Vitamin D: The sunshine vitamin
Monday 11th August
It's essential for strong bones and healthy bodies but is your family getting enough vitamin D, asks Lesley Dobson.
When it’s bright outside, the urge to bask in the sunshine can be almost irresistible. As well as the pleasure of feeling its warm rays on our skin, we actually need the sun to keep us healthy. But for many of us, the fear of sun damage, and the associated risks of skin cancer can overshadow the health benefits.
Sunshine is, in fact, the body’s main source of vitamin D, which it needs to build strong bones and to help prevent rickets in children. Vitamin D is also believed to be a factor in protecting against cardiovascular disease, diabetes (types 1 and 2) and multiple sclerosis.
It is the ultraviolet (UV) light in the sun’s rays that is so important. When UV makes contact with our skin, it triggers the production of vitamin D. Recent figures, however, indicate that many of us have a deficiency. Rickets, the condition that caused bow-legs in Victorian working-class children, has shown a resurgence and the number of cases is growing in the UK.
“Many adults spend a lot of time indoors these days,” says Dr Colin Michie, consultant senior lecturer in paediatrics at Ealing Hospital NHS Trust. “And for children, it’s even worse – they’re spending more time in front of computer screens and barely getting outside at all.
“Exposure to sunshine, the main human source of vitamin D, is very low now. People seem to be positively frightened by sunshine. When they do go out they cover up with sunblock and ultraviolet blocking agents.”
Who’s at risk?
Some groups are more prone to serious vitamin D deficiency than others. “Pregnant and breastfeeding mums are the largest at-risk group in the UK,” explains Colin. “They need extra vitamin D because they give lots of their vitamin D to their foetus, or to the baby they’re feeding, and so end up being short of it themselves.”
This message is even more important for women who have multiple births – twins or triplets – and mums-to-be who already have one child or more. Because each baby receives some of its mother’s vitamin D, with each subsequent baby the mother has less left for herself.
If you come from an African-Caribbean or Asian background, you’re also in a high-risk group. This is because darker skin is less efficient than paler skin at producing vitamin D. If you also wear traditional clothing, which covers you entirely, and spend a lot of time indoors, you’re unlikely to make any vitamin D.
“Children need vitamin D,” explains Colin. “This is especially important for the two- to five-year-olds, and the teenagers. They go through growth spurts and put on a lot of height very quickly, which means that they’re building bone. You want that bone to be strong, so in order to put calcium into it you need vitamin D,” he says, explaining that vitamin D helps the body absorb calcium.
“Anyone under five should have vitamin D supplements,” he adds. He isn’t alone in this view. The chief medical officer for England, Professor Dame Sally Davies, has asked the National Institute for Health and Care Excellence (Nice) to look into providing free vitamins for all under-fives.
For older people, aged 65 and over, there is also a risk of low levels of vitamin D. If you are considering taking vitamin D supplements, however, talk to your doctor first, in case it would conflict with prescription medicines.
Other sources of vitamin D
“Unfortunately, you get very little vitamin D from food,” says Eliza Matthews, the children’s services lead at Benenden Hospital. “Babies who are fed on formula milk don’t usually need anything extra as the milk is fortified with vitamin D. Mums who are breastfeeding may be recommended to take supplements, to make sure they have enough.”
The best food sources are oily fish, such as salmon, sardines and mackerel, and eggs. “You can also find some foods are fortified with vitamin D, including cereals, margarine and powdered milk,” explains Eliza. This information will appear on the packaging. So if in doubt, check.
So how much sun do we need?
Saying “get out in the sun” may be good advice from the point of view of topping up on vitamin D. However, in terms of protecting sensitive skin from sunburn, and the risk of developing skin cancer, it’s important to strike the right balance.
So, how long should we spend in the sun? “Because everybody’s skin is different, there’s no single recommendation for the amount of sun you need to make enough vitamin D,” explains Jessica Kirby, senior health information manager for Cancer Research UK.
“The amount of vitamin D you make depends on a lot of environmental conditions – the strength of the UV rays, the cloud cover, your altitude and your skin.”
It’s therefore impossible to say how many minutes an individual would need, but the following tips will help.
- The simple rule is to enjoy the sun but to avoid sunburn, by using sun protection products, and by staying in the shade between 11 am and 3 pm.
- Know your skin type – if you have pale skin, freckles, red or fair hair, and blue or green eyes (type 1 skin), you’re likely to burn more quickly than someone with dark skin and hair.
- Follow the UV index – more detailed weather forecasts will tell you the UV index for your area for each day.
- Take extra care with the delicate skin of babies and children. Babies under six months old shouldn’t be exposed to direct sunlight.
- Visit Cancer Research UK’s website, which provides useful information including tables to help you calculate your risk of burning (skin type combined with UV index).
This article first appeared in benhealth (issue 27, summer 2014), the magazine for members of benenden.