SPOTLIGHT ON...........Probiotics for Performance - She Runs Eats Performs

Episode 78

Published on:

25th Nov 2021

SPOTLIGHT ON...........Probiotics for Performance

 SPOTLIGHT ON....Probiotics for Performance

 Are you aware that Probiotics, in the form of food and/or nutritional supplementation, may support your running performance?

It is well known that Probiotics have the ability to enhance general health through modulation of the immune system and maintaining intestinal barrier integrity as well as by limiting pathogen adhesion to host tissue BUT a lot less is known about 

Probiotics potential to enhance exercise performance. Research in the area of Probiotic use as an ergogenic aid in sport and exercise performance is relatively new, but growing especially linked to athletes and their Gastrointestinal health and Immunity. BUT research is also looking at Probiotics linked to specific aspects of exercise and performance including recovery, physical fatigue, and body composition. 

So here we:

  • Delve into the effects of Probiotics on athletic performance
  • Discuss the different types of Probiotics (Food and Supplements)
  • Give advice on choosing Probiotics



Understanding Probiotics and What They Are

In our digestive system (and other parts of the body, but primarily the digestive tract) reside many different microbes that are both helpful and potentially harmful. This is known as an individual’s Microbiome – each person’s microbiome being unique to them. 

Most microbes (also known as microbiota) are symbiotic meaning both the human body and microbiota benefit. BUT some, in smaller numbers can be pathogenic (promoting disease). 

In a healthy body, pathogenic and symbiotic microbiota coexist without problems. BUT if there is a disturbance in that balance—brought on for example by an infectious illness, a certain eating style/diet choice, or the prolonged use of antibiotics or other bacteria-destroying medications then DYSBIOSIS (imbalance of the microbiota) occurs, stopping these normal interactions. 

As a result, the body may become more susceptible to illness/disease, primarily immune related disorders as 70% of the immune system resides in the digestive tract.  

Probiotics (which can be taken in the form of food or nutritional supplements) are micro-organisms that are widely considered to be health-promoting. Both the World health Organisation (WHO) and the International Olympic Committee (IOC) state: “Probiotics are live micro-organisms that when administered orally for several weeks can increase the numbers of beneficial bacteria in the gut. These have been associated with a range of potential benefits to gut health, as well as modulation of immune function”.

In the general population research into Probiotics has determined their ability to enhance health in many different ways including:

  • Modulation of the immune response
  • Maintenance of the intestinal barrier
  • Limiting pathogen adhesion to host tissue
  • Production of different metabolites such as vitamins, short-chain fatty acids (SCFAs), and other molecules that act as neurotransmitters involved in gut–brain axis communication and health

BUT the research into Probiotics and their effects on sports and exercise performance is much more limited.   


What is the research saying about Probiotics for Exercise Performance?

Recent research has indicated that probiotic supplementation could promote specific improvements in exercise performance through various pathways in athletes and physically active individuals using targeted strains of probiotics. The research appears to be focusing on Probiotics in athletes in relation to Gut health and Immunity but also particular aspects of exercise and performance including:

  • Recovery
  • Physical fatigue
  • Body composition

In the International Society of Sports Nutrition (ISSN) Position Stand on Probiotics published in 2019 they reported that those who are highly physically active tend to have:

  • A higher abundance of health-promoting bacterial species
  • Increased microbiome diversity 
  • Greater increase in faecal metabolites including Short Chained Fatty Acids (SCFAs); acetate, propionate, and butyrate. These SCFAs being important for colon health, metabolic processes and vitamin and energy production 

 It would also appear that physical activity could help:

  • Increase the ratio of different beneficial bacteria species (Bacteroides:Firmicutes ratio)
  • Stimulate the proliferation of bacteria which can support mucosal immunity 
  • Improve barrier functions – thinking of the intestinal barrier 
  • Stimulate bacteria capable of producing substances that protect against GI disorders.

