Healing Cancer With Light (7)
Welcome to page 7 of Healing & Preventing Cancer With Light featuring three articles on the subject, Sunlight, cancer, leukemia & cancer prevention, Skin Cancer, Malignant Melanoma and Sunlight, and Sunlight - the ultimate detoxifier?, each excerpted from the book "Daylight Robbery - The Importance of Sunlight to Health" by Dr. Damien Downing.
Sunlight, cancer, leukemia & cancer prevention
extracted from Dr. Downing's Daylight Robbery (Chapter 6: The Big C & a Little UV)
Sunlight is a killer! This is the clear message from the medical profession at present. The warm, sensual feeling that you get from lying in the sun is probably immoral, and you ought to be at home taking antibiotics. Yet we persist in taking holidays in the sun, and nipping out of doors at lunchtime. Can it be that we know something the doctors don't? It definitely can, and some of the evidence to prove us right has been around for half a century. Put aside for a moment the question of skin cancer - which is dealt with in the next chapter - and think about cancers in general, which kill far more people every year.
Twenty-five years ago Dr John Ott investigated the background to a report that children at a school in Illinois had five times the national rate of leukaemia.[1] He found that the schoolhouse was a plain, modern building with very large windows in every room, and all the pupils who developed leukemia had been in two particular classrooms. In these two rooms the teachers always kept the large curtains completely drawn across the windows to reduce glare and distraction, and to keep the children's attention on schoolwork. The indoor lighting was therefore on all the time, and this was 'warm white' fluorescent. The whole class spent its working day in light of twilight intensity, with no blue or UV light at all except at playtime - and in Illinois they have some hard winters, during which the children might not go out to play at all.
Several years later the two teachers in question left the school, and their replacements kept the classroom curtains open all the time. The lights were also replaced with cool white fluorescent ones, and of course needed to be used less. From then on there was not a single case of leukemia in the school for as long as Dr Ott followed it up. No other explanation has been put forward for this remarkable mini-epidemic of leukaemia; although in isolation it proves nothing, it started Dr Ott thinking about the possibility of a link between sunlight and cancer.
In fact this had been commented on half a century ago. In 1936, a report in The Lancet by Peller, a US Navy doctor, suggested an inverse relationship between skin cancer and all other cancers. He observed that Navy personnel had eight times the skin cancer rate of the rest of the population, but only forty per cent of the total death rate from cancer.[2] He proposed that the obvious explanation for this was the greater amount of sunlight to which men serving in the Navy were exposed. Nowadays, many naval personnel probably spend their whole working lives at computer consoles, but in 1936 they naturally led an outdoor life and were in the sun a great deal.
Peller made the startling suggestion that by using high intensities of light, either sunlight or ultraviolet from a carbon arc lamp, we should actively induce skin cancers in patients, in order to protect them from other cancers. As cancers go, those skin cancers that have been clearly shown to be related to sunlight have obvious advantages; the most important of these is that they are visible at a much earlier stage, and can therefore be dealt with. The success rate of surgery has always been good, and if you had to choose which cancer to get, skin cancer would be an excellent choice.
In fact, skin cancers cause only nine per cent of the deaths from cancer every year, and organ or internal cancers ninety one per cent. What's more, the survival rate from skin cancer is very good - about ninety five per cent of sufferers live for five years or more after diagnosis, whereas only thirty six per cent of cancer victims in general live that long. The exception, of course, is the relatively rare skin cancer called malignant melanoma, which is discussed in the next chapter.
The global view
The really strong sunlight effect starts to show through when you examine the relationship betweeen sunlight exposure and cancer incidence on a global scale - the epidemiology. This has been looked at in some detail on several occasions. The simplest and clearest study is that performed by Hoffman for the Prudential Life Assurance Company in 1924.[3] He analysed the frequency of cancers of all types in a total of 130 cities around the world (looking at almost 300,000 cancer deaths) and matched this against their latitude. The results are clearly shown in the graph above. The further the city from the equator, the greater the number of cancers. The ratio of highest frequency to lowest is around 2.5:1, which looks as though it may turn out to be a magic figure of some sort.
This study concentrated on people living in cities, so that factors such as lifestyle and levels of development shouId not interfere. But in 1940, when Dr Frank Apperley looked at the total mortality from cancers across the United States in both rural and urban areas, the picture he found was just the same, and very clear. He measured two factors that are likely to match closely with the average exposure of individuals to sunlight: the percentage of the population involved in agriculture (and so out of doors most of the time), and the amount of solar radiation recorded by the local Met station. He plotted these measures against the number of cancers.
