Runners Immune Health: A New Perspective

March 23, 2023

Runners Immune Health: A New Perspective

Many runners experience illness and infection, especially upper respiratory tract infections and digestive illness and concerns. These issues can lead to time away from running, or at least a reduced training load until fully recovered, which can be frustrating.

There appears to be significant developments in the approach to supporting an athlete’s immune health nutritionally, so here we outline the current scientific thinking on this subject.

We give you:

    1. An overview of the potential paradigm shift in optimising an athlete’s immune health
    2. An introduction to the nutritional influence in supporting this paradigm shift
    3. Some ideas of how to introduce the nutritional recommendations into your meal plan

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Runners Immune Health: A New Perspective


Outlining the key paradigm shift with regards to immune health and athletes and discussing the new and current scientific thinking.

The paradigm shift involves the concept of immune resistance versus immune tolerance: 

Immune resistance – is the established approach to supporting immune health, and it continues to be relevant whereby diet and/or dietary supplements are utilised to counter an apparently weak immune system

Immune tolerance – is the paradigm shift which focuses on the beneficial interactions between pathogens and the immune system. In other words, the immune system’s ability to tolerate or “endure” microbes, yet, control infection at a non-damaging level.

By focusing on immune tolerance, it is thought that more targeted nutritional supplementation could be used in helping reduce the infection burden in athletes, because the body would be able to endure the microbes. It is thought that this approach could be more beneficial than using nutrition to help the body fight any infection occurring.

At the moment, this new perspective in immune health is theoretical, however, it is gaining ground and the research into this area is ongoing.



See Below


Delving into the nutritional influence in supporting this paradigm shift in immune health of athletes.

The key nutrients of interest include:

  • Protein
  • Probiotics
  • Vitamin C
  • Vitamin D


Amino Acids (the building blocks of protein) are required for the production of many infection fighting proteins such as immunoglobulins and cytokines therefore a low protein status could mean increased risk of infection severity. It is recommended that as you age, your protein intake should increase therefore aim to have between 1.2g-1.6g per Kg of body weight per day.


The role of Probiotics is to help facilitate homeostasis of the beneficial bacteria within the intestinal microbial family. Remember, approximately 70% of the immune system is contained within the gut.

Probiotics (live microorganism) and prebiotics (providing fuel for the microbes) through supplementation are thought to have tolerogenic effects on the immune system through their ability to influence the microbes within the gut as well as the intestinal/mucosal (barrier) immune system.



Vitamin C is found in high concentrations in leucocytes (white blood cells that fight infection), however levels fall dramatically during a common cold (or other infection).

It has been proposed that vitamin C supplementation could improve immune tolerance by reducing the risk of excessive tissue damage during infection.

Additionally, Vitamin C levels are also known to be low in the presence of oxidative stress (an imbalance between the production of free radicals and the antioxidants to neutralise them) and heavy training alone can lead to increased oxidative stress!! This increase in Oxidative Stress is known to increase the risk of URTIs!!

Studies have shown that by increasing Vitamin C intake via supplementation in athletes, it reduces the risk of an URTI developing.


In recent years research has determined that Vitamin D has a close association with immune health and this is because Vitamin D Receptors are expressed on many immune cells including: T-cells and B-cells.

Regarding immune tolerance, it is thought that an adequate Vitamin D status may help prevent any overly lively immune responses following T-cell activation. In turn, this could lead to a reduction in severity and length of any infection including URTIs.


TIPS on introducing Probiotics and Vitamin C into a regular meal plan


  • Research suggests a daily intake of approximately 1010 live bacteria per day for at least 28 days.
  • Strains to include: Lactobacillus Fermentum, Lactobacillus Casei Shirota and Bifidobacterium
  • This has been found to shorten the duration of and reduce the severity of a URTI
  • If you are considering a probiotic supplement consult with a qualified practitioner
  • It important that you choose a probiotic to suit your personalised health requirements including contraindications with medications
  • Probiotic supplements may be used as a therapeutic tool, however it’s very important to include probiotic and prebiotic foods as a regular part of your food plan. Here are some suggested foods:
  • Kimchi and sauerkraut
  • Tempeh
  • Miso
  • Cultured milk and yogurt – including Kefir
  • Kombucha – fermented green tea
  • Pickled foods for example: gherkins, onions, capers


Food sources include:

  • Citrus fruits: Orange, Grapefruit, Lemon, lime
  • Berries: Black Currant, Strawberries
  • Tropical Fruits: Kiwifruit, Papaya, pineapple, Mango, Guava, cantaloupe melon
  • Green leafy/Cruciferous vegetables: Broccoli, kale, parsley, brussels sprouts, spinach, watercress
  • Red and green peppers, tomatoes
  • Offal – liver


  • Cooking and exposure to oxygen can reduce the vitamin C content of food by up to 25%
  • Where appropriate eat these foods raw or gently cook/steam to preserve nutrient value
  • Eat a rainbow of colourful fruits and vegetables every day and follow the suggestion of ½ plate of vegetables or salads at each meal (equates to 7-9 portions) and 2 portions of fruit per day to help maintain adequate vitamin C status
  • Including these foods regularly in the diet could be an excellent way of maintaining Vitamin C levels if levels are already adequate
  • If levels are diminished for whatever reason, for example: infection or oxidative stress, then supplementation may be required.
  • Consult with a Nutritional Therapy Practitioner to determine the correct supplement and dose for your individual needs
  • Remember high dose vitamin C supplementation may could lead to blunting of training adaptations. Current recommendations are to ensure any supplementation is taken at least 2hrs prior or post endurance exercise to try to avoid any blunting effects



It is advised to have vitamin D levels tested regularly, approximately twice a year. Then, depending on the test results, engage with a Nutritional Therapy Practitioner who can recommend appropriate vitamin D supplementation

Vitamin D testing is relatively inexpensive and can be performed at home

Here at Runners Health Hub we have the details of some recommended testing companies in our SHOP on our website: Click on the SHOP button on the tool bar on the righthand side of the home page then scroll down to Our Favourite Nutritional Screening Tests

Female Factors

Runners Immune Health: A New Perspective

Two recent studies carried out on female athletes showed that approximately HALF of them were classified as having low energy availability (LEA). This LEA appeared to be associated with a 4-8 times higher risk of developing an upper respiratory tract infection (URTI). It must be stressed that it was an association with, rather than a causation of an URTI. BUT it does suggest that LEA may be a risk factor for reduced immunity and infection.


Runners Immune Health: A New Perspective

  1. The current scientific thinking about immune health in athletes is shifting from the concept of immune resistance to the idea of immune tolerance
  2. Focusing on immune tolerance it thought to mean more targeted nutritional supplementation could be used in reducing the infection burden in athletes
  3. Regarding immune tolerance in athletes, the current nutritional focus is on Protein, Probiotics, Vitamin C and Vitamin D
  4. Introducing adequate amounts of foods containing these nutrients/microbes into your meal plan on a regular basis may be sufficient to maintain already adequate levels
  5. BUT…if insufficiency or deficiency in any of these nutrients/microbes are present then nutritional supplementation may be required
  6. Finally, we recommend you work with a qualified practitioner when considering nutritional supplementation as requirements and suitability of supplements needs to be personalised

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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.

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