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How Sunlight Can Prevent Serious Health Problems

by Richard Hobday, taken from his book, The Healing Sun To purchase a copy of this book, please visit www.findhornpress.com or www.steinerbooks.org

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.

The diseases discussed in this chapter are thought by some researchers to be linked to inadequate levels of vitamin D in the body. What you have to bear in mind when you scan the table below is that in many cases the association with lack of vitamin D and sunlight has not been proven, but this is largely due to the fact that, until quite recently, comparatively little research has been carried out into the effects of vitamin D on the immune system. Another thing to bear in mind is that in Britain, as elsewhere, the vitamin D status of the general population has not been measured. So we could all have rather less of it circulating in our bloodstream than we need to have. Before we start looking at specific diseases, perhaps it would be as well to try and determine how prevalent vitamin D deficiency, or insufficiency, really is by looking at the results of some of the latest research on the subject.

Lack of sunlight, and diseases related to it

Breast cancer

Colon cancer

Diabetes

Elevated blood pressure

Heart disease

Multiple sclerosis

Ovarian cancer

Osteomalacia

Osteoporosis

Prostate cancer

Psoriasis

Rickets

Seasonal Affective Disorder

Tooth decay

Tuberculosis

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 ofsunlight, 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.

Sunlight and Brittle Bones
The incidence of hip fracture shows a similar geographical distribution to vitamin D insufficiency in France, being higher in the east and centre of the country than in the sunny west and south. This is significant, because if there were a major problem with vitamin D status amongst a large section of the urban populations of developed countries, then one might reasonably expect to see a correspondingly high incidence of degenerative bone disease and hip fractures. Traditionally, sunlight deprivation has been linked with weak or brittle bones. One of the earliest references to this was made more than two thousand years ago by the Greek historian Herodotus (480-425 BC), who noted a marked difference between the remains of the Egyptian and Persian casualties at the site of battle of Pelusium which took place in 525 BC:

Osteoporosis, The 'Silent Epidemic'
The bone disease osteoporosis is becoming so common in western countries as to be termed a 'silent epidemic'. Osteoporosis affects one in three women over fifty in the UK and one in twelve men. Each year about 50,000 wrist fractures, 40,000 vertebral fractures and 60,000 hip fractures are diagnosed annually. Some 20 per cent of these hip fractures are followed by death, and those who survive often suffer permanent disability and dependency. More women die as a result of hip fractures than cancer of the cervix, ovary and womb combined. For reasons that are not fully understood, bone quality is deteriorating amongst a significant proportion of the older population, and low levels of vitamin D are implicated.

Typically, women begin to lose about one per cent of their bone mass each year from about the age of 30 to 35, and men from the age of about 55. When women reach the menopause this loss can accelerate because oestrogen, which helps their bones to absorb calcium, begins to decline. In some individuals bones become thin and honeycombed, and are prone to fractures which can occur spontaneously. The hip and wrist are most susceptible, and crumbling of the spine is common. Loss of height and spinal deformity — the so-called 'Dowagers Hump' — characterize the disease. Injuries caused by osteoporosis can be very difficult to cure, as by the time the disease is diagnosed or a fracture occurs the structure of the bone has altered to such an extent that as much as a third of bone mass may have been lost. The orthodox view is that the condition is largely irreversible, so treatment is aimed at preventing further bone loss, rather than rebuilding the remaining skeleton.

In men, osteoporosis can be caused by low levels of the hormone testosterone or other health problems, but nearly half the cases of male osteoporosis has no known cause. Where women are concerned, hormone replacement therapy is considered the most effective way to halt the decrease in bone mass which occurs after the menopause. Osteoporosis may have more to do with a weakened immune system or poor nutrition than hormonal imbalance. With advancing age the intestine becomes less efficient at absorbing calcium from the diet, and the British diet probably contains insufficient calcium to compensate for any persistent loss from the body. But, whatever the cause of osteoporosis, the disease places a tremendous strain on public resources because of the cost of operations and aftercare. In the UK, the National Health Service spends more than £900 million on the treatment of osteoporosis each year. With the populations of western countries ageing, osteoporosis seems likely to place an ever increasing burden on already overstretched healthcare systems. More than one million skeletal fractures occur annually in the United States as a result of osteoporosis, of which 300,000 are hip fractures. The World Health Organization estimate that worldwide the annual number of hip fractures could rise from 1.7 million in 1990 to 6.3 million by 2050.

At the present time, conventional medical thinking holds that lack of sunlight does not play a major role in the genesis of the disease. This is understandable given the current attitudes towards the sun, and the fact that no one seems to have examined to any great extent the relationship between osteoporosis and sunlight exposure. But lack of sunlight does seem to exacerbate the disease. It has been recognized for over two decades that vitamin D deficiency is associated with increased risk of hip fracture: some studies suggest that roughly 30 to 40 per cent of elderly patients with hip fractures are deficient or insufficient. More significantly, there is a pronounced seasonal variation both in bone density and in the incidence of hip fractures. Bone density is at its lowest during the winter, more hip fractures occur in the winter months than at other times of the year, and hip fractures become more common with increasing latitude. Most falls and fall-related injuries take place in the home, so this seasonal variation in fractures is not due to ice and snow causing falls.

There is evidence that the over seventies can benefit from taking calcium and vitamin D supplements. A study published in the Lancet in 1994 showed that women in homes for the elderly who received a daily dose of 800 IU of vitamin D and 1200 mg of calcium over an 18-month period had a reduced risk of fracture. Some 3,270 women took part, and there was a 25 per cent reduction in the number of fractures after three years of treatment compared to those women who did not receive the supplements. There have since been other studies which show that non-vertebral fractures in the elderly can be reduced by giving oral vitamin D and calcium supplements, but the relative contribution of vitamin D and calcium is not known.