This was then refined further by looking only at people over forty five (the age group in which the large majority of cancers occur), and only at the white population, who have an incidence of cancer several times higher than that of black people. Neither of these restrictions altered the results at all; the effect was the same for both methods of analysis. As you can see from the graph, the more time people are outdoors, and the more sunlight in the area where they live, the fewer cancers they develop. Interestingly, the highest ratio comes out once again to a little over 2:1.
So what mechanisms could explain this link between light deficiency and cancer? Well, several of them. The problem with researching this kind of thing is that there is no single clearcut process involved to make it nice and easy for the scientist. Sunlight is so fundamental to our lives, and affects us in so many ways, that it may be impossible to demonstrate a single link. But we can pull several strands out of the knot, each of them a connection.
The guts of the matter
In a large North American study, higher vitamin D levels appeared to give significant protection against cancer of the colon. The analysis made was of the amount of vitamin D in the diet, not of blood levels. The researchers found that the group with the lowest vitamin D intake were about 2.5 times more likely (there's that number again) to develop bowel cancer than those with the most vitamin D in their diet.[4] We know that much of the population in this country [presumably Great Britain] is vitamin D-deficient for much of the year, even more so than in America. Raising people's levels of this vitamin may protect them in some way from cancer. However, when this connection was examined in Japan, there did not appear to be the same correlation. This may be due, suggests the paper, to the fact that the Japanese, living nearer the equator, have a greater exposure to sunlight, and therefore more sunlight-derived vitamin D in their blood.[5] In these circumstances, dietary vitamin D will not be so important. The best-known reason why vitamin D is important is that it increases our uptake of calcium from the diet. We know that calcium plays an important part in cancer of the bowel, actively calming down the rapidly dividing cells. Vitamin D will enable these cells to take up more calcium, and this may begin to explain the sunlight effect. More recently, laboratory studies have found that there are receptor sites for vitamin D on cancer cells, and that it appears capable of converting human leukaemia cells back into normal cells - at least in the test tube.
A breach of security
It has been estimated that we each develop cancer once a week on average. This is how often a cell in our bodies is likely to go "rogue" and start dividing rampantly. But fortunately for us, when this happens the cell also undergoes a change in the proteins on its surface, and our immune system swiftly identifies it as "not-self", as a threat to our health, and eliminates it. In other words, developing a cancer - a real cancer - is a sign not of something going wrong with our genes, but of something wrong with our immune systems.
This is why people with AIDS are so vulnerable to strange malignancies such as Kaposi's Sarcoma. Their immune systems are damaged by the virus, which attacks the T-cells, a type of white cell crucial to the production of antibodies against invaders. AIDS particularly kills off the T-helper cells, which are normally in balance with T-suppressor cells. T-helpers stimulate the immune system to attack, while T-suppressors discourage it from so doing. With a disproportionately low level of T-helpers the immune system is powerless against infections, cancers and other threats to our wellbeing.
Yet there are people alive in America who have had AIDS for several years but are now fit and well. They have found ways to stimulate their bodies' production of T-cells when conventional drugs were powerless to help. A variety of methods appear to have benefited them - meditation, herbs, acupuncture and megadose vitamin C among the most important.
It is now clear, from very recent studies on the skin as an immune organ, and from old studies on the effects of sunlight on the white blood cell count, that sunlight can have a dramatic effect in this area. When sunlight hits the skin, it stimulates the topmost layer of living cells, the keratinocytes. These are the cells which produce the keratin, the hard outer layer of dead skin that protects us from germs and injuries. It was always thought that they had no other function. But new evidence has proved that when they are triggered by ultraviolet light, keratinocytes produce a chemical called interleukin-1. IL-1 has a simple but potent effect: it causes white cells, and T-cells in particular, to multiply in number.
Since this is the only way that such cells can be mobilised quickly to respond to a threat, IL-1 has been the focus of considerable interest among immunologists in recent years. Despite detailed research, though, it has been clear that we are a long way from the day when we can synthesise it in a laboratory. Now there hardly seems to be any point. Why spend millions on manufacturing something which our own bodies will make for free in response to sunlight?
So in order to raise your white cell count, mobilise your immune system against attacks by infection or even by cancer, and absorb more protective calcium, all you need to do is sunbathe. This may help to explain why children get so many infections in winter, when we are all at risk from sunlight deficiency - and why influenza epidemics alway seem to happen then too. But it may also be an important strand in the understanding of why sunlight protects against cancer.
