How do we boost our immune system and keep ourselves healthy over the winter months? Is there anything we can do or take to reduce how often we get sick? Sports and Performance Dietitian Rebecca Hay explains.

What is the immune system really? It involves several components that work together to defend the body against pathogens and repair body tissue that is damaged through illness or exercise.

Some of the systems involved are:

  • Physical, like skin and lining of the respiratory tract
  • Cellular, like white blood cells
  • Protein production, like immunoglobulins

There are both nutritional and lifestyle factors that help us look after the immune system.

Some of the lifestyle factors include less stress, practicing good infection control procedures – like washing our hands regularly, getting enough sleep and exercising. Nutritional factors include eating lots of fresh vegetables, fruits and whole grains and not drinking too much alcohol.

Good nourishment from food is step one in providing a good base for our immune system. There is evidence to suggest that deficiencies in vitamins A, B6, C, and E, Selenium, Iron, Zinc, Folic Acid and Copper can have an impact on the immune system, while Vitamin D has more robust evidence behind it for improving immune response.

While you can take a tablet to get all of the above nutrients, there are other benefits in getting these nutrients from food – along with vitamins and minerals, we get dietary fibre, prebiotics and energy. More vegetables, fruits and wholegrain foods help to look after these nutrients.

Probiotics encourage the growth of good bacteria in our gut, while prebiotics and dietary fibre feed the good bacteria, promoting a healthy gastrointestinal system. Having plenty of healthy bacteria in the gut helps the functioning of immune and epithelial cells (or lining) in the intestine.

It is well established that Vitamin D is important to keep bones and muscles healthy. It is now becoming clear that Vitamin D is also important in the functioning of our immune system.

It works in the immune system to reduce inflammation and improve antimicrobial defences. Food is not the best provider of Vitamin D but it can be obtained free by exposure to the UV radiation from the sun. Guidelines for sun exposure can be found via The Cancer Council’s website.

Getting enough energy through our dietary intake is also an important part of keeping our immune system functioning.

Regular exercise, for athletes in particular, can compromise the functioning of their immune system with over restriction of energy around exercise and training. So the best practice is to recover properly after exercise with a meal that includes carbohydrates, protein, fat and some fruit, vegetables or salad.

So before you reach for the supplements to give your immune system a boost, have a look at the quality of your diet and lifestyle. It really could be that simple.

Where to find micronutrients, probiotics and prebiotics:


Food sources

Vitamin A

Carrot, sweet potato, dark green leafy vegetables, capsicum,  rockmelon, fish and liver

Vitamin B6

Green peas, mushrooms, peanuts, chicken, liver, tuna, turkey and avocado

Vitamin C

Oranges, capsicum, broccoli, kale, strawberries, grapefruit and brussels sprouts

Vitamin D

Fatty fish (tuna, salmon, mackerel), cheese and egg yolk

Vitamin E

Almonds, sweet potato, spinach, avocado, pumpkin and sunflower seeds and olive oil

Folic Acid

Green leafy vegetables, green beans, citrus fruits, wholegrain bread and cereal, rice and pasta


Brazil nuts, tuna, sardines, turkey, chicken and oysters


Spinach, beef, prawns, kidney beans, pumpkin seeds and oysters


Red meat, seafood,  beans (legumes) and dark green leafy vegetables


Sunflower seeds, lentils, almonds, dried apricots, asparagus and beef liver


Onion, garlic, banana, asparagus, barley, oats, apples, linseeds, wheat bran and seaweed


Yoghurt and fermented foods like sauerkraut, pickles and miso soup