How vitamin D can make a difference

As the days get shorter and duller, the UK gets less and less sunlight - which means its residents get less and less of the sunshine vitamin D.

And not getting enough of this essential vitamin can lead to health problems, including the bone-deformity disease rickets, which is on the rise in UK children.

Now, National Vitamin D Awareness Week (October 19-25) is hoping to alter misconceptions about how easy it is to get the necessary amount of vitamin D. Timed to coincide with the clocks going back and days getting shorter, the week aims to increase understanding of the health issues associated with declining levels of vitamin D.

Bone Health

The vitamin helps keep bones and teeth healthy by controlling the amount of calcium and phosphate in the body, and aids the maintenance of a robust immune system. Plus, a new Danish study has suggested that higher exposure to sunlight in the teenage years may delay the onset of multiple sclerosis.

Dr Sarah Brewer, a former GP and now a registered nutritionist and author, explains that it’s increasingly recognised that getting the right amount of vitamin D has a number of health benefits.

“Vitamin D was once thought to be all about calcium and bone health,” she says, “but it’s now recognised as having effects all over the body through it’s hormone action and ability to interact with DNA.”

Summer Sun

Most people should be able to get all the vitamin D they need from a healthy balanced diet and summer sun, as vitamin D is produced naturally when the skin is exposed to UVB radiation from the sun. However, there’s not enough sunlight at the right wavelength between October and April in the UK for people to produce the vitamin under their skin.

Partly because of this, and the fact that children play outside less than they used to, the number of children suffering from vitamin D deficiency tripled in the four years up to last year, and in England alone, around a sixth of children are thought to have low vitamin D levels.

In children, whose bones are growing, vitamin D deficiency can cause rickets, which makes the bones soft and weak and can lead to deformities. The disease was rife in the Victorian era and had been virtually wiped out, but cases have risen five-fold in the past 15 years.

“Rickets is increasing, and less time spent outdoors is only one factor,” explains Dr Brewer.

“While kids can make some vitamin D in their skin, this only occurs when the UV index is 3 or more. We make no vitamin D during autumn and winter in the UK, and during summer on cloudy days.

“And even when the sun’s shining, not everyone produces vitamin D efficiently.”

In addition, the proper use of a sunscreen with a protection factor of SPF15 reduces vitamin D synthesis by 99%.

Cancer Risk

But how do parents ensure their children are getting enough sun in the summer without putting them at more risk of skin cancer from too much sun exposure?

“To balance adequate production of vitamin D against skin cancer risk, the usual advice is to obtain 10 to 15 minutes of sun exposure to the face, arms, hands or back, two or three times a week, without sunscreen,” says Dr Brewer.

Longer exposures don’t provide additional benefit, she says, as vitamin D is rapidly degraded by excess UV radiation.

Sensible Supplements

Vitamin D can be found naturally in a small number of foods including oily fish, fish liver oils, animal liver, eggs and butter, as well as fortified sources such as margarine, breakfast cereals, yoghurts and milk - although UK milk isn’t routinely fortified.

However, it’s hard to get an adequate amount of the vitamin from food alone.

Current government advice is that at-risk groups, including pregnant women, children up to the age of five, adults over 65 and people with darker skin, as well as those who don’t expose their skin to sunlight, should take a daily vitamin D supplement.

Late last year, the National Institute for Health and Care Excellence (NICE) recommended increasing access to vitamin D supplements, and a recent report by the Scientific Advisory Committee on Nutrition (SACN), an independent advisory body to the Government, suggested that all people in the UK over the age of one should supplement with vitamin D due to the lack of sunlight exposure and because natural food sources alone aren’t enough to boost vitamin D levels.

Dr Brewer agrees that vitamin supplements are key.

“It’s already recommended by the Department of Health that all children from six months to five years are given supplements, in the form of vitamin drops which contain vitamins A, C and D,” she says.

“The only way to know if a child is getting enough vitamin D for sure is to follow Department of Health guidelines and give them a supplement until at least the age of five, and to ensure they have a vitamin D-rich diet.”

• Dr Sarah Brewer’s free booklet Do You Need A MultiVitamin? is available at nutritionupdates.subscribemenow.com.