Free oxidising radicals
Free oxidising radicals are small negative ions with the ability to split molecules and damage cells. These atoms and small molecules with a negative charge on them are produced in chemical reactions, in the atmosphere, in food and in our bodies. Some of them are very short-lived, only existing for minute fractions of a second. However, they have a tendency to propagate rapidly, so that the production of one free oxidising radical (FOR) can, within a very short space of time, lead to a large number.
Whether single or multiple, they have a powerful ability to react with biological molecules in damaging ways. They can break open the DNA in our chromosomes, although there are mechanisms to prevent their getting near it in its safe harbour in the cell nucleus. When they do come into contact with DNA they can split it open and alter the genetic information, leading to mutations.
They also split open antibodies, the molecules used by our immune systems to attack infections and clear allergens out of the system. This can lead to effects very like allergic reactions in some people. Also, they can break open collagen molecules, the structures that make up ligaments and hold our tissues together, and give skin its elasticity. This is why pollution and smoking can age your skin.
On the other hand, free oxidising radicals are actually used by the white cells of the body to attack infecting agents. As a white cell engulfs a virus or bacterium, it pumps highly toxic FORs into the forming vacuole in order to kill the micro-organism. Thus FORs are necessary to the healthy functioning of our immune system; in other words, they are an example of something that is necessary in the right amounts, but can be toxic in overdose.
Our bodies possess a series of mechanisms for controlling FORs, mopping them up rapidly and preventing them from damaging tissues. These are known as antioxidants. The major ones are essential nutrients such as vitamins A, E, and C, the amino-acid glutathione, and certain minerals such as selenium. Some of these, such as vitamins A and E, protect by mopping up FORs themselves, so preventing them from damaging our cells. Others, such as selenium, are components of the enzymes which rapidly process and inactivate FORS. Damage produced by smoking, alcohol, radiation or even sunburn due to ultra-violet light, are all FOR effects. They are all prevented by high levels of antioxidants, in this case particularly vitamin A.
So FORs can be produced by large doses of ultraviolet light, but we can protect against this by an adequate intake of antioxidant nutrients, and by avoiding excess fat in our diet. Since we live in a light-poor environment, diet is more important in this respect than overdoses of light, with the exception of the annual jaunt to the Costa Packet. Torremolinos in summer is full of English people overdosing on sunlight, on alcohol, on greasy food, possibly on tobacco too. Along with the raffia ponies and peeling backs, they bring home a system so overloaded so rapidly that they may need the rest of the year in a dark room to recover. That we do not all develop skin cancer after our summer holidays only proves the effectiveness of the body's defences when we are in good health.
Fat and weak
Some of the molecules most vulnerable to the effects of free oxidising radicals are the oils and fats making up our cell walls, which are obtained from our diet. It is now well understood that the more oils there are in our diet the more antioxidants we need to protect them. Without these protective mechanisms, the fats may be damaged by FORs, and it is thought that their molecules may be twisted into an abnormal and highly toxic form, known as trans-fats. The greater the surplus of fats and oils over antioxidant nutrients in our bodies, the greater the probability of trans-fats being formed, and this alone may explain many cancers. Overdoses of ultraviolet light may cause this change, but only if we are short of the protective nutrients. Once again it is a matter of nutritional balance.
Despite the current powerful trend of opinion against them, it appears that saturated fats are not in themselves toxic. They do harm us, though, in two specific ways. Firstly, a high animal-fat diet may contain simply too much fat surplus, with the risk of trans-fats being formed. But polyunsaturated oils too can cause both of these damaging effects, so lashings of sunflower oil or margarine on your baked potato may be just as harmful as butter.
Secondly, saturated fats, which have no double bonds along their chain of carbon atoms, can simply replace unsaturated fats in the diet, and some unsaturated oils are necessary for health. The importance of unsaturation is that it means the presence of double bonds in the chemical structure of the oil. These double bonds can be opened up by enzymes and used, rather like a child's construction toy, to build new molecules. This enables the oils to be utilised by the body for cell walls and for the production of a range of other chemicals; in particular for a group of hormones called Prostaglandins. Because we need a regular supply of them to process into other molecules, certain of these oils and fats are known as essential fatty acids.
Prostaglandins control a large variety of biological functions, including inflammation in response to injury or infection, the formation of blood clots in arteries and veins, and the contraction of the uterus in childbirth. Saturated fats are useless in this respect, and are therefore only able to be stored and used as calories. We need polyunsaturates for normal functioning, but the greater our intake, the more molecules we have circulating which need to be protected against FOR damage, including that from UV light.
