A new paper by the International Society of Sports Nutrition (ISSN) suggests probiotics for increased athletic performance, recovery, and heath.
We’ve known about microorganisms in our guts for a long time. For over 100 years, we’ve hypothesized that we could change the species of organisms in our gut to improve our health. But only recently have we realized that a specific microbiome could enhance athletic performance.
Will exercise-enhancing live microorganisms be the next big thing in athletic supplementation? It is a very exciting idea.
According to the ISSN, probiotics can improve immune system functions and reduce GI distress, including increasing gut permeability.
The research review is particularly interesting to athletes because it shows that a person’s gut microbiota composition, or how many and of what type of microorganisms live in the gut, depends on the level of exercise and the amount of protein consumption.
That’s right—athletes have different microorganisms living in their gut than sedentary people.
Without understanding what we’ve already discovered about probiotics, the review by the ISSN can sound like a fantasy.
Below are some fascinating facts about probiotics to help make sense of the complex relationship athletes have with their microorganisms.
What are probiotics?
So, what are probiotics, anyway? The answer to that question, or at least how you interpret the answer, depends on how much you know about your microorganisms. Yep, I said your.
Your microorganisms are as unique as your fingerprint.
It’s worth the rabbit-hole to understand your microbiome. Some enthusiasts claim that we have so many living microorganisms in and on our bodies that to be “human” is really to be “a superorganism whose metabolism represents an amalgamation of microbial and human attributes.” (Gill)
To fully appreciate probiotics, first, we need to be aware of what role microorganisms, like probiotics, play in our health.
Microorganisms, or microbes, consist of single-celled organisms like bacteria, archaea, fungi, and viruses. All of the microbes in and on your body are collectively called the human microbiota or the microbiome (often used interchangeably).
In 2012, researchers published the human microbiome, the first catalog of all the parasitic, commensalistic, and mutualistic microorganisms that call your body home.
They identified 10,000 species in and on your body, many of which have never been seen before.
Researchers likened it to a new frontier. Lita Proctor of the National Institutes of Health, who's leading the Human Microbiome Project, told NPR "The human we see in the mirror is made up of more microbes than human.” (Stein)
According to the National Institutes of Health (NIH) estimate, 90% of cells in the human body are bacterial, fungal, or otherwise non-human. (Turnbaugh, et al.)
The human gut is a hotspot for life and contains around 40,000 bacterial species, 9 million unique bacterial genes, and 100 trillion microbial cells. (Frank, et al.) (Yang, et al.)
To be clear, the millions of microorganisms that live in and on your body aren’t all on your side. For example, some of those microorganisms are harmful viruses and bacteria (like Staphylococcus aureus).
But for most, their relationship with you isn’t always black and white, good vs. evil.
Others, like those in the genus Klebsiella or species like Enterococcus faecalis and E. coli are benign in the gut, but cause major infection if they get into a wound or other opening in your body.
Still, others are only a problem if they rapidly reproduce and dramatically increase in numbers (called “blooming”).
Harmful or helpful, benign or dangerous, one thing is certain: our relationship to our microorganisms is complex and interwoven.
And when you consider just how much life your own body supports, you start to wonder, what can they do for me?
Getting to know your microorganisms: Who’s who?
People have a microorganism fingerprint. Literally. Samples taken from hands show that each person has a unique mix of pathogens.
Researchers found that each participant housed 3,200 different species of bacteria, with only five species found on every participant.
It’s theorized that your microbial fingerprint begins at birth.
During pregnancy, a mother’s microbiome is optimized for an infant, leading researchers to believe that we get much of our microbiome during birth.
Your microbiome stabilizes around 3 years old, but as you age, factors like diet, environment, exercise, and how often you take antibiotics continue to refine your microbiome. (Davis)
We’re beginning to understand to what effect diet and exercise can change your microbiome.
Athletes tend to host greater biodiversity and host more health-promoting bacteria, which in turn, make them better equipped for top performance.
According to the ISSN, athletes have “functional capacity that is primed for tissue repair and a greater ability to harness energy from the diet with increased capacity for carbohydrate, cell structure, and nucleotide biosynthesis” (Barton).
The athlete’s superior gut microbiome is likely due in part to regular, strenuous exercise paired with diet.
