Training Nutrition - Probiotics to Improve Your Athletic Performance


Training hard is a crucial part of a winning athletic strategy, but a proper endurance training nutrition plan can help you with your performance.

Training Nutrition - Probiotics to Improve Your Athletic Performance

Table of contents

  • What are probiotics?
  • Types of probiotics
  • What are prebiotics
  • The best time to take probiotics and dosage
  • Side effects
  • Benefits of probiotics for endurance athletes
  • Probiotics and fatigue after prolonged endurance exercise training
  • Upper respiratory tract infections in endurance athletes
  • Intestinal disorders in endurance athletes
  • Practical Tips

Did you know that our body’s entire surface in contact with the external environment is covered with microbes? Many bacteria, viruses, fungi live in symbiosis with the human body. The best example is our immune system; if the balance between the gut microbiota and our body is disrupted, it can result in inflammation, changes in metabolic processes, and lead to many diseases. But not only that, it can lead to an uncontrolled reproduction and growth of harmful bacteria, causing a wide variety of infections.

Newborns have an utterly sterile gastrointestinal tract until the first breastfeeding when the colonization of the gut occurs. In other words, the mother passes its healthy bacteria to the child. One strain’s predominance occurs through the interaction of antibodies and prebiotics in breast milk with environmental microorganisms. And that is precisely what makes the gut microbiota nearly unique for each person, something like our fingertips.

Most people associate microbes with something negative, but that is far from the truth. There are also good microbes that are an integral part of the human body. We give them a safe environment rich in nutrients, and they contribute to the maintenance of our homeostasis.

Maintaining this balance is essential, as even a small disturbance could have a negative impact on your athletic performance. For this reason, probiotic supplements and foods are increasingly present in the diet of athletes. But what are probiotics exactly, and how do they work?

What are probiotics?

Probiotics are live microorganisms that have beneficial effects on our health when administered in adequate quantities. To be considered a probiotic, a microbe needs to be isolated from a human, survive after being ingested, reach our intestine, and have a beneficial interaction with our body.

The concept of probiotics was born in 1908 when Nobel laureate Elie Metchnikoff hypothesized that the longevity and good health of the Bulgarian farmers are linked to high consumption of fermented foods like milk. In fact, all fermented foods are naturally rich in probiotics.

What do probiotics do?

  • help us digest carbohydrates
  • synthesize vitamin K and some group-B vitamins
  • improve our immune system
  • work in symbiosis with our cells to prevent intestinal permeability and let the harmful bacteria enter our bloodstream
  • Types of probiotics?

    Probiotics usually contain the two most common groups of bacteria:

    1. Bifidobacteria (includes strains like animalis, breve, infantis, longum, adolascentis, lactis and bifidum)
    2. Lactobacilli(includes strains like acidophilus, casei, johnsonii, reuteri, rhamnosus, salivarius, plantarum, crispatus)

    Sometimes probiotics can contain yeasts like Saccharomyces boulardii. The researchers noted that this particular yeast could be useful in controlling diarrhea and other common gastrointestinal symptoms

    What are prebiotics?

    Prebiotics are a type of soluble dietary fiber that stimulates the growth and development of the beneficial bacteria present in the human gut.

    The concept and the study of prebiotics began in the 1990s, as scientists aimed to provide specific nutrients to the intestinal “good”bacteria, to stimulate their growth. They found several beneficial properties of Lactobacilli strains, but they also encountered difficulties in making them resist gastric pH. With a trial and error method, they found optimal nutrients to stimulate the growth and development of beneficial bacteria that managed to survive the hostile conditions of the gastric environment.

    An excellent example of a natural prebiotic is Jerusalem artichoke. It is one of the few plants in which there is an abundant quantity of inulin, ranging from 50 to 75% of the dry weight. Inulin is a soluble prebiotic fiber, and therefore it supports the development and growth of gut microbiota.

    Best prebiotic foods

    • Onions and garlic
    • Bananas
    • Apples
    • Spinach
    • Asparagus
    • Dandelion greens
    • Leek
    • Oats
    • Cocoa

    The best time to take probiotics and dosage

    There are still no well-defined protocols given the small number of studies. Here are the current recommendations for athletes:

    • The most used species are L. casei, L.fermentum, L.acidophilus, and L.rhamnosus.
    • Dosage varies between 1 to 10 Billion CFU.
    • The intake period varies between 4 and 16 weeks and should start at least seven days before the competition or intense training period.
    • Probiotics should be taken remotely from competitions to evaluate the reactions of the athlete.

    As probiotics are live microorganisms, they must survive the gastric pH to reach the large intestine. When we eat, our stomach secretes gastric acid in significant amounts. Even smelling or thinking about food can initiate the vagal stimulation of the cells that secret gastric acid. But on an empty stomach, the pH is lower (more acidic). That is why you should take probiotics during a meal, to be sure that the gastric acid will affect the path of bacteria as little as possible.

    Side effects of probiotic supplements

    Studies conducted to date suggest that probiotic supplements are generally safe. However, mild side effects may occur in the first few days after you start the supplementation.

    Benefits of probiotics for endurance athletes

    Training hard is one of the crucial parts of a winning athletic strategy, and it should be as important as recovery. You already know that proper nutrition and optimal sleep quality both affect your performance and recovery. But they can also be influenced by your gut microbiota. Training makes the composition of the microbiota in athletes different from the rest of the population, diverse and more efficient. But prolonged and intense endurance exercise can have a deleterious impact on the intestinal tract and immune system.