While it is much more convenient for the elderly to take supplements rather than sunbathe, this dietary approach to the problem means that they are denied all of the other benefits that sunlight exposure could bring besides the synthesis of vitamin D in the skin. Of course, like modern hospitals, elderly people's homes are not designed for sunbathing. The days of sun lounges, verandahs and porches are long gone, as is the solarium. In view of the osteoporosis epidemic, and the incidence of other degenerative diseases which may be linked to sunlight deprivation, designers should be encouraged to include them. Alternatively, sunlamps could be introduced as it is established that ultraviolet radiation from artificial sources will correct vitamin D deficiency in the elderly. However, given current concerns about skin cancer, ultraviolet radiation is unlikely to be adopted in favour of oral supplements for the foreseeable future.

As far as osteoporosis is concerned the conventional view is that the best way to prevent it in later life is to build up high bone mass during childhood and adolescence by taking regular exercise and getting plenty of vitamin D and calcium. Then, if calcium has been absorbed to a sufficient degree, the loss of bone mass associated with ageing starts from a level that is less likely to drop below the 'fracture threshold', at which point the risk of breaking bones increases. In practice, this means either getting out in the sun or taking oral supplements such as cod-liver oil, and engaging in strenuous activities during childhood. Yet parents are currently being actively discouraged from exposing infants to sunlight, and are being advised to put factor 15 sunscreen on their children whenever they go outside in the summer months. This may prevent sunburn, but not bone disorders in later life.

Rickets and Osteomalacia — The 'Diseases of Darkness'
There are several diseases which are traditionally associated with sunlight deprivation but the most widely known is called rickets. This used to be a very common condition in this country and, although medical textbooks refer to rickets as a dietary-deficiency disease caused by a lack of vitamin D, it was actually caused by air-pollution blocking out the sun's ultraviolet rays.

During the 17th and 18th centuries the bulk of the urban population in Europe and North America lived in overcrowded insanitary slums, with narrow, sunless alleyways and dark courtyards. As the Industrial Revolution got under way, and in the years that followed, these slums were covered in a permanent pall of smoke produced by the burning of coal in homes and factories. One of the constituents of this smog was sulphur dioxide, a gas which causes respiratory problems and acid rain. Sulphate particles can also form a persistent layer of acid haze which reflects ultraviolet radiation at the very wavelengths that are needed to synthesize vitamin D in the skin. So, thanks to a combination of bad housing and air pollution there were few opportunities for children to get enough sunshine. Not surprisingly, rickets was endemic at this time and became known as the 'English Disease'.

Children living in these inner-city areas who had severe rickets suffered from bone deformities and muscle weakness. Their bones softened with the result that there was an outward curvature of their legs and a curvature of the spine. Their teeth were late coming through and often fell out. This softening, weakening and demineralisation of the bones also affected adults, in whom the condition is referred to as osteomalacia. Although rickets was rarely fatal in itself, it resulted in high rates of infant and maternal deaths: women who had developed the disease in childhood often had deformities of the pelvis which made childbirth very hazardous.

At the beginning of the 20th century there were towns and cities in which more than 80 per cent of the children were affected by rickets, irrespective of social class, and there was still a great deal of confusion as to the cause. Some said it was lack of exercise; others that it was an infectious disease. Two other popular theories were that it was the result of a poor diet, or that it was caused by lack of fresh air and sunlight. Research into the causes of the disease followed two distinct paths. In 1918, scientists discovered that rickets could be cured in animals by feeding them cod-liver oil, which contains high levels of vitamin D. Having shown that vitamin D could cure rickets, it was assumed that it was a diseasecaused by vitamin deficiency; and subsequent studies by nutritionists reinforced the view that diet and vitamin D were the most important factors. Yet, at the same time, it finally became clear to scientists and physicians that rickets develops when people are deprived of sunlight, a fact which had largely been ignored in spite of strong scientific and circumstantial evidence.

Although it was known that sunlight could cure or prevent this crippling bone disease, few physicians in the 19th century were prepared to accept that something so simple as sunbathing could be an effective remedy. Indeed, to this day, it is still widely held that rickets is a disease of bad diet rather than lack of sunlight. Contrary to popular belief, and much conventional medical thinking, rickets and osteomalacia are diseases of darkness and not diet. Providing you get sufficient exposure to the sun, a diet lacking in vitamin D will not cause these diseases.

Tuberculosis and The Sun
Moving from a country which has many hours of sunshine each day to one where sunlight is in relatively short supply can lead to vitamin D deficiency. In Asian families, infants who are breast-fed for long periods are prone to vitamin D deficiency, rickets, if their mothers are not getting sunlight or taking vitamin supplements. Women who come to Britain from South Asia are particularly susceptible to tuberculosis because their diet, strict dress codes and tendency to remain indoors prevent them getting sufficient sunlight and vitamin D to ward off the disease. In their country of origin, where sunlight is strong, the small areas of skin they expose to the sun when wearing traditional clothes are adequate for the photochemical production of enough vitamin D to stay healthy. But not in Britain, where the sun shines far less often and its ultraviolet rays are weaker. So, their vitamin D levels can fall rapidly in the first year after their arrival, and the risk of their developing active tuberculosis then remains high for the first five years of residence. Elderly white males are also sometimes at risk of developing TB because they show the same tendency to remain indoors during the day and consume a diet which lacks vitamin D.

Tuberculosis is a disease which was once thought to have been vanquished but which has moved back to the top of the public health agenda during the last decade. The incidence of tuberculosis in the UK population peaked in the early 1800s and then fell steadily as public health reforms were introduced and nutrition, hygiene and housing improved. At one time the so-called 'white plague' killed more of the UK population than all other infectious diseases combined, but by the 1950s, when drugs such as streptomycin became available and the BCG vaccination was introduced, tuberculosis was no longer the threat to public health it once had been.

