Author: Colin Michie FRCPCH FRSPH FLS
He claimed he'd sailed round the world. "Monsieur Seven Seas"
they christened him, from a cod-liver-oil label
with its wriggling swordfish. But his words were not clear.
They were Greek to her. Or old African babble.
~Derek Walcott, Omeros, 1990
You will have thought about your chances if you were infected with Covid-19. Just how sick might you get? The Covid-19 pandemic is testing countries, islands, cities, communities, our neighbours. But can we improve our odds if the virus tested us?
A safe, effective vaccine against Covid-19 will reduce the chances of being infected by this pathogen, once it is widely used. Several candidate vaccines are being tested and it will take time to find out how well these might protect us. Meanwhile, physical distancing and hand hygiene, supported with facemasks and testing are crucial tools to limiting the spread of Covid-19. This virus is infectious! No country has found that immunity from those who have already had Covid-19 protects others particularly well. Any “herd immunity” will need a vaccine to become useful.
But returning to our question: How might I stand up to Covid-19 virus if it infected me? There are no universal rules; we all differ. There is a useful guide: Planting the sucker, follow the root. We tend to resemble our families – if they are tough in the face of infection, we will tend to be like them. Or, if they always catch all the viruses, we are likely to be just the same!
Our airways with their immune systems and those of the eyes are first-line defences with their surface secretions. Many different genes control these protective layers that contain viral deterrents and antibodies. In the circulation, there are cells dedicated to eating and killing foreign invaders. Most of these systems shoot at anything, as it were, but some can be trained to be more sophisticated. For instance, if you have had the BCG vaccine to protect you against tuberculosis, or perhaps the measles, mumps and rubella vaccine, you probably have greater resilience in fighting other infections, including Covid-19. There are ongoing trials to find out how efficient these two vaccines might work as enhancers of your defences.
Should a virus breach your mucosal membranes, it will excite your immune system and cause inflammation. Covid-19 is particularly good at this, often causing a storm of messenger molecules or cytokines. These cause severe illness, particularly in the elderly. Inflammation and a cytokine storm both result in oxidation, damaging cells, their membranes and their mitochondria powerhouses. Early targets are the cells in the lungs and their blood vessels, causing pneumonia.
Can we prevent or slow inflammation and oxidation? Yes. This is one of the actions of dexamethasone, one of the few pharmacological agents found to be of benefit, particularly in the treatment of Covid-19 pneumonia in Hospital. Many nutrients, including vitamins A, C, D, K2, zinc, fatty acids and dietary fibre routinely reduce oxidative damage. Polyphenols could also be beneficial. These are found in coffee, tea, red wine, sorrel and vinegars, for instance, often in those brownish dregs or lees at the bottom of your cup. Should we therefore take supplements of these to improve our viral resilience? Again, this is a sucker and root problem. We all differ in how many of these molecules we use, or re-use, when fighting virus oxidation in our bodies. There are very few big treatment trials testing them.
Of all the nutrients or nutraceuticals, one stands out – vitamin D. Many individuals, including the elderly in the Caribbean, are short of this vitamin. Higher levels of vitamin D have been linked to better outcomes when coming into contact or being infected with Covid-19. Vitamin D improves chest function, muscle strength, heart, bones and teeth. We can make vitamin D in our skin on exposure to the blue light in sunshine. Exposure to sunshine will also deliver powerful tissue-damaging ultraviolet rays, however, particularly in tropical zones.
It is safer, and you will show less ageing of your skin if you have sufficient vitamin D in your diet. Vitamin D is found in fish such as mackerel, herring or wahoo; in red meat, liver, egg yolks, mushrooms and fortified foods. Alternatively, supplements are available. This includes that unforgettable gold of the ocean, cod liver oil, once so very popular with Caribbean mothers and school nurses. And what of the other vitamins and micronutrients? Are there not immune-boosting benefits from taking “extra” vitamin C, or zinc, for instance? This is an ongoing debate, but published trial data are not convincing. A healthy diet that incorporates at least five fruit- or vegetable-portions a day ensures we should eat enough of these other micronutrients.
To improve your chances with Covid-19 during this pandemic, follow those public health recommendations: stay healthy, avoid lung-damaging habits such as smoking, keep physically active and ensure you and your families have enough vitamin D. This virus is a significant enemy.