Athletes who train hard are more vulnerable to flu, viruses and infections, but you can galvanise your body’s defences with these immunity-boosting nutritional strategies.

Illness is a serious issue for athletes. Even before Covid-19, UK Sport research suggested a third of missed training sessions are caused by respiratory tract infections, digestive issues or urogenital issues. And the result is always an unwelcome disruption to your training.

The good news is that exercise itself is fantastic for your immunity – unless you overdo it.

“Exercise boosts your circulation by releasing millions of white cells (immune cells) into your blood stream,” explains Professor Gleeson, an expert in immunology at Loughborough University. “But high-volume coupled with high-intensity could depress your immunity.”

Quality sleep and sensible recovery will reduce your risk of ‘immunity burnout’, but your secret weapon in the fight against microbes, viruses and bacteria is your diet.

“A good diet can help to prevent your immune system from failing when you are under stress or doing hard training,” explains Professor Gleeson. 

Nutrition Advice To Boost Your Immune System | Men's Fitness UK

Carbs are crucial to maintaining a healthy immune system

Don’t ditch carbs

Carbs are not your enemy: scoffing a banana or an oat bar during exercise will actually help to protect your immune system.

“A good supply of carbs helps to prevent your blood sugar levels dropping, which could cause a spike in the stress hormones that depress your immunity,” says Professor Gleeson.

“Aim for 40g of carbs per hour of exercise. And try to match your overall energy intake to your overall expenditure each day to avoid any deficiencies.”  

Pump up the protein

Protein builds muscle, but it also aids your immune system. That is why Professor Gleeson says athletes should consume 1.2-1.6g of protein per kg of bodyweight per day, as opposed to the 0.75g recommended for the general population.

“Protein is needed to produce antibodies and multiply the cell lines that will defend you against any pathogen,” he says.

Eat the rainbow

Vitamin C hogs the headlines when it comes to immunity, but Professor Gleeson says athletes really need a broad spectrum of nutrients to optimise their immunity.

For example, the vitamin E in cereals can prevent infection, while the vitamin B12 in meat aids the production of white blood cells.

“The best strategy is just to aim for colourful plates in order to get a good mix of the 46 essential nutrients,” he says.

As a sample meal plan, he suggests fruit with wholegrain cereal for breakfast; a mushroom, tomato and onion omelette for lunch; and steak with peppers, squash and leafy greens for dinner.

“Colourful fruit and veg contain polyphenols and flavonoids, some of which have anti-inflammatory and antioxidant effects, which increase your tolerance to microbes.”

On the supp

Professor Gleeson also flags up compelling new research on immunity-enhancing supplements. Studies suggest consumption of probiotics leads to fewer days of respiratory illnesses, and a wave of research suggests vitamin D supplementation also enhances immunity.

“Athletes may benefit from probiotics, and they should definitely take a vitamin D3 supplement over winter to optimise their immune function,” adds Professor Gleeson.

“And with research suggesting vitamin D also enhances the antibody response to some vaccinations, now is a good time to top it up.”

Nutrition Advice To Boost Your Immune System | Men's Fitness UK



The proportion of athlete illnesses that result in a serious disruption of training, according to the Journal of Sports Medicine. 


The sensible weekly increase in training volume recommended to avoid weakening the immune system, according to a review published in the European Journal of Sports Science.


The recommended amount of carbs consumed per hour of exercise to limit any impairment of the immune system, according to the Journal of Applied Physiology.


The reduction in the duration of cold symptoms caused by taking zinc lozenges, according to researchers from the University of Helsinki.


Words: Mark Bailey