Most athletes only think about their gut when they get a side stitch or have ‘issues’ on race day. The truth is that the microbes that live in the human gut have proven to be widely influential on human health. While in grad school for microbiology, I began to get curious about the role of microbes on endurance performance. This article will cover gut microbes and potential ways they can affect performance, and how we can cultivate good microbes.

One of my favorite facts about microbes is that the bacteria that live in and on our bodies outnumber our human cells 10:1! The microbial population in our gut contains millions of bacteria, composed of hundreds of species, and dozens of different groups that provide us with different digestive functions. The community in the gut is different from that of the community behind the ear or in your mouth. Many of the gut microbes are anaerobic organisms, and contribute to different parts of the digestion process. Diseases such as inflammatory bowel syndrome, obesity, allergies, autoimmune, and cardiovascular disease can all be linked to the health of the gut microbiome.

It is not just the gut mcirboes that are important either. For example, take the recent beet juice craze for performance enhancement. Nitrate is converted to nitrite by the microbes in your mouth for use in the nitric oxide (NO) system, a cardiovascular signaling molecule. A healthy microbial community all the way down the alimentary tract is critical to getting the most benefit of a healthy diet. Gut microbes also prime the immune system and keep it running well.

On of the most important and wide-spread effects of a gut microbiome imbalance is leaky gut syndrome. This syndrome is more or less synonymous with fat storage. What happens with leaky gut is that your food is not completely digested, and leaks through the walls of the gut and into the blood stream. You body initiates an immune response, which leads to inflammation, which signals the body to store fat (because you are in hard times, your body thinks you need it). Being lean and at a competitive weight is important for endurance athletes – to get lean, you need to heal and maintain a healthy gut microbiome.

Another large detriment to poor gut health is a reduced ability to access fat as fuel. In an “obese” gut, microbes signal to store fat rather than burn it, which is counter to the needs of many endurance athletes who want to access their fat for energy use. Another critical point here is that it doesn’t take much for your gut to begin to change from healthy to poor. Studies have shown that a diet high in sugar and fat, a so-called ‘western’ diet, can start to change the gut microbes to an “obese” gut community within 24 hours. But the good news for you athletes is that exercise helps to change the gut microbiome towards the good (decreasing levels of proteobacteria, and more diversity).

The main cause of a diseased state in the gut appears to be low diversity of organisms. If your diet is too heavily weighted towards simple sugars and starches, which are absorbed more quickly, you rob your gut of the good microbes that develop from slower digesting foods such as fruits and vegetables. Whole fruits are better than juice, because they contain both soluble and insoluble fiber. The key fiber here is called inulin, a vegetable fiber. So remember: just like in the rainforest, the more species you have, the more stable your ecosystem will be. I like to think of my gut as a garden, and the encourage growth of the right species.

Specifically, you want to target vegetables that are high in the fiber inulin. These vegetable can be considered pre-biotics, which upon digestion help maintain the health gut community already in your gut. The best vegetables for your microbiome are:

-Artichoke
-Carrots
-Garlic
-Jerusalem Artichoke
-Jicama
-Leeks
-Onions
-Radishes
-Tomatoes

Foods to avoid (can negatively affect your microbes):
-Processed foods
-Trans fats
-High fructose corn syrup
-Juices
-Dried and canned fruit
-Processed meats

In addition, adding probiotics can help you get the right balance. Fermented foods such as yogurt, kombucha, sauerkraut, and kimchi increase GI microbe diversity. They also contain valuable enzymes and vitamins that are not obtainable by other means.

Of course, get your good oils by eating nuts and nut butters, fish, olive oil, sunflower seeds, and flax.

You know how they feed antibiotics to cows to make them get bigger faster? Well, they do the same thing to humans! By tearing down your microbial community, antibiotics shift your body into fat storage mode. Antibiotics and an excess of sugary sports drinks should be avoided by endurance athletes.

Have you ever had a gut cramps from eating too many bloks? While sports and recovery drinks are valuable during and after hard training and racing sessions, your energy stores can usually be replenished with a nice dinner and a good nights sleep. I recommend my athletes only use sports and recovery drinks for their hardest workouts and races. Likewise, antibiotics don’t just knock down the bad bacteria, they also kill the good ones, and it can take up to two years (!) for the gut to fully recover. Avoid taking antibiotics when you can.

Also, check out Raphael Kellman’s great new book The Microbiome Diet: The Scientifically Proven Way to Restore Your Gut Health and Achieve Permanent Weight Loss for more detailed scientific back ground and recipes for good microbiome foods.

Question: What could you change today to enhance your gut microbiome health?