This data suggests that physical exercise alone could really help support an individual’s gut microbiome, however this would be moderate exercise only because it is well known that endurance exercise and/or overreaching/overtraining could affect the Gut and the immune system negatively leading to symptoms/illnesses including:

  • Abdominal cramping
  • Acid reflux (heartburn)
  • Nausea/vomiting
  • Diarrhoea
  • Intestinal Permeability
  • Upper Respiratory Tract Infection (URTI)
  • Urinary Tract Infection (UTI)

Interestingly, one of the potential benefits of introducing probiotics in an athlete is due to Probiotics ability to modulate the immune system to help increase defenses against URTIs. 

Another potential benefit of Probiotics for an athlete is linked to the fact that the microbiome may have indirect influence on different aspects of exercise performance and recovery. So, it is thought that the use of Probiotics could help modulate the microbiome to promote overall good health, exercise adaptation, increased VO2 Max and overall training load/performance. The mechanism of action of Probiotics to achieve this outcome is thought to be the downregulation pro-inflammatory molecules and upregulation of anti-inflammatory molecules. 

BUT more research is required to fully determine the use of Probiotics as a potential Ergogenic Aid. 


Types of Probiotic Supplements Available

Probiotics come as either a single or multi strain supplement and all have strain-specific differences in their ability to colonise the Gastrointestinal Tract BUT the type and magnitude of benefits to health also differ between different population groups, including between men and women. 

In research both single and multi strain Probiotics have shown mixed results. The most commonly used ones in research include:

  • Lactobacillus - strains include: L Fermentum, L Gasseri, L Caei, L Plantarum, L Acidophhilus and L Rhamnosus
  • Bifidobacterium – strains include: B Animalis, B Subtilis

They also use the genus:

  • Streptococcus
  • Bacillus

According to the ISSN Position Stand (2019) it would appear multi strain Probiotic supplementation is more effective in exhibiting enhanced sports performance. Some research results have indicated:

  • Increase in VO2 Max
  • Increase in aerobic power
  • Increased in training load
  • Increased time to exhaustion

BUT, it is important to remember that some other studies have not found such an effect.


FOOD FIRST approach for a healthy microbiome

You may not be aware that fermented foods such as sauerkraut and kimchi are not actually currently classed as Probiotics…although they DO contain live microbes. The reason for this is because these products have not been sufficiently studied for their health benefits as stipulated by the definition of probiotics. BUT it is well know that these foods contain live cultures/microbes therefore they could still support our running performance as well as our overall health.  

Other foods falling into this category of fermented foods include:

  • Tempeh
  • Miso
  • Cultured milk and yogurt – including Kefir
  • Kombucha – fermented green tea
  • Pickled foods e.g. gherkins, onions

A nutrient well known for its beneficial effects on an individual’s microbiome (rather than being a probiotic itself) is Carbohydrate. It is the wholegrain/complex carbohydrate and fruits and vegetables that are beneficial because of the fibre contained within them, which is associated with microbial abundance and/or diversity. A great reason to EAT A RAINBOW and switch to BROWN rather than WHITE carb products for everyday great health and running performance. Aim to do this CONSISTENTLY.

It is also thought that Protein could be a strong modulator of the gut microbiota in athletes with Whey protein being the protein source of choice. BUT research into this is novel and has yet to be carried out on humans. Hopefully these studies will be carried out in the near future. 



  1. GENDER could be a factor in the inconsistencies in study results. One study noted reduced severity of self-reported symptoms of lower respiratory illness and use of cold and flu medication over an 11-week winter training period with Lactobacillus Fermentum supplementation compared to placebo. BUT this reduction in severity of symptoms was only observed in the MEN not the WOMEN. So, the question is…is this linked to the Probiotic being more effective in Males OR could it be linked to the self-reporting? An interesting question.
  2. There appears to be some limited evidence to suggest that discrepancies exist between males and females regarding outcomes following Probiotic supplementation, even after supplementation of probiotics with the same dose. 

It is clear that future studies are needed with the view of establishing a Probiotic recommendation for each sex.


Key points to consider when choosing a Probiotic supplement

REMEMBER the FOOD COMES FIRST approach for general and sporting health. Introducing some of the fermented foods and complex carbohydrate foods mentioned before could be a great place to start. 

When considering a probiotic supplement consider working with a professional to determine the correct one for you and your health and running goals. Remember everyone has a unique microbiome, therefore the probiotic strains required could differ too. Also, there are many different Probiotic products available all claiming to have health and performance benefits. It is a bit of a minefield, so working with a Professional could help take the confusion out of the decision making.

