Vitamin D

Vitamin D helps to 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 and tenderness as a result of a condition called osteomalacia in adults.

Good sources of vitamin D

From about late March/April to the end of September, most of us should be able to get all the vitamin D we need from sunlight on our skin. The vitamin is made by our body under the skin in reaction to sunlight.

If you are out in the sun, take care to cover up or protect your skin with sunscreen before you turn red or get burnt. Between October and early March we don't get any vitamin D from sunlight.

Good food sources are:

• oily fish  such as salmon, sardines, herring and mackerel
• red meat
• liver
• egg yolks
• fortified foods such as most fat spreads and some 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 isn't fortified, as it is in some other countries.

How much vitamin D do I need?

Babies from birth to one year need 8.5 to 10 micrograms (8.5-10mcg) of vitamin D a day.

Children from the age of one year and adults need 10 micrograms (10mcg) of vitamin D a day. This includes pregnant and breastfeeding women and population groups at risk of vitamin D deficiency (those with minimal exposure to sunshine and those from minority ethnic groups with dark skin).

From about late March/April to the end of September, most of us should be able to get all the vitamin D we need from sunlight on our skin.

Should I take a vitamin D supplement?

Advice for infants and young children

The Department of Health recommends that:

• Breastfed babies from birth to one year of age should be given a daily supplement containing 8.5 to 10mcg of vitamin D, to make sure they get enough. 
• Babies fed infant formula should not be given a vitamin D supplement until they are receiving less than 500ml (about a pint) of infant formula a day, because infant formula is fortified with vitamin D
• Children aged 1 to 4 years old should be given a daily supplement containing 10mcg of vitamin D

You can buy single vitamin D supplements or vitamin drops containing vitamin D (for use by under-fives) at most pharmacies and supermarkets. Women and children who qualify for the Healthy Start scheme can get free supplements containing the recommended amounts of vitamin D.

See the  Healthy Start website for more information on the scheme.

Advice for adults and children over five years old

Because vitamin D is found only in a small number of foods, it might be difficult to get enough from foods that naturally contain vitamin D and/or fortified foods alone. So everyone, including pregnant and breastfeeding women, should consider taking a daily supplement containing 10mcg of vitamin D.

Between late March/April to the end of September, the majority of people aged five years and above will probably obtain sufficient vitamin D from sunlight when they are outdoors. So you might choose not to take a vitamin D supplement during these months.

However, some groups of people will not get enough vitamin D from sunlight because they have very little or no sunshine exposure. So the Department of Health recommends that people should take a daily supplement containing 10mcg of vitamin D throughout the year if they:

• are not often outdoors, such as those who are frail or housebound
• are in an institution such as a care home
• usually wear clothes that cover up most of their skin when outdoors

People from minority ethnic groups with dark skin, such as those of African, African-Caribbean or South Asian origin, might not get enough vitamin D from sunlight so they should consider taking a daily supplement containing 10mcg 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 more calcium to be absorbed by the body than can be excreted. This leads to high levels of calcium in the blood (hypercalcaemia).

Too much calcium in the blood can weaken the bones and damage the kidneys and the heart.

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

Do not take more than 100mcg of vitamin D a day, as it could be harmful. This applies to adults, including pregnant and breastfeeding women and the elderly, and children aged 11-17 years.

Children aged 1-10 years should not have more than 50mcg a day.

Infants under 12 months should not have more than 25mcg a day.

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.

Your body doesn't make too much vitamin D from sun exposure, but always remember to cover up or protect your skin if you are out in the sun for long periods, to reduce the risk of skin damage and skin cancer.