You may have seen us mentioning Vitamin D just once or twice on social media recently! There are theories abounding that it is a magic prevention for Covid-19 and it’s getting more press attention than ever before. So, let’s explore the facts to give you the information you need to decide whether it’s worth taking a vitamin D supplement.
Firstly, the big one, Covid-19… does vitamin D offer a preventative measure?
Coronavirus hit the UK in January 2020 meaning that the medical world has only been able to study the disease for less than a year. However, there are increasing studies and statistical models which now prove a link between high levels of vitamin D in the blood and a decreasing chance of catching the virus together with a large reduction in symptoms if you do catch the virus.
Earlier this month the Health Secretary, Matt Hancock, asked government advisers to produce new guidelines on the use of Vitamin D in relation to the pandemic – and we have just seen it announced that nearly 3 million sick and elderly people across England will be given free vitamin D as part of the fight against Covid-19 this winter.
One of the reasons there is so much interest in this vitamin is due to a trial which took place in Spain this August. It involved 76 patients with Covid-19. During the trial, 50 of them were given a high dose of vitamin D. Half the patients who were not given it had to be placed in intensive care and two of them, sadly, died. Only one person who received the vitamin D required ICU admission but was later released with no further complications.
It makes pretty powerful reading.
Leading scientist Dr Gareth Davies, armed with a PhD in Medical Physics from Imperial College, has returned to the field of research to look into the coronavirus pandemic. He states that, vitamin D deficiency is a “major problem” and is linked to severe Covid-19 outcomes. His work continues to unfold in the media so keep an eye out…
A number of studies have also suggested that low vitamin D levels are associated with a higher risk of death from coronavirus, and some believe sufficient levels of it can reduce tissue damage from lung infections.
So should everyone be taking Vitamin D anyway then, just in case?
Our bodies need vitamin D for proper functioning of our immune system and to keep our bones and muscles healthy. That’s proven. And that’s why the government recommend all breastfed babied babies and children aged 1-4 take a supplement while those all-important bones are growing.
The NHS also recommend that adults take a vitamin D supplement from October to April although many health care professionals think we should supplement with Vitamin D all year round. The reason for this timeframe is that vitamin D is mainly created from direct sunlight contacting our skin – specifically ultraviolet B (UVB) radiation. The sun weakens dramatically in autumn and winter. Couple that with more hours spent indoors and wearing more clothes and there becomes a need to get the nutrient from another source.
Interesting fact: cloud cover reduces the amount of vitamin D your body produces as does wearing suncream – so popping outside into direct sunlight for a short period to expose your skin without sun protection could be beneficial. NEVER let yourself get sunburnt though.
What dose of the vitamin should I be taking?
Michael Holick a world-renowned professor of medicine and physiology at Boston University Medical centre recommends the following dose amounts:
| Age | Daily Requirement | Upper Limit |
| 0 – 12 Months | 400 – 1000 International Units (IU) | 2000 IU |
| 1 – 8 Years | 400 – 1000 IU | 2000 IU |
| 9 – 18 Years | 400 – 2000 IU | 4000 IU |
| 18 – >70 Years | 1,500 – 4,000 IU | 10,000 IU |
To put these doses in context a recent study study found that 30 minutes of midday summer sun exposure in Oslo, Norway was equivalent to consuming 10,000–20,000 IU of vitamin D!
You may see the dosage described in micrograms (μg) on many commonly sold vitamins: 40 IU = 1 μg, 1,000 IU = 25 μg, 4,000 IU = 100 μg
Does skin colour affect Vitamin D production?
Darker-skinned people have more melanin, a compound that protects against skin damage by reducing the amount of UVB light absorbed. Darker-skinned people need more time in sunlight to make the same amount of vitamin D as lighter-skinned people.
Can I take too much vitamin D i.e. overdose on it?
You can’t overdose on it from the sun – although sunburn is another matter. But when you take too much as a supplement over a long period it can cause too much calcium to build up in the body which can cause damage to bones and vital organs. So please do not exceed the guidelines.
Dr Gareth Davies certainly suggests that 4,000 IU daily is “perfectly safe” for adults over winter.
Can I get vitamin D naturally from food?
Yes, you absolutely can! But it can be challenging to get enough and there are limited options for vegetarians and vegans. You could consider a lower dose of supplement if you can regularly get a lot of the following foods into your diet:
- Oily fish
- Egg yolk
- Red meat
- Offal
- Fortified foods such as milk, margarine, some breakfast cereals and yogurt.
Some of the supplements say Vitamin D, some say D2 or D3 – what’s the difference?
Vitamin D is more than just one vitamin. It’s a family of nutrients that shares similar chemical structures. In your diet, the most commonly found members are vitamin D2 and D3. Both types help you meet your vitamin D requirements, but they are different.
When our skin is exposed to sunlight it is vitamin D3 that it makes.
Vitamin D3 is only found in animal-sourced foods, whereas D2 mainly comes from plant sources and fortified foods. Almost all vitamin D3 supplements are derived from lanolin, which is extracted from sheep’s wool.
Research suggests that vitamin D2 is less effective than vitamin D3 at raising blood levels of vitamin D. So for the maximum benefit, it’s vitamin D3 that you need.
That was a veritable vitamin D marathon… final words from us
Actually, we are going to borrow some words from an Australian GP named Peter J Lewis we saw quoted recently on the British Medical Journal site which sums the matter up nicely.
“There are now close to 30 or so studies demonstrating that having optimal blood levels of…vitamin D…reduces covid-19 risks: reduced risk of infection; reduced risk of severe disease; reduced risk of dying. Many researchers now regard the evidence as ‘overwhelming’. Despite this, there still will be those who say that we need ‘more research’, but in the meantime, there is little to be lost (vitamin D supplements are inexpensive and have low risk of toxicity) and a huge amount to gain by recommending a decent daily dose of vitamin D3…”