Food & Nutrition

5 foods that boost the immune system

5 foods that boost the immune system
Published 17 July 2018

Foods for a healthier winter


Winter signals cold and flu season, so it’s time to tweak your healthy patterns and seek as many ways as possible to boost your immunity. Ultimately we know that a balanced eating plan, regular activity, low-stress levels, and a good night’s sleep are the best strategies. Here’s a rundown of the nutrients you need to keep your immune system strong and where to get them.


1. Omega-3s

Long chain omega-3s from fish are known to help prevent inflammation, especially in rheumatoid arthritis, which can play up during the colder months. When it comes to giving your immune system a boost, recent studies have shown that fish oil rich in DHA enhances the activity of white blood cells and therefore may help protect against the cold. But it’s all about getting the right amount, as you can have too much of a good thing. Studies show high doses of fish oil supplements may actually alter the body’s immune function in ways that can lead to a dysfunctional immune response to viral or bacterial infections. So don’t just pop a pill without checking with a health professional first.


Food sources of omega-3s

Oily fish like salmon, mackerel, tuna, and sardines are the main sources of long chain omega-3s, while eggs and lean red meat provide smaller amounts. Fortified foods, such as milk, are also a good choice. The long chain omega-3 content of canned fish differs widely due to canning methods, age and species of fish, so when you’re choosing between products, go for a brand that clearly lists the total omega-3 (DHA plus EPA) content on the label.

Try this: Baked salmon fillets with green beans, watercress, grated beetroot, orange segments, and pomegranate seeds.


Are all omega-3s the same?

No. There are three different types – EPA and DHA, which are the long chain omega-3s that fish (and especially oily fish) are rich in, and ALA, which is a plant-based fatty acid found in foods like walnuts, linseeds, and chia seeds, as well as canola oil. The body has to metabolise ALA into the protective forms of EPA and DHA, and because it’s not very effective at doing that, long chain omega-3s are considered to be the biggest provider of the health benefits associated with omega-3 fatty acids. The Heart Foundation recommends eating 2-3 serves of fish, including oily fish, a week – the equivalent of up to 500mg a day of fish oils.


2. Iron

Iron is essential for the production of haemoglobin, which carries oxygen around the body. Low iron levels can cause fatigue, poor concentration, irritability, lowered immunity, and frequent infections.


Food sources of iron

Tofu and other plant-based sources, such as legumes, wholegrains, and iron-fortified breakfast cereals, are good choices – team them with foods containing vitamin C to increase iron absorption. But lean red meat – and to a lesser extent, poultry and fish – remains the most readily absorbable source of iron. For an alternative red meat meal, try grilled kangaroo – it’s lower in SmartPoints® than grilled lamb or beef.

Try this: Roasted tofu with soy sauce. Toss 100g firm tofu slices with 3 tbs soy sauce. Spray with oil and roast at 220°C for 25 mins. Serve with stir-fried vegies.


3. Vitamin D

A major role of vitamin D is to assist calcium absorption from the foods you eat and build strong, healthy bones. However, vitamin D also boosts immunity and has been linked to cardiovascular health, insulin responsiveness and protection against type 2 diabetes.


Sources of vitamin D

Regular, direct sun exposure remains the best way to get your vitamin D, but you can also boost your intake through food. Other dietary sources of vitamin D include oily fish like sardines, mackerel, salmon and tuna, eggs, fortified foods like margarine and milks, plus red meat. ‘Vitamin D mushrooms’, which have been pulsed with UV light, are another excellent source of vitamin D and are available from some retailers and supermarkets. Alternatively, you can expose regular mushrooms to direct midday winter sunlight for 1-2 hours.

Try this: Start the day with a poached egg and Vitamin D mushrooms sautéed with garlic, which has antibacterial properties.


4. Vitamin C

While vitamin C can give your immune system a boost, the research around popping supplements and reducing the severity of the common cold isn’t that convincing. To ward off winter bugs, your best bet is to eat more whole foods rich in vitamin C.


Food sources of vitamin C

Along with citrus fruits including oranges, tangelos, limes, mandarins and grapefruit – all ripe and ready in the colder months – look for gold kiwifruit, which has twice the vitamin C content of an orange and the same potassium content as a banana. With powerful antioxidants called lutein and zeaxanthin, kiwifruit has been studied for its potential role in boosting immunity, as well as protecting against macular degeneration – a leading form of blindness.

Try this: Make kiwi and strawberry porridge. Cook ½ cup rolled oats and 1 cup of water in a microwave on high for 4 ½ minutes. Stir in 50g diced, hulled strawberries. Top with 25g sliced strawberries and 1 diced kiwi.


5. Probiotics

Research shows probiotics can improve digestion, help protect against disease and enhance immune function. Probiotics can also help to restore good bacteria in your gut after a course of antibiotics.


Food sources of probiotics

Probiotic yoghurts and drinks are a nutritious and easily accessible choice – look for brands that contain at least 100 million colony-forming units (CFU) per serve. You can also get a boost of friendly bacteria from ‘pickled’ vegies such as the German staple of sauerkraut and traditional Korean kimchi. Both are cabbage-based dishes that are made by lactic acid bacteria fermentation. But don’t expect the mass-produced, shelf-stable pickles available in the supermarket to provide the same benefits as ‘fresher’ products. Unfortunately, the canning or bottling process destroys any healthy organisms, or they may have been preserved using vinegar, rather than fermentation. Choose products available from health food and specialty stores, such as Asian grocers, instead, or make your own. You don’t need expensive equipment – a large sterilised glass jar will do the trick. Fermenting takes a few days and it keeps in the fridge for months.

Try this: Counteract winter hibernation and get some probiotics in the process with a bowl of pumpkin soup topped with no-fat Greek-style yoghurt and a sprinkling of ground nutmeg to garnish.