Debate rages over vitamin D – can we get enough from sunlight or should we take supplements? In this quick guide we round up the key facts about vitamin D that you should know and answer some of the most common questions to help you sort nutritional fact from fiction.
Is vitamin D essential?
Yes, everyone needs vitamin D for healthy bones and teeth as it helps to control the amount of calcium and phosphorous we absorb. It also controls the release of some hormones. Vitamin D is one of the family of fat-soluble vitamins and can be stored in the body for long periods, so you don’t necessarily need it every day.
Which foods contain vitamin D?
Oily fish such as mackerel, salmon, sardines and pilchards are naturally rich in vitamin D. Meat, especially liver, and egg yolks contain it too. Some other foods also have it added, especially breakfast cereals and some powdered milks. Find out more ways to increase your vitamin D levels naturally.
Why is Vitamin D called the sunshine vitamin?
Most of the vitamin D we need is made in the body when the skin is exposed to the UVB in sunlight. In the UK in the winter, the amount and type of UVB we receive is insufficient for vitamin D production in the skin so the stores we build up in the summer need to last through winter.
Of course, it is important to take care of your skin in the summer sun, but the vitamin D we need can be made in a relatively short time. One of the most interesting facts about vitamin D is that, for most people, just 15 minutes or so a day spent outside with face and forearms uncovered and without sun cream, is sufficient. This is less than the time it takes skin to redden and burn, but don’t forget to use sun cream if you are out for longer.
How can I tell if I have enough vitamin D?
National surveys in Britain suggest that only about one adult in seven under 65 years old falls below the level defined as vitamin D deficiency, but this rises to one in three older adults. Low vitamin D is particularly common in those who live in institutions or who are housebound.
In adults, prolonged vitamin D deficiency causes osteomalacia, a softening of the bones leading to pain and weakness. It is also linked to osteoporosis and a higher risk of bone fractures. Vitamin D deficiency in children leads to rickets and osteomalacia, with poor bone growth and ultimately deformities such as bowed legs.
Rickets remains a problem in the UK, especially among some ethnic minority groups who wear concealing clothing and/or with darker skin that takes longer to make vitamin D from sunlight.
How can I protect my baby from vitamin D deficiency?
Babies are a risk from vitamin D deficiency, especially if they are born with low stores of it. Doctors advise pregnant women and breastfeeding mums to take a vitamin D supplement to ensure their baby receives enough. New advice also recommends that, as a precaution, all babies under one year should have a daily 8.5-10mcg vitamin D supplement to make sure they get enough. Formula milk for babies and toddlers contains vitamin D, so an additional supplement would not usually be required. After weaning, it is important to feed them vitamin D-rich foods and spend time outdoors.
Do overweight people need extra vitamin D?
Some studies found people who are overweight have less vitamin D circulating in their blood. Vitamin D is stored in body fat so it may get ‘locked up’ in fat cells, or overweight people may expose their skin less to sunshine. But there is no evidence overweight or obese people need to take extra vitamin D.
Can extra vitamin D improve my health?
There have been claims that vitamin D can protect against all kinds of diseases, from multiple sclerosis to heart disease. This is based mostly on research on animals, in the laboratory or by comparing the health of people in different countries with different diets or variable exposure to sunlight. The links between vitamin D and diseases other than those linked to bones have not been conclusively proven.
Two clinical trials tested the effects of taking vitamin D supplements on the risk of developing bowel cancer – and both showed no effect. Experts have concluded that, for most people, there is no good evidence that taking extra vitamin D supplements has any health benefit.
Should I take a vitamin D supplement?
The new advice from Public Health England is that adults and children over the age of one should have 10 micrograms (mcg) of vitamin D every day. This means that some people may want to consider taking a daily supplement containing 10mcg of vitamin D, particularly during autumn and winter.
People who have a higher risk of vitamin D deficiency are being advised to take a supplement all year round. At-risk groups include people whose skin has little or no exposure to the sun, like those in care homes, or people who cover their skin when they are outside.
People with dark skin, from African, African-Caribbean and South Asian backgrounds, may also not get enough vitamin D from sunlight in the summer, and should consider taking a supplement. It is also now recommended that children aged one to four years should have a daily 10mcg vitamin D supplement all year round.