You may have heard that taking vitamin D supplements can help fight coronavirus – either by preventing you from catching it or by lessening the symptoms if you do. But is there any truth in this? Should we all be supplementing our diets – and our children’s diets – with vitamin D?
Is there any evidence that vitamin D supplements can prevent or treat coronavirus?
No, nothing definitive. A recent (Dec 2020) evidence review by the National Institute of Health and Care Excellence (NICE)¹ concluded that “there was not enough evidence to recommend vitamin D supplements solely for preventing Covid-19” and there was also “not enough evidence to recommend using vitamin D for treating Covid-19”.
It’s true – and the NICE review did acknowledge this – that some studies suggest that low levels of vitamin D in your body may be associated with “more severe outcomes” from Covid-19 infection. But because many of the conditions that can cause low vitamin-D levels – heart disease, for example – are, in themselves, also risk factors for severe Covid-19 outcomes, it’s unclear whether it’s specifically the low vitamin-D levels that are causing the severe outcomes or the other conditions.
It’s also worth knowing that a 2020 systematic review and meta-analysis study² found that vitamin-D supplementation has a “modest protective effect” again respiratory-tract infection – and Covid-19 does mainly affect the respiratory tract. However, when the Scientific Advisory Committee on Nutrition (SACN) looked at the study³, they concluded the results from the studies analysed were inconsistent – and more research was needed before a clear effect could be established.
What should we all conclude from this? Our expert family GP Dr Philippa Kaye says, “There has been lots of talk about ‘boosting’ your immune system with vitamin D but the truth is that vitamin D may support your immune system to function effectively, rather than boost it to work better.
But aren’t we all being advised to take vitamin D anyway?
Well, yes, we are! But to maintain bone and muscle health, rather than to ward off Covid. NICE is recommending that adults and children take vitamin D supplements throughout the winter months (the end of September to the beginning of April) to maintain bone and muscle health.
And, as the NHS advises, this is especially important this year, as we’ve all been spending so much more time indoors because of lockdowns and other coronavirus-related restrictions.
What’s more, some people – including children, those who are rarely outdoors, and those who have dark skin (especially African, African-Caribbean or south Asian families) and naturally tend not to make enough vitamin D from sunlight – are also being advised to keep taking vitamin-D supplements all year round.
How much vitamin D should I take?
Here is what NICE recommends, unless you have a medical condition that means you cannot take a supplement containing vitamin D or shouldn’t take the same dose as other people your age:
- For children aged 1 to 4 years: 10mcg a day – all year round
- For babies from birth to 1 year, if breastfeed or having less than 500ml of formula milk a day: 8.5mcg a day – all year round
- For adults and children over 4 years old with dark skin or who are rarely outdoors: 10mcg daily – all year round
- For other adults (including pregnant and breastfeeding women) and children over 4 years old: 10mcg a day – in winter months
It’s important to note here that we’re talking micrograms (mcg), not milligrams (mg), and that you should stick to the recommended dose. Taking too much vitamin D can be harmful, especially if you’re pregnant, breastfeeding or a child.
Where can I get vitamin D supplements?
Vitamin D supplements – in tablet form for adults and drops for babies – are available in most good pharmacies and supermarkets.
If you are categorised as extremely clinical vulnerable to coronavirus, you can apply through the NHS to get a 4-month supply of vitamin D for free.
If you are pregnant or have a child under 4 and you are on benefits, or if you are pregnant and under 18, you can apply to get vouchers for free vitamin D supplements through the NHS Healthy Start scheme.
About our expert, Dr Philippa Kaye
Dr Philippa Kaye works as a GP in both NHS and private practice. She attended Downing College, Cambridge, then took medical studies at Guy’s, King’s and St Thomas’s medical schools in London, training in paediatrics, gynaecology, care of the elderly, acute medicine, psychiatry and general practice. Dr Philippa has also written a number of books, including ones on child health, diabetes in childhood and adolescence. She is a mum of 3.
1. Covid-19 Rapid guideline: vitamin D. NICE guideline [NG187] Published date: 17 December 2020
2 .Vitamin D supplementation to prevent acute respiratory infections: systematic review and meta-analysis of aggregate data from randomised controlled trials. Joliffe et al 2020. MedRxiv. https://doi.org/10.1101/2020.07.14.20152728
3. Update of rapid review:Vitamin D and acute respiratory tract infections. Scientific Advisory Committee on Nutrition. December 2020
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