Having a healthy immune system is important at every stage of life.
Your immune system is a complex network of cells, tissues and organs that protects you from infections and helps your body respond appropriately to things that may cause harm.
Nutrition plays an important role because your immune system needs adequate energy, protein, vitamins and minerals to function normally. However, there is no single food that can “boost” your immune system overnight.
Instead, the goal is to give your body the nutrients and lifestyle support it needs for normal immune function.
Here are some practical, food-first ways to support your immune health.
Herbs and Spices
Herbs and spices are a delicious way to add variety to your diet.
Foods and spices such as:
- Garlic
- Onion
- Ginger
- Turmeric
- Cinnamon
- Cumin
- Clove
- Chilli
- Black pepper
- Rosemary
- Thyme
- Parsley
contain a variety of plant compounds, including polyphenols and other bioactive compounds.
Many of these compounds have antioxidant or anti-inflammatory activity in laboratory research. However, this does not mean that adding a particular spice will prevent you from getting sick.
Think of herbs and spices as one way to increase the variety and nutritional quality of your overall diet.
And there is no need for expensive powders or special “immune-boosting” products.
Using garlic in a pasta sauce, ginger in a stir-fry or cinnamon in your porridge is enough.
Polyphenols
Polyphenols are a large group of naturally occurring compounds found in many plant foods.
They are found in foods and drinks such as:
- Fruit and vegetables
- Extra virgin olive oil
- Nuts and seeds
- Wholegrains
- Herbs and spices
- Tea
- Cocoa and dark chocolate
Polyphenols can interact with many biological pathways, including pathways involved in oxidative stress, inflammation and the gut microbiome.
Research is investigating their potential role in immune health, but rather than focusing on a particular polyphenol or “superfood”, the best approach is to eat a wide variety of plant foods.
Easy ways to include more polyphenol-rich foods
- Cook with extra virgin olive oil.
- Include a variety of fruit and vegetables throughout the day.
- Enjoy green, black or white tea if you like them.
- Include nuts and seeds regularly.
- Add herbs and spices to meals.
- Enjoy cocoa or dark chocolate as one food that can fit into a balanced eating pattern.
The important part is the overall dietary pattern, not one particular food.
Protein and Zinc
Protein and zinc are both important for normal immune function.
Your immune system is constantly making and replacing cells and proteins, so adequate protein intake is important. Zinc is involved in numerous aspects of immune-cell development and function and also helps maintain the integrity of tissue barriers.
Good food sources of protein and zinc include:
- Seafood
- Lean meat
- Poultry
- Eggs
- Dairy foods
- Legumes
- Nuts
- Seeds
- Wholegrains
A varied diet can provide plenty of these nutrients.
What about zinc and the common cold?
This is where the evidence is quite interesting.
Research suggests that zinc lozenges or syrup may shorten the duration of a common cold when started soon after symptoms begin, although results vary between studies and products. The benefit appears to depend on the form, dose and timing of zinc.
This is different from saying that eating zinc-rich foods will prevent a cold.
It is also important not to take high-dose zinc supplements routinely without a reason, as excessive zinc can cause adverse effects and interfere with copper absorption.
Don’t Fear Sugar — Focus on Your Overall Diet
You may have heard that eating sugar “suppresses your immune system”.
This is an oversimplification.
There has been laboratory research into how high concentrations of glucose and other dietary factors can influence immune-cell function, but this does not mean that eating one sweet food or having one high-sugar meal switches off your immune system.
Your body needs glucose as an important energy source, including for immune-cell activity.
Rather than trying to eliminate sugar completely, follow the Australian Dietary Guidelines and limit foods and drinks high in added sugars while focusing on a varied, nutritious diet.
That means there is still room for foods you enjoy.
You don’t need to fear fruit, carbohydrate foods or the occasional sweet treat.
Drink Enough
Fluids are essential for normal body function, including circulation, temperature regulation and many processes involved in immune health.
However, there isn’t one universal amount of water that every adult needs each day.
Fluid requirements vary according to factors such as:
- Body size
- Physical activity
- Climate and temperature
- Pregnancy or breastfeeding
- Illness
- Diet
- Individual fluid losses
Water is an excellent everyday choice, but other drinks and foods also contribute to your fluid intake.
Milk, tea, coffee, soups and foods with a high water content can all contribute.
