Skin Cancers and Diet

Part 3: Skin cancers — Sunscreens (Continued)

No one believes that exposure to UV leads to skin cancer more ardently than dermatologists. Dr Roger Ceilley, a leading American dermatologist, proclaimed in 1998, 'We're going to have millions more cases of skin cancer in the next decade' if people forgo sunscreen.[i] In fact, of course, that is exactly what we are seeing — but in people who do use sunscreens.

There is, however, some evidence that regular use of sunscreens helps prevent the formation of actinic keratoses.[ii] But so does eating meat. US scientists at the Arizona Cancer Center, University of Arizona, noted that a previous study conducted showed that vitamin A supplements significantly reduced the risk of squamous cell skin cancer in patients with moderately severe actinic keratoses.[iii] Natural sources of Vitamin A are better than supplements. Fruits and vegetables with orange and yellow colouring, and green leafy vegetables contain beta-carotene, a precursor of vitamin A, but the body poorly converts beta-carotene into vitamin A. The best dietary sources of vitamin A are animal products, such as eggs and liver; cod liver oil is also an excellent natural source of vitamin A.

New sunscreens can cause brain damage

There is now a new range of sunscreens, but these seem to widen the range of dangers.[iv] These new products contain tiny nanoparticles which have caused long-term neurological damage in studies on mice. Scientists say the tiny particles may have different chemical compositions, and because nanoparticles are so small they are more easily absorbed into the skin, raising potential risks. It will be years before the safety of nanotechnology can be proven, yet the particles are already being put into use in sunscreens, toothpaste, makeup and other products.

The polyunsaturated fat connection

Since the 1960s linoleic acid, and vegetable margarines and cooking oils that contain it, have been shown time and again to increase the risk of many types of cancer, including skin cancers.

Drs B S and L E Mackie, working on Australia's Sunshine Coast have a great deal of experience in skin cancers. They say: 'In view of the work of Black and Erickson in mice and our own work in humans, we believe that human subjects who are at high risk of melanomas and other solar-induced forms of skin cancer should be advised to be moderate in their intake of dietary polyunsaturated fats.'[v]

Patricia Holborrow also points out that the increase in melanomas could be a result of Australians' dietary changes to polyunsaturated fats. 'Recently,' she wrote, 'I followed up four families that started in 1976 to use a diet with preferred oils as safflower and sunflower oil and low in salicylates and additives (that interfere with the metabolic pathway of these fats). There had been three cases of cancer resulting in two deaths in these families.'

The Australians are as paranoid about heart disease as are the Americans. I was in Australia in 1995 and noticed that it is even their custom to remove the cream from milk and replace it with polyunsaturated vegetable oil.

Speak against current guidelines — and lose your job?

Johnathan Rees, Professor of dermatology, University Department of Dermatology, Newcastle upon Tyne, appraises the current melanoma 'epidemic', saying:

'There is after all no robust empirical evidence to defend most health promotion in this area. It has been suggested that the antithesis of science is not art but politics; melanoma is perhaps an example of the two having become mistakenly intertwined.'[vi]

Professor Rees is lucky that he still has a job. Michael F. Holick, a professor at Boston University, was asked to resign in April 2004 from the university's Department of Dermatology because of his book, The UV Advantage, in which he describes the importance of sunlight in boosting vitamin D levels; and for simply advocating a few minutes of sunlight exposure per week. The Department chairman, Barbara Gilchrest, MD, told the Boston Globe that the book ?is an embarrassment for this institution and an embarrassment for him'.[vii] Gilchrest's disapproval of Holick stems from the fact that his statements, superficially at least, seem to be at odds with the medical profession's consensus on the damaging effects of sunlight. Dermatologists have been warning the public for years that sunlight is a cause of melanoma. Some of them, possibly frustrated at the failure of most of their treatments to reverse advanced melanoma, now regard sun exposure without sunblock as analogous to promiscuous sex without condoms. But ultraviolet sunlight (particularly UVB) has essential functions. And Boston is in the far north of the USA, where usable sunlight is scarce and vitamin D is hard to come by.

If there is debate about this subject, isn't a university the right place for such debate to be conducted? Unfortunately, examples such as this where dissidents are summarily dismissed or reviled by their peers is actually common in the medical world.

References

[i]. Fackelmann, Kathleen. Melanoma madness. The scientific flap over sunscreens and skin cancer. Science News June 6, 1998; 153 (23): 360.

[ii]. Dover JS, Arndt KA. Dermatology. JAMA 1994; 271: 1662-63.

[iii]. Alberts D, Ranger-Moore J, Einspahr J, et al. Safety and Efficacy of Dose-Intensive Oral Vitamin A in Subjects with Sun-Damaged Skin. Clin Cancer Res 2004; 10: 1875-1880.

[iv]. Nanoparticles in sun creams can stress brain cells. Nature, 16 June 2006.

[v]. Mackie BS, Mackie LE. Dietary polyunsaturated fats. Med J Aust 1988; 149: 449.

[vi]. Rees J L. The melanoma epidemic: reality or artefact. BMJ 1996; 312: 137-8.

[vii]. Allen S. BU advocate of sunlight draws ire. Boston Globe, April 13, 2004.