There are two aspects to protecting yourself against Covid-19. The first is sticking to the public health advice to wash hands and maintain social distancing but making your immune system as resilient as possible is the second aspect that we have heard much less about.

In my opinion we are not passive victims to viral infection. Some people never get flus, and some seem to always be sick. Some seem to be more resistant than others. And more than that, when some people do get a viral infection, they get very sick while others are hardly affected.

We are seeing this with Covid-19, with the majority recovering in their homes, but a small proportion of people (around 4 per cent dying from it). What factors affect our susceptibility and ability to recover?

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These are some of the things I am doing to stay well.

1. Sleep. This is always my "go to". I am amazed how many times I have been able to prevent a cold from progressing by going to bed early.

2. Diet. We are only just starting to appreciate how powerful a healthy diet is in preventing illness and supporting the immune system.

My rules are: (a) Avoid sugar completely, especially soft drinks. We each have five litres of blood. There should only be 4 grams, (less than a teaspoon) of sugar in that blood. So, a teaspoon of sugar in your coffee or a biscuit at morning tea doubles the sugar in the blood, with serious negative effect on the immune system. Data coming out of Wuhan shows that patients with blood glucose less than 5.4mmol/l were unlikely to develop Acute Respiratory Distress Syndrome and need ventilation, compared with those with blood glucose above 7.4 mmol/l.

(b) Avoid foods that are likely to cause inflammation such as processed vegetable oils like canola oil and stick to natural fats such as avocado, olive oil and butter.

(c) Avoid highly processed carbohydrates such as cakes, biscuits, doughnuts and lollies as these spike the blood sugar, increase insulin levels and cause inflammation. Eat whole foods, natural foods that have recently been growing in the garden or swimming, flying or walking about.

I think sleeping well and eating well have enormous protective and immune supporting effects.

3. Moderate daily exercise, such as walking, especially if this involves getting some sunlight, is very immune supporting.


4. Social contact. We still have many appropriate ways we can care and support each other. Kindness is immune supporting.

5. Minimising anxiety. Chronic stress and anxiety have a negative effect on the immune system. It is important to stay up to date with the ever-evolving public messages but if you are finding yourself anxious and overwhelmed, take a break from the news feeds and posts. Get your information from reliable sources such as the Ministry of Health and Lakes District Health Board.

6. Supplements. I have always been an advocate of the advice to focus on getting your nutrients from your diet but there is some evolving research from China. High dose intravenous vitamin C is currently being studied in China. Results are awaited but it has been added as one of the official treatment protocols in China. The evidence on oral vitamin C is not strongly conclusive.

Vitamin D, selenium and zinc are all important for immune function. The research on selenium is interesting. There is no information specifically on Covid-19 but pre-2019 coronavirus have been found to integrate large amounts of the host's selenium, using it up and limiting the host's ability to mount an immune response. I will be taking a multimineral and multivitamin (and increasing my brazil nut intake to increase selenium).

Dr Glen Davies is a GP in Taupō practicing lifestyle medicine. He is one of the leaders of Reverse T2 Diabetes Taupō and was runner-up in NZ GP of the year at the NZ Health Care Awards 2020.