You need a strong immune system to fight off the coronavirus, but how important are vitamins for this?
Authorities from the World Health Organization to our Department of Health agree that the best protection against Covid-19 is social distancing and frequent hand-washing. But another important step not receiving as much exposure is building a strong immune system, to help you better ward off infection.
What does the research show?
In a review paper published in April 2020 in the journal Nutrients, biochemistry and biophysics professor Adrian Gombart of the Linus Pauling Institute in the US and colleagues examined the results of studies on different nutrients and their influence on the immune system.
They found that "a wealth of clinical data" showed vitamins and other micronutrients - such as zinc, iron, selenium, magnesium and copper, and omega-3 fatty acids - play important and complementary roles in supporting the immune system. They also found that "inadequate intake and status of these nutrients is widespread, leading to a decrease in resistance to infections".
Our bodies are particularly vulnerable in times of stress, and it’s hard to imagine a more stressful time than the present, with the Covid-19 pandemic threatening lives and livelihoods. Yet, in self-isolation, many of us have been comforting ourselves with junk food, rather than eating a healthy balanced diet rich in vitamins and micronutrients.
Why are vitamins C and D so important?
Especially important, the review concluded, are vitamins C and D. While the exact role of vitamins in our defences is still unclear, it’s known that vitamin C is needed to scavenge free oxygen radicals and fight pathogens, Gombart says, and for the production of antibodies to keep the likes of Covid-19 in check. As an antioxidant, vitamin C can help reduce inflammation, and inflammation of the lungs is a symptom of Covid-19.
Vitamin D plays a key role in the regulation of immune-related genes, and clinical studies in the Journal of Pharmacology and Pharmacotherapeutics suggest supplementation may decrease the chance of respiratory tract infections (although the researchers noted that more well-conducted trials were needed).
Such findings have led Gombart and others, such as geneticist and gerontologist Isabelle Schiffer of the Forever Healthy Foundation, to suggest that during the pandemic we increase our dose of these vitamins and other micronutrients with supplements. But most mainstream health authorities maintain that our best defence is simply to have a varied healthy diet of whole foods in their natural form.
"Supplements can’t replicate the complex variety of micronutrients and protective phytochemicals that work together in foods like vegetables and fruits to provide what our bodies need to function optimally," says Cape Town GP Dr Neville Wellington. "For example, when vitamin E is isolated it works less efficiently than when eaten in nuts and seeds, which have compounds that interact with it."
Too much of a good thing
There’s also a danger in taking too much of a vitamin, especially fat-based ones (A, E, D and K), which can be toxic as our bodies store them in fat (rather than excrete them in pee, as they do water-based vitamins like C). Some vitamins can also be harmful if you have certain medical conditions, or can work against mediations, cautions Wellington.
The bottom line
As yet there is no evidence that vitamin and mineral supplementation is effective in preventing or treating Covid-19 infection – but it seems only sensible to boost our immune systems by eating a balanced diet with a variety of vegetables and fruit, whole grains and legumes, some protein (meat, fish, eggs) and healthy omega-3 oils.
"Spend about 10 minutes unprotected in sunlight several times a week to boost your levels of vitamin D (‘the sunshine vitamin’), and five times longer if you’re dark-skinned," says Lila Bruk, a registered dietitian in Johannesburg. "The exact amount of sunlight you need will also be determined by your vitamin D blood levels and the weather conditions where you are," she says.
What should you do if you think you have a vitamin deficiency?
If you suspect you may have a vitamin deficiency, speak to your health-care provider, Bruk advises – especially if you’re a strict vegetarian or vegan, have a food allergy or intolerance or an underlying health condition, or are on medication that may affect nutrient absorption. Follow their advice, don’t just self-medicate.
Good vitamin sources from food
Sweet potatoes, carrots, spinach, kale, pumpkin, cantaloupe
Animal products (meat, fish, dairy, eggs), and leafy greens
Citrus, strawberries, kiwis, red peppers, broccoli
Sunlight, oily fish (salmon, sardines), meat, chicken, eggs, fortified cereals, margarine, beans, broccoli and mushrooms. "Place sliced mushrooms in the sun for 15 minutes to absorb more vitamin D," says Bruk.
Nuts and oils from the likes of soybean, corn, canola, safflower and sunflower
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