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How athletes can overcome digestive issues

Gastrointestinal (GI) complaints are common among athletes, particularly in those who compete in endurance sports.

Causes of GI complaints among athletes vary from blood flow and gut permeability to the posture of the athlete or the repetition of high impact mechanics (such as those suffered by marathon runners). Nutritional causes also have a major role to play.

Likewise the effects and severity of complaints are highly individualised and range from nausea and belching to more serious symptoms. One thing is clear however, GI complaints have the potential to, and do have a negative impact on performance.

Avoiding GI Complaints - Nutritional Interventions


It may seem like common sense, but you must start your race or training well hydrated. If you are not well hydrated your digestive system will not function properly and this can aggravate GI symptoms.

Reduce your fibre intake

Fibre plays an important role in keeping you regular, however in the run up to race day, and indeed during an endurance event it is advisable to avoid foods that are high in fibre. High fibre intake in the run up to endurance events can increase bowel movements which leads to fluid loss, and has been linked to a higher prevalence GI complaints.


The digestive tract is home to trillions of bacteria and it is important to maintain a healthy balance of good or 'friendly' bacteria. Probiotics help to repopulate friendly bacteria which in turn help to aid digestion and nutrient absorption. Probiotic yogurts are well known for containing probiotic cultures but they can prove to be expensive. At Team Sky we instead choose to use Healthspan Elite's High Strength Probiotic which provides 20 billion friendly bacteria per capsule.

Fruit and vegetables

Everyone knows that achieving five portions of fruit and vegetables a day is important to ensure that you are getting all the nutrients that you need from your diet.

What is less well known is the role that alkaline forming fruit and vegetables have in reducing acidity in the gut. Blood pH has a slightly alkaline range 7.35-7.45, and when more alkaline forming foods are introduced into the diet urine becomes slightly more alkaline indicating that less acid needs to be removed from the blood. Smoothies are a great way to increase your intake of fruit and vegetables. The riders on the Grand Tours will also take Healthspan Elite Performance Greens which we supported in development, to contain an abundance of alkaline forming ingredients.

Understand what works for you

The last thing you want is to be caught out on race day. During training experiment with different pre-race meals, supplements and fuelling strategies to find out what works best for you.

Dr James Morton SENr is a professor of exercise metabolism and nutrition at LJMU and Head of Nutrition for Team Ineos. He has authored over 120 research publications in the fields of sports nutrition, physiology and metabolism, as well as numerous books.

Find out more about Professor James Morton.

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Nothing beats a healthy, balanced diet to provide all the nutrients we need. But when this isn’t possible supplements can help. This article isn’t intended to replace
medical advice. Please consult your healthcare professional before trying supplements or herbal medicines.