Many of us are lacking a nutrient that could be vital to protect the body against a range of illnesses. Could you be at risk too?
FOR YEARS we’ve been told to cover up, stay out of the sun and slap on factor 50 to protect ourselves against skin cancer but now some experts are admitting that overdoing the “safe-sun” message could contribute to a new health epidemic – vitamin D deficiency.
As well as osteoporosis, low levels of vitamin D have been linked to a range of serious conditions from heart disease to diabetes.
To find out the truth, Good Housekeeping magazine asked 12 randomly chosen staff members to undergo a blood test to check their levels. The tests were carried out by Harley Street GP Dr Richard Cooper. To his and their disbelief every one of these apparently healthy women had low blood levels of vitamin D and nearly half of them were clinically deficient.
Experts consider a blood level of 75 and over (measured in nmol per litre) to be the optimal level of vitamin D. Anything below 25 is classified as clinically deficient.
None of the volunteers, aged from 24 to 63, had vitamin D blood levels even approaching 75. The two with the highest scores had just returned from sunny holidays and some of the volunteers had scores below 25.
Good Housekeeping’s Dr Sarah Jarvis was stunned when she discovered her own level was low.
“I was absolutely horrified and really shocked, particularly by my own results,” she says. “I actively avoid sunbathing and burning but I don’t avoid being outside. I’ve been aware for a while there is an issue with vitamin D and that it could be a ticking time bomb for osteoporosis in later life.
“It has made me rethink the way I look at my patients. On a personal level I am so deficient that I am now having injections to get my vitamin D levels back to normal. Then I will think seriously about taking supplements.”
There’s growing evidence these results are a snapshot of what is happening among women in general.
Studies show that around half of us have inadequate vitamin D levels and during winter and spring one in six is severely deficient even at the very low minimum level set by UK authorities.
For the first time in many years cases of childhood bone disease rickets, which is caused by vitamin D deficiency, are on the rise. So what’s the explanation?
Unlike other nutrients where our intake comes almost exclusively from food we get around 90 per cent of our vitamin D from the action of sunlight on our skin.
For a variety of reasons we’re not getting nearly enough, says professor of endocrinology at Newcastle University Simon Pearce.
“Appropriate sunlight exposure is key for vitamin D synthesis and the sun-safe message has been overstated,” he says.
“Other important factors are that women in particular are unlikely to work outside and people are eating far less fish which is a good source of vitamin D.”
It’s hardly surprising levels are low when sunlight is so scarce, especially in the north of Britain.
Scotland gets only a little more sun than Eskimos inside the Arctic Circle but without the same vitamin D-rich fish diet.
Anthony Norman, professor emeritus of biochemistry at the University of California, says: “Vitamin D has been shown to play an important role in the immune system, the heart and blood vessels, the pancreas, muscle development and brain development.”
A study last year funded by the Medical Research Council (MRC) found vitamin D has a direct influence on 229 genes involved in disease, particularly those associated with multiple sclerosis, Crohn’s disease and type 1 diabetes. Scientists at the University of Copenhagen found the vitamin plays a crucial role in activating our immune defences.
Who is at risk?
The Government already recommends supplements for pregnant and breastfeeding mothers, children under four, people over 64 and those with darker skin or whose skin is not exposed to the sun very much.
People of African or Asian origin are particularly vulnerable as they need more sun to make the same amount of vitamin D.
Older people have a reduced ability to make vitamin D and people who are obese are also at greater risk.
What we don’t know
There are still many unanswered questions. How much vitamin D we need on a daily basis is a complex issue. Age, weight and skin colour can all affect the amount that we might need.
Unlike other countries the UK has no recommended daily intake level for people aged four to 65.
The Government’s Scientific Advisory Committee on Nutrition’s working group is reviewing the evidence and this will form the basis for new UK recommendations which are expected later this year.
Professor Pearce thinks we need to add vitamin D to food, particularly milk and orange juice.
How much sun is enough?
The current advice is to spend a few minutes outside in the middle of the day regularly without sunscreen.
Again there is no standard answer as the level of sun exposure needed to make enough vitamin D depends on your skin type, amount of skin exposed, time of day, latitude, altitude and cloud cover.
However our need for vitamin D isn’t a green light to fry in the sun.
Vitamin D production stops well before the skin starts to become red so never allow your skin to redden or burn.
Darker-skinned people will be able to spend more time in the sun than those with fairer skin who burn more easily.
What is now needed are large-scale clinical trials that use high doses of vitamin D to raise blood levels while measuring the impact on disease. The good news is that it’s starting to happen around the world.
What it means for you
“While we shouldn’t overreact, the impact of vitamin D on bone health is a certainty and on that basis alone those with lower levels need to address the issue,” says Dr Cooper.
Although vitamin D is found in fortified margarines, oily fish, eggs and some breakfast cereals, food is only a small part of the equation and anyone who gets very little sun should consider supplements.
Current UK advice is that taking up to 25mcg of vitamin D3 daily is safe. It can also be taken in liquid form.