Gut Microbiome

By Exercise Physiology Brisbane - 17th May 2017

In a recent human cross-sectional study (39 subjects; diet, age and body-mass controlled), VO2peak (cardiovascular fitness) was associated with greater production of butyrate and gut microbial diversity (1). Butyrate helps to regulate sodium, water absorption and the absorption of calcium and other minerals, which is important for endurance exercise (2). In a study of 12 breast cancer survivors (3), gut microbiota diversity was associated with changes in cardiovascular fitness, fatigue and anxiety; participants with greater diversity had better fitness, less fatigue and anxiety. In a study on mice (4), swimming time (endurance) was longer in mice with a more diverse gut microbiota.

With this research in mind, and with cardiovascular fitness being one of the biggest predictors for chronic disease risk and all cause mortality; it's important to know how can we get more butyrate into our diet, and thus achieve a more diverse gut microbiota. Read more about prebiotics and butyrate in our Nutrition as Medicine section.


Prebiotics - improving your gut microbiome 

Prebiotics are a form of fibre; a non-digestible carbohydrate that pass through the gastrointestinal tract and stimulates the growth and acidity of good bacteria in the large intestines (1,2,3). This good bacteria is responsible for many health outcomes (1,2,3). For example, 95% of serotonin is produced within the gut - an unhealthy gut can lead to an unhappy mind (4).

Prebiotics may also assist with (3):

Prebiotics include inulin, galactooligosaccharides (GOS), fructooligosaccharides (FOS) and resistant starch (e.g. unripe bananas, pre-cooked cold potatoes, cold pasta, cold legumes).

A list of other foods can be found in the table below (1):


Jerusalem artichokes, chicory, garlic, onion, leek, shallots, spring onion, asparagus, beetroot, fennel bulb, green peas, snow peas, sweetcorn, savoy cabbage


Chickpeas, lentils, red kidney beans, baked beans, soybeans


Custard apples, nectarines, white peaches, persimmon, tamarillo, watermelon, rambutan, grapefruit, pomegranate.  Dried fruit (eg. dates, figs)

Bread / cereals / snacks

Barley, rye bread, rye crackers, pasta, gnocchi, couscous, wheat bran, wheat bread, oats

Nuts and seeds

Cashews, pistachio nuts, psyllium


Human breast milk, acacia fibre (sap from Acacia Senegal tree)

How do these prebiotics work? Good bacteria “feed” on prebiotics, such as resistant starch and produce short chain fatty acids; the most significant of which are acetate, butyrate,and propionate.  

Of these three short chain fatty acids (SCFA), butyrate is extremely beneficial effects on the colon and overall health (2). Butyrate helps to keep toxins in the gut and out of the blood stream.  As a result, this helps to decrease inflammation, obesity and a myriad of other chronic diseases (2).  As discussed previously, butyrate is also associated with cardiovascular fitness!

So, what are you waiting for? Get some more prebiotics and resistant starch foods into you. Five grams/day is recommended for prebiotics (out of a total of 25 gram per day of fibre for females and 30 grams for males). There are prebiotic supplementations to assist, such as: Prebitoin (3). If you're wanting to learn more about this, a good starting point is the book: 'Gut' by Giulia Enders (4).

Further reading and sources of the above information: