Vitamin D And The Sunscreen Controversy
For years, even decades, Vitamin D has been the almost forgotten stepchild of nutrition. With increasing scientific research into the vitamin, however, that lowly status has ended as its many benefits become apparent.
Vitamin D’s Many Protective Effects
Recent research suggests that higher levels of Vitamin D in the blood may lower the risk of multiple sclerosis (MS), a degenerative neurological disease that currently affects around two million people worldwide.
In the latest study, a large-scale investigation based upon stored blood samples from more than 7 million U.S. military personnel, researchers found that the risk of MS fell significantly as blood levels of the vitamin rose.
People with the highest levels of Vitamin D apparently had a 62% lower risk of MS than those with the lowest levels.
Although previous research had already found that women who take Vitamin D supplements are 40% less likely to develop MS, this latest finding, published in the Journal of the American Medical Association (JAMA), is especially significant, as the study is the first large-scale analysis to demonstrate a direct connection between blood levels of Vitamin D and the risk of developing MS.
If the JAMA study is confirmed, therefore, MS appears poised to join an increasing list of conditions including cancer, diabetes, heart disease, high blood pressure, lung disease, osteoporosis, and schizophrenia against which it is believed Vitamin D has a protective effect.
Crucially, however, and unlike most of the other vitamins, the majority of the body’s supply of Vitamin D does not come from food, but is produced in our skin when we are exposed to ultraviolet light from the Sun. Around 90 per cent of our total supply of Vitamin D is obtained in this way.
As such, it is interesting to note that the prevalence of MS is nearly zero in equatorial regions and that its incidence in populations increases dramatically the further people are located from the equator. Because of this, some researchers have long hypothesised that a crucial environmental factor in MS could well be an individual’s degree of sunlight exposure and his or her resulting production of Vitamin D.
Significantly, therefore, a number of scientists now believe that our growing use of sunscreens and reduced time spent outdoors could consequently be contributing to an increasing incidence of Vitamin-D deficiency – and thus to an increased risk of disease.
Deficiency More Common Than Thought
Surprising though it might seem, Vitamin-D deficiency is still quite widespread in the UK, where I live; and, in recent years, the number of cases of rickets – the Vitamin-D deficiency disease of childhood, characterized by impeded growth, and deformity, of the long bones – has actually increased. Some estimates claim that at least 60 per cent of the UK population is now Vitamin D deficient.
Over in Ireland, meanwhile, the Food Safety Authority of Ireland (FSAI) has just published a report recommending the implementation of a national policy of Vitamin-D supplementation in all Irish infants aged 0-12 months. This recommendation follows a review undertaken by the FSAI’s Scientific Committee which highlights the re-emergence of rickets in Irish infants. According to the FSAI’s report, as many as 23 cases of rickets have been reported in recent years at two Dublin-based pediatric hospitals alone.
Amongst adults, several population groups are at particular risk of Vitamin-D deficiency.
Dark-skinned people living in northern climates are especially at risk, for example, as reduced sunlight exposure and the increased efficiency of darker skin in blocking out ultraviolet (UV) radiation combine to make adequate production of the vitamin more difficult. A recent study carried out in the outpatient department at a hospital in Birmingham, in the UK, for example, found a particularly high prevalence of deficiency in Afro-Caribbean and Asian people.
Vegans and vegetarians are also at increased risk of being deficient in Vitamin D because, with the exception of foods such as breakfast cereals that are fortified with it, Vitamin D does not generally occur naturally in non-animal foods.
Similarly, night workers and people who do shift work also have a higher risk of Vitamin-D deficiency, due to their reduced exposure to sunlight.
Perhaps not surprisingly, therefore, some scientists are now starting to suggest that rather than preaching complete sun avoidance, public health authorities should instead be looking to find a balance between avoiding an increase in the risk of skin cancer and achieving enough ultraviolet radiation exposure to produce optimum levels of Vitamin D. In this respect, the fact that, in 2005, the Association of Cancer Councils of Australia openly acknowledged – for the first time – that some exposure to the sun was healthy, is highly significant, given that Australia has one of the highest rates of skin cancer in the world.
In fact, the scientific evidence to support such a policy is already quite strong, and some research even suggests that the use of sunscreens actually causes more cancer deaths than it prevents. For example, a scientific review published in 1993 of over fifty years’ worth of medical literature on this subject found that whilst frequent regular sun exposure acts to cause cancers that have a 0.3% death rate with 2,000 U.S. fatalities per year, it also acts to prevent cancers that have death rates from 20-65% with 138,000 U.S. fatalities per year.
In another interesting twist, some experts now believe that the oft-quoted health benefits of the so-called Mediterranean diet may in reality have as much to do with the relatively higher levels of sun exposure in the region – and thus the increased levels of Vitamin D – as they do with the food.
Easy Does It
So, where does this leave us? Should we all now abandon the use of sunscreens and burn ourselves to a cinder at every available opportunity?
Clearly, to do so would be extremely foolhardy, because whilst some unprotected sun exposure may well be a good thing, excessive exposure can undoubtedly cause fatal skin cancers.
Indeed, one could perhaps draw a parallel with alcohol here, in that whilst moderate drinking has been found to be of benefit to the heart-and-circulatory system, excessive drinking is known to increase the risk of developing heart disease.
In all likelihood, therefore, and as the aforementioned scientific review pointed out, it would appear that sunlight has a paradoxical relationship with melanoma – the most serious type of skin cancer – in that severe sunburning initiates it, whereas long-term moderate sun exposure inhibits it.
Perhaps, then, we would be best advised to heed the words of the Greek poet Hesiod, who, as early as 700 B.C., wisely wrote that “moderation is best in all things.”
So far as sun exposure goes, the evidence would appear to be growing that this could be very sound advice indeed.
So, as we approach the Summer holidays, my advice would be to take some sun, enjoy some of your favorite tipple, and, above all, apply some good old-fashioned common sense when deciding what constitutes “moderation.”
Remember the cigarette brand that “more doctors smoke”? Personally, I have more than a sneaking feeling that the over-zealous advice about sun avoidance and sunscreen that we have all been subjected to in recent years could eventually turn out to have been just as unwise.