The Healing Sun by Richard Hobday presents evidence showing an increase in disease with a decrease in sunlight exposure. This article asks the question: How Common is Vitamin D Deficiency?
How Sunlight Can Prevent Serious Health Problems
by Richard Hobday, taken from his book, The Healing Sun
Each year lack of sunlight probably kills many thousands more people in this country and others at similar latitudes than skin cancer. At first glance this may seem a rather outrageous statement but it could be true. In 1995 almost 1400 men and women in England and Wales died of malignant melanoma. Coronary heart disease killed 139,000 of their compatriots in the same year. Clearly, if sunlight had only a small protective effect against heart disease then the number of lives saved by regular moderate exposure to the sun would greatly outweigh the number lost to malignant melanoma. The same argument can be applied to a number of other serious degenerative and infectious diseases that together claim hundreds of thousands of lives in Britain each year, and which appear to be associated with sunlight deprivation.
How Common is Vitamin D Deficiency?
There seems little doubt that throughout much of northern Europe and the United States vitamin D deficiency is a very common problem among elderly people. A recent European study showed that in the winter months more than a third of 70-year-olds are deficient. According to a paper published in the Lancet in 1995, scientists measuring levels of vitamin D in the blood of 824 elderly subjects in 11 European countries found that levels in 36 per cent of men and nearly half the women were deficient. Those who took oral supplements or exposed themselves to UV radiation from sunlamps had satisfactory levels but, surprisingly, the lowest levels were found in the warmer southern European countries. Further investigation showed that wearing clothes to protect from the sun — the normal custom — was a strong predictor of vitamin D deficiency. The elderly are often house bound or confined to nursing homes and are unable to get into the sun. So, if they do not take vitamin D to compensate for lack ofsunlight, and their diets are lacking in calcium, they are at considerable risk from fractures and bone disorders. As far as oral supplements are concerned, some of the latest research suggests that in the absence of sunlight the elderly may need as much as 800 ID of vitamin D a day, and this level of supplementation may be required after only a few weeks spent indoors. This is enough time for the effects of sunlight deprivation to become apparent if you have not built up reserves of vitamin D to cope with it.
Vitamin D deficiency is not restricted to the house bound elderly. A study of young men on normal diets who were deprived of sunlight by being kept indoors at the Royal Navy’s Institute of Naval Medicine, showed that within six weeks their vitamin D stores had fallen sufficiently to cause inadequate absorption of calcium and a negative calcium balance. After two months of this regime their vitamin D levels had fallen by half and they had begun to lose calcium at a faster rate than they could take it in. By the tenth week there was a shortfall of one third in the calcium intake they needed to maintain a healthy balance. So, the prospects for anyone on a normal diet who is housebound or institutionalized are not favourable if they are unable to get out into the sun. Patients who have been in hospital for several weeks are clearly at risk. As Dr Damien Downing suggests in his book Day Light Robbery, if you are having bone surgery, try not to spend too long in hospital beforehand as a deficiency of vitamin D might well prejudice your chances of a speedy recovery. Fifty years ago, it was common for orthopaedic patients to be wheeled outside in their beds in good weather so that they could derive some benefit from any sunlight and fresh air that was available. While they were outside braving the elements, nursing staff could ensure the wards were thoroughly ventilated and cleaned. Needless to say, modern hospitals are no longer designed for this. If the extent of vitamin D deficiency amongst hospital patients is as significant as some studies suggest, there are grounds for architectural modifications.
Having looked at the vitamin D status of the elderly and institutionalized, what about the wider populations of northern industrialized nations? Is vitamin D deficiency as common amongst otherwise healthy adults in the general population as it appears to be amongst the elderly? The latest findings suggest that the problem may be far more widespread in developed countries than it once appeared to be. Researchers at Boston’s Massachusetts General Hospital recently found that 66 per cent of patients on a general medical ward who consumed less than the recommended daily amount of vitamin D were deficient. These patients were younger than those in many earlier studies of vitamin D status, with an average age of 62 years, and only a minority of them were housebound or residents of a nursing home before being admitted, so they could be considered to be broadly representative of the general population.
What is particularly striking about the findings of this research, which was published in the New England Journal of Medicine in 1998, is that low levels were found in 46 per cent of patients taking multivitamins, many of which contained 400 IU of vitamin D. Of the patients who had actually consumed more than the recommended daily allowance of vitamin D for their age, one in three were still deficient. One possible explanation for this shortfall is that when the recommended daily intakes were calculated for the citizens of the United States it was assumed that everyone would be getting a proportion of their vitamin D from the sun. Hospital patients, as we have already seen, are not well placed to do this. But if the general population in urban areas in the United States are not taking the recommended amount and are not getting out in the sun either, then it is reasonable to conclude that the prevalence of vitamin D insufficiency, if not deficiency, is rather high.
The problem is not confined to the United States. The results of a survey of the vitamin D status of adults living in cities throughout France published in the journal Osteoporosis International in 1998 confirms that there is a high prevalence of insufficiency amongst the adult populations in urban areas because they lack sunlight exposure. Dairy products are not fortified with vitamin D in France, and the average daily intake is usually less than 100 IU a day, so vitamin D status depends mainly on the amount of sunlight available. In this study the lowest levels of vitamin D were measured in the north and centre of the country and the highest in the south west.
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