Human studies
In 19S9 Dr Ott finally had the opportunity he longed for: he was asked to participate in a study on the effects of sunlight on cancer in human patients. A physician at the Bellevue Medical Center in New York arranged for fifteen people with diagnosed cancer to organise their own sunlight therapy. Throughout the summer months, they spent as much time as possible out of doors, without any glasses or sunglasses. They also avoided artificial lights and televisions as much as possible.When the summer ended, the physician in charge attempted to evaluate the results. She found that fourteen out of the fifteen patients had shown no further spread in their cancers, and some even appeared to have improved. The fifteenth had continued wearing spectacles, and so would have blocked ultraviolet light from entering her eyes. Although there were no controls in this experiment, and it had run for only a few months, both Dr Ott and the doctor thought that it showed sufficient effect to be worthy of further, more detailed, investigation.
The medical authorities to whom he presented these results, with a proposal for further research, thought otherwise, and no more research was done on humans. But another medical friend of Dr Ott's did become interested, and set up an experiment using a strain of mice (known as C3H mice) that are very prone to developing cancerous tumours spontaneously. He reared separate litters under pink fluorescent tubes, under 'daylight' white tubes and under sunlight, The mice under the pink tubes showed cancers first, a month before those under white tubes and three months before those in daylight.
Strangely, this study was refused for publication! Much more work will have to be done before the medical community will accept any value for light in treating cancer, and there is no sign of it being done at present. Yet the results of the small study on humans were strongly positive, and any drug company would be delighted if it would show such a positive response to their product after only a few weeks. Take all of this evidence together and a pattern does emerge. It seems clear that we can modify our lifestyle in one simple way that will decrease our risk of developing cancer, and may even offer hope of help when we do develop it.
References
1. Ott, John, Health and Light, Pocket Books, New York, 1973.
2. Peller, S., 'Skin Irradiation and Cancer in the U.S. Navy', American Journal of Medical Science: 194; 326-333, 1937.
3. Hoffman, F.L., The Mortality of Cancer Throughout the World, Appendix E, Prudential Press, 1915.
4. Apperly, F.L., 'The Relation of Solar Radiation to Cancer Mortality in North America', Cancer Research.
5. Garland, C., et al., 'Dietary Vitamin D and Calcium and Risk of Colorectal Cancer', Lancet: 1; 307-309, 1985.
Skin Cancer, Malignant Melanoma and Sunlight
extracted from Dr. Downing's Daylight Robbery (Chapter 7: The Melanoma Debate)
1987 saw the most widespread campaign ever to try and persuade us that sunlight is dangerous and we should avoid it. Yet we still go on summer holidays in our millions, and we still come back feeling that it was worthwhile, and that we'll go again next year. Can it be that we are all so foolish that we ignore the medical evidence for the sake of two weeks of sensuality, or might our instincts be telling us the opposite of what the medical profession is telling us?
It is worth looking at the evidence with a fresh eye. For instance, everybody knows that sunlight causes skin cancer. But it is that simple? We know that cancers are much more common in hot, sunny areas such as Queensland, due to solar exposure - or do we? We all know that malignant melanoma is a skin cancer that is caused by sunburn - but is it?
The last two statements are both questionable. The first is half correct - squamous cell and basal cell carcinomas of the skin are more common in white-skinned people living in very sunny areas such as Queensland. This does not apply to cancers anywhere else in the body. The last statement is, at best, misreading of the evidence. Malignant melanoma is more common in people with the sort of skin that burns easily, but we are not in a position to say that the sunburn actually causes the cancer - it may even protect against it.
We have to take all this very seriously, because in the UK one quarter of all deaths are due to cancer. There are about 200,000 new cases of cancer every year, and of these about ten percent are skin cancers. This in turn breaks down to ninety eight per cent squamous and basal cell cancers, and two per cent melanomas.
But - and it's a very big but - the chances of surviving a skin cancer are excellent: ninety five per cent of patients are alive five years after diagnosis. This compares with thirty six per cent survival for cancers in general.[2] So, as we remarked in the previous chapter, if you have to get cancer, then skin cancer is definitely the wisest choice.
The one big exception is melanoma, of course. Although it is very rare - about 0.2 per cent of all cancers - it is the only skin cancer that normally metastasises (spreads to distant parts of the body), and the death rate is much higher. The five-year survival rate is fifty per cent, much poorer than the other skin cancers. It still doesn't rank in the top ten killers, but if it were avoidable by something as simple as staying out of the sun, this would plainly be a sensible thing for us all to do.
