When it comes to dietary considerations for endurance exercise, carbohydrates, iron, and electrolytes such as sodium and potassium are nutrients that are commonly of focus. Perhaps protein consumption comes to mind when thinking about recovering from a long or strenuous run.
Foods that favorably affect the bacteria colonies that populate our intestines, such as indigestible carbohydrates and phytochemicals from fruits and vegetables, are only now getting a second thought. Evidence suggesting the importance of these foods for endurance athletes, and particularly in the recovery phase of endurance activity, is growing rapidly. One function of a healthy composition of gut bacteria is to enhance the barrier function of the intestine, which prevents harmful substances in the intestine from traveling through the barrier cell layer and setting off an inflammatory immune response.
What Happens During (And After) Exercise?
During endurance exercise, blood flow is restricted to the intestines as it instead travels to the working muscles and body surface for cooling. This results in a stressful event called ischemia in the intestines. When endurance exercise ends, blood flow returns to the intestinal tissue, which also can be a stressful event. The combination of these stresses can result in death of some cells important to maintaining the barrier function of the intestine, which then can lead to an inflammatory state due to harmful substances passing through that barrier layer.
In addition, Wang and colleagues reported in the journal PLoS One that the oxygen deprivation and subsequent returning of blood flow to the colon, such as that which happens during endurance activity, resulted in an increase in abundance of the inflammatory bacterial population E. coli in the colon. While more work must be done in this area, it has been suggested that consumption of a beneficial probiotic Lactobacillus strain of bacteria may alleviate this harmful response to endurance activity in the intestines.
Your Anti-Inflammatory Immune Response
Another function of the intestinal bacteria is to regulate the immune system. Certain species of bacteria have been identified for their ability to stimulate certain immune cell populations. Recently, a study by Williams and colleagues published in the British Journal of Nutrition indicated that consumption of prebiotics, which is a general term for food components that intestinal bacteria feed on such as indigestible carbohydrates and phytochemicals, resulted in alterations in the inflammatory immune response in those who suffered from exercise-induced asthma. These alterations resulted in a reduction in asthma symptoms, which has great implications for endurance performance for those who suffer from this condition.
Your Performance: The Essential Role of Gut Bacteria
We have only scratched the surface of identifying the role of the intestinal bacteria in overall health, but it is becoming increasingly clear that it is a necessary consideration when trying to fuel our bodies for optimal performance.
Stay tuned for an upcoming post where I’ll discuss foods that have been identified as having the potential to enhance the beneficial intestinal bacterial populations.
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