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Avoid COVID-19 and naturally boost your immune system

By David Coory

It will be interesting to see how the Covid-19 virus responds to the northern hemisphere summer.

Sunny tropical countries are far less affected so far, and also poorer countries whose food is mostly unprocessed, like Africa and India.

COVID-19 deaths in perspective

People don’t die of COVID-19 itself. In nearly every instance they die of pneumonia which is always lurking, ready to pounce when our defences become weak enough. Pneumonia is an infection of the lungs which denies our body oxygen. About 130 mostly elderly New Zealanders currently die of pneumonia each month, mostly from existing flu viruses.

Pneumonia was also the main cause of death during the 1918 Spanish Flu pandemic, that fast acting, violent virus killed about 18,000 people per million worldwide of all ages (see graph) and 9000 New Zealanders died in just three months. We can be thankful our young are being spared this time around.

Asian and poorer nations are resisting this virus 100 times better than Europe and the USA.

After four months, the worldwide death rate for COVID-19 is around 300 persons per million for nations like Europe and USA, with their obesity and diabetes-producing processed food diets.

Whereas for poorer nations, and Asian nations like Singapore, Japan, China, Hong Kong, Taiwan, etc, which have varied, largely unprocessed food and lower sugar diets, deaths are 100 times lower, currently (late April) less than three persons per million.

All current COVID-19 death rates are a tiny fraction of the 18,000 persons per million who died of the 1918 Spanish Flu. So we may be overreacting, even with the increased risk to our unhealthy elderly in rest homes.

Will COVID-19 die down after a few months?

Hopefully it will. Viruses traditionally lose their virulence within months if allowed to peak, but COVID-19 is widespread and highly contagious.

However, during the 1918 Spanish Flu pandemic, when 8500 Western Samoans died, nearby American Samoa immediately closed their port to all shipping and as a result, not one American Samoan died. When the virus eventually found its way there some months later, it had lost its virulence and caused sickness but no deaths.

Can we become immune to COVID-19?

Experts claim it takes about 60-70% of a population to be infected with a virus to confer herd immunity. An effective vaccine may also achieve herd immunity, but dismal results from current annual flu vaccines are not encouraging.

Why are children naturally immune to COVID-19?

Most of our young are already immune to the virus due to youthfully high Glutathione levels (see Glutathione explanation).

Is lockdown the best way to stamp out this virus in NZ?

The current policy of our NZ leaders is to try and manage the virus in NZ by lockdown and then isolate our country until the virus virtually dies out overseas. But lockdowns and border closures cost us billions, lead to serious economic depression and can easily cause more deaths and suffering than they save. Job losses are already estimated to be at least 200,000 in NZ, and household poverty and domestic violence have increased. This kind of severe stress and depression can greatly weaken our immune system for all diseases.

However, many families and communities have become closer during our NZ lockdown.

Can we boost our natural immunity with key nutrients?

This could be our best NZ option, to isolate just those infected, and at the same time boost our natural immunity. This can be done with a more natural and less processed diet to keep our vitamin A and C levels high, also our zinc, magnesium, selenium and iodine levels, and vitamin D from the sun. These are all key immune system nutrients.

I myself am in my mid 70’s – an age group at risk from COVID-19, but I still have much work to do, so I take steps each day to avoid viruses by building my natural immunity. (See section on page 5 as to how I do this.)

Nine ways to boost our immunity

I’d now like to share some of what I’ve discovered in my 32 years as a health and nutrition researcher. I believe we can greatly reduce our COVID-19, or any flu infection risk, even in old age, by boosting our immune systems with more natural, unprocessed food, or supplements if desired. We should still try and avoid hand-to-eyes, nose and mouth infection from our hands.

Zinc and magnesium

These two minerals are essential for our immune system, especially zinc. During the 1918 Spanish Flu epidemic, the compressed-air braking units on six Christchurch trams were adapted to operate a zinc-sulphate sprayer so that people could walk slowly through the tram in clouds of zinc vapour.

Many doctors were sceptical it would do any good, but the death rate per thousand in Christchurch was 60% less than Auckland or Wellington (although Dunedin figures were low also).

Chinese health authorities are now recommending zinc in the treatment and prevention of COVID-19 infections.