A practical approach is to drink regularly throughout the day and increase your intake when you are hot, active or losing more fluid than usual.
If you are experiencing vomiting, diarrhoea or significant fluid loss, an oral rehydration solution may be more appropriate than simply drinking water.
What About Beta-Glucans?
Beta-glucans are types of complex carbohydrates found in foods such as oats and barley, as well as in fungi and yeast.
They have received considerable research attention because some beta-glucans can interact with the immune system.
There is evidence that specific yeast beta-glucan preparations may reduce the incidence or duration of upper respiratory tract infections in some healthy adults. However, these findings cannot automatically be applied to every beta-glucan-containing food.
For example, eating mushrooms provides beta-glucans as well as fibre, vitamins and minerals, but it would be too strong to claim that eating mushrooms will prevent you from getting a cold.
Oats and barley are also useful foods to include because they provide beta-glucans along with other valuable nutrients and fibre.
Love Your Gut
Your gut and immune system are closely connected.
A large proportion of immune tissue is associated with the gastrointestinal tract, where the immune system constantly interacts with food, microorganisms and other substances entering the body.
Rather than saying that “70% of your immune system is determined by your gut”, it is more accurate to say that the gut contains a substantial amount of immune tissue and plays an important role in immune regulation.
One of the best ways to support this environment is to eat a varied diet containing plenty of plant foods.
Include:
- Vegetables
- Fruit
- Wholegrains
- Legumes and beans
- Nuts
- Seeds
These foods provide fibre and a wide range of vitamins, minerals and plant compounds that contribute to overall health and interact with the gut microbiome.
Some fibres can also be fermented by gut microorganisms, producing metabolites such as short-chain fatty acids that are involved in communication between the gut, immune system and the rest of the body.
What about probiotics?
Some probiotic strains have been studied for their effects on immune function and respiratory infections.
However, probiotics are strain-specific, meaning that evidence for one probiotic strain cannot automatically be applied to every probiotic supplement or fermented food.
Likewise, fermented foods such as kimchi, sauerkraut and miso may contain live microorganisms, but this does not automatically make them probiotic foods.
The practical approach is to enjoy fermented foods you like as part of a varied diet rather than feeling that you need a specific daily dose of “good bacteria”.
Don’t Forget Vitamin and Mineral Adequacy
Your immune system requires a wide range of nutrients, including vitamins A, C, D and E, B vitamins, zinc, selenium, iron and other minerals.
Deficiencies in some of these nutrients can impair immune function.
This is why a balanced diet is so important.
Eating a variety of foods from the Australian Dietary Guidelines food groups helps provide the nutrients your immune system needs.
Examples include:
Vitamin C: citrus fruit, kiwifruit, berries, capsicum, broccoli and tomatoes
Vitamin A: eggs, dairy and liver, as well as beta-carotene from foods such as carrots, sweet potato and leafy green vegetables
Vitamin D: sunlight is an important source in Australia, with smaller amounts available from foods such as oily fish, eggs and fortified products
Zinc: seafood, meat, poultry, dairy, legumes, nuts and seeds
Selenium: seafood, meat, eggs, dairy, wholegrains and nuts
Iron: meat and seafood, as well as legumes, tofu and iron-fortified foods
You don’t need every nutrient in every meal.
Think about your overall diet across the week.
Sleep: Give Your Immune System Time to Recover
Nutrition isn’t the only factor that matters.
Sleep also plays an important role in immune function.
Research has shown that sleep restriction can alter aspects of immune function. In one experimental study, even a night of partial sleep deprivation reduced natural killer cell activity, which returned toward baseline after recovery sleep.
Rather than focusing on one dramatic statistic, the practical message is simple:
Regularly getting enough sleep supports your overall health and immune function.
Most adults should aim for around 7–9 hours of sleep a night, although individual needs vary.
Creating a regular sleep routine, limiting caffeine late in the day and allowing enough time for sleep can all help.
Take a Deep Breath
Stress and immune function are also closely connected.
Short-term stress can temporarily alter immune activity, while prolonged psychological stress can affect immune regulation and other aspects of health.
This doesn’t mean you need to eliminate all stress from your life.
Instead, look for realistic ways to manage stress, such as:
- Going for a walk
- Spending time outside
- Practising yoga
- Meditation or mindfulness
- Doing something creative
- Spending time with people you enjoy
- Watching a favourite movie
- Taking your dog for a walk
The best stress-management strategy is often the one you are actually able to enjoy and maintain.
