We want to make sure we’re in the best possible condition to prevent getting Covid-19, or if we get it, be able to fight it off as soon as possible. The great news is, there are a number of things you can do to help your immune system stay strong.

1. Vitamin C

Vitamin C is an antioxidant that plays a major role in the body’s defence system, for example pulmonary defence.

Vitamin C-rich foods are mainly vegetables, such as broccoli, green leafy vegetables, peppers, Brussel sprouts, potatoes (not too many) and some fruit, for example kiwifruit, berries and oranges.

Potatoes, although they are high in carb, do have quite a bit of vitamin C. What you could do with with potatoes is cook them and then cool them, and eat them the next day, for example in your lunch salad. Cooked, cooled potatoes have got a lot of resistant starch, which helps gut health and the little friendly critters that line the gut.

I also want to mention vitamin C supplements. A lot of people have been flocking to the pharmacy to buy vitamin C. If you are going to buy vitamin C, we recommend the lipospheric version, because vitamin C is best absorbed in this form (vitamin C is bound to fat droplets).

Am I taking vitamin C? Yes, I had some lipospheric vitamin C sitting in my cupboard and I’ve started taking them. I only have about 8 or 10 left, and I’m sucking one down every day or two to try and ration myself. When I finish these, am I going to go out and buy some more? Probably not, because there’s enough that I’m going to do to boost my immune system and make sure that it is as robust as possible.

2. Antiviral foods

There is a range of foods which might not necessarily be supported by the most robust science, but they are still purported to be antiviral or have antiviral properties. These include foods like garlic, onions, leeks, broccoli, shiitake mushrooms, green tea and cinnamon, and also herbs like oregano and thyme. So look, I wouldn’t recommend that you go out to your herb garden and eat a cup of thyme or oregano every night, but I think when you are cooking, it might be a good idea to maximise the use of these foods. Cook with garlic and onions, cook with thyme and oregano, and at least you know that your meal is going to be packed with antiviral foods.

Even if these things don’t necessarily help to ward off viruses like we’d like them to do, they are delicious foods.

3. Natural probiotics

Live yogurt and fermented foods, such as sauerkraut and miso soup – these foods are going to be helpful for our gut, and our gut in turn is going to be helpful to protect the immune system. Last time I talked about that bi-directional relationship between the gut and the brain and the systemic effects it has on the reproductive system; on the muscle and joint systems of the body; the immune system; cardiovascular system – pretty much every system in the body.

4. Other micronutrients

I’ve talked about vitamin C, but I also want to talk about vitamins A, C, D, E and selenium.

Vitamin A comes mainly from animal foods, in particular things like liver, and fatty fish.

Vitamin D comes from animal foods, but your best bet is to get into the sun, because the sun interacts with the vitamin D in its non-bioavailable form in the body and it activates it to make it bioavailable. So getting in the sun is really important, and it’s particularly important for us in the Southern hemisphere at the moment. We want to make sure that we get as much vitamin D to make sure that our stores are as high as possible to help us ward off our winter ills.

Vitamin E is another antioxidant, rich in nuts and seeds. I would recommend getting vitamin E from whole seeds rather than seed oils, because with that comes a whole lot of processing and a whole lot of Omega-6, which can potentially be quite inflammatory in the body.

Selenium is another antioxidant. We find it in a range of foods, but Brazil nuts is a great source. Just two Brazil nuts a day will give us our daily intake of selenium, so very easy to get that in.

Next we’ve got zinc. Zinc is well-known for being antiviral and to help protect against colds and flus, and decrease symptoms when we get it. The best source of zinc is meat. A hundred grams of beef contains 4.8 milligrams of zinc and that is almost half of your daily requirements of zinc. Shellfish is high in zinc. In fact, if you eat six medium sized oysters, that gives you 32 milligrams of zinc, which is almost 300% of your daily value. So in other words, two oysters would sort you out for your zinc, which is good because they’re quite expensive. Hemp seeds is another good source of zinc. Sprinkle them over salads or yogurt or use them in smoothies. Three tablespoons of hemp seeds gives you between 31-43% of your recommended intake. You can also find zinc in legumes, nuts and seeds, dairy and eggs.

Another one which you’ll be excited about is dark chocolate. A hundred grams of dark chocolate, that has 70-85% cocoa, contains about 3.3 milligrams of zinc, which is about a third of your daily intake. Just a little a warning – don’t rely on eating a whole bar of chocolate for your zinc intake. Perhaps have some oysters and then a couple of pieces of your chocolate. But if you are going to have chocolate, go for the dark variety for some extra zinc. For those people who want to supplement zinc, word has it is that zinc lozenges is the better way to go than tablets.

5. Food + other healthy behaviours = the best you can be

Food and diet are incredibly important to the immune system, but the whole is more than the sum of the parts. A healthy diet goes very much hand in hand with other lifestyle factors. Sleep is important. Try to get your eight hours sleep each night. In his book, Why We Sleep, Matthew Walker suggests that we should wake up to our natural cues and not use an alarm clock. When I read the book I thought, “Well, I’ll never be able to do that apart from the weekend,” and now, in lockdown, here’s an opportunity to do just that.


I don’t use my alarm clock anymore. I wake up to my natural cues, and I’m getting a little bit more sleep, which is absolutely doing wonders and contributing to a strong immune system.


Regular exercise is important. Don’t go too crazy on exercise because that can have the opposite effect and dampen down the immune system. You want to do some strength training, and you can do a lot with your body weight just on your lounge floor. You want to do some endurance training to work your cardiovascular and lung system in fitness. This could be some brisk walking, running or biking, if you are allowed to, depending on the lockdown rules where you are. Just work within those constraints. And also stretching, whether it’s yoga or mobility exercises – stretching is really good for both your physical health and mental health. I know a lot of people put off stretching because they say they don’t have enough time. Well, now is the perfect time to do some stretching and complement your range of exercise from strength to cardiovascular fitness, underpinned by some good stretching.

Relationships are important. Nurturing relationships, in a non-contact way, is crucial to keep you buoyed up and keep you happy. It could be Facebook Lives, it could be Zooming or Skyping, it could be drinks over the fence with your neighbours, at a distance. Whatever it is that you can do, definitely do that.


Find that thing that kind of grounds you every day.


Lastly, I want to talk about stress, because that is the thing that underpins everything. Find that thing that kind of grounds you every day. It might be going for a walk or a run. It might be doing some stretches. It might be lighting some candles, doing meditation or deep belly breathing. It might be watching some Netflix. Just find it. Find the thing every day that brings you down to a level of destress as much as you can in this situation.


Read more

COVID-19 Prevention fact sheet

What is known about supplements, medications and metabolic risk factors?

By Prof Grant Schofield, Public Health; George Henderson, Research writer; Dr Catherine Crofts, Pharmacist; Dr Glen Davies, GP; Dr Caryn Zinn, Dietitian


Learn more

Dr Caryn Zinn and Prof Grant Schofield are the lead instructors for PreKure’s Nutrition Certificates:

Start up-skilling yourself today!