With the common forms of skin cancer, squamous and basal cell, the relationship with sunlight is clear. They occur usually on the exposed surfaces, such as the face, scalp and the back of the hands, [] in people who have spent many years working out in the sun. They are particularly common in people who have lived for some time in the tropics. In other words, it is long-term steady exposure to sunlight, for several hours a day, over many years, that triggers off these cancers.
Because it is so much less common, it has been much harder to gather sound evidence on melanoma and its relationship to sunlight. But until recently, a single fact was always quoted as proof that it was triggered by sun. This was the particularly high incidence of melanoma in Queensland, in Northern Australia. This is one of the hottest and sunniest places on earth, and it seemed that the link was obvious and inescapable.
Yet when studies were done in Queensland itself, it was found that within the state boundaries, the sunnier the area the fewer melanoma cases occurred. The disease was more common in the coastal areas, which had less sunlight in summer, when the amount of UV was higher. This clearly bemused the doctors doing the research, as they had no other explanation for melanoma than damage from UV.[3]
The next episode in the story also occurred in Australia, with a survey in New South Wales which showed that there was a greater risk of melanoma in women who had been exposed to fluorescent light at work than in those who have not. The longer these women had been working under fluorescent lights, the greater their risk of developing the cancer. Sunlight appeared to play no significant part in causing the problem. [4]
Critics of this study said that this might be a false result due to the fact that people of a higher social class were more prone to melanoma, and also - but incidentally - were more likely to work in offices with fluorescent lighting, But a study in the New York area confirmed the finding in a group who were all predominantly middle class.
With no difference between the social class of the melanoma sufferers and the non sufferers, fluorescent lights still appeared to increase the risk. [5]
That was in 1982. In 1984 a large study of 507 melanoma cases and 507 matched controls (matched for age, sex and place of residence) was performed in Western Australia. This one found that, if anything, exposure to sunlight protected against melanoma. People who regularly spent ten hours a week or more in the sun had a lower chance of developing the disease, and the longer time they spent in the sun each week the lower their risk. There was an increase of melanoma in people who went boating or fishing twice a week, but this was more than the increase in those who sunbathed - hardly strong evidence of a sunlight link. In fact, the worse a person's history of sunburn in the past, the less the chance of their developing at least one type of the cancer, known as nodular melanoma. [6]
The final piece of research, which looks as though it may have made sense of the whole conundrum, was conducted in Canada in 1985. This showed that the real risk came not from sunburn, but from having the type of skin that burnt easily. Whether or not a person actually got sunburned was not important in comparison to their tendency to burn easily and tan poorly. Those with the most sensitive skin had twice the risk of melanoma of those who never burned. [7]
Despite all this, the Royal College of Physicians Report published in April 1987 still said that sunlight was the culprit in melanomas. The conclusion was largely based on the research of one doctor in Glasgow who found a high proportion of people with a history of bad sunburn in her study. She took no account, however, of the point made by the Canadian study, that people who burn badly are likely to have sensitive skin - and of course in Scotland a very high proportion of the population has Type One, or Celtic, skin. They may never tan, only develop freckles, and the lack of melanin in their skin makes them susceptible to sunburn.
There are several small points that round out this argument. Firstly, studies in the laboratory show that vitamin D suppresses malignant melanoma - and also leukemia - in test tube experiments. [9] Understandably, no one is attempting to reproduce this in humans, but it does offer a possible explanation for the apparent protective effect of regular sunlight against melanoma.
Secondly, the ultraviolet wavelengths that produce vitamin D [in] the skin are entirely absent from normal fluorescent light - and the total UV exposure from working under fluorescent lights for a year has been calculated to be equivalent to forty minutes of autumn sun.[10] So how can UV be the culprit?
Thirdly, the incidence of malignant melanoma is going up most rapidly in some far from tropical areas such as Scandinavia and Scotland. It has been estimated to be doubling approximately every ten to twenty years. [11] Nobody has yet shown how this increase could be due to exposure to sunlight. But it could very well be due to increasing exposure to indoor lighting.
Finally, despite the recommendations in the RCP report there is evidence that sunscreens make no difference to the incidence of melanoma. Indeed, there has been for some time proof that they may even contribute to causing skin cancer, as well as certainly helping to trigger off photosensitivity - skin rashes in response to sunlight. [12] When Apperley, who showed that cancers in general decreased with sunlight exposure, looked at the incidence of skin cancer throughout the continental USA, he found the relationship with sunlight depended on the average temperature. Over a critical level of 42 C, increases in exposure to sunlight clearly caused an increase in the rate of development of skin cancers - of all types. Below that temperature, however, the rate decreased with increasing exposure to sun.[13]
It would appear, then, that in hot, tropical countries there is a risk of sunlight causing skin cancer, particularly in white skins, of course. In temperate climates such as northern Europe, on the other hand, sunlight is likely to protect. This would also tie in with the finding that, in contrast to Panner's figures mentioned in the last chapter, English researchers have found that rates of skin cancer and total cancers vary together.[14] In temperate climates such as ours, sunlight may protect us from both skin cancers and cancers in general, while in hot climates it may encourage skin cancers (basal cell and squamous cell), but still protect against other cancers.
