Probiotics are considered a miracle weapon for intestinal health and a strong immune system. And athletes also benefit from the good bacteria. You can find all the important information about the functions of probiotics and their advantages in our article.

What are probiotics?

Thousands of strains of different types of bacteria populate our entire intestine. They make up the intestinal flora. Some of these intestinal bacteria are probiotics - living microorganisms that supplement and support the natural intestinal flora. They are called lactobacilli, bifidobacteria, enterococci and Escherichia coli, for example. Since these microorganisms are resistant to the acid found in the stomach, they cannot be broken down - and settle in the intestine, where they inhibit the growth of harmful bacteria, fungi and yeasts and maintain the balance of the intestinal flora.

The good bacteria are either found in foods that contain natural probiotics or are enriched with probiotic bacteria through fermentation. Some examples:

• Yogurt : One of the best-known sources of probiotics, yogurt contains live cultures of bacteria such as Lactobacillus acidophilus, Bifidobacterium, and Streptococcus thermophilus.
• Kefir : Fermented milk drink that contains probiotic bacteria, including Lactobacillus and Bifidobacterium.
• Sauerkraut : This is fermented cabbage that naturally contains probiotic bacteria such as Lactobacillus.
• Kimchi: Kimchi is a Korean fermented vegetable dish that contains a variety of probiotic bacteria, including Lactobacillus kimchii.
• Tempeh: This fermented soy product is rich in proteins and probiotic bacteria such as Bacillus subtilis.
• Kombucha : tea drink made by fermentation with a culture of bacteria and yeast containing various probiotic strains.
• Sourdough bread: Made by fermenting dough with wild yeasts and lactic acid bacteria. It may contain a small amount of probiotic bacteria, although the level varies depending on the manufacturing process.

Since a balanced diet cannot always be optimally integrated into our stressful everyday lives, probiotics can also be taken as dietary supplements, which are available as capsules, powder or in liquid form. In addition to a complete amino acid profile, vitamins and minerals, our SYNT Athletic Whey also contains probiotic bacterial strains such as Lactobacillus acidophilus and Bifidobacterium bifidum, which promote digestion and strengthen the immune system. With a high-quality whey protein, you are not only investing in muscle building, but also optimally supplying your intestinal flora.

Probiotics and their benefits for the intestinal flora

Probiotics support the balance of the intestinal flora, improve digestion and promote the processing of food. (1). Furthermore, probiotics can reduce symptoms of gastrointestinal diseases such as irritable bowel syndrome, diarrhea and constipation (2). And those who depend on taking antibiotics benefit from additional probiotic intake. This is because they can reduce the negative effects of antibiotics on the intestinal flora by promoting the growth of beneficial bacteria (3). Some studies also suggest that probiotics regulate body weight, possibly through an influence of the probiotics on metabolism and food intake (4).

Probiotics and their positive effects on the immune system

A large proportion of all immune cells are located in the small and large intestine, which is why almost 80 percent of defense reactions take place here. It is therefore no wonder that the intestine is also referred to as the seat of the immune system . Scientific evidence has already provided proof that probiotics can have a positive effect on intestinal health and the immune system:

• stimulation of the production of immune cells
  Scientists studied the effects of probiotics on the immune defense against infections. They found that probiotics can stimulate the production of immune cells and reduce the release of pro-inflammatory cytokines, leading to improved defense against infections in the body (5).
• strengthening the mucous membrane barrier
  One study examined the effects of probiotics on the intestinal mucosal barrier. The results showed that probiotics, particularly certain strains of Lactobacilli and Bifidobacteria, strengthen the intestinal mucosal barrier and reduce intestinal permeability. This ultimately helps to reduce inflammation and improve intestinal (and therefore immune) health (6).

How do athletes benefit from probiotics?

It has been proven that physical activity has a positive quantitative and qualitative effect on the composition of all microorganisms in our body. As a result, mucous membrane immunity and the barrier function of the intestine improve. At the same time, however, intensive exercise can lead to gastrointestinal complaints. Around 30 to 50 percent of endurance athletes complain of gastrointestinal complaints such as flatulence, abdominal pain, diarrhea, stomach pressure, heartburn or nausea shortly after starting physical activity (7). One of the reasons for this is that the greater the strain on the body, the greater the impact on the gastrointestinal tract. This is because intensive activity redistributes blood in the body. Organs that are not essential for survival, such as the intestine, receive less blood, while the muscles and other important organs - for example the brain and kidneys - receive more of it.

