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This Week - V : Vitamin D

Vitamin D helps regulate the amount of calcium and phosphate in the body.

These nutrients are needed to keep bones, teeth and muscles healthy.

A lack of vitamin D can lead to bone deformities such as rickets in children, and bone pain caused by a condition called osteomalacia in adults.

Government advice is that everyone should consider taking a daily vitamin D supplement during the autumn and winter.

People at high risk of not getting enough vitamin D should take a daily supplement throughout the year.

There have been some reports about vitamin D reducing the risk of coronavirus (COVID-19). But there is currently not enough evidence to support taking vitamin D solely to prevent or treat COVID-19.

Good sources of vitamin D

From about late March/early April to the end of September, most people should be able to make all the vitamin D they need from sunlight.

The body creates vitamin D from direct sunlight on the skin when outdoors.

But between October and early March we do not make enough vitamin D from sunlight.

Vitamin D is also found in a small number of foods.

Sources include:

• oily fish - such as salmon, sardines, herring and mackerel
• red meat
• liver (avoid liver if you are pregnant)
• egg yolks
• fortified foods - such as some fat spreads and breakfast cereals

Another source of vitamin D is dietary supplements.

In the UK, cows' milk is generally not a good source of vitamin D because it is not fortified, as it is in some other countries.

How much vitamin D do I need?

From about late March/early April to the end of September, the majority of people should be able to make all the vitamin D they need from sunlight on their skin.

A microgram (mcg) is 1,000 times smaller than a milligram (mg). The word microgram is sometimes written with the Greek symbol µ followed by the letter g (µg).

Sometimes the amount of vitamin D is expressed as International Units (IU). 1 microgram of vitamin D is equal to 40 IU. So 10 micrograms of vitamin D is equal to 400 IU.

Advice for adults and children over 4 years old

During the autumn and winter, you need to get vitamin D from your diet because the sun is not strong enough for the body to make vitamin D.

But since it's difficult for people to get enough vitamin D from food alone, everyone should consider taking a daily supplement containing 10 micrograms of vitamin D during the autumn and winter.

Between late March/early April to the end of September, most people can make all the vitamin D they need through sunlight on their skin and from a balanced diet.

You may choose not to take a vitamin D supplement during these months.

People at risk of vitamin D deficiency

Some people will not make enough vitamin D from sunlight because they have very little or no sunshine exposure.

The Department of Health and Social Care recommends that adults and children over 4 take a daily supplement containing 10 micrograms of vitamin D throughout the year if they:

• are not often outdoors - for example, if they're frail or housebound
• are in an institution like a care home
• usually wear clothes that cover up most of their skin when outdoors

If you have dark skin - for example you have an African, African-Caribbean or south Asian background - you may also not make enough vitamin D from sunlight.

You should consider taking a daily supplement containing 10 micrograms of vitamin D throughout the year.

What happens if I take too much vitamin D?

Taking too many vitamin D supplements over a long period of time can cause too much calcium to build up in the body (hypercalcaemia). This can weaken the bones and damage the kidneys and the heart.

If you choose to take vitamin D supplements, 10 micrograms a day will be enough for most people.

Do not take more than 100 micrograms (4,000 IU) of vitamin D a day as it could be harmful.

Some people have medical conditions that mean they may not be able to safely take as much. If in doubt, you should consult your doctor.

If your doctor has recommended you take a different amount of vitamin D, you should follow their advice.

You cannot overdose on vitamin D through exposure to sunlight. But always remember to cover up or protect your skin if you're out in the sun for long periods to reduce the risk of skin damage and skin cancer.

If you want to find out more about this week's subject you can visit the Original article on the NHS website. If you are worried by any aspect of your health make sure you go and see your doctor or book an appointment at your local clinic.