Emily Brown

Written by Emily Brown


How to Add Probiotics to the Runner’s Dietary Plan: Understanding the Microorganism-Athletic Connection

In today’s world, where just about every hand soap and cleaning product you buy says “anti-bacterial,” where we are taught to store and cook food to eliminate bacteria, and where antibiotics are a frequently prescribed to treat certain illnesses, it seems logical that we would perceive most bacteria as harmful.

But some bacteria types actually make us healthier and could reduce the incidence of some frequently occurring health issues that runners encounter.

Beneficial vs. harmful bacteria

Trillions of bacteria exist in the body, some of which are considered “bad” and others that are “good.”

Bad bacteria can cause illness, while good bacteria can improve digestion and enhance the immune system.

The goal is to maximize the good and force out the bad bacteria. This can be achieved in several ways, the most prominent being the use of prebiotics and probiotics.

What are probiotics?


Definition: “Microbial foods or supplements that can be used to change or re-establish the intestinal flora and improve the health of the host.”

What they do: Probiotics directly repopulate the intestinal tract with beneficial organisms.

Since antibiotic therapy kills both good and bad bacteria, probiotics are often taken concurrently to replace the beneficial organisms.

Probiotics can also enhance intestinal health in the following ways:

  • Good bacteria can inhibit the overgrowth of bad (pathogenic) bacteria by competing for attachment sites and life-supporting nutrients.
  • Good bacteria produce organic compounds that decrease the intestines’ pH level and inhibit the growth of pathogenic bacteria, which are sensitive to acid.

Where to get them: Probiotics are mainly found in fermented dairy products, like live-culture yogurts and kefir.

When buying yogurt, look for the phrase “live and active cultures” and a low sugar content on the label.

One of the most reliable and widely available brands is Dannon-Activia yogurt and DanActive drinks, the benefits of which have been backed by a number of peer-reviewed journal studies.

Probiotics can also be found, to a lesser extent, in other fermented foods like unpasteurized sauerkraut, miso and tempeh.

Remember that high temperatures are more likely to destroy bacteria; if the food has been heated, it has probably lost the bulk of its cultures and health benefits.

Probiotics can also be taken as supplements in capsule, tablet, liquid or powder form. Some of the most trusted brands include Align and Culturelle.

When choosing a supplement, keep these things in mind:

  • Look for a supplement that contains at least 1 billion CFUs (colony forming units) per serving.
  • Find a brand that contains both Lactobacillus and Bifidobacterium — these are the most common probiotic types.
  • Ensure the cultures remain active — store them in a cool place and watch the expiration date.

Prebiotics: The probiotic companion nutrient

Definition: “Nondigestible food products that stimulate the growth of symbiotic (relying on the host for nutrients) bacterial species already present in the colon.”

What they do: Unlike probiotics, prebiotics are not live bacteria, but insoluble fibers that ferment rather than digest in the intestinal tract and give beneficial organisms nutrients and a fertile environment. In other words, they help create a comfortable living environment that makes the good bacteria want to stick around.

Where to get them: Prebiotics are mainly found in unprocessed, fibrous and carbohydrate-rich foods including:

  • Raw chicory root, Jerusalem artichoke, and asparagus
  • Bananas
  • Wheat, oats, rye, and barley
  • Onions, leeks, and garlic
  • Legumes and soybeans
  • Honey and flax

Some food manufacturers fortify products with prebiotics, giving them added health benefits.

To see if a product has added prebiotics, look for one or more of the following terms on the label:

  • FOS (fructo-oligosaccharide)
  • Polydextrose
  • Lactulose
  • Lactitol
  • Inulin

Keep in mind prebiotic foods are typically highly fibrous and if added to your diet too quickly, gas, bloating, constipation and stomach cramps are potential side effects. Add them gradually and drink plenty of water.

Benefits relevant for runners

“Synbiotics” is a terms that describes when enough probiotics and prebiotics are consumed together to benefit health optimally. For a runner, the most important result is enhanced immune function.

As described earlier, the organisms in the intestines naturally compete for nutrients and attachment sites. A higher level of beneficial bacteria means fewer harmful, infection-causing microbes survive, reducing the incidence and duration of the intestinal and upper respiratory tract infections that runners seek to avoid.

The results of a 2010 controlled-trial published in the British Journal of Sports Medicine showed that elite male distance runners that used probiotics during training reduced the severity and duration of respiratory illness.

Probiotics also have positive effects on the GI system, which can be very beneficial for a runner who finds himself taking frequent pit stops.

Activia has demonstrated constipation relief, and you can also use probiotics to prevent and alleviate diarrhea, particularly during a course of antibiotics when the disorder is likely to occur.

Lactose intolerance is also improved; sufferers have reported an easier time digesting yogurt.

Finally, probiotics improve the GI tract’s ability to absorb nutrients, particularly iron, calcium, and magnesium — essential nutrients for a healthy runner’s dietary plan.

Essential notes

Not all bacteria are bad! As evidenced above, adding more good bacteria to your diet could make a huge difference in your ability to train harder, longer, and healthier.

You can start today by consuming 1-2 servings of “live active” yogurt each day and backing it up with insoluble fiber-rich foods and plenty of water.

And of course, continue to protect yourself from the bad bacteria by washing your hands, properly storing and preparing your foods, and keeping your guard up around people who are ill.


Mahan LK, Escott-Stump S (2004). Krause’s Food, Nutrition, and Diet Therapy, 11th ed. Philadelphia, Pennsylvania: Elsevier.De Paula JA, Carmuega E, Weill R. Effect of the ingestion of a symbiotic yogurt on the bowel habits of women with functional constipation. Acta Gastroenterologica Latinoamericana, 2008; 38(1):16-25.

Cox AJ, Pyne DB, Saunders PU, Fricker PA. Oral administration of the probiotic Lactobacillus fermentum VRI-003 and mucosal immunity in endurance athletes. British Journal of Sports Medicine, 2010; 44(4):22-226.

Kekkonen RA, Vasankari TJ, Vuorimaa T, Haahtela T, Julkunen I, Korpela R. The effect of probiotics on respiratory infections and gastrointestinal symptoms during training in marathon runners. International Journal of Sport Nutrition and Exercise Metabolism, 2007; 17(4):352-363.

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4 Responses on “How to Add Probiotics to the Runner’s Dietary Plan: Understanding the Microorganism-Athletic Connection

  1. While I for one fully support our bacterial overlords, I’ve always been faintly suspicious of “probiotic” claims, for the simple reason that there are a vast number of types of bacteria in our guts, and it’s not at all clear to me that the handful of types commonly found in these foods and supplements are necessarily sufficient. For a fascinating look at this in the New Yorker, see http://www.newyorker.com/reporting/2012/10/22/121022fa_fact_specter?currentPage=all

  2. Any thoughts on probiotics surviving the acidity of the stomach? There are many brands and claims, some suggesting enteric coated pills, others saying their bacteria strains are resistant and can survive, making it to the intestines after passing the harsh stomach environment. Timely article for me. In the middle of a Z-Pack post sinus/ear infection. Looking to make sure my flora is tip top after.

    • Different brands will contain different bacteria. You want to choose a strain or strains that are effective for your infection type. I don’t know very much about specific products or how they work. Some bacteria are acid-resistant but I don’t know which strains these are and if they are effective. I’ve read from some sources that the enteric coating or capsules doesn’t work but others that say it does. Sorry I can’t be of more help. I would do a little research to find a trusted brand that has some scientific backing to its claims (not always easy to find with dietary supplements).

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