With the apparent defeat of TB in the UK and in other developed countries in the years that followed, pharmaceutical companies saw little merit in developing new drugs, so fundamental scientific research into the disease came to a halt and has only recently resumed. Fifty years after the introduction of streptomycin, tuberculosis is still responsible for more deaths worldwide than any other single infectious disease. Some eight million people contract tuberculosis each year and three million die from it. The incidence of the disease is increasing in both developing and industrialized countries, partly because of the emergence of strains that are resistant to the limited range of available antibiotics. These strains are becoming established in the developed world and elsewhere, posing a serious threat to international public health.

Tuberculosis requires treatment with a combination of antibiotics for anything from six months to over a year. Any interruption in the programme allows the bacterium to develop resistance to the drugs and, as a consequence, become more dangerous. In the UK tuberculosis is still comparatively rare: there are now about 6,500 new cases each year. About 5 per cent of these new cases are resistant to one antibiotic, and just over 1 per cent are multi-drug resistant. Tuberculosis has close associations with the human immunodeficiency virus (HIV) which causes AIDS. The chances of someone infected with tuberculosis going on to develop the active form of the disease are much higher if they are also carrying HIV infection: they succumb as their immune system deteriorates. In several parts of the Third World these two diseases, tuberculosis and AIDS, have been spreading concurrently, with tragic consequences.

About a third of the world's population is infected with tuberculosis bacteria. But in the vast majority of cases the body's immune system keeps the bacteria dormant or inactive. This is because when the bacteria enter the body via the respiratory system they become enclosed in the lymph nodes around the lungs where they are coated in layers of calcium. These enclosures can break down. Poor general health, poor immune status, malnutrition, alcoholism and drug abuse can cause this to happen, but most infected people lead normal healthy lives and only 5 to 10 per cent develop active tuberculosis.

The symptoms of tuberculosis include a cough, rapid loss of weight, loss of appetite, night sweats and haemoptysis — spitting blood when coughing. Tuberculosis is usually diagnosed after a chest X-ray has been taken and a sample
of phlegm examined under a microscope. Patients who have bacteria visible in their sputum are usually admitted to hospital. After a minimum of a fortnight's treatment they are non-infectious and can continue their drug therapy at home. In cases where the disease has reached an advanced stage, patients may have to spend long spells in special wards. The microbe Mycobacterium tuberculosis is carried from one person to another in airborne droplets, so it can be spread by coughing and sneezing. It can also be spread by spitting, and can attach itself to dust particles. Given the right conditions, tuberculosis bacteria can stay viable for months; but fortunately it is quite difficult to become infected unless one is in a confined space with little fresh air circulating and no sunlight. This is why tuberculosis often spreads amongst poorer families who live in cramped conditions, or homeless people in crowded, badly ventilated public dormitories, or amongst inmates in overcrowded prisons.

'Surgical Tuberculosis'
Sunlight can help prevent tuberculosis developing in susceptible individuals by keeping up their vitamin D levels, and it can also prevent the disease spreading in dwellings by killing the bacterium. This is why there has been such a close association between sunlight and tuberculosis in the past. The beneficial effects of sunlight on tuberculosis patients were widely recognised in the early years of the 20th century. Sunlight therapy was used to prevent people who were susceptible to the disease from developing it, and also to spare those who had tuberculosis from the attentions of surgeons.

The most common form of the disease is tuberculosis of the lungs, or pulmonary tuberculosis. There are other forms which can manifest in the joints, bones, spine, intestines and skin. These are now referred to collectively as extra-pulmonary tuberculosis, but used to be called 'surgical tuberculosis'. This is because during the second half of the 19th century, with the introduction of anaesthetics and antiseptics, surgery had entered what was to become known as its 'golden era', and radical, intensive surgery became the accepted treatment for non-pulmonary forms of the disease. The results of all this surgical activity were often disappointing: patients were left permanently disfigured or crippled, with no guarantee that the tuberculosis would not return. So rather than resort to surgery, some physicians began to use so-called 'conservative' measures such as nutritional therapy, exercise and fresh air to improve their patients' general health, and increase their resistance to the disease. A few used sunlight. And so it was a revolt against surgery which brought heliotherapy back from obscurity and into mainstream medical practice, as we shall see in Chapter 4. Given the right conditions, the sun's rays can be used to prevent and treat tuberculosis. They may also have rather more positive influence on other diseases, such as cancer, than is generally accepted.

Sunlight and Cancer Prevention
Vitamin D performs a number of important functions besides its role in mineral absorption. By regulating the level of calcium in the blood Vitamin D influences the nervous system, as calcium aids nerve impulse transmission and muscle contraction. It influences the secretion of insulin by the pancreas and plays an important part in regulating the body's immune system. Vitamin D is also involved in the growth and maturation of cells: in laboratory experiments the biologically active form of vitamin D has been shown to inhibit the growth of cancer cells.

Skin cancer, in all its forms, is much more common than it used to be. In Nordic countries the incidence of malignant melanoma is increasing by an average of 30 per cent every five years, and there are now over 100,000 new cases worldwide each year. As a result of the rapid increase in skin cancer in Europe, Scandinavia, North America and Australasia there are now annual public health campaigns which advocate avoidance of the sun. What tends to be overlooked in these campaigns is that skin cancer is only one of a number of cancers that are on the increase. Cancer is now the cause of a quarter of all deaths in the UK, and claims about 146,000 lives each year. It is the most common cause of mortality after coronary heart disease, with some 300,000 new cases registered annually.

In 1911, about 7 per cent of the UK population, some 37,000 in total, died of cancer each year. By 1980 it was generally held that one in four people would develop cancer over the course of their lives and one in five would die from it. Now we are told that one in three of us are destined to develop the disease and, in a recent study commissioned by the charity Macmillan Cancer Relief, it was predicted that cancer will affect one in two Britons in the next generation. Much of the steady increase in the incidence of cancer during the 20th century is attributable to smoking, but not all. The Macmillan study forecasts that prostate cancer will triple by 2018 with more than one in four men affected during their lifetime compared with one in ten in 1990. Breast cancer will rise from 9 per cent of women in 1990 to 1 3.7 per cent. The increase in these cancers is due, in part,to the growing proportion of elderly people amongst the population, but by no means all of these cancers can be attributed to ageing.

In some respects cancer is to industrialized countries today what tuberculosis was to the 18th and 19th century: a major cause of death and misery which defeats the best efforts of conventional medicine. Rather ironically the way cancer has been, and continues to be, managed is very similar to the way 'surgical tuberculosis' was dealt with a century ago — before heliotherapy was rediscovered. Then, as now, all of the emphasis was on removing the manifestation of the disease and not on enhancing the patient's ability to overcome it. The cure for cancer remains elusive despite the fact that billions have been spent on research over the last thirty years. Indeed, there can be few areas of scientific research that have had more resources thrown at it and have yielded such modest results. Although from time to time there are well-publicized breakthroughs in laboratory-based cancer research, the benefits to cancer patients are not clear cut.

As far as conventional medicine is concerned, the preferred methods treating cancer are surgery, radiation or chemotherapy. Cancer cells are removed or destroyed and no attempt is made to eliminate the disease by strengthening the body's natural defence systems. Indeed, chemotherapy and radiation do exactly the opposite. Against this background it is understandable that people are turning to non-interventionist 'conservative' techniques as an alternative, or supplement, to surgical and chemical remedies. A number of alternative therapies have been developed for cancer which claim to use the body's own healing powers rather than drugs or machine-medicine, with varying degrees of success. Sunlight has been used to treat cancer and there is evidence that goes back over half a century which suggests that sunlight exposure prevents deep-seated cancers from developing.

Now, although sunlight can cause basal cell and squamous cell skin cancers in susceptible people, there is a very good correlation between sunlight exposure and low incidence of internal cancers. Death rates from cancer increase with distance from the equator. Or, to put it another way, the nearer you live to the equator the less chance you have of developing an internal cancer. This association has been clearly demonstrated in a number of studies such as the one carried out in 1941 in the United States by Dr Frank Apperly. He examined the statistics on cancer deaths across North America and Canada and found that compared with cities between 10 and 30 degrees latitude, cities between 30 and 40 degrees latitude averaged 85 per cent higher overall cancer death rates; cities between 40 and 50 degrees latitude averaged 118 per cent higher cancer death rates, and cities between 50 and 60 degrees latitude averaged 150 per cent higher cancer death rates. Dr Apperly also looked at the relationship between sunlight, ambient temperature and skin cancer. He concluded that sunlight produces an immunity to cancer in general and, in places where the mean temperature is less than about 5.5°C, or 42°F, even to skin cancer. However, at mean temperatures higher than this, solar radiation causes more skin cancer despite the increased general immunity to the disease.

So, the nearer one is to the equator, the less chance there is of developing cancer of the breast, colon, lung, etc. There is an increased risk of developing skin cancer but this decreases in cooler climates with mean temperatures below 5.5°C, or 42°F. Dr Apperly appears to have been the first scientist to investigate the relationship between ambient temperature and skin cancer. He also suggested, as others have done before and since, that exposure to sunlight might be an effective way to reduce the number of deaths from internal cancers. He concluded his review of the statistics as follows:

There have been a number of scientific studies in the last 20 years which support the view that sunlight can inhibit cancer, and it is clear that the mortality and incidence of breast cancer and colon cancer in North America and other areas of the world increases with increasing latitude. In 1992, Dr Cordon Ainsleigh published a paper in the journal Preventive Medicine in which he reviewed 50 years worth of medical literature on cancer and the sun. He concluded that the benefits of regular sun exposure appear to outweigh by a considerable degree the risks of squamous-basal skin cancer, accelerated ageing, and melanoma. He found trends in epidemiological studies suggesting that widespread adoption of regular moderate sunbathing would result in approximately a one-third lowering of breast and colon cancer death rates in the United States. Colon cancer and breast cancer are the second and third leading causes of cancer deaths in North America and Dr Ainsleigh estimated that about 30,000 cancer deaths would be prevented each year if moderate sunbathing on a regular basis became the norm.

The subject was reviewed again in another American paper published in 1995, entitled Sunlight — Can It Prevent as well as Cause Cancer? The authors were concerned that medical research was largely directed towards investigating theharmful effects of sunlight on fair-skinned individuals, and not on people with dark skin who lived in, or had emigrated to, parts of the United States where the incidence of sunlight was low. They concluded from their review that although there was no definitive proof that sunlight and vitamin D protect humans from the development and progression of carcinomas of the breast, colon or prostate, there were good grounds for questioning any broad condemnation of moderate sun light exposure. They felt that for some Americans — those with heavily pigmented skin — lack of solar radiation could be rather more of a problem than too much: that it may well contribute to the high incidence of prostate cancer in black American men and the particularly aggressive progress of cancer of the breast in black women. The final sentence of this paper is as telling, in its own way, as the one at the conclusion of Dr Apperly's paper of 1940 quoted above. The authors suggested that the:

Significantly, recent laboratory research confirms that vitamin D deficiency may be an important factor in the emergence of cancer of the breast as well as cancer of the colon, prostate and, to a lesser extent, leukaemia, lymphoma and melanoma. Scientists are getting to grips with the mechanisms which account for vitamin D's capacity to retard the progress of cancer. So, the findings of epidemiological studies of sunlight and cancer are supported by work in the laboratory. There are trials under way to see if the vitamin D can be used to treat prostate cancer and other malignancies. There do not, however, appear to have been any major clinical trials to establish whether sunlight can be used in cancer therapy, although there have been reports of its use.

Colon Cancer and The Sun
With health campaigns warning against sunbathing because of the risks of developing cancer it easy to see why the cancer inhibiting properties of sunlight have been largely overlooked. Certainly, there has been little support for the hypothesis that sunlight inhibits the development of internal cancers from mainstream cancer researchers. This is not altogether surprising given the slowness with which the association between rickets and sunlight came to be accepted by much of the medical establishment.

During the 18th and 19th centuries, rickets occurred mostly at latitudes of 37 degrees or higher, in towns and cities where air pollution reduced the amount of sunlight that would otherwise have been available. There are some striking parallels between rickets and cancer of the colon, in that almost all western countries at latitudes north of 37 degrees in the northern hemisphere, or south of that latitude in the southern hemisphere, have high rates of colon cancer. It is the second leading cause of death from cancer, after lung cancer, in the United Kingdom, the United States, Canada, Ireland and New Zealand and, as was the case with rickets, the problem is worse in areas with high levels of air pollution.

The first epidemiological research suggesting that vitamin D from sun exposure has a protective effect against colon cancer was published in the International Journal of Epidemiology in 1 980 by Drs Frank and Cedric Garland (see Table 3). They looked at the geographic distribution of cancer deaths in the United States and found that mortality from colon cancer decreased in areas of the United States with greater sun exposure, the number of deaths in the industrialized northeast of the United States being one third higher than in sunnier regions such as Hawaii, New Mexico and Arizona. Migration to a sunny latitude — from, say, New York to Florida — is associated with a decreased risk of colon cancer. Also, a childhood and adolescence spent in one of the world's sunnier regions reduces the risk of the disease for those who migrate in the opposite direction, and the protective effect appears to last a lifetime.

Table 3: Colon Cancer and Latitude
Country	Latitude (°) I	Death rate per 100,000 population
Northern Ireland	54	16.4
Republic of Ireland	53	16.6
England and Wales	52	15.3
Netherlands	52	14.7
Germany	51	16.5
Belgium	50	15.5
Austria	47	15.2
Switzerland	47	12.2
France	46	11.2
Canada	45	13.5
New Hampshire, USA	44	11.5
New York, USA	43	12.4
Connecticut, USA	42	11.5
Rhode Island, USA	42	12.2
Massachusetts	42	12.1
Italy	42	10.5
New Zealand	41	19.7
New Jersey, USA	40	12.9
Spain	40	7.8
Greece	39	5.2
Japan	36	9.3
New Mexico, USA	34	9.1
Arizona, USA	34	8.8
Australia	33	15.8
Israel	31	11.8
Chile	30	6.1
Florida	28	9.9
Mexico	23	2.7
Hawaii, USA	20	8.5
Guatemala	15	0.5
Annual Age-Adjusted Death Rates from Colon Cancer per 100,000 Population by Latitude of Residence for Women in Selected Areas, 1986-1990. After Garland, C.F., Garland, F.C., and Gorham, E.D., 'Epidemiology of Cancer Risk and Vitamin D' in Vitamin D: Molecular Biology, Physiology, and Clinical Applications, (Ed. Holick, M.F.), Humana Press, New Jersey, 1999

Breast Cancer and The Sun
Breast cancer is the most common form of cancer in women, causing about 370,000 deaths annually worldwide. Each year some 220,000 women in Europe and 1 80,000 women in North America are diagnosed with the disease. About 15,000 British women die of breast cancer annually, a death rate that is higher than elsewhere in western Europe. One in 12 British women will develop breast cancer at some time in their lives and, as we have already seen, the incidence of breast cancer is increasing. The reasons for this are not altogether clear, but lack of sunlight could be a factor. In 1 989 the Drs Garland, together with Dr Edward Gorham, published the first ever epidemiological work on the relationship between sun exposure and breast cancer (see Table 4). Their research demonstrated that, as in the case of colon cancer, there was a strong negative correlation between available sunlight and breast cancer death rates. The chances of women from areas of the United States with less available sunlight dying of breast cancer were 40 per cent higher than those of women who lived in Hawaii or Florida. Worldwide, the lowest rates for breast and colon cancer occur in the Caribbean, South and Central America, North Africa and South Asia. Countries in these regions are within 20 degrees of the equator, where the sun's rays are particularly strong, and where mortality rates for breast and colon cancer are 4-6 times lower than in northern Europe or North America.

Table 4: Breast Cancer and Latitude
Country	Latitude (°) I	Death rate per 100,000 population
Northern Ireland	54	26.9
Republic of Ireland	53	25.7
England and Wales	52	29.0
Netherlands	52	25.8
Germany	51	21.9
Belgium	50	25.6
Austria	47	22.0
Switzerland	47	24.9
France	46	19.0
Canada	45	23.5
New Hampshire, USA	44	25.0
New York, USA	43	25.6
Connecticut, USA	42	23.6
Rhode Island, USA	42	25.7
Massachusetts	42	25.0
Italy	42	20.4
New Zealand	41	25.0
New Jersey, USA	40	25.8
Spain	40	15.0
Greece	39	15.1
Japan	36	5.8
New Mexico, USA	34	19.4
Arizona, USA	34	20.0
Australia	33	20.5
Israel	31	22.5
Chile	30	12.7
Florida	28	20.9
Mexico	23	6.3
Hawaii, USA	20	15.0
Guatemala	15	2.3
Annual Age-Adjusted Death Rates from Breast Cancer per 100,000 Population by Latitude of Residence for Women in Selected Areas, 1986-1990. After Garland, C.F., Garland, F.C., and Gorham, E.D., 'Epidemiology of Cancer Risk and Vitamin D' in Vitamin D: Molecular Biology, Physiology, and Clinical Applications, (Ed. Holick, M.F.), Humana Press, New Jersey, 1999

The Garlands' research shows that in the United States individuals at high risk for breast cancer also have a high risk for colon cancer. They tend to be urban, living in the less sunny and more polluted north-eastern states, where soft coal with a high sulphur content is burned extensively for electricity generation, smelting and heating. The air pollution which was responsible for their forebears developing rickets is still present. It may not be as severe, but it is still blocking out ultraviolet radiation and inhibiting the synthesis of vitamin D. This could account for the marked difference in the risk of breast and colon cancer in the urban northeast compared with rural areas. A similar association between breast and colon cancer, air pollution and latitude levels has been shown in Canada and Italy. Also, breast cancer is twice as common in the northern republics of the Soviet commonwealth — the former USSR — than in republics in the south, with intermediate rates at intermediate latitudes.

While it is clear that the mortality and incidence of breast cancer and colon cancer in North America and other areas of the world increases with distance from the equator, there is one notable exception to this trend, japan is a heavily industrialized country which is situated at a relatively high latitude, but which has had a low incidence of breast and colon cancer. This anomaly has been attributed to the fact that the traditional Japanese diet is unusually rich in vitamin D from fish, the average intake of vitamin D there is about ten times that of the average level for adults in the United Kingdom or the United States. Dietary intake of vitamin D and calcium influences the incidence of colon cancer in a similar way to that of rickets: both vitamin D and calcium are needed to keep colon cancer and rickets at bay.

Dietary intake of fat or fibre or fruit and vegetables has very little influence on the north-south gradient of colon and breast cancer in North America. Intake of fruit and vegetables is actually slightly higher in the northeast than in the rest of the country. The consumption of high-fibre cereals and bread is lower in the south than the northeast and dietary fat intake does not vary by region across the country.

Prostate Cancer and The Sun
Prostate cancer shows a similar geographic variation to cancers of the breast and colon. The known risk factors for this cancer are older age, dark skin and northern latitudes, all of which are associated with a decreased synthesis of vitamin D. The highest rates of prostate cancer occur in the United States, Canada and Scandinavia, while Japan has a low incidence of the disease. A study published in the journal Cancer in 1992 found that there was a significant north-south trend in the United States with a reduction in deaths from the disease as sunlight intensity increased. Mortality rates were highest in the northeast of the United States and lowest in the southwest. They were also lower amongst white-skinned Americans than in African-Americans and this could not be attributed to any differences in socioeconomic status. In common with breast and colon cancer, mortality rates from prostate cancer show an inverse association with the availability of ultraviolet radiation from the sun. As prostate cancer is the most prevalent non-skin cancer amongst men in the United States, and the second leading cause of male cancer deaths, this is an illuminating piece of research for older men — especially those with darker skin who are at higher risk of developing this condition.

Ovarian Cancer and The Sun
The incidence of ovarian cancer is higher in North America and northern Europe than in Africa and Asia; with some of the lowest levels in Japan. A study published in the International journal of Epidemiology in 1994 showed that in the United States there is a strong inverse association between mean daily solar radiation and deaths from ovarian cancer. Women aged between 45 and 54 living in northern states were shown to have five times the ovarian cancer mortality rate of women of this age group living in the south of the country. Of course there is, as yet, no proof that sunlight prevents ovarian cancer or any other forms of internal cancer from developing. But, then again, there is evidence, albeit limited, that some cancer patients actually benefit from exposure to the sun.

Sunlight Therapy and Cancer
There have been a number of reports of sunlight being used on cancer patients to good effect but, unfortunately, much that has been published on the subject is largely anecdotal. One form of cancer which clearly benefits from sunlight exposure is, ironically, a form of skin cancer. This is the rare malignant skin cancer mycosis fungoides which has been treated very successfully with the sun's rays. The results of a study carried out at a clinic in Davos, Switzerland, reported in the journal Hautarzt in 1986, showed that the majority of patients with this serious condition who underwent sunlight therapy in the Alps went into remission — some for over a year.

As far as internal cancers are concerned, few physicians seem to have actually used sunlight therapeutically. One notable exception is the American physician Dr Zane Kime. In his book, Sunlight Could Save Your Life, which was published in 1980, Dr Kime describes how he encouraged one of his patients with breast cancer to sunbathe. He took this rather unusual step following a consultation with a 41-year-old woman whose breast cancer had spread to her lungs and bones. She had already undergone a mastectomy and chemotherapy but to no avail. Dr Kime did not treat the cancer directly but, instead, introduced a programme to improve the general health of his patient. She was only allowed to eat whole foods, and all of the refined polyunsaturated oils and fats were removed from her diet. She was also encouraged to spend time sunbathing; and the combination of diet and sunlight seems to have achieved remarkable results. Within a few months the patient was back at work and in the years that followed there were no apparent symptoms of her metastasized cancer. Unfortunately Dr Kime did not devote much of his book to this episode, nor did he state how many years of remission his patient enjoyed and, sadly, Dr Kime died in 1992.

Some years before Dr Kime's apparent success, a study into the effects of sunlight on cancer was carried out at the Bellevue Medical Centre in New York. During the summer of 1959, fifteen patients diagnosed with cancer were encouraged to arrange their own sunlight therapy. They spent as much time as they could outdoors without glasses, and especially sunglasses. They were also instructed to avoid artificial light sources and television sets as much as possible. Dr John Ott, who is a renowned investigator of the effects of light on health and is probably the greatest innovator in the field since Niels Finsen, was involved in this project. It was Doctor Ott who first alerted the American public of the hazards to health posed by the emission of X-ray radiation from television sets, and he also developed some of the first full-spectrum lighting. He says in his book Health and Light that the results of the study of the effects of sunlight on cancer patients were sufficiently positive to justify a more detailed programme of research, but that support was not forthcoming.

