Ing. Elisabeth Schön, MSc

The influence of sports on our gut flora

The foundation of a healthy intestine and a strong immune system is a fit body and vice versa. A healthy intestinal flora indirectly promotes our physical performance. In return, exercise has a positive influence on the composition of the gut bacteria in our digestive tract. Find out, how you can use sports to promote your gut health and what your intestines need so that your body can stay fit.

Microbiome and sports

Univ.-Doz. DDr. Barbara Prüller-Strasser*

The intestinal flora, also known as the microbiome, is comprised of all the microorganisms that inhabit our intestines. Many studies show that the composition of our intestinal flora has a big impact on the barrier function of the intestinal mucosa and therefore our immune system. If the balance between the helpful and the harmful bacteria is disturbed, the barrier function, as a consequence, is weakened. This means that our gut bacteria play a central role in our immune defence. The intestines and immune system are therefore firmly associated with one another.

The human intestine is inhabited by a variety of bacteria during birth and shortly afterwards. Food especially has a big effect on the population of a baby’s intestine: Breastfeeding leads to the proliferation of lactic acid producing Bifidobacterium and Lactobacilli. The lactic acid produced by these microorganisms creates a slightly acidic pH-value in a child’s intestine and therefore makes it difficult for pathogenic bacteria to colonise.

Even your diet as an adult makes a big difference to the quality of your intestinal flora. In addition, sports is proven to have a positive effect on the microbiome. In that way, sports can positively influence the quality and quantity of wholesome intestinal inhabitants. On top of it all, the immune system is strengthened. „An intact microbiome is essential for our immune system. Evidence shows that sports can increase the amount and diversity of gut bacteria“, confirms Univ. lecturer DDr. Barbara Prüller-Strasser, scientist in the areas of prevention, diet and health at the Medical University of Innsbruck. „Sport stimulates the production of antibodies and can lead to a local increase of anti-inflammatory enzymes in the intestines.“ On the other hand, a weakened intestine results in a weakened immune system, which again has a negative impact on physical performance.

Restraint leads to a healthy gut

Consistent and moderate activity has an anti-inflammatory effect on our bodies. According to Prüller-Strasses, it is the only sustainable habit that can prevent inflammatory diseases such as atherosclerosis, reduce obesity and avoid the resulting diseases such as metabolic disorders and gastrointestinal complaints.

„Repeated, intensive workout sessions as well as overtraining, however, can have an adverse effect on the immune function and result in a higher risk of developing diseases“, explains the expert. This leads to a decrease in the activity of phagocytes, the body’s own scavenger cells – and even the number of antibodies in the mucosa decreases substantially after exercise. For a short period, the body is especially susceptible to bacteria and viruses. Due to this so-called Open-Window-Effect, hobby and professional athletes have an increased risk of infection up until 48 hours after physical exercise, especially in their upper airways.

Für den Aufbau der Muskelzellen ist unter anderem die essentielle Aminosäure Tryptophan erforderlich. Diese ist die Proteinquelle wie Puten- und Rindfleisch, Fisch und Eiern oder auch in Walnüssen und Kürbiskernen enthalten.

When digestion causes problems

Physical exercise is always accompanied by a greater turnover of oxygen and food, as well as an increased perfusion of the used muscles. During physical activity, the muscles take the needed blood from other organs such as the digestive tract, which leads to digestive complaints. „A lack of fluids during endurance training can have a negative effect on the intestinal resorption of foods and digestion due to the decreased blood flow“, explains Prüller-Strasser.

The intestinal mucosa, above all else, takes most of the strain after an intense workout as it increases the permeability. This means that pathogenic microorganisms and other harmful particles can easily pass through the intestine into the bloodstream and subsequently weaken the immune system.

Probiotics can offer a targeted relief. They take effect directly in the intestines and increase the number of helpful microorganisms. Because the intestine is the biggest immune organ in the human body, it (probiotics) can have a positive effect on the immune system. „Probiotic supplements, which usually contain 10^10 colony producing units, can improve the barrier function of the mucosa and reduce the occurrence, severity and duration of infections in the upper airways and digestive tract“, clarifies Prüller-Strasser.

Sports evidently has a positive effect on the gut flora. Probiotics also increase the number of helpful microorganisms in the intestines.