According to the ISSN, exercise can do amazing things. Exercise can:
- Enrich microbiota diversity
- Increase the Bacteroidetes-Firmicutes ratio
- Stimulate the proliferation of bacteria which can modulate mucosal immunity
- Improve barrier functions
- Stimulate bacteria capable of producing substances that protect against GI disorders (Jager)
But it’s important to remember that your microbiota composition relies on more than just exercise. It also depends on what you eat.
As the article points out, it’s hard to separate the effects of diet from exercise because they are so intertwined.
For example, athletes generally eat different foods compared to sedentary populations. They also eat these foods in different amounts and at different times.
What we do know is that diets high in protein, carbs, and dietary fiber all create a unique microbiota, which seems to be further refined by exercise. For now, diet and exercise aren’t easily separated.
Research-backed benefits of probiotics for athletes
Whether you get your microbiome from diet or exercise (or more likely, from a combination of the two), it does appear that your microorganisms can do amazing things for you.
Research suggests that probiotics can:
- Increase the absorption of nutrients in your gut
- Improve immune system functions
- Improve gut-barrier function
- Act as an anti-inflammatory
- Improve overall health
So, how exactly can your microbiome help you perform at your highest level?
Probiotics may expedite muscle recovery
The ISSN reports that the research on probiotics and recovery is promising.
Probiotics can expedite muscle recovery during resistance training.
One study of 10 subjects supplemented 20 g of protein with the probiotic Bacillus coagulans for 8 weeks.
Participants followed a resistance training program that intended to increase vertical jump power. Indeed, the probiotic group outperformed the control (Georges).
A follow-up study found that Bacillus coagulans increased recovery and decreased soreness after single-leg resistance training (Jager).
Probiotics may improve immune system functions
Athletes can struggle with their immune system. Overtraining, psychological stress, lack of sleep or poor sleep can all decrease immunity.
So what does that have to do with your gut? As the ISSN points out, “approximately 70% of the immune system is located in the gut.”
And it appears that probiotics can improve immune response.
Certain probiotics can reduce the number, severity, and duration of upper respiratory tract infections (URTI).
The ISSN analyzed 22 studies on probiotics and immune health. 14 of them showed significant improvement and 8 showed no effects.
One study looked at 465 active people with an average activity load of about 6 hours per week. Researchers looked at two different probiotic groups vs the control for 150 days. One strain showed a 27% reduction in URTIs. (West)
Probiotics may improve GI function
Long endurance events can cause nausea, cramping, bloating, vomiting, and diarrhea. Exercise-related GI distress is likely caused by the redistribution of blood from the gut (where it’s needed for digestion and absorption) to the skin to help cool the body.
GI distress can reduce the absorption of nutrients, cause discomfort, and decrease performance.
Out of the 10 studies on GI health and probiotics, only four reported positive results. Six reported no effect. But all might not be lost.
As the authors point out, there were many variations in the studies, including strain of bacteria, dose, duration, and participants. The studies that reported improvements showed a decrease in GI episodes, among other factors.
Probiotics may improve general health, including body composition and mood.
The following benefits of probiotics need much more research to be conclusive but are worth noting.
According to the ISSN, early human research shows a correlation between probiotics and the following benefits:
- Improved body composition, including increased lean body mass
- Normalized age-related decline in testosterone levels
- Reduction in cortisol levels (improved response to stress)
- Reduction of exercise-induced lactate
- Increased cognitive function
- Anti-inflammatory benefits
While more research is needed, it appears that we are only beginning to understand what our guts can do for us. And because of the incredible amount of biodiversity in our bodies, we may be able to pick and choose which probiotic we’d like to increase.
Scientists have already identified strains of probiotics and their reported benefits. For a list of strains related to human health, read the ISSN review.
Where can I find probiotics?
Probiotics are available in foods like yogurt and sports bars. They are also found in capsules, tablets, and powers.
However, as the review notes, not everything labeled “probiotic” will have the desired result.
Health benefits are extremely dose and strain-dependent.
Furthermore, even though a specific strain may improve health, simply ingesting a few times may not be enough for the bacteria to take.
Look for brands that list the strain and dose of probiotics on the label.
Matt Mosman (MS, CISSN, CSCS) is a research scientist, endurance athlete, and the founder and Chief Endurance Officer at EndurElite. Matt holds his B.S. in Exercise Science from Creighton University and his M.S. in Exercise Physiology from the University of California. Matt and his family reside in Spearfish South Dakota, where they enjoy running, mountain biking, camping, and all the outdoor adventures Spearfish has to offer.
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