Dr. Dwayne Jackson

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M&F: Gut Health for Gains

Vital Science Gut Health

Gut Health for Gains


Dwayne N. Jackson, PhD


In the quest for lean muscle gains, gut health is often overlooked. High protein diets containing very little variety, very low fibre, and lack of micronutrient-dense foods currently rule the fitness landscape—setting up many fitness enthusiasts and athletes for gut health issues down the road. The scientific literature backs this notion.



As a health specialist, year after year I see exponentially increasing numbers of very fit individuals and pro athletes coming to me for help with symptoms of poor gut health caused by diets lacking these essential gut-healthy components.


Signs that you have gut health issues:


  1. You have symptoms of irritable bowel syndrome (IBS) like abdominal pain, bloating, and issues with bowel movements (constipation, diarrhea, or a combination)
  2. You have food sensitivities (not to be mistaken with allergies) which cause gas, bloating, abdominal pain, and diarrhea. Recent research has linked the development of food sensitivities to microbial dysbiosis, which triggers immune responses and subsequent inflammation
  3. You feel generally inflamed, tired, and foggy-headed
  4. You have recently experienced unexplained weight gain


Your digestive tract is your personal food processor, keep it running smoothly!

If you are focused on building muscle, then you should do everything in your power to optimize your gut health. After all, a healthy digestive tract assures you are processing, digesting, and absorbing all the nutrients from the food you consume.


This becomes most important when we are looking to build a lean muscular physique, as poor gut health means poor absorption of nutrients, increased inflammation, and immune system compromise.


Good gut health requires maintaining dense and diverse gut microbiota.


There are an estimated 100 trillion microorganisms in your body. These bacteria, known as microbiota, inhabit your skin and all your body’s orifices. However, most of these microbes reside in your digestive tract.


Maintaining a diverse, dense, and healthy balance of gut bacteria is essential to quality of life, as a robust microbiota plays a crucial role in maintaining your overall well-being, including muscular health.


When gut bacteria become imbalanced, a condition known as dysbiosis, they frequently cause intestinal inflammation by turning on immune system processes that promote inflammatory signalling. This low-grade inflammation can cause increased intestinal permeability, also known as “leaky gut syndrome”.


A lack of microbial diversity in the gut sets the stage for inflammation.


In leaky gut syndrome, inflammatory endotoxins like lipopolysaccharide ‘escape’ the digestive tract and circulate in the blood, this leads to systemic inflammation— a condition that promotes muscle atrophy (muscle loss), weakness, and damage to muscle fibres, not to mention a plethora of health issues.


Studies indicate that harmful opportunistic microbes such as E. coli and B. fragilis activate the immune system and trigger inflammatory responses when there is a lack of diversity among the various strains of beneficial bacteria. In fact, scientists have discovered that chronic inflammation-related diseases are frequently accompanied by gut dysbiosis.


Gut-Muscle Axis


The gut microbiota interacts with our muscles. Through this interaction, gut health plays a significant role in muscle function via its role in inflammation, immunity, energy metabolism, and insulin sensitivity. As a result, one’s state of gut health is related to their exercise performance and state of well-being.


In the gut, non-digestible fibres are fermented by our colonic microbiota. This fermentation process produces short-chain fatty acids (SCFAs) acetate, propionate, and butyrate. In humans, regular exercise increases also SCFA production, which is associated with enhanced physical performance.


The majority of SCFAs are absorbed through the digestive tract and contribute to energy metabolism. Colonic epithelial cells largely utilize butyrate as an energy source. In addition to being digested in muscle tissue, acetate can also penetrate the blood-brain barrier to improve cognitive performance. Furthermore, the liver can utilize propionate as a precursor for glucose production.


In addition, SCFAs increase the integrity of the intestinal barrier, hence minimizing the risk of local and systemic inflammation caused by a leaky gut. Strong evidence from preclinical investigations suggests that SCFAs may be important modulators of physical performance.


The Association Between Exercise, Muscle, and the Gut Microbiota Composition


Human exercise studies indicate that regular physical activity modulates the composition of the gut microbiota and, conversely, the gut microbiota play an important role in physical performance.


Overall, the composition and metabolic activity of gut microbiota aids in the digestion of foods and improve energy utilization during exercise, which provides metabolic benefits for athletes during high-intensity exercise and recovery. Studies demonstrate that the metabolic activity and pathways associated with amino acid and carbohydrate metabolism are more efficient in those with healthy gut microbiota compared with those who are sedentary and/or have gut health issues.


