Many individuals know digestion is important for breaking down food into nutrients that the body uses for energy, growth and cell repair. But how many people understand the connection between digestion and athletic performance?

The current American diet, for the most part, is high in processed foods, saturated fat and sugar, and low in fiber. Studies show this type of diet reduces the beneficial bacteria in one’s system—making it harder for the gut to absorb nutrients—and increases inflammation throughout the body.

This can result not only in production of inflammatory substances in the intestines, but may also cause systemic inflammation in the body and impact brain function—both of which inhibit athletic performance and recovery.

When it comes to sports performance, gut bacteria (which are influenced by one’s diet, among other factors), can affect how well an athlete will perform and how quickly they recover. Research also suggests exercise prevents the growth of bad bacteria through the body, thereby helping the body digest food and absorb what it needs from it.

Athletes are becoming more aware of how their overall performance can be affected by what they eat. Digestive health specifically may impact various aspects of sports performance. Some of the ways optimum gut health may benefit athletes include the potential for:

• Reducing inflammation

Inflammation is the root cause of many chronic diseases and can also interfere with athletic performance in many ways, but mostly it may significantly slow down post-workout recovery. Research has shown improving one’s microbiome balance reduces systemic inflammation, which provides both short-term relief and long-term risk reduction.

Maintaining a balanced microbiome is key to helping reduce systemic inflammation and provides a more stable environment within the body, which makes it easier for athletes to handle the repeated stress placed on their bodies.

• Boosting energy levels

A mix of friendly bacteria in the microbiome may help boost energy levels. It does this by impacting the adenosine triphosphate (ATP)—or energy—cycle. ATP is the body's biochemical way to store and transport energy.

A healthy microbiome can also improve metabolism. This could in turn help all athletes, including those in endurance sports, last longer and perform better by supplying essential metabolites to their mitochondria, the cell’s powerhouse.

Another function of a healthy microbiome is helping to reduce fatigue through better lactic acid uptake, controlling the redox function, and therefore delaying fatigue symptoms and overall energy levels.

• Improving mental strength

Some may argue success in sports is 100% mental. Athletes and coaches often attribute poor performance in competition to thinking too much, and not keeping one’s head “in the game.” The gut microbes talk to the brain through the vagus nerve, which regulates internal organ functions like digestion, heart rate and respiratory rate.

Although it is premature to state conclusively that the microbiome can impact mental health—more research is needed in this area—some studies suggest the gut may affect a person’s mindset and mental focus. In some cases, when gut microbes are imbalanced, they’ve been shown to contribute to mental illness. One study linked dysbiosis, or gut microbiome imbalance, to anxiety and depression.

On the flip side, having a healthy gut microbiome can contribute to mental strength. The composition of the gut microbiome significantly affects wellness areas relied on for athletic performance, including mood, pain tolerance, cognitive performance, mental clarity and attitude. More simply put, athletes will perform better when their mental strength is better.

• Shaping ideal body composition

The gut microbiome plays a role in body mass composition (muscle vs. fat), amount of white fat vs. brown fat, as well as blood glucose response to meals. This means having a healthy microbiome would lead to increased energy and nutrient uptake from food, or proper digestion, therefore improving metabolism, body weight and how efficiently the body is performing. Body composition changes tend to be more challenging if the gut microbiome is out of balance.

• Improving sleep

Athletes know they need proper sleep to perform well and for proper recovery, but many of them may not know their gut makes some of the neurotransmitters that help them sleep.

Gut microbiome imbalance is also associated with poor sleep quality and lowered cognitive flexibility. This is because the gut microbiome controls levels of various hormones such as cortisol, serotonin and gamma-aminobutyric acid (GABA), which all impact sleep quality.

The microbiome also affects the body's ability to make melatonin, a hormone important to a healthy sleep-wake cycle. Quality sleep, good gut health, energy levels and performance are all connected in a cycle that can either build up a person—or bring them down.

• Supporting antioxidant defense system

Top-performing athletes, as well as everyday athletes, need a high-functioning immune system to consistently perform at their peak so they can recover quickly to stay at the top of their game. About 70-80% of a person’s immune cells are created in the gut, so the balance in the microbiome is a powerful system the human body uses for antioxidant enzymes to stay well.

Immune system health is associated with a balanced gut microbiome. This gut microbiome-regulated antioxidant enzyme system helps prevent tissue damage from exercise, protects against intense exercise-induced oxidative damage, is linked to the physical status of athletes, reduces physical fatigue and improves exercise performance.

Takeaways on digestion and health

Taking a holistic look at digestion provides a better understanding of the positive effects a healthy diet can have on the entire body—and its potential impact on athletic performance. Steering clear of processed foods can help balance gut bacteria and aid digestion, which research shows contributes to a range of benefits. These benefits include reduced inflammation, more energy, better body composition, improved sleep, a healthier immune system and improved mental strength.

Although gut microbial composition alone cannot predict any state of health or disease, prioritizing the microbiome health may help individuals without diseases stay healthy—and perform at their best.

Michelle Ricker, RDN, is the director of worldwide health education and training at Herbalife, and a member of the company’s global nutrition advisory board. She is also a certified health and fitness instructor through the American College of Sports Medicine (ACSM) and the National Academy of Sports Medicine (NASM). With more than 25 years of experience in the field of nutrition, fitness and genomics, Ricker has experience developing supplements and fitness technology, and has worked extensively with multiple professional athletes to develop nutrition and fitness plans.