Here's something that might surprise you: you can't actually "boost" your immune system. A healthy immune system already works at the level it is meant to, and no food or supplement will push it higher. What good nutrition can do is make sure your body has everything it needs for that system to work normally.
What you will learn in this fact sheet
This fact sheet cuts through the marketing to explain what nutrition can and can't do for your immunity.
- Which nutrients support normal immune function, and the foods that provide them.
- What the evidence actually says about supplements and natural therapies.
- Which foods and habits are worth limiting.
- Why blood glucose matters if you are living with diabetes.
Can food boost your immune system?
There is a lot of marketing built around immunity. Here is what the evidence supports.
- "Specific foods can boost your immune system."
Not true. There is no single food, nutrient or supplement that can lift your immunity beyond normal levels. What a varied, well-balanced diet with plenty of fruit and vegetables does is supply all the nutrients your body needs for your immune system to function normally. - "You need supplements to boost your immune system."
Not true for most people. A good diet will generally give you what you need. Only take supplements when a healthcare professional advises you to. - "Natural therapies will stop you getting sick."
The evidence is weak. There is limited evidence that natural therapies such as garlic and echinacea help with seasonal colds, and no evidence that they prevent viral infection.
If you are living with diabetes, maintaining a healthy diet alongside your medications is particularly important. Some evidence suggests that long periods of higher blood glucose levels can increase the risk of viral infections.
Nutrients that support normal immune function
These three nutrients are important for the normal functioning of your immune system, and there is moderate evidence they help protect against colds and flu. You can get all of them from food.
- Zinc — lean meat, fish, shellfish, nuts, seeds and legumes.
- Vitamin C — oranges, strawberries, tomatoes, broccoli and kiwi fruit.
- Vitamin D — eggs, liver and oily fish such as salmon, plus a daily dose of sunshine at safe times.
What to limit to protect your immune system
- Ultra-processed foods high in saturated and trans fats — such as potato chips, pastries and fried foods.
- High sugar foods — such as cakes, lollies, ice-cream and chocolate.
- Excess alcohol. Australian guidelines recommend healthy adults drink no more than 10 standard drinks a week, and no more than 4 on any one day. People living with diabetes and/or heart disease may need to drink less.
- Low fibre intake. Choose wholegrains where you can, limit ultra-processed foods, and eat plenty of fruit and vegetables.
- Lack of physical activity. Evidence has shown that three weeks of inactivity is equivalent to 30 years of ageing on the cardiovascular system.
More than food
Nutrition is only part of the picture. Getting enough sleep, exercising regularly and managing stress all help your immune system work as it should — and they support your heart and metabolic health at the same time.
Download your free fact sheet
Our nutrition fact sheet gives you the mythbusters, the key nutrients and a recipe to get you started — on a single page you can print or keep on your phone.