The world-famous Swiss sunlight therapist Dr Auguste Rollier (1874-1954) reported some success with Hodgkin's disease, a cancer that affects the lymph glands. But when Rollier was practising heliotherapy — in the first half of the 20th century — cancer was not as common as it is today, and tuberculosis posed a much greater threat to public health. By the time cancer became a major health problem, sunlight therapy had all but disappeared from medical practice. This explains, in part, why sunlight does not appear to have been used on cancer patients to any extent.

Now although patients with Hodgkin's lymphoma seem to have benefited from Dr Rollier's sunlight therapy, in recent years several researchers have suggested that sunlight exposure actually increases the risk of developing non-Hodgkin's lymphoma, which is a different form of lymphatic cancer. Non-Hodgkin's lymphoma is one of the fastest-increasing cancers in the UK and other countries. The reasons for the rise in incidence of this cancer are not well understood, but it does occur frequently amongst people with the HIV virus, and patients whose immune systems are suppressed by chemotherapy, or by the drugs used to prevent organ rejection after transplant surgery. Individuals who are taking immuno-suppressive drugs over long periods develop cancer much more readily than the normal population. People in this position are particularly susceptible to cancers of the skin, and so must be especially careful to avoid strong sunlight. However, as far as non-Hodgkins lymphoma is concerned the most detailed research to date, published in the British Medical Journal in 1997, could find no positive association with sunlight. So something other than sunlight may be causing it.

Sunlight and The Heart
The western world's number one killer is coronary heart disease. It accounts for one third of all deaths in industrialized countries annually, and 7 million deaths worldwide. If you are unfortunate enough to have a heart condition, or you come from a family with a history of heart disease, or high blood pressure, you will probably have been made aware of the impact that your lifestyle and diet can have on your future well-being. By keeping your weight down and taking regularexercise the likelihood of ill health is far less than if you pursue a sedentary way of life, eat convenience foods and smoke. As you may have gathered from chapter 1, sunlight has a marked effect on some of the imbalances in the body which are associated with heart disease. Not only does sunlight lower blood pressure and cholesterol levels, but the results of tests reported in the American Journal of Physiology in 1935 show that exposure to ultraviolet radiation can also increase the amount of blood ejected from the heart — the cardiac output — by as much as 39 per cent. If sunlight does influence the functioning of the cardiovascular system to anything like this extent, one would expect to see more heart disease when and where there was less available solar radiation.

More people die of heart attacks in the winter than in the rest of the year and, as with cancer, deaths from heart disease become more common with increasing distance from the equator. Blood cholesterol levels also increase with distance from the equator, and it is countries in the northwest of Europe, such as Britain, which have the highest cholesterol levels and deaths from heart disease. The highest incidence of heart disease in the British Isles is amongst less well-off families in Scotland, Northern Ireland, and the northwest of England. In a study published in the Quarterly Journal of Medicine in 1996, sunlight deprivation was identified as a potential risk factor. Bad housing, minimal participation in outdoor physical activities such as gardening and insufficient money for holidays in sunny places were cited as reasons for lack of sunlight exposure amongst this high-risk group.

Significantly, coronary heart disease is also particularly high amongst Indo-Asian immigrants in Britain who, as we have already seen, tend not go out in the sun. The researchers who carried out this study put forward the hypothesis that high levels of cholesterol in the blood may accelerate existing coronary heart disease but are not the cause of it. They suggest that it is a microbe — possibly the low-grade respiratory pathogen Chlamydia pneumoniae — which may be to blame, and that sunlight deprivation increases the opportunism of this organism in a similar manner to the way it favours tuberculosis. If this is the case, immigrants to this country who have no natural immunity to this pathogen, or whichever organism might cause coronary heart disease, would be at even more risk of infection once their immune systems become compromised due to vitamin D deficiency. Like cancer, in spite of a massive research effort, a great deal about heart disease remains unknown and unexplained. Sunlight or, rather, lack of it may have a much more significant influence on the genesis of heart disease than is currently recognized and in my opinion this needs to be thoroughly investigated as a matter of urgency.

Sunlight and Diabetes
According to the World Health Organization, approximately 1 35 million people suffer from diabetes mellitus worldwide. There are two main forms of the disease: insulin dependent diabetes and non-insulin dependent diabetes. The onset of insulin dependent diabetes is most common in childhood and occurs as a result of the body's auto-immune system destroying the cells in the pancreas which produce insulin. As the name implies, insulin dependent diabetes requires treatment with insulin. Non-insulin dependent diabetes is less serious and can be treated with diet, exercise, drugs which increase the production of insulin, or insulin itself. It is the more common form of the disease and accounts for almost 90 per cent of all diabetes cases. Non-insulin diabetes occurs after the age of about 40 years in people who are genetically disposed to it and who are often overweight and unfit. The World Health Organization predict that the number of people with diabetes is set to rise to 300 million by 2025 because of population ageing, unhealthy diets, obesity and a sedentary lifestyle.

A deficiency of insulin results in increased concentrations of glucose in the blood which, in turn, causes damage to blood vessels and nerves. Diabetes can lead to severe complications in the longer term, including heart attacks, kidney failure, blindness, and gangrene in the lower extremities. Heart disease kills 75 per cent of people of European origin with diabetes. Studies have shown vitamin D to have a protective effect against childhood diabetes. The results of large pan-European trial published in the journal Diabetologica, in 1999, suggest that vitamin D supplements taken in infancy protect against, or arrest, the initiation of a process that can lead to insulin-dependent diabetes in later childhood. If this is the case, it seems reasonable to suggest that exposure to sunlight in early childhood may be important in preventing the onset of the disease — although no one seems to have investigated this possibility.