Additionally, certain Probiotics could have adverse effects in some individuals including:

  • Systemic infection
  • Detrimental metabolic effects
  • Adverse immune responses

They are definitely NOT recommended for individuals with health conditions including:

  • Severe acute pancreatitis
  • IBD
  • Liver disease
  • HIV

Some other points to consider:

The different forms they come in: 

  • Capsule/tablet form 
  • Powder sachets
  • Liquids

How you take them is a personal choice. 

Remember they come in single and multi-strain varieties 

Do they need to be refrigerated or not? When making a choice consider your lifestyle - if you travel a lot or need to take your supplement whilst at work then a non-refrigerated variety would be most suitable. 

There are a few minor digestive side effects that may occur when first taking a Probiotic supplement including:

  • Flatulence
  • Rumbling tummy

It is suggested Probiotic Supplementation should be taken for a minimum of 14 days

REMEMBER, overall Probiotics are viewed as safe for the general population (as described by the European Food Safety Authority) 



1) The word Probiotic, is derived from the Latin “Pro” meaning “for” and the Greek word “biotic’ meaning “life”….so…probiotics are “FOR LIFE”

2) Probiotics are micro-organisms that are widely considered to be health-promoting. 

3) Current research indicates that probiotic supplementation could promote specific improvements in exercise performance through various pathways in athletes….using targeted strains of probiotics.

4) Some of the exercise benefits include:

  • Increase in VO2 Max
  • Increase in aerobic power
  • Increase in training load
  • Increased time to exhaustion

5) Commonly used Probiotic Supplements in exercise performance studies include:

  • Lactobacillus  - strains include: L Fermentum, L Gasseri, L Caei, L Plantarum, L Acidophhilus and L Rhamnosus
  • Bifidobacterium – strains include: B Animalis, B Subtilis
  • Streptococcus
  • Bacillus

6) Fermented Foods may also be supportive, however they cannot be called Probiotic Foods as there has not been sufficient research into their use in Athletes. 

7) There are many things to consider when choosing a Probiotic supplement including:

  • What form you want to take it e.g. capsule or powder
  • Refrigerated or non-refrigerated
  • Single or multi-strain
  • CFU (Colony Forming Units) content

8) Finally, we would recommend working with a professional when considering Probiotic supplementation, especially if you have any underlying health concerns or conditions

Related Topics:

Avoiding Digestive Distress as a Runner

Performance effects of Overtraining Syndrome

Endurance Running and the Immune System


The suggestions we make during this episode are for guidance and

advice only, and are not a substitute for medical advice or treatment.

If you have any concerns regarding your health, please contact

your healthcare professional for advice as soon as possible.

Aileen Smith and Karen Campbell met at as nutrition students (Institute for Optimum Nutrition, London) and became lifelong friends and nutritional buddies! Both have a love of running and a passion for nutrition, delicious food and healthy living.

Together they host RUNNERS HEALTH HUB. A place for like-minded runners who are looking for simple ways to support running performance, energy, endurance, and general great health.

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About the Podcast

She Runs Eats Performs
for mid-life female runners of all abilities
Are you confused about the science around nutrition for runners? Listen in to learn about the WHY, HOW, WHAT, and WHEN of eating to fuel your running performance.

We are here to help you translate sports nutritional science, into easy to apply tips and plans, helping you enjoy peak running performance. We focus on the FEMALE FACTORS every mid-life woman needs to know to be a healthy runner.

About your host

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Aileen Smith

Nutritionists, Educators, Podcasters, Runners and Friends

We have a love of running and a passion for nutrition, delicious food and healthy living. She Runs Eats Performs for female runners of all abilities who are looking for simple ways to improve their running performance and their health with nutrition and lifestyle.
We enjoy sharing our nutritional expertise, reviewing the latest sports science and most of all helping you to take easy action so you can enjoy your running life to the full.
We are here to help you achieve great health and good shape whilst staying injury-free with easy-to-understand sports nutritional concepts and easy-to-implement tips and plans.

Aileen and Karen are BANT and CNHC Registered Nutritional Therapists.