The Microbiome and Your WOD

There are as many bacterial cells inside you as human ones. It’s time to start thinking about how your microbiome affects your WOD, and how your WOD affects your microbiome.

(Unit 1 of 7)

In CrossFit, when we think about community, we’re usually talking about our box, our instructors, and our fellow fire breathers. But there is another deeply personal, unseen community along for each and every one of your WODs—one that plays a vital role in your workout and your systemic health. It’s called your microbiome. 

Your body is not just composed of muscle, skin, fat, and organ cells. You are also home to an interconnected, incredibly diverse system of microorganisms—many of which are bacteria, but also viruses, fungi, and other single-celled organisms called archaea. The majority of these microbes live inside your gut, but they also reside pretty much everywhere else in your body, like your skin, your mouth, your nose, and your armpits. These microscopic residents comprise different biomes within your body: ecosystems all their own, where tiny organisms that have lived inside you all your life, and that adapted to live inside your ancestors long ago, go about their existence. 

Your microbiome is not a minority. In fact, a recent study shows that the bacterial component alone makes up just as many cells in your body as the human ones—a roughly 50/50 split. That’s roughly 38 trillion (!) bacteria.

Those 38,000,000,000,000 bacterial symbionts (organisms co-existing alongside our human cells) and their metabolites (substances important for cellular processes) are connected to almost every function in the human body. Microbes help break down the food you eat and facilitate the production of vitamins B and K. They produce neurotransmitters that stimulate muscle contractions and help you poop. They help to protect your skin. They create mucus that protects your intestinal lining and “biofilm” that protects your oral cavity from pathogens. They even interact with your central and autonomic nervous system through what scientists call the gut-brain axis.

Your microbiome is unique to you. It’s also constantly in flux, affected by external factors like diet, exercise, alcohol, and sleep. Your WOD performance can be no different and can be intricately linked to your invisible workout partners.  

The Microbiome and Your Workout

A Brief Glimpse at Microbes and Your Workout

Which is all to say: Your microbiome is important to your systemic health. Fantastic. But how exactly should we go about understanding the connection between our microbes and our WOD? Here are a few examples of how understanding your microbiome can help improve your CrossFit workouts and your whole-body health. We’ll address each of these issues on a deeper level in upcoming units.

Minimizing Acute Leaky Gut

The epithelial lining of your small intestine covers more than 4,000 feet of surface area and, unsurprisingly, plays an important role in digestion and absorption. When it’s not working correctly, your gut lining is more permeable, allowing pathogens and pro-inflammatory molecules to enter your bloodstream. Scientists and medical professionals call this problem of increased permeability “Leaky Gut Syndrome.” Unfortunately, a number of studies have shown that 60 minutes of endurance exercise, or just 30 minutes of resistance exercise, can cause acute gut leakiness—which may partially explain why athletes who work out longer and harder have an increased risk of symptoms like cramps, diarrhea, bloating, nausea, and bleeding. Implications on long-term health remain unclear, but in the shorter term, the connection is clearer: increased intensity and/or frequency of training increases your body’s (beyond the gut) exposure to potentially dangerous pathogens and pro-inflammatory constituents from native bacteria in your gut. There’s good news, however. Some studies have demonstrated promising benefits for probiotic use in intensively training athletes which might help minimize the negative effects of leaky gut. There is also evidence that probiotic supplementation can beneficially influence intestinal barrier integrity in acute diseases. 

Optimizing Post-Workout Eating

In 2013, researchers at Maastricht University in the Netherlands studied 24 young men who ingested protein immediately after a single bout of resistance exercise. Alongside clinical signs of damage to the small intestine in line with leaky gut syndrome, they noted that dietary protein digestion and absorption rates were decreased when compared to the test subjects’ protein digestion and absorption without the workout. “Resistance-type exercise induces small intestinal injury … causing impairments in dietary protein and absorption kinetics during the acute postexercise recovery phase,” the researchers wrote in a resulting paper. This appears to be the first evidence suggesting  that eating immediately after such exercise was suboptimal. But post-workout protein remains vital for the delivery of protein-derived amino acids, which are important for muscle damage repair and reconditioning. What does this mean for your post-workout eating routine and “nutrient timing”? Can probiotics help? When and what should you eat after a workout? We’ll discuss further soon.

Debunking Lactic Acid and other Short-Chain Fatty Acids

Lactate and lactic acid have long been stigmatized as metabolic waste products and fatigue agents produced during any type of moderate to intense muscular work. Even though such “dogma” reigns strong and loud, decades of evidence tell a different story. Abundant research shows that lactate is readily produced by your body (mostly skeletal muscle, from the unavoidable use of carbohydrate/glucose as a fuel), both at rest and during exercise. More importantly, a variety of studies show it can be used as a metabolic and brain fuel during exercise, and does not cause the “burn” you feel on your last rep of dumbbell front-rack lunges. Instead, the “lactate shuttle theory” describes the role that lactate plays as an important messenger molecule in a complex feedback loop during exercise and recovery. Additionally, lactic acid (producing) bacteria (LAB) have been found to act as probiotics (that is, live microorganisms that confer a health benefit to their host) within important metabolic pathways in your body — including the production of  short chain fatty acids (SCFAs), which are produced by gut probiota when they break down fiber and trigger anti-inflammatory cells. SCFAs support your body’s metabolism, immune system, and can be used as fuel by both gut cells and muscle cells. In short: don’t hate on the lactate. A healthy gut microbiome is your unseen workout partner.

Curiosity is rewarded.

If you are reading this, we have a challenge for you—take this quiz. Correct answers may earn you (what we call at Seed) magic.


About the Author:

Anthony L. Almada, MSc, FISSN is a member of the research and development team at Seed, which develops probiotics to impact human and planetary health. He and is trained as a nutritional and exercise biochemist (UC Berkeley). He has been a co-investigator on over 50 university-based clinical trials exploring the effects of diet, dietary supplements, and therapeutic interventions upon muscle performance, body composition, whole body metabolism, and joint function in health and disease. In 1990 he created the “thermogenic” category. In 1993 he co- founded the first company to introduce creatine monohydrate to North America. He has worked with CF Games and Regional athletes, top Olympic gold medal swimmers, professional cyclists, physique athletes, and NFL teams. He has been part of Seed’s R&D division since late 2018.

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