Foods that can help boost your immune system
Forget arming yourself with toilet paper. As coronavirus spreads in Australia, these are the immune-boosting foods that are worth hitting the supermarket for.
As Australians grapple with COVID-19 in the community, measures like social distancing and thorough handwashing have become the first line of defence to help minimise its spread.
Giving our immune systems a fighting chance to stay in top shape can also help limit the risk of infection – and reduce the severity if it does occur.
“Vitamin and nutrient deficiency can increase your susceptibility to infection,” says nutritional scientist Matt Legge.
“You need to make sure you’ve got adequate nutrition to prevent deficiency, so your body is capable of having a solid first line of defence.”
While various nutrients can help your immune system, nutritionist Rick Hay says vitamins C, A, D and zinc in particular keep it regulated and operating at its best.
“If you’re eating a nutrient-dense diet, you’re going to get all the vitamins and minerals, including vitamin C, vitamin A, D, zinc – those that have been well researched to show they can support immune function,” he says.
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Found in most fruits and vegetables (but citrus fruits, berries, broccoli and capsicum are particularly good sources), vitamin C is considered a leading player in the immune-boosting stakes.
A potent antioxidant, vitamin C has a key role in helping to fight free radicals in the body, and Matt says it is important in actually making immune cells.
“If you don’t have enough vitamin C your immune cells won’t function correctly. Vitamin C is needed to generate the free radicals used by the immune system to kill microbes,” he says.
Vitamin A has anti-inflammatory properties and helps regulate immune response.
“It’s also great for the respiratory tract, and it helps with strengthening the mucus membrane,” Rick says.
Reach for orange and yellow fruits and vegetables, green leafy vegies, and eggs to get your vitamin A fill.
Vitamin A in higher doses are not suitable for pregnancy.
Often associated with the sun vitamin D, plays an important role in immune function.
“Vitamin D has a great reputation not just stimulating the immune system, but helping to modulate it, so it helps create an efficient immune response,” Matt says.
“It stops the over-reacting immune response that might cause excessive amounts of damage.”
While vitamin D is synthesised from cholesterol when the sun hits the skin, food sources include mushrooms, fish, and cod liver oil.
Supplement form is also an effective way to prevent vitamin D deficiency.
Zinc – found in nuts, seeds, chickpeas, lentils, beans, dairy and wholegrains – is central to optimum immune function, helping to manage susceptibility to infection and regulate normal development and function of cells.
“Our immune cells get signals to respond to a virus by the release of certain chemicals,” Matt says.
“The little antennas that pick up on these chemicals are often zinc dependant.
“If you have zinc deficiency, your immune system may not know there’s a virus there and it needs to respond.”
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How to load up your meals and drinks to boost immunity
Eat the rainbow
Introducing a variety of colour to your diet through your fruits and vegetables will ensure you’re getting a good supply of key nutrients for immune support, says Rick.
“Anything that’s brightly coloured and natural is where you want to be going,” he says.
“Look for anything blue like blueberries, purple like aubergine, leafy greens (kale, spinach), yellow such as squash and oranges such as orange, carrots, sweet potatoes.
“All of them have not only the main vitamins and minerals to help boost immune function, but also an array of phytonutrients, which give us antioxidant benefits, which help us further.”
Matt and Rick say it’s easy to include these foods in your diet.
Eat them fresh in salads or stir fries or add them to soups, curries and stews – which can also be frozen and enjoyed later.
The can also be blended into nutritious smoothies or juices.
Stay hydrated with a variety of liquids
Matt says nutrient-loaded drinks in particular can play an important role in protecting yourself against coronavirus.
“What researchers have noticed with this virus is it doesn’t handle the digestive tract very well,” he says.
“We want to keep it moving away from the throat, so constant sipping on liquids can keep that mucus moving down into the digestive tract.”
Hot liquids could also play a defensive role.
“There’s evidence (coronavirus) doesn’t handle high temperatures over 38C,” Matt says.
“So, the hot drinks, the soups, stews, broths and teas might also be a really good idea.”
What foods should you keep on hand?
Matt and Rick recommend fresh fruit and vegetables where available, as well as a range of nuts and seeds to snack on, add texture to salads or stir fries, or even garnish stews and curries.
If fresh isn’t available, Rick says frozen, tinned or even packet versions are nutritionally beneficial, but suggests including a variety of colour.
“Get some nice frozen fruit and veg, green beans, frozen broccoli, organic frozen corn,” he says.
“They’re so nutrient dense – it’s the pigment where the most beneficial phytonutrients are.”
They recommend keeping cereals and wholegrains such as brown rice and wholemeal pasta, tinned beans and lentils, as well as tinned tuna and mackerel.
If your usual foods are in short supply, think outside the square and try something new.
“You can get pastas made from lentils and chickpea, and even good old baked beans you can now get in different flavours such as chilli,” Rick says.
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How much immune-boosting food should I eat each day?
As a rule of thumb, Rick suggests filling half your plate with colourful fruits and vegetables to get the recommended daily nutrient intake through your diet.
“If your plate isn’t half colourful you’re not going to be getting much of an effect,” he says.
“Mid-morning and mid-afternoon snack on a piece of fruit and a handful of nuts and seeds, and at each meal include some colour.”
While getting adequate nutrients is important for immune support, Matt says overloading is not recommended.
“Preventing deficiency is important to have an effective and efficient immune system but you don’t need to take high doses, and in fact supplementing with megadoses outside of what is normally available in our diet is not recommended for this particular virus,” he says.
If you are experiencing symptoms of coronavirus, call the 24/7 hotline on 1800 675 398. You can also use the Healthdirect symptom checker.
Instant Consult offers on-the-spot online GP consultations and can issue medical certificates, prescriptions, radiology and pathology requests and specialist referrals.
Written by Claire Burke.