The overall picture, then, seems to be that sunlight in large doses for long periods may cause skin cancer, particularly in the tropical heat, but sunlight at any dose level protects from cancers in general. The more sunlight you receive, the better protected you are. We know that sunburning with its production of free oxidising radicals is the factor that encourages the development of skin cancer. There is no reason to think that this is the protective factor against other cancers, so the way to take your sunlight as a cancer protection is in frequent small doses, insufficient to burn you. The secretary who slips out of the office at lunchtime and sunbathes in the park for forty minutes has the right idea. As well as gorgeous brown legs, she is giving herself protection against cancer.
Atmospheric filter
The wavelengths that are responsible for sunburn are those with the highest energy content - ultraviolet. Because their wavelength is shorter, there are more waves per metre of length, or per second, hitting the skin, and therefore more energy is transferred. Compared to ultraviolet, infra-red has a very low energy content. The whole of our biology is based round the fact that there is a very sharp cut-off point for ultraviolet transmission through the atmosphere.
There are two gateposts framing the narrow inlet for solar radiation. On the low frequency, long wavelength side, much of the solar spectrum is absorbed by carbon dioxide and water, while on the short wavelength side the most important absorber is ozone. It is the fact that ozone absorbs best at a wavelength of 260 nanometres, and the absorption then tails off completely above 300, that gives us the cut-off point for solar radiation at around 300 nanometres.
There has been concern among scientists in recent years about the danger that certain environmental pollutants, particularly the propellants in aerosol cans, may destroy the ozone layer in the atmosphere and lead to an increase in the amount of ultraviolet reaching the earth. However, the ozone level varies greatly from hour to hour and from day to day, in response to normal environmental and weather factors. The level of ozone in the atmosphere has been measured for over fifty years in the Swiss Alps, and in some other places, and no clear trend has been demonstrated so far. This is true notwithstanding the finding of an apparent 'hole' in the ozone layer above Antarctica. Although such a discovery suggests that our environment is being disturbed by man's activities, it is still a local phenomenon and does not appear to reflect a general reduction in the ozone layer - yet. Indeed, some scientists think that it may always have been there and we have only just noticed it.
Smog
Pollution from car exhausts and industry produces a range of chemicals in the atmosphere, including both the components of acid rain (sulphates and nitrates in particular), and indeed ozone itself. In this circumstance, with a very high local concentration at just above ground level, ozone is more important as a toxic pollutant than as a sunscreen. In fact, the level of ozone in smog appears to be increased by ionisation triggered by ultraviolet light. Monitoring of the intensity of sunlight in Washington DC and California has shown a reduction in the sunlight reaching the earth of more than ten per cent over the last fifty years, with a twenty six per cent reduction in the ultraviolet fraction.[1] The only evident cause of this is environmental pollution.
Therefore, if you live under a smog, as many people in cities around the world now do, you receive less ultraviolet light because it is absorbed by the smog. You also breathe less fresh air and more pollution. Once again, modern life has increased the toxic component of our intake while reducing the nutritional or beneficial component. In this case, it appears that ultraviolet light helps to make the problem worse by interacting with the chemical components of smog. But the real culprit is not the ultraviolet light, it is the products of fossil fuel combustion that go to make up pollution.
Photoreactivation
It is ultraviolet light of around 295 nanometres wavelength (UVB) which has the potential to cause damage to DNA and other molecules. These are the shortest wavelengths - and therefore have the highest energy - of any light reaching the earth. Thus they have the greatest potential for transferring energy to our bodies - for producing either benefit or damage.
Damaged DNA may lead to a cellular mutation - an abnormal cell which can be the start of cancer, or in the next generation of a genetic change or a congenital abnormality. Although several people have suggested that this is necessary for evolution, that an element of randomness is needed to keep things changing, it is certain that the process does lead to cancers and deformities. Under normal circumstances, all such genetic mutations are filtered out of the body by the immune system.