The role of tryptophan in muscle regeneration

Tryptophan also plays a big role in the immune reaction, where it is needed for the synthesis of proteins. During any inflammatory process in our body and especially in our intestine, this essential amino acid is desperately needed. As a consequence, the distribution of pathogenic agents or the growth of malignant cells can be reduced. The use of tryptophan is, therefore, an integral part of the defence mechanism. During an intense workout, inflammatory reactions in our bodies occur, which is why athletes have an increased degeneration of this amino acid.

Tryptophan is also needed for the synthesis of serotonin, the so-called „happiness hormone“. If too much tryptophan is broken down, either due to excessive sport or an inflammation in the intestines, the production of serotonin can be reduced. This can, in turn, reduce memory performance or lead to depression.

Tryptophan, however, isn’t only needed to counteract pathogenic agents and malignant cells, but also to build healthy, normal cells such as our muscle cells. While doing exercise, tiny tears develop in the muscle cells which are responsible for the famous sore muscles. In order to repair these injuries, our body needs plenty of tryptophan. Athletes, therefore, have a higher demand for this essential amino acid. It has to be supplied through the intake of food because the body can’t produce any at all. Tryptophan can be found in food sources such as turkey, beef, fish and eggs as well as walnuts and pumpkin seeds.

Achieve your ideal weight with your microbiome

Sports brings joy and regular exercise can free up your mind – for whatever which reason we practise sports, the pleasurable effect is that we reduce our amount of body fat. But not only exercise alone, but also the intestine contributes to a healthy and ideal weight. According to Prüller-Strasser, there is convincing evidence that the composition of the bacteria in the intestines has a big influence on our body type: Studies show that „good“ bacteria in our intestines have a direct impact on our body weight or, more specifically, the amount of body fat.

The balance between the Firmicutes and their antagonists, the Bacteroidetes, is especially responsible for a stable weight. We gain weight if the balance is shifted towards the Bacteroidetes. They are, so to speak, the bacteria that make us fat. The composition of the intestinal microbiome even influences our appetite.

Physical activity can have a positive influence on the ratio between Firmicutes and Bacteroidetes and therefore prevent being overweight. This doesn’t mean, however, that you should neglect your food. „An energy balance, enough glycogen stores, fatty acids as well as sufficient protein and micronutrient intake are the best prerequisites for a healthy intestinal flora and a functional immune system“, concludes Prüller-Strasser. Even the intake of selected probiotics can contribute to a balanced ratio of intestinal bacteria.

*Univ.-Doz. DDr. Barbara Prüller-Strasser, scientist in the areas of prevention, diet and health at the Medical University of Innsbruck.

Tips against sore muscles

Sore muscles aren’t a result, as earlier thought, of an accumulation of lactic acid in the muscles but rather a consequence of small tears in muscle tissue, so-called micro traumas. Thanks to the consequent inflammation, water invades the tissue and cause oedema. After 24 hours, the body starts to dispose of the inflammatory substances which then come into contact with the surrounding nerve cells and trigger the pain.

How to prevent sore muscles:

A proper warm-up lowers the risk of physical strain
Focus on protein-rich foods directly after training, especially branched chained amino acids (valine, leucine, isoleucine) which have the best effect.
Cold showers or baths (5-15°C) directly after training can prevent muscle soreness

What can I do if it’s too late?

Gentle massages with extensive effleurage can improve blood flow. Caution: vigorous massages prolong the recovery!
Warmth in the form of a bath, sauna or mud treatment (Fango-Packages) can ease the pain.
Ginger and turmeric have anti-inflammatory and pain-relieving properties and can accompany your food.

The foundation of a successful workout

Before the workout

Stay focused on your goal: Remember why you started training and what you are training for.
Drink plenty of water – even before your workout!
Fill up your glycogen stores: Make sure you eat enough carbohydrates an hour or two before training.
Wear the right clothes: It can still be quite cold in spring, make sure to wear warm clothes when doing sports outdoors so as not to catch a cold.

This is what the intestine needs

A balanced diet is the best prerequisite for a healthy intestinal flora and helps maintain or lose weight.
Eat plenty of antioxidative vitamins and polyphenols from plants in the form of fresh (and colourful) fruits and veggies.
Vitamin D: Supply your body with enough Vitamin D in summer by going out into the sun and in autumn and spring by taking food supplements.
Helpful gut bacteria in the form of highly dosed probiotics can support the immune system and prevent digestive complaints.

After the workout

Take off sweaty clothes immediately to prevent infections
Stretching can help make the used muscles flexible and supple.
Electrolytes and minerals can be taken to rectify the deficit that was created through sweating.
Taking sufficient protein up to half an hour after a workout supplies the muscles with the necessary building blocks.