Trillions of bacteria live in a community in your gut and this is called the gut microbiota. The community of bacteria, along with their genetic material is the gut microbiome. The balance between good and bad bacteria can affect many processes within the body. Achieving balance in this community is achieved through eating a healthy, balanced diet with enough fibre. Combining eating the recommended amount of fibre (30g per day) along with exercise has the greatest effect of the gut microbiome.
Benefits of fibre
Fibre provides many long and short-term benefits to digestive and cardiovascular health which include:
Slows macronutrient absorption in the small intestine
This leads to a more gradual release of energy (figure 1), important during training and competition. A fast release of energy from food would cause a sudden fall in energy available during exercise and results in fatigue. Foods with a lower glycaemic index (GI) due to a higher fibre content lead to a slow release of their energy by the body over time. This provides you with energy over a longer time period to fuel your training or competition.
Figure 1. The blood glucose response depends on the Glycaemic effect of food and how quickly energy is released from foods you eat. The blue line represents high GI foods and the orange line represents low GI foods.
Blunting of the insulin response
Reduces absorption of carbohydrates in the small intestine. Suggested that it maintains insulin sensitivity within athletes in the long term.
Delays gastric emptying and small intestinal transit time, Ileal Brake mechanism
Increases movement through the GI tract to decrease constipation or can reduce diarrhoea.
Fermentation of dietary fibre produces short chain fatty acids (SCFAs)
By feeding the microbes in your large intestine you also increase the amount of energy available to other metabolites. Prebiotic fibre should account for 17% of your total fibre intake (5g/day). This is because it is fermented by microbes in the large intestine. The metabolites produced are SCFAs. There are three main SCFAs propionate, butyrate and acetate that have functions in maintaining gut health.
Prebiotics feed the probiotic bacteria that already exists within your gut. Prebiotics are a type of fibre but not all fibre is prebiotic fibre. It can be found in some foods such as onions, garlic, leeks, Jerusalem artichokes, asparagus and bananas. However, surveys suggest that in the UK, only a third of us eat enough overall fibre and so supplementing your diet with prebiotics may be advisable.
Overall eating fibre can help you to maintain gastrointestinal health!
Nutrition tips to increase your fibre intake
- Both meals and snacks should contain some fruits and vegetables
- Try to opt for wholegrain carbohydrates and nutrient-rich snacks
- Snacks can contain fibre: oatcakes with peanut butter, fruit smoothie with milk and banana, baked beans with wholemeal toast, rye crispbread with low fat cheese and grapes, vegetable sticks and houmous, unsalted nuts and seeds, malt loaf.
Prebiotic Fibre supplements
The gut microbiome is thought to be essential in the adaptive processes that your body makes in response to exercise.
Exercise can have a positive effect on the gut microbiome. However, intense training and high protein diets can lead to gastrointestinal symptoms that may cause discomfort or effect performance and training ability.
When adequate amounts of fibre (including prebiotic fibre) cannot be achieved through the diet alone, a supplement such as Bimuno® should be considered.
Bimuno® is certified by Informed Sport. This means that each batch produced is tested for banned substances by LGC’s world-class sports anti-doping laboratory. This can be ordered from our website.