Want to improve your gut health? Here are 3 simple science-backed things you can do today to get started:


  • EAT MORE FIBRE: The body digests most types of carbohydrates (like sugars and starches) into absorbable simple sugars that we use as energy. On the other hand, fibre passes undigested through to the large intestine where it adds bulk to stool and, in the case of fermentable fibre, becomes food for the beneficial bacteria that colonize the gut. Fermentable types of fibre are called prebiotics. Although fibre has numerous proven health benefits, very few people meet their daily fibre requirements.


Foods with high fibre:

    • whole grains (whole wheat products, oats, barley, popcorn, wild rice, etc.)
    • legumes (beans, lentils, peas, edamame)
    • nuts/seeds (chia seeds, flaxseed, pumpkin seeds, almonds, pistachios, walnuts, etc.)
    • Most fruits and berries
    • And Most vegetables


Daily fibre intake targets:

MEN- greater than 38 g per day

WOMEN- greater than 25 g per day


When aiming to improve your fibre intake, use many different fibre sources and introduce them slowly. It’s also vital to keep track of how much water you’re drinking. If you eat extra fibre but don’t drink enough water, your stools will become overly dry, which will cause or worsen constipation. To avoid this, make sure to drink 3-4 litres of water daily.


  • CONSUME PREBIOTIC DIETARY POLYPHENOLS: Like fibre, compounds from food called polyphenols also nourish the gut microbiota. Because, like fibre, many dietary polyphenols are minimally absorbed in the small intestine, so they make their way to the large intestine intact where they are utilized by intestinal microbes to produce SCFAs.

Polyphenols are natural compounds found in berries, fruits, vegetables, grains, herbs, and spices. These polyphenols give foods their colour and taste and protect them from oxidative damage. They offer a multitude of health benefits, including support for the microbiome. Polyphenols are healthy for the entire body, as their potent antioxidant effects decrease oxidative stress in our cells. If you are sensitive to foods high in fermentable prebiotic fibre, a diet high in polyphenols provides prebiotic benefits and may be better tolerated.


  • CONSUME AN ABUNDANCE OF PROBIOTIC FOODS: Probiotics are good bacteria that we consume with food or as supplements. They help establish and support colonies of healthy bacteria that reside in the intestines. Research tells us that probiotics decrease leaky gut, reduce inflammation, improve immunity and symptoms of dysbiosis, recover metabolic health, and increase exercise performance.


Probiotics do not have to come from supplements. In fact, unless you are dealing with severe dysbiosis, I suggest getting your probiotic bacteria from daily frequent consumption of:

    • Organic (sugar-free) grass-fed yogurt and kefir
    • Pickled and fermented vegetables like organic sauerkraut or kimchi
    • Organic sourdough bread
    • Drinks like kombucha


Here’s an example of how to significantly increase your probiotic consumption throughout the day:

    • 200g of kefir in the morning
    • 3 tbs of organic sauerkraut with lunch
    • 250 ml of kombucha midafternoon
    • A slice of organic sourdough bread and 3 tbs of kimchi with dinner.



Belkaid, Y. & Hand, T. (2014). Role of the microbiota in immunity and inflammation. Cell, 157(1), 121-141.

Buford, T.W. (2017). (Dis)Trust your gut: the gut microbiome in age-related inflammation, health, and disease. Microbiome, 5, 80.

Caminero, A., Meisei, M., Jabri, B., & Verdu, E.F. (2019). Mechanisms by which gut microorganisms influence food sensitivities. Nature Reviews. Gastroenterology & Hepatology, 16(1), 7-18.

Casas, R., Sacanella, E.,. & Estruch, R. (2016). The immune protective effect of the Mediterranean diet against chronic low-grade inflammatory diseases. Endocrine, Metabolic, & Immune Disorders Drug Targets, 14(4), 245-254.

Ferreira, C.M., Vieira, A.T., Vinolo, M.A.R., Oliveira, F.A., Curi, R., & Martins, F. (2014). The central role of the gut microbiota in chronic inflammatory diseases. Journal of Immunology Research, 2014, 689492.

Przewłócka K, Folwarski M, Kaźmierczak-Siedlecka K, Skonieczna-Żydecka K, Kaczor JJ. (2020). Gut-Muscle AxisExists and May Affect Skeletal Muscle Adaptation to Training. Nutrients. May 18;12(5):1451.

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