A 1998 study, reported in the peer-reviewed medical journal ‘Pediatrics’ used a 10mg daily zinc supplement to reduce recurring lung infections in 609 children, down from 44% to 12%.

Sufficient zinc can be difficult to obtain from modern foods and is best supplemented, ideally from a multi-mineral supplement. Men require 14mg a day and women 8mg. A lessened sense of smell and taste is a reliable sign of a deficiency of zinc.

Magnesium is also lacking in processed foods. Again, best supplemented – 420mg a day for men and 320mg for women and best taken in the first half of the day.

Iodine and selenium

These two essential immune system minerals are widely lacking in NZ nowadays. We need 150mcg of iodine a day for good immunity. This is easy to obtain from kelp powder, or a multi-mineral supplement.

Selenium need is 60mcg for women and 70mcg for men. Brazil nuts are a good source.


There is ample scientific evidence that silver particles in the blood deactivate viruses.

In a study published in 2011 by the peer reviewed ‘Journal of Nanobiotechnology’ researchers reported: "The efficacy (effectiveness) of AgNPs (silver nanoparticles) against HIV-1 (a virus) has been reported by many laboratories including ours. It has been demonstrated that AgNPs function as broad-spectrum virucidal (virus killing) and bactericidal agents”.

Fresh air, sunshine and vitamin D

Viruses don’t thrive outdoors. American Plains Indians claim they never got colds or flu when they lived in their well ventilated tepee tents, open to the air at the top.

Also, sunny tropical countries (ie, high vitamin D populations) at present have around 100 times lower infection rates of COVID-19. Vitamin D is a key immune hormone. It is obtained from sensible summer sun exposure, or from a supplement – 1000iu a day is recommended. An ideal blood test level is 120nmol/L. Our liver can store vitamin D for months.

Unprocessed food

Vitamins A and C are also key for immunity. Vitamin A is found in butter, yellow fruits, and yellow and dark green vegetables. Vitamin C is found in all fruits and vegetables.


Glutathione is a protein combination made by our liver. It’s the natural defence of every cell in our body from bacteria and viral infections. Youthful supply is high, which is why children are resistant to COVID-19, but as we age past 30, our liver makes less and less.

Taking glutathione as a supplement doesn’t work, but our natural liver production can be boosted by whey protein powder, raw eggs, raw fruit and vegetables and vigorous exercise.

Reducing fear

Fear of catching COVID-19 and anxiety over lockdown and its job losses is a heavy cause of stress, and a major immune system suppressant. Best to limit our exposure to never-ending bad news reports and maintain social contacts (as best we can).

Three natural treatments for COVID-19 induced pneumonia

Intravenous Vitamin C

Japanese intravenous therapy expert Dr Atsuo Yanagisawa, recommends that COVID-19 pneumonia be treated with high amounts of intravenous vitamin C. Dosage is from 50 to 200mg per kg body weight per day, according to severity of illness. He says, "Intravenous vitamin C is a safe, effective, and broad-spectrum antiviral." Chinese doctors now also recommend intravenous vitamin C to combat the virus.

Vitamin C, thiamine and cortisol

A 2017 clinical study by Eastern Virginia Medical School showed giving pneumonia patients 200mg of thiamine every 12 hours, 1,500mg intravenous of ascorbic acid (vitamin C) every six hours, and 50mg of cortisol every six hours for two days, reduced pneumonia type infection death rates from 40% to 8.5%, without any side effects.

Antiviral malaria zinc-boosting drug Chloroquine

Taking 200mg, three times a day of the proven antiviral malaria drug Chloroquine for 10 days can bring a significant improvement in COVID-19 induced pneumonia. This drug works by forcing more zinc into body cells. It can have side effects however, but these are able to be modified by also taking Proguanil, another drug used in the treatment of zinc deficiency.

How David maintains his immune system against winter ills

I daily spray my throat and under my tongue with liquid colloidal silver. I ensure my zinc, selenium and iodine intake is high by taking a daily, high quality, multi-mineral and vitamin capsule. I sun bathe during summer to maintain good vitamin D levels and eat an apple and other fruit every day.

Should I sense an attack beginning, I immediately take two capsules of an immune boosting supplement containing echinacea, garlic, olive leaf, astragalus, vitamin C and zinc and carry on taking two of these every few hours for a day, or perhaps two days, until all symptoms vanish.