Whether or not sunbathing can prevent insulin dependent diabetes, it is known that sunlight has a similar effect to insulin in that it lowers concentrations of glucose in the blood. As previously discussed in Chapter 1, although this is not particularly noticeable in normal individuals, the effect is dramatic in diabetics. It is for this reason that anyone who is diabetic should be careful if they sunbathe, as they may have to reduce the amount of insulin they take to maintain normal blood sugar levels if they are in strong sunlight for any length of time. As with heart disease, the incidence of diabetes is higher amongst the Indo-Asian community than the indigenous British population, and this may be another manifestation of chronic vitamin D insufficiency.

Multiple Sclerosis
Multiple sclerosis is a disease of the central nervous system in which the myelin sheaths covering nerve fibres are damaged, leading to a range of symptoms associated with disruption of nerve function, such as paralysis and tremors. There are about 80,000 people with multiple sclerosis in the United Kingdom, and 250,000 in the USA. The cause, or causes, of the disease are not clear, but it is known that the incidence of multiple sclerosis increases dramatically with latitude, and that exposure to sunlight in childhood and adolescence protects against the disease in later life.

Latitude was first identified as an important risk factor as long ago as 1922. Then in 1960 scientists discovered that multiple sclerosis was related to the amount of sunlight available annually and during the winter months. They concluded that, directly or indirectly, solar radiation has a protective effect against the disease. There is strong circumstantial evidence that vitamin D protects against multiple sclerosis, which helps to explain why in Switzerland the disease is common at low altitudes and much rarer at high altitudes where the intensity of ultraviolet radiation is much stronger. In Norway there is a much greater prevalence of multiple sclerosis inland than on the coast, where fish is consumed in large quantities, providing an excellent source of dietary vitamin D. In other parts of the world where the diet includes large amounts of fish, such as Japan, the incidence of multiple sclerosis is lower than would be expected on the basis of latitude alone.

One explanation for the sun's role in preventing the disease is that getting sunlight into the eyes affects the immune response of the central nervous system in some, as yet unexplained, way. The authors of a recent article in the journal Medical Hypothesis put forward two possible explanations for this. One is that sunlight may inhibit the development of an eye condition called 'retrobulbar optic neuritis' which affects about 85 per cent of people who then go on to develop multiple sclerosis. Inflammation in the retina of the eye and in the brain is thought to be the first stage in the development of multiple sclerosis, and the sun's rays may act on the immune system to prevent this occurring. The authors also suggest that sunlight could protect against the disease in a similar way to that in which it acts to prevent another illness related to latitude, seasonal affective disorder. Bright light prevents seasonal affective disorder because, as we saw in Chapter 1, it suppresses the secretion from the pituitary gland of the neurohormone melatonin. It seems that by inhibiting the secretion of melatonin sunlight might also protect against multiple sclerosis by strengthening the immune system and preventing demyelination.

Unfortunately, over the last forty years the association of multiple sclerosis with lack of sunlight in childhood and adolescence has not been as widely recognized as it might have been. Yet, if the disease is to be avoided, irrespective of the precise mechanism involved, there are good grounds for discouraging children from wearing sunglasses, and encouraging regular moderate sunlight exposure.

Sunlight and Tooth Decay
Having looked at the influence of sunlight on cancer, heart disease, diabetes and multiple sclerosis, let us return to the bones or, rather, the teeth. We have to go back a long way to find published evidence of a relationship between sunlight and dental caries, but there is some. In 1939 an American study of 94,000 white males aged between twelve and fourteen years showed a clear correlation between sunlight and tooth decay. Those who lived in the northeast of the USA, where mean annual sunlight was less than 2,200 hours per year, had two thirds more cavities than their compatriots who lived in the southwest of the country and received more than 3,000 hours of sunshine per year.

The results of another investigation, published in the Journal of Nutrition in 1938, showed that the incidence of dental caries amongst American children varied according to the time of year. The highest incidence was found in the late winter and early spring, and very low values were recorded during the summer months. If this is correct, then there is much to be said for making routine dental appointments at the beginning of autumn when your vitamin D levels are highest and your teeth are strongest.

Psoriasis
Sunlight therapy is particularly effective in cases of psoriasis; a benign but chronic inflammatory skin condition which affects 1 -2 per cent of the World's population. The degree to which psoriasis affects sufferers can vary from a very mild form with just a few scaly red patches on the elbows, to a more severe condition where sores completely cover the body, except the face. The disease can cause significant distress and a very restricted social life, and can require hospitalization. The symptoms of psoriasis can be relieved by the administration of a photosensitizing drug, such as 8-methoxypsoralen, by mouth followed by exposure to UVA radiation. Systemic immunosuppressive drugs, such as cyclosporin, are administered in severe cases. However, heliotherapy can clear up psoriasis without the need for such strong medication. It is often preferred to conventional therapies by patients and is particularly effective in severe cases.

During the last thirty years tens of thousands of patients, mainly from western Europe, have been given sunlight therapy for psoriasis at the Dead Sea, in Israel. The high mineral content of the water, combined with solar radiation, improves the condition of about 80 per cent of the patients who go there for medical treatment. The condition has also been treated successfully with sunlight in other parts of the world. In one recent study, published in the British Journal of Dermatology in 1998, some 46 Finnish patients received four weeks of heliotherapy treatment in the Canary Islands, Spain. They were sent abroad because in Finland solar radiation is too weak and sunny days are too infrequent to have any real impact on long-lasting psoriasis. The study showed that it was only really cost-effective to send patients to the Canaries for the sun if their psoriasis was so severe that they required regular hospital admissions or outpatient treatments. For psoriatic patients heliotherapy remains an effective, if rather expensive, alternative to systemic drugs.