Frequently asked questions about Vitamin D 

Frequently asked questions about Vitamin D 

What does vitamin D do? 

Vitamin D controls calcium and phosphate levels in the body. This helps to maintain bones, teeth, muscles and general wellbeing. 

Who is most at risk of low levels of vitamin D? 

Low levels of vitamin D are also called “vitamin D deficiency”. National advice tells us there is a greater risk of vitamin D deficiency in people who: 

  • are over 65 years of age 
  • are overweight 
  • are pregnant or breastfeeding 
  • are spending a lot of time indoors 
  • have darker skin tones such as those of Mediterranean heritage or Black, Asian and Minority Ethnic (BAME) background including those of mixed race 

How much vitamin D should I be taking every day? 

Normally you will get enough vitamin D from sunlight between March and September. However, the NHS is recommending that we take 400 units (10 micrograms) of vitamin D each day if we are at risk, to prevent deficiency. 

What are the effects of vitamin D deficiency? 

The main symptoms are bone pain or unexplained tiredness. 

What should I do if I have signs of vitamin D deficiency? 

If you are an inpatient with the Trust you should discuss this with the ward team. If you are an employee you can discuss it with your GP or with occupational health. Everyone else should discuss this with their GP. Serious deficiency is treated medically with higher doses of vitamin D than those usually taken in supplements. 

Is there a link between vitamin D deficiency and COVID-19? 

There is no proven link. Research is ongoing. Avoiding deficiency is still a good idea whether you are worried about COVID-19 or not. 

Is there anyone who should not take vitamin D supplements? 

You should not take these supplements if you are already taking supplements or medicines that contain vitamin D (sometimes called colecalciferol). People taking digoxin or those with severe kidney or liver problems should speak to their doctor before taking vitamin D supplements. 

What other sources of vitamin D are there? 

Your skin makes vitamin D when exposed to sunlight. Other sources include foods such as tofu, fortified cereals, egg yolks, fatty fish, soy milk and red meat. It can still be difficult to get enough vitamin D from food alone. 

What side effects do vitamin D supplements have? 

Most people do not experience side-effects. If they do then these can include abdominal (tummy) pain, headache and nausea. 

Is it safe to take vitamin D if I am pregnant or breastfeeding? 

Yes, as long as you take the dose advised. Your pregnancy supplements may already contain vitamin D, so check first. 

Where can I get vitamin D supplements? 

These can be bought from pharmacies, health food shops and many supermarkets, including on-line. Inpatients can be prescribed vitamin D supplements if they and their prescriber agree it would be helpful while they are on our wards. 

I have dietary requirements, can I still take vitamin D supplements? 

If buying supplements you will need to check at the time. If supplements are provided to you then you will need to discuss your requirements with your healthcare team. Supplements might not be strictly vegan. The Vegan Society advise that veganism is a lifestyle that “seeks 

to exclude as far as possible and practicable, all forms of exploitation of and cruelty to, animals for food, clothing or any other purpose”, but that it is not always possible to find a medicine or supplement that is truly vegan. Find out more at 

What about religious fasting such as Ramadan? 

Vitamin D supplements are only taken once a day and the timing is not important, so there is no need to take them during the hours of fasting. 

Where can I find more information about vitamin D? 

The NHS website has a lot of information about vitamin D. Visit

Produced by Twané Walker – Registered Dietitian 

January 2024