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The Importance of Diet for Immune Function

Immune function enhancing whole foods

The immune system is a complex network of cells, tissues, and organs that work together to protect the body.

For our immune system to work efficiently, it needs to differentiate between what belongs to us and what doesn't. This means it should be able to distinguish between harmful non-self-molecules, such as viruses and bacteria that invade our system, and non-self-molecules that are harmless, such as those found in the food we consume.

The Role of a Wholefood Diet

Proper nutrition is crucial for regulating immune responses and maintaining the function of immune cells. A diverse diet that includes plenty of fruits, vegetables, whole grains, nuts, seeds, and protein from meat, seafood, and legumes can help support the immune system.

Ensuring you are consuming a wide variety of whole foods provides your body and immune system with a broad variety of essential vitamins, minerals, healthy fats, and proteins, which are required for all cells in our body to function at their best.

Diets with a large amount of processed, packaged, and refined sugary foods tend to be nutrient deficient. They are generally associated with increased inflammation in the body, disturbances in the balance between good and bad bacteria within the gut and an imbalanced immune system. Following a highly restrictive diet for extended periods can result in nutrient deficiencies.

Maintaining a healthy diet according to the seasons

Generally, during the winter months, we experience an increased number of infections from colds and cases of flu, mainly from spending more time indoors and in closer proximity to other people.

After we become infected with a virus or bacterial pathogen, our immune system becomes activated, increasing the demand for energy and nutrients, especially during a fever.

It is paramount to have sufficient nutritional reserves during an infection to ensure that immune cells can function effectively and respond quickly. This can be achieved by adopting a year-round whole-food diet and selecting fresh, locally available, and seasonal foods.

the word nutrients in photos of nutrients for immune function

Nutrients for Healthy Immune Function

Vitamin C

Supports the increase of antibodies to fight off infections and helps the body determine necessary immune protection by differentiating white blood cells. It also possesses potent antioxidant properties.

Food sources include green leafy vegetables, broccoli, capsicums, citrus fruits, tomatoes, berries, and kiwi fruit.

Vitamin D

Supports the innate immune system, our first line of defence, and has antibacterial activity within immune cells.

Food sources include fatty fish such as salmon, sardines, mackerel, sundried mushrooms and cod liver oil.

Vitamin A

Is a powerful antioxidant that helps antibodies respond more effectively to invading pathogens, supporting the immune system.

Food sources include beef liver, sweet potato, carrot, capsicum, pumpkin, spinach, mangoes and apricots.


This nutrient is vital for supporting immune responses, particularly the development and communication of immune cells. Zinc plays an essential role in regulating the necessary inflammatory response of the immune system when we become infected and acts as an antioxidant. Research has shown that a mild zinc deficiency is linked to dysfunctional adaptive and innate immune responses and increased infection risk.

Food sources include seafood (especially oysters), beef, pork, chicken, legumes, seeds, nuts, eggs and whole grains.


Is a powerful antioxidant that can assist in decreasing inflammation, particularly in the respiratory system. A selenium-deficient diet may weaken the immune system, increasing infection risk.

Food sources include seafood, organ meats and nuts such as Brazil nuts.

The Importance of Hydration

Research has shown that our immune cells function better when we are adequately hydrated. The mucous membranes in our mouth require plenty of water to produce salivary immunoglobulin A. Immunoglobulin A is one of the first lines of defence against invading bacteria and viruses.

Dehydration has been linked with poorer functioning of immune cells, specifically neutrophils, a white blood cell type that helps fight infection. Being adequately hydrated also helps to deliver nutrients and oxygen to your cells.

Aim to stay well-hydrated, especially during winter when thirst may not be as noticeable. Incorporate herbal teas and bone broths to support hydration.

To maintain good hydration levels, consuming a minimum of 2-2.5 litres of water per day as a baseline is recommended. The recommended water intake may vary based on factors such as exercise, weight, pregnancy and breastfeeding.


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