    Researchers are continually conducting studies to discover how probiotics bring health benefits to endurance athletes, what kind of benefits, and possible side effects.

    There are still many questions to be answered, and many theories to be proven. But until now, studies have reported promising results of probiotic intake in athletes like.

    • Reduction of respiratory infections, with significant improvement in symptoms;
    • Improved immune system (lymphocyte activity) inexhausted athletes;
    • Reduction of gastrointestinal symptoms;
    • Improvement in antioxidant plasma levels, which reduce the adverse effects of oxidative stress;
    • Improved recovery from muscle-damaging exercise;
    • Decreasing the perception of fatigue during and after training/competition.

    An optimal physical condition, which includes good gut health, is one of the prerequisites for achieving successful athletic performance. Probiotics seem to be among the few useful tools you have to prevent some health issues that could affect your performance.

    Studies that have examined the effect of probiotics on endurance athletes are still insufficient to draw definite conclusions and set up clear guidelines.

    Until now, researchers were able to prove that some specific probiotic strains can reduce the frequency, severity, and duration of several gastrointestinal symptoms, upper respiratory tract infections, and possibly fatigue.

    Recent studies have shown that probiotic supplementation (S. thermophiles) can positively affect the modulation of muscle inflammation, facilitating the recovery phase.

    Probiotics also seem to significantly improve the absorption of nutrients, boosting your energy levels.

    Probiotics and fatigue after prolonged endurance exercise training

    Only one study reported clear ergogenic effects of probiotics in terms of increased fatigue resistance, which may also be due to an improved immune system.

    Researchers documented how supplementation for four weeks with a probiotic capsule (containing Lactobacillus, Bifidobacterium, and Streptococcus) in ten runners resulted in a delayed onset of fatigue compared to the period when those runners were not taking probiotics.

    Upper respiratory tract infections in endurance athletes

    Viral infections of the upper respiratory tract are the most common health conditions in endurance athletes. A common cold or a sore throat is not a big deal for the general population as the symptoms rarely interfere with daily tasks. For endurance athletes, the symptoms of a “simple” viral infection can have significant consequences.

    A prolonged period of intense physical activity can result in a transient depression of the leukocyte function. Not only, lack of sleep, inadequate nutrition program, and stress can also lead to an increased risk of infections. That means that your immune system does not work at its best, and pathogens could take hold, causing you to face an onset of symptoms with a significantly negative impact on your progress and performance.

    Encouraging results emerged from several studies. Let take a look at some:

    1. This study reported a reduction in the number of days with upper respiratory symptoms by more than 50% in 20 healthy elite male distance runners taking L. fermentum. Also, the administration of this probiotic was associated with a significant reduction in the severity of symptoms.
    2. In this study, the researchers noted a reduction in the incidence of upper respiratory infections in endurance athletes with the supplementation of fermented milk (L. casei). No changes in the severity of symptoms were noted. Eighty-four highly active individuals were enrolled in this study, randomized to placebo and probiotic groups.

    Despite some conflicting data and not entirely clear mechanisms for some strains, the probiotic supplements can be considered good support for athletes’ immune system.

    Intestinal disorders in endurance athletes

    Studies reported that endurance athletes are often subject to gastrointestinal disorders, presenting one or more symptoms of different severity. These symptoms usually include nausea, vomiting, abdominal swelling and cramps, diarrhea, and, in severe cases, even intestinal bleeding.

    These symptoms can sometimes lead to long-term health problems, force you to abandon the competition or reduce your athletic performance.

    The origin of gastrointestinal disorders induced by harsh training and competitions is multifactorial.

    What exactly happens to your gastrointestinal tract during the competition or endurance training?

    The recall of blood at the musculoskeletal level causes the redistribution of blood flow. Insufficient blood supply to the gut can lead to transient bowel ischemia in athletes. The intestinal barrier becomes weak, and the permeability increases. When this happens, help from probiotics can make a difference.

    Probiotics can compete with pathogens and reinforce the adhesion between enterocytes. One of the enterocyte cells’ primary function is absorbing molecules from the gut and transferring them to the bloodstream and the surrounding tissues. They act as a passive barrier. If the barrier gets weak, pathogens can pass easily to the bloodstream, causing infection.

    Practical Tips

    • Before running to the pharmacy to get probiotic supplements, you should get your gastrointestinal function and the state of gut microbiota evaluated. If you don’t present gastrointestinal symptoms during training and competition, or suffer from recurrent respiratory infections, you can continue with your athletes nutrition plan without adding probiotic supplements. Remember that a balanced diet is the key to a healthy body, and a proper nutrition plan is the best tool you have to reach peak performance.
    • Single-strain probiotics have shown significantly lower efficacy than mixed formulations. Have this in mind if you decide to take supplements.
    • A varied diet low in sugar and processed foods supports the development of balanced gut microbiota.
    • Fiber-rich foods promote microbial diversity andthe growth of many gut microbiota species (see prebiotic foods).
    • You should consume fermented foods such as yogurt, cultured buttermilk, kefir, miso, and kimchi.
    • It is best to take probiotic supplements about 30 minutes before or during a meal. Avoid taking probiotics with acidic foods and hot drinks.

    In sum, due to a lack of studies, there are still no clear guidelines or protocols relating to probiotics and athletic performance in endurance athletes. But the potential benefitson the immune system, gastrointestinal tract, and athletic performance reported in the studies to date are very encouraging.

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