Vitamin D is essential for good health and a strong immune system – which has never been more important than in the age of COVID-19. Are you getting enough?
When it comes to strengthening immunity to battle the coronavirus, one advantage some South Africans may have over people elsewhere is our sunshine. This is because sunshine is the best natural source of vitamin D, ‘the sunshine vitamin’ – which along with helping to maintain strong bones, is known to boost your immune system.
The health risks of a vitamin D deficiency
Immunologists at the University of Glasgow have noted that people deficient in vitamin D are three or four times more likely to catch a cold. And in a recent study by Trinity College Dublin, adults who took vitamin D supplements reported a 50% drop in chest infections. Now scientists at the University of Grenada in Spain are running a trial involving 200 patients with COVID-19, looking to establish if the vitamin can help fight the disease.
How can you make sure you're getting enough vitamin D?
In the meantime, it seems only sensible to make sure you’re getting enough of the ‘Sunshine Vitamin’. Sunlight creates vitamin D by converting cholesterol in your skin into the storage form of the vitamin, which your kidneys later convert to the active form used by your body.
It takes about 10 minutes of exposure to UV light on a sunny day several times a week to supply what you need if you have fair skin, but five times that if you’re dark-skinned, says Lila Bruk, a registered dietitian in Johannesburg. This is because the extra melanin in dark skin helps protect it from the sun’s UV rays, but reduces its ability to make vitamin D.
How do you know if you are at risk for a vitamin D deficiency?
In the past, South Africans were thought to get more than enough vitamin D from the sun, but today, when we spend so much of our time indoors and use sunblock to protect ourselves against skin cancer, deficiency can occur in vulnerable individuals.
You may be among them if you stay indoors all the time - like the sick and many elderly - have dark skin, are a strict vegetarian or vegan, have a milk allergy or lactose intolerance, suffer from a liver or a digestive disease such as coeliac or Crohn's disease, or take medication that may inhibit the absorption of vitamin D, including laxatives, anti-seizure drugs and steroids.
In that case, speak to your health-care provider, who can arrange tests and advise you.
Which foods are high in vitamin D?
"While sunshine is the best natural source of vitamin D, you can also get it from certain foods. If you’re deficient, you may benefit by eating more oily fish - such as salmon and sardines, meat - especially beef liver, chicken, eggs, milk, fortified cereals, yoghurt, margarine, beans, broccoli and mushrooms", says Bruk. "If you put sliced mushrooms in the sun for 15 minutes, they absorb significant amounts of vitamin D, making them a high vitamin D food," she adds. You can also take a supplement.
Current guidelines for vitamin D are 600 international units (IU) a day for adults up to age 70, then 800 IU.
"It’s advisable for all adults to check their vitamin D levels once a year to make sure they’re in the normal range and pick up any deficiencies," Bruk says. "But, don’t take supplements if no deficiency is present." Vitamin D is a fat-soluble vitamin, stored in your liver and fatty tissues. Unlike water-soluble vitamins (such as C), if you take excess you won’t just pee it way – and too much can be toxic.
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