Exercise
Regular physical activity is another important part of healthy immune function.
Research suggests that regular moderate-intensity physical activity is associated with beneficial effects on immune health and may reduce susceptibility to respiratory infections.
However, very prolonged or unusually strenuous exercise can temporarily increase susceptibility to infection, particularly when combined with inadequate recovery and other stressors.
The message isn’t “exercise more”.
It is:
Move regularly, recover well and choose activities you enjoy.
Walking, swimming, resistance training, cycling, dancing, yoga or playing sport can all contribute to an active lifestyle.
Your Immune System Doesn’t Need to Be “Boosted”
It can be tempting to search for foods, drinks or supplements that promise to “supercharge” your immune system.
But your immune system is not something you simply want to make as strong as possible.
It needs to be well regulated — strong enough to respond to harmful pathogens while also avoiding unnecessary inflammation and damage to your own tissues.
This is why the goal should be supporting normal immune function, rather than trying to constantly “boost” it.
Adequate nutrition is particularly important when someone is deficient or malnourished. For well-nourished people, taking high-dose supplements does not necessarily provide additional protection against infection.
Take Home Message
You can’t guarantee that you won’t catch a cold or another infection.
But you can give your body the best foundation for normal immune function.
Rather than searching for one “immune-boosting” food, focus on the bigger picture:
Eat a varied diet. Include plenty of fruit and vegetables. Choose wholegrains and legumes. Include adequate protein. Eat foods containing zinc and other essential nutrients. Stay hydrated. Move regularly. Get enough sleep. And find practical ways to manage stress.
Herbs, spices, tea, mushrooms and fermented foods can all be enjoyable additions to this pattern, but they don’t need to be viewed as magic immune boosters.
A healthy immune system is built from consistent nutrition and lifestyle habits over time, not one food or supplement.
How Feed Your Future Dietetics Can Help
Nutrition advice about immunity can become confusing very quickly, particularly when social media is full of claims about immune-boosting foods, supplements and detoxes.
At Feed Your Future Dietetics, I help you separate evidence-based nutrition from the latest trend and build realistic strategies around the foods you actually enjoy.
Whether you’re looking to improve your overall nutrition, support your immune health, manage a health condition or simply create a more balanced eating pattern, personalised dietetic support can help.
With over 10 years of experience supporting Australians with their nutrition and health goals, Feed Your Future Dietetics provides individualised dietetic support Australia-wide via Telehealth using Zoom or Microsoft Teams.
To learn more or book an appointment:
ashleigh@feedyourfuturedietetics.com
References
- National Institutes of Health, Office of Dietary Supplements. Dietary Supplements for Immune Function and Infectious Diseases. This evidence review highlights the importance of adequate vitamin and mineral status for normal immune function and the limitations of routine supplementation in people without deficiencies.
- Australian Government. Australian Dietary Guidelines. Recommendations include eating a wide variety of nutritious foods from the five food groups and limiting foods high in added salt, added sugars and saturated fat.
- Arioz Tunc H, Calder PC, Cait A, et al. Impact of non-digestible carbohydrates and prebiotics on immunity, infections, inflammation and vaccine responses: a systematic review of evidence in healthy humans. Critical Reviews in Food Science and Nutrition. 2026.
- Rios-Hoyo A, et al. Dietary modulation of the immune system. Current Opinion in Food Science. 2025.
- Rahmani J, et al. Effects of yeast β-glucans for the prevention and treatment of upper respiratory tract infection in healthy subjects: a systematic review and meta-analysis. 2021.
- Prasad AS. Zinc in human health: effect of zinc on immune cells. Molecular Medicine.
- Hemilä H, Chalker E. Zinc for preventing and treating the common cold. Cochrane Database of Systematic Reviews.
- Cohen S, et al. Sleep habits and susceptibility to the common cold. Archives of Internal Medicine.
- Irwin MR, Opp MR. Sleep health: reciprocal regulation of sleep and innate immunity. Neuropsychopharmacology.
- Pedersen BK, Hoffman-Goetz L. Exercise and the immune system: regulation, integration, and adaptation. Physiological Reviews.
- Gleeson M, et al. Exercise, infection and immunity: an evolving relationship. Exercise Immunology Review.