When cancer develops this is detected at an early stage by the immune surveillance and the cells are killed and removed. Clinical cancer is therefore more a sign of an immune problem than of something unusual in the way of genetic events. Transplant patients who have received immunosuppressant drugs so that they will not reject the transplanted heart or kidney have an eighty times greater than normal chance of developing cancer. AIDS sufferers also have a tendency to develop unusual forms of cancer such as Kaposi's Sarcoma. Both groups have in common a low level of immunity to infections and to cancers.
But it has always been known that some organisms have the ability to repair DNA damage in a manner that is dependent on ultraviolet light. Many micro-organisms have been shown to contain a protein molecule - an enzyme - which absorbs near-ultraviolet light (UVA), and is thereby activated to repair broken strands of DNA. [17]
The chemicals that are measured as an indicator of DNA damage are known as pyrimidine dimers. These are small x molecules of DNA which have been broken free of the chromosome and then joined together in pairs to form dimers (which consist of two identical molecules). Evidence of repair of DNA damage is obtained if these dimers are split into two monomers again. The process by which this occurs in response to UV light is called photoreactivation. It has always been known that it occurs in small organisms, but until recently it was thought that higher animals did not perform this function. In the past decade there has been increasing evidence that it occurs in a range of mammals, and the hunt was therefore on for evidence of its occurence in humans.[18]
In 1986 Betsy Sutherland, a researcher at Brookhaven National Laboratory in New York, finally demonstrated that photoreactivation occurred in human skin. She described its parameters quite clearly: it is light-dependent, being stimulated best by light of wavelength 350 to 400 nanometres, which is in the near ultraviolet range. When such light hits the skin, the process happens very rapidly, clearing most of the dimers out of the tissue within minutes.[19]
There is also some non-enzymatic repair that is still dependent on light, but occurs by chemical reactions that do not depend on human enzymes. Although this can be measured in skin also, it occurs at a much slower rate, taking about an hour to remove half of the dimers. Clearly it is less important than photoreactivation.
The remarkable fact is that although ultraviolet stimulates synthesis of DNA, and therefore cell activity and multiplication, it suppresses DNA synthesis during the first hour after exposure.[20] During this hour, the photoreactive enzymes are able to repair most of the damaged DNA in readiness for the burst of cellular activity that then occurs. Therefore, as well as having a potential for damaging human tissues, ultraviolet light is also essential for the repair of such damage. We are so well adapted to our solar environment that there is a built-in protective mechanism, triggered by sunlight, to protect us against the possible harmful effects of this same sunlight.
The message seems clear. Although some doctors and scientists are still determined to prove that sunlight is damaging and should be avoided, the evidence is mounting in its favour. We are designed to feed on sunlight, and we suffer if starved of it. But changes in our lifestyle over the past few decades have only advanced a process started by the industrial revolution, driving us indoors and away from the sun. Attemping to rectify this by brief binges of sunlight for a fortnight in the summer may well have harmful effects that offset their benefits. We should aim to nourish ourselves with sunlight regularly, every week of the year.
References
1. Cramer, W., 'The Prevention of Cancer', Lancet: 1; 15,1934.
2. Fry, J., Sandier, G., and Brooks, D., Disease Data Book, MTP Press Ltd., Lancaster, 1986.
3. Green, A., and Siskind, V., 'Geographical Distribution of Cutaneous Melanoma in Queensland', The Medical Journal of Australia, April 1983.
4. Beral, V., et al., 'Malignant Melanoma and Exposure to Fluorescent Lighting at Work'. Lancet, 7 August 1982.
5. Pasternak, B.S., 'Malignant Melanoma and Exposure to Fluorescent Lighting at Work', Lancet, 26 March 1983.
6. Holman, C.D.J., and Armstrong, B.K., 'Relationship of Cutaneous Malignant Melanoma to Individual Sunlight Exposure Habits', Journal of the National Cancer institute, Vol 76, No 3, March 1986.
7. Elwood, J.M., et al., 'Sun Exposure and Malignant Melanoma', Br. J. Cancer: 51; 543549, 1985.
8. MacKie, R.M., 'Links Between Exposure to UV Radiation and Skin Cancer', Journal of the Royal College of Physicians, Vol 21 No. 2, April 1987.
9. Colston, K., et al., 1, 25 - Dihydroxyvitamin D and malignant Melanoma: The Presence of Receptors and Inhibition of Cell Growth in Culture', Endocrinology: 108;1083-83,1981.
10. Pasternak, B.S., et al., 'Malignant Melanoma and Exposure to Fluorescent Lighting at Work' (Letter) Lancet: 1; 704, 1983.
11. MacKie, R.M., et al., 'Malignant Melanoma in Scotland 1979-1983'. Lancet: 2; 859-862, 1985.
12. Hodges, N.D.M., et al., 'Evidence for Increased Genetic Damage due to the Presence of a Sunscreen Agent', J. Pharm. Pbarmacol: 28; 53, 1976.
