Gut health, sport and exercise

Tom Davies: Professional triathlete and Ironman, was the youngest man to cycle around the World.

Gut health and sport are closely linked, as the health of the gut can affect athletic performance, recovery, and overall well-being. The gut is home to trillions of microorganisms, collectively known as the gut microbiota. In fact, there are more genetic materials from bacteria in and on our bodies than from our own cells. Not a surprise then that the microbiome  plays a critical role in digestion, metabolism, muscle recovery, immunity, brain function and mood. Research suggests that a diverse and balanced gut microbiota can enhance nutrient absorption, reduce inflammation, modulate the immune system, and produce beneficial metabolites such as short-chain fatty acids.

In the context of sport, gut health can have several benefits, including:

1. Improved nutrient absorption: The gut microbiota helps break down complex carbohydrates, fibre, and proteins. This can lead to better absorption of essential nutrients such as vitamins, minerals, and amino acids, which are crucial for muscle growth, repair and energy production.
2. Reduced inflammation: Inflammation is a natural response to injury or infection and strenuous exercise but chronic inflammation can impair athletic performance and increase the risk of injuries and illnesses. The gut microbiota can help regulate inflammation by producing anti-inflammatory compounds such as butyrate, lactate, and propionate. By reducing inflammation, athletes  experience less muscle soreness, faster recovery, and improved endurance. For example, a study published in the Journal of the International Society of Sports Nutrition found that a probiotic supplement containing Lactobacillus fermentum reduced post-exercise muscle damage and inflammation in endurance athletes. Similarly, a study published in the European Journal of Applied Physiology found that a probiotic supplement including Lactobacillus helveticus reduced inflammatory markers in rugby players during a training camp.
3. Enhanced immune function: The gut microbiota plays a critical role in training the immune system to recognize and respond to pathogens. Athletes are often exposed to infectious agents in crowded environments such as gyms, locker rooms, and sports venues. A healthy gut microbiota can help strengthen the immune system, reduce the risk of infections, and speed up recovery from illnesses.
4. Better motivation to train: The gut-brain axis is a bidirectional communication pathway between the gut and the central nervous system, which regulates mood, cognition, and behaviour. The gut microbiota can influence the production of neurotransmitters such as serotonin, dopamine, and GABA, which are involved in mood regulation, stress response, and sleep quality. By improving gut health, athletes may experience less anxiety, depression, and fatigue, and more focus, motivation to train and confidence.
5. Optimal body composition: Gut health can also affect body composition, which is a key factor in athletic performance. A balanced gut microbiota can help regulate energy balance by modulating appetite, satiety, and metabolism. Athletes who maintain a healthy weight and body fat percentage may have more strength, speed, and agility, and lower risk of injuries and chronic diseases.

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How can athletes improve their gut health? Here are some tips:

1. Eat a varied and balanced diet: A diverse diet that includes plenty of fruits, vegetables, whole grains, lean proteins, and healthy fats can provide the nutrients and fibers that the gut microbiota needs to thrive. Avoid processed foods, sugary drinks, and excessive alcohol, which can disrupt the gut microbiota and promote inflammation..read more
2. Eat foods with health bacteria: Some foods are naturally rich in probiotic bacteria such as kimchi, kefir and sauerkraut. Try to eat one or more of these every day.
3. Stay hydrated: Drinking enough water can help maintain digestive health and prevent constipation, which can lead to bloating, discomfort, and reduced performance. Athletes should aim to drink at least 2-3 liters of water per day, and more if they sweat heavily or exercise in hot conditions.
4. Manage stress: Stress can affect gut health by altering the gut microbiota, increasing inflammation, and impairing immune function. Athletes should practice stress-management techniques such as meditation, yoga, or deep breathing, and prioritise rest and recovery.

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Evidence for the benefits of probiotic supplements in Sport

In recent years, there has been increasing interest in the potential role of probiotics in sport, particularly for enhancing performance, improving motivation to train, reducing fatigue, and promoting recovery.

Studies have shown that athletes have a distinct gut microbiota profile compared to sedentary individuals, with higher levels of bacteria associated with carbohydrate and protein metabolism. However, intense and prolonged exercise can also affect the gut microbiota, leading to an imbalance in microbial diversity and composition. This disruption can cause gastrointestinal symptoms such as bloating, diarrhea, and cramps, which can impair performance and recovery.

Probiotics, particularly lactobacillus, have been shown to help restore gut homeostasis by improving the balance and diversity of the gut microbiota, enhance nutrient absorption, reduce inflammation, and modulate immune function in athletes. In addition, probiotics may also produce metabolites such as short-chain fatty acids that can benefit athletic performance and recovery. Several studies have investigated the effects of probiotics on exercise performance and recovery, with mixed results:

1. Improved endurance: Some studies have suggested that probiotics may enhance endurance performance by improving energy metabolism and reducing fatigue. For example, a study published in the International Journal of Sports Nutrition and Exercise Metabolism found that athletes who consumed a probiotic supplement including Lactobacillus acidophilus,  for four weeks had a significant increase in time to exhaustion compared to a placebo group.
2. Improved recovery: Probiotics may also aid in recovery by reducing muscle damage, soreness, and oxidative stress. For example, a study published in the Journal of Science and Medicine in Sport found that a probiotic supplement containing Lactobacillus rhamnosus reduced muscle soreness and improved muscle function in rugby players following a match. Similarly, a study published in the Journal of the International Society of Sports Nutrition found that a probiotic supplement containing Lactobacillus casei improved recovery time and immune function in endurance runners following a marathon.