Day 26 of our Bitesize Nutrition challenge is to take some time outside to soak up some sunshine (and vitamin D), but:

  • The UVB rays from the sun are only strong enough to make vitamin D from April to October in the UK
  • Awareness of the risk of skin cancer from sun over exposure
  • Limited absorption of UVB rays through clothing, sun screen, and some moisturisers/make-up with SPF factor

Barely a day goes by without at least one article linking vitamin D and Covid-19. It can be very confusing – and that’s from a Nutritionists perspective, so what is the real story and should you take vitamin D to support your immunity? We discuss this in our Immunity webinar and also below.

There’s been so much misinformation spread through uncertainty and fear. An article 10th 2020 Sept claimed “Vit D supplements could keep Covid-19 patients out of intensive care”. Researchers gave 50 patients in a Spanish hospital 100mcg over a week (NHS recommends 70mcg weekly limit).

It’s important to remember, as identified in a recent paper by one of my MSc Nutritional Medicine lecturers:

  • Vitamin D is essential for good health
  • People in the UK have low levels of vitamin D particularly during Winter months or if confined indoors
  • Possible exacerbation of low vitamin D status during Covid-19 crisis from reduced exposure to the sun.
  • Guideline is 400IU/10mcg per day in UK
  • There’s no strong evidence vitamin D in high levels will prevent or treat Covid-19, but there is evidence of health risks when high levels of vitamin D are taken especially in people who have other health issues e.g. reduced kidney function.

Public Health England previously stated vitamin D is essential for health of bone, muscle, and teeth. In clinical trials vitamin D prevented/reduced the incidence of rickets, whilst surprisingly to many people it also reduced joint and bone pain (osteomalacia). Typically, people found reduced discomfort in the long bones (hips and knees) and anecdotally we hear from people experiencing reduced pain even in the smaller bones in their hands.

Where do you get vitamin D from?

By far the best source of vitamin D is from the sun UVB rays. If however we take the UK (in particular the South of the UK) the UVB rays are insufficient for our bodies to make vitamin D between the months October to March so we should take a vitamin D3 supplement.

The suggested amount of sun exposure to the face and arms between April – September is 10 minutes in the middle of each day for people who are fair skinned increasing to 25min for darker skin tones. Wearing sun cream (check moisturisers and make-up too) will limit the amount of UVB rays absorbed, as will clothing.

Where possible eat foods which contains vitamin D (eggs, red meat, oily fish e.g. salmon, sardines, mackerel, fortified foods such as breakfast cereals) as part of your regular balanced diet, but evidence suggests food alone doesn’t provide sufficient amount of vitamin D.

How much & how often?

Vitamin D will not prevent Covid-19, but it should be part of a healthy lifestyle (food and external exercise).

The UK supplement guidance is 400IU/10mcg daily. People particularly at high risk of vitamin D deficiency are babies, pregnancy women, the elderly (formula fed babies may not need supplementation if their formula may already contain vitamin D).

There are risks associated with taking too much vitamin D as a supplement – over the long term it may cause more calcium to be absorbed by the body leading to high calcium in the blood (hypercalcaemia) damaging kidneys and the heart. As with all medicine and supplements dose as directed and consult a GP if unsure.

Vitamin C

Immunity is not just about vitamin D, so many vitamins and minerals are also involved including vitamin C. Here’s a link to an article we wrote about immunity and vitamin C.


We now know a lot more about our microbiome and just how important it is for immune health. You can read more about how a good microbiome helps to support your immunity through eating fibre and when and where to add prebiotics and probiotics to your diet.

If you’d like to find out more tips to improve your health, check out our webinars and our Bitesize Nutrition podcasts, in particular the episode with Professor Susan Lanham-New on Covid & vitamin D. If you’re not into podcasts (yet!) click on the podcast link in this paragraph to listen free without registration on your phone or PC, or find Bitesize Nutrition on iTunes & Spotify.

Don’t forget to let us know what you think using #nutritionchallenge30

A reminder:

  • The information in this article is for educational purposes and should not replace medical advice.
  • The information is not intended to diagnose or treat any medical condition.
  • If you have a diagnosed medical condition, you should consult a doctor before making any major changes to your diet, and;
  • Some supplements may interact with medications and you should check with your GP before commencing any supplement programme.
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