13. Apperley, F.L., 'The Relation of Solar Radiation to Cancer Mortality in North America', Cancer Research.
14. Conrad, K.K., and Hill A.B., 'Mortality from Cancer of the Skin in Relation to Mortality from Cancer of Other Sites'. Am. J. Cancer: 36; 8397, 1939.
15. Coyle, J.D., Hill, R.R., and Roberts, D.R. (eds), Light, Chemical Change and Life, Open University Press, Milton Keynes, 1982.
16. Ott, John, Health and Light, Pocket Books, New York, 1973.
17. Achey, P.M., et al., 'Photoreactivation of Pyrimidine Dimers in DNA, from Thyroid Cells of the Teleost Poccilia Formosa'. Photochem Pbotobiol: 29; 305-310,1979.
18. Sutherland, B.M., 'Pyrimidine Dimer Formation and Repair in Human Skin'. Cancer Research: 40; 3181-3185, 1980.
19. Sutherland, B.M., 'Photoreactivation and Other Ultraviolet/Visible Light Effects on DNA in Human Skin', Ann. N.Y. Acad. Sci: 453; 73-79, 1985.
20. Pathak, M.A., 'Activation of the Melanocyte System by Ultraviolet-Radiation and Cell Transformation', Ann. N.Y. Acad. Sci: 453; 328-339, 1985.
Sunlight - the ultimate detoxifier?
extracted from Dr. Downing's Daylight Robbery (Chapter 13)
[I]t is only the Russians who have fully appreciated this effect of sunlight and put it to use. Their experiments showed that animals exposed to the correct doses of sunlight were capable of clearing a wide range of toxins out of their system considerably quicker than animals reared away from the sun. The toxins that they studied included quartz and coal dusts, toxic minerals such as lead, cadmium and mercury, liver poisons such as carbon tetrachloride, and the neurotoxins which these days are so heavily used worldwide as pesticides. They found that sunlight speeded up the clearance of toxins from the body twice to as much as twenty times. The best effect was obtained when sunlight exposure had started some time before exposure to the toxin.
References
Gabovich, R.D., et al., 'Effect of Ultraviolet Radiation on Tolerance of the Organism to Chemical Substances', Vestn Akad Med Nauk SSSR: 3; 26-28, 1975.
About the author of Daylight Robbery - The Importance of Sunlight to Health
Dr Damien Downing M.B., B.S., Lic.Ac.
Qualified at Guy's Hospital, London in 1972, and worked in hospitals and general practice in London, Leeds and York. He spent three years in the Solomon Islands as Medical Officer of Health for the capital, with responsibility for Mental Health Services and the Village Aid Project. On his return to the UK in 1980 he established a private practice, focusing on nutritional and alternative therapies.
Since 1980 his work has established him as a leading figure in nutritional medicine in the UK. He has undertaken pioneering work in the treatment of allergy, the linking of behavoural disorders with nutrition, light therapy and the treatment of M.E./C.F.S.
In 1984 he co-founded the British Society of Nutritional Medicine with three colleagues and he is still on the committee of its successor, the BSAENM. Since 1989 he has been first co-editor, now senior editor, of the Journal of Nutritional and Environmental Medicine.
In 1991, with Professor R Lacey at the University of Leeds, he co-founded Parascope, a joint-project laboratory investigating intestinal parasitosis. He is a medical advisor to the Hyperactive Children's Support Group and to several other charities.
He currently lives in London.
Publications:
* Daylight Robbery - The Importance of Sunlight to Health (Arrow Books 1998)
* Why M.E.? with Dr Belinda Dawes (Grafton Books 1989)
* Soleil Vital (Editions Jouvence 2002) -the update of Daylight Robbery, so far in French only.
Above bio courtesy Nutrition Associates:
NUTRITION ASSOCIATES offer a unique and effective approach to the treatment of persistent health problems. Many illnesses have their root in poor nutrition, allergies, metabolic problems, chronic infections or even sunlight deficiency. When the body's defences are exhausted, disease can take a hold.
We offer medical advice and treatments based on nutrition and allergy principles. We hold regular clinics in London, Edinburgh,York, Harlow and Windsor. This is not alternative medicine - what we do is based on scientific principles. Nor is it orthodox medicine - we believe that most medical drugs are powerful, but can have powerful side effects, and should be treated with respect. We believe in working with the body as much as possible, by supporting and stimulating the body's own ways of combatting disease.
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