by Beth Shutt, RD, CSSD, LDN

Ed. Note—we're in that patch of time between Thanksgiving and the end-of-year holidays, when athletes tend to start examining a little more closely what is going into their systems. Although we don't encourage limiting your intake through the holidays (too much stress and anxiety), there are things you can do to improve your health and performance in 2021 through some tweaks to a rapidly emerging area of nutrition.

If I had to choose the hottest topic in nutrition research right now, spanning all populations including (but not limited to!) athletes, critically ill patients, those who suffer from gastrointestinal disorders, or simply a healthy sedentary population, the gut microbiome is that topic. What is this microbiome exactly, however? Most reasonably attentive athletes have seen the term bandied about in news articles here and there. The gut microbiome, as defined by molecular biologist Joshua Lederberg, is the totality of microorganisms, bacteria, viruses, protozoa, and fungi along with their collected genetic material in the gastrointestinal tract. The gut microbiome, which is comprised of more microbial cells than the number of cells that make up the entire human body, plays an important role in many metabolic processes, many of which can influence athletic performance. These processes include the fermentation of undigested carbohydrates into short-chain fatty acids (SCFAs), fat metabolism, vitamin synthesis, and (perhaps most important in the current times), stimulates the maturation of the immune system and protects against potentially pathogenic microbes. It is even known to play a role in cognitive performance. Simply put, think of this microbiome as an army that resides in your gut and fights off outside invaders, builds important materials, and fortifies your body, allowing you to go about your business as usual. In addition, several studies have examined those short-chain fatty acids, finding a potential link between their creation and improved endurance performance. So let's optimize your gut!

First of all, our primary goal is diversity. A healthy gut is characterized by a wide range of different kinds of helpful microbes. Dysbiosis, or a loss of microbial diversity, has been associated with various immune regulated conditions and disease states, and in addition has been linked to obesity. The mice in that study we linked to above? They were fed a diet with low microbial diversity and—unsurprisingly—their endurance performance suffered (mice, tiny treadmills). The importance of a diverse gut microbiome is applicable to all, but for athletes specifically, who train and perform at high intensities and often encounter challenges associated with gastrointestinal and immune health during and after races, positively affecting gut bacteria is of particular interest. Any strategy that improves an athlete’s ability to sustain consistency in training and racing, by reducing sick days and their vulnerability to infection, is ultimately a strategy that should be pursued.

So what can we do, as athletes, to maximize the health and diversity of our gut microbiota?  First of all, eat a wide range unprocessed, whole foods, as doing so leads to a more diverse gut microbiome. In particular, eat fermented foods for their probiotics. Probiotics, often referred to as “good gut bacteria”, positively affect the gut microbiome.  Examples of these foods are yogurt (make sure the label says “live and active cultures), kefir, kombucha, sauerkraut, pickles, miso, tempeh, kimchi, sourdough bread and some cheeses.

Consider taking probiotics in supplemental form, especially so if you don’t enjoy the strong taste and smell of fermented foods. Klean Probiotic is an example of probiotic supplement, that is also NSF-Certified For Sport. Supplements should contain at least 10 billion CFU per serving. Also focus on getting prebiotic foods in your diet daily. Prebiotics are typically non-digestible fiber compounds that, among other roles, serve as “food” for probiotics by stimulating their growth and activity. Prebiotics can be found in foods such as apples, Jerusalem artichokes, asparagus, bananas, barley, berries, chicory, cocoa, dandelion greens, flaxseed, garlic, green vegetables, leeks, legumes (beans, chickpeas, lentils), oats, onions, tomatoes, and wheat. You can also take prebiotics in a supplemental powder form.

Much remains unknown in regards to the gut microbiome and future research is needed. One particular area of interest is the potential use of athlete specific probiotics, as probiotic benefits appear to be strain-specific. Another area of interest is the investigation of particular types of nutrients, such as different types of fibers, proteins, fats, etc., and their impact on the microbiome composition, to create an ideal profile for an athlete’s diet. Regardless of your level of commitment to performance, continue to train/be physically active as research has shown the beneficial impacts of exercise on the gut microbiome and its diversity. Finally, take antibiotics only when necessary as they negatively affect the diversity of the gut microbiome. Those mice in the study we cited above? Another one of the groups was given two weeks of antibiotics, effectively wiping out their gut microbes. As a result? They also struggled with their endurance running. 

Beth Peterson RD, CSSD, LDN is a Registered Dietitian and Board Certified Specialist in Sports Dietetics. She holds a Bachelor’s Degree in Nutrition from Penn State University where she ran cross-country and track and field. In addition to working as a Core Diet dietitian, Beth is the Operations Director and Head Coach for The Run Formula, the run-only sister company of QT2 Systems.