation reduced the duration of upper respiratory symptoms and the severity of gastrointestinal symptoms.

The study involved Bimuno, a GOS offered by Clasado Biosciences, which funded the study.

Sports and strains

A review published in the International Journal of Environmental Research and Public Health evaluated the effects of probiotic supplementation on performance and performance-related conditions in athletes. A grant from the Italian Ministry of University and Research supported the review.

Researchers from the University of Naples in Italy analyzed the results of 13 studies. Seven of the studies concerned endurance athletes, while one involved rugby players, one involved badminton players and one involved baseball players. Three studies referred to non-specified categories of athletes.

Evidence suggested integrating athletes’ diets with some bacterial strains and having athletes consume multi-strain compounds may improve performance and positively may affect performance-related aspects such as fatigue, muscle pain, body composition and cardiorespiratory fitness, the researchers concluded. The type of supplementation and the sport was variable among the studies examined.

High-intensity exercise may have detrimental effects on health, according to the review. Such exercise may cause an increase in intestinal permeability and a decrease in the thickness of intestinal mucus, potentially allowing pathogens/toxins to enter the bloodstream. Gastrointestinal disorders such as diarrhea and heartburn may interrupt training or competing in sports events.

“As the volume of the literature on this subject grows, it will be possible in the future to carry out more detailed analyses on specific performance domains and on specific athletes’ categories,” the researchers said. “Further research should also allow us to study in depth the precise role of each specific bacterial strain assumed alone or in combination with others, to establish which can be the most effective probiotic formulation to achieve specific results on the basis of sport and athletes’ characteristics.”