The permeability of the intestines can also increase. This suppresses the immune system (called immunosuppression) and pathogens can more easily enter the bloodstream. This phenomenon is known as the "open window effect". This means that even if intensive exercise increases the immune system in the short term, it drops just as sharply again later during recovery. During this time (the range is from a few hours to several days), the body is particularly susceptible to infections, which can lead to respiratory infections, for example, and downtime. This is annoying not only for professional athletes, but also for amateur athletes. Numerous tests have shown that various probiotics have the potential to successfully buffer these negative effects.

According to scientific studies, athletes were able to achieve performance-enhancing and health-promoting effects by taking the following probiotics (8, 9):

• Lactobacillus plantarum showed a performance-enhancing effect in triathletes, helping to maintain and even increase endurance performance.
• Four weeks of supplementing a so-called multi-strain probiotic containing Lactobacillus, Bifidobacterium and Streptococcus reduced muscle pain and a feeling of heaviness in the legs in rugby players. Runners benefited from increased endurance performance after just a shorter period of use.
• The intake of Lactobacillus gasseri significantly shortened the recovery time of runners.

• Lactobacillus shirota improved the aerobic capacity of badminton players.
• After taking a preparation containing Bifidobacterium, Lactobacillus and Lactococcus for three weeks, the subjects' cardiorespiratory fitness increased significantly, including VO ₂ max in long-distance runners. A slight decrease in substances that trigger inflammatory reactions in the body was also measured. The athletes' body composition (such as total body fat percentage, muscle mass and visceral fat percentage) also changed positively, depending on gender.
• Bacillus subtilis improved body composition in soccer players and volleyball players, depending on the dose taken.
• Strength athletes benefited from a shortened recovery time after taking Streptococcus thermophilus and Bifidobacterium breve for three weeks, and training-related inflammation also decreased.
• After three months of administration of probiotics of the genus Bacillus subtilis, anti-inflammatory properties were observed in baseball players.

From a scientific point of view, it can be summarized that, in addition to the positive effects on the intestinal flora and immune system, the intake of certain probiotics has the potential to improve the performance of athletes, shorten recovery time and reduce training-related inflammation.

Sources:

1: Plaza-Diaz, Julio et al. "Beneficial effects of probiotics on human health: microbiota and gut-mediated pathways." Nutrients vol. 12.1 299. Jan 14, 2020, doi:10.3390/nu12010299.

2: Didari T, Mozaffari S, Nikfar S, Abdollahi M. Effectiveness of probiotics in irritable bowel syndrome: Updated systematic review with meta-analysis. World J Gastroenterol. 2015 Mar 14;21(10):3072-84. doi: 10.3748/wjg.v21.i10.3072. PMID: 25780308; PMCID: PMC4356930.

3: Goldenberg, Joshua Z et al. "Probiotics to prevent Clostridium difficile infection in patients receiving antibiotics." JAMA vol. 312.15 (2014): 1480-4. doi:10.1001/jama.2014.13800.

4: Million, Matthieu et al. "Obesity-associated gut microbiota is enriched in Lactobacillus reuteri and depleted in Bifidobacterium animalis and Methanobrevibacter smithii." International journal of obesity (2005) vol. 36.6 (2012): 817-25. doi:10.1038/ijo.2011.153.

5: Childs CE, Calder PC, Miles EA. Diet and Immune Function. Nutrients. 2019 Aug 16;11(8):1933. doi: 10.3390/nu11081933. PMID: 31426423; PMCID: PMC6723551.

6: Anderson, Rachel C et al. "Probiotics for gut barrier function: Beyond the role of fiber." World journal of gastroenterology vol. 16.2 (2010): 402-14. doi:10.3748/wjg.v16.i2.402.

7: de Oliveira EP, Burini RC, Jeukendrup A. Gastrointestinal complaints during exercise: prevalence, etiology, and nutritional recommendations. Sports Med. 2014 May;44 Suppl1(Suppl 1):S79-85. doi: 10.1007/s40279-014-0153-2. PMID: 24791919; PMCID: PMC4008808.

8: Di Dio M, Calella P, Pelullo CP, Liguori F, Di Onofrio V, Gallè F, Liguori G. Effects of Probiotic Supplementation on Sports Performance and Performance-Related Features in Athletes: A Systematic Review. Int J Environ Res Public Health. 2023; 20:2226.

9: Jäger, R., Mohr, AE, Carpenter, KC, Kerksick, CM, Purpura, M., Moussa, Antonio, J. (2019). International Society of Sports Nutrition Position Stand: Probiotics. Journal of the International Society of Sports Nutrition , 16 (1).