Sunlight prevents cancer
SunSmart recommendations risk health
For immediate release: March 22, 2005
From: Oliver Gillie, independent researcher and health writer, director
of Health Research Forum
of the public is being put at risk by recommendations to cover up and
stay out of the sun in the UK. These recommendations, which are part of
Cancer Research UK’s SunSmart programme, increase the risk of several
types of cancer, and may also increase deaths from melanoma, the most
serious form of skin cancer.
Increased exposure to sunlight or greater intake of vitamin D has been
found to reduce the risk of five common cancers in case/control studies.
These are cancer of the colon, breast, ovary, prostate and lymphoma
1-7. Additional evidence based on differences in incidence of cancer
in northern versus southern states of America have found that some 16
or more different types of cancer are less common in the sunny south 8.
For example, the risk of prostate cancer, which causes some 10,000 deaths
a year in England, has been found to be reduced by sunbathing and by foreign
holidays. And sunburn in childhood is even associated with a reduced risk
of prostate cancer, presumably because people who become sunburnt have
greater exposure to the sun 9.
Some 50 per cent of people in Britain and Ireland obtain insufficient
vitamin D which increases their risk of cancer and other diseases 10.
Sunlight is the major source of vitamin D in the UK. Only small amounts
are obtained in foods such as eggs, butter or margarine, meat, some breakfast
cereals and oily fish. Vitamin D supplements do not provide enough extra
vitamin if taken at the usually recommended levels.
The SunSmart recommendations are likely to cause vitamin D shortage if
followed carefully. And, if the latest research is correct, following
SunSmart may increase the risk of several cancers including melanoma.
Two recent scientific articles suggest that increased sun exposure reduces
the risk of either getting melanoma or of dying from it.11,12
Other studies have found that adults who work outdoors and children who
play outdoors where they are regularly exposed to the sun are less likely
to develop melanoma than those who work or play indoors 13,14.
Occasional or irregular exposure of the skin to the sun is associated
with an increased risk of melanoma, possibly because it is associated
with low levels of vitamin D or because irregular exposure does not lead
to a protective tan and skin thickening. The slogan “there is no
such thing as a healthy tan”, used to promote SunSmart, has put
a generation of people at increased risk of melanoma. Sunburn, which is
most likely to occur in people who have irregular exposure, is associated
with an increased risk of skin cancer including melanoma 11.
The increase in melanoma in the UK may be caused in large part by increases
in obesity, and lack of exercise, together with increased travel by car
and increased indoor leisure activities which keep people out of the sun
as well as reducing exercise 15-17. Foreign travel
to sunspots where skin is exposed without any previous tanning may also
be a factor.
linked to insufficient vitamin D
Bones: Sunlight and vitamin D are vital for bone health – both for
preventing fractures which cost the Health Service more than £2bn
a year and for preventing rickets in infants 18,19.
Children from immigrant families are particularly vulnerable to rickets
because dark skin takes up to six times as long to make the same amount
of vitamin D as white skin. Vitamin D supplements have been shown to prevent
both falls (due to the action of the vitamin on the nervous system) and
fractures in a number of double blind randomised trials 20.
A study of nurses in the US has shown that those who consume more vitamin
D in food and supplements have less risk of vitamin D 21.
A very comprehensive study of MS in northern countries including Canada,
UK, Denmark and Sweden has shown that people who are born in May (after
the winter) have an increased risk of MS while those born in November,
who benefit from higher summer levels of vitamin D in the mother during
the last months of pregnancy, have a decreased risk of MS22.
Ring Professor George Ebers for more information: 01865 228579 or 228568.
Diabetes: Risk of diabetes type 1 is also
increased in people whose mothers had insufficient vitamin D during pregnancy
pressure: Sunbathing on sunbeds has been shown to reduce blood
pressure significantly 25.
MORE INFORMATION about links between vitamin D and chronic disease and
sunlight policy can be found with detailed references in:
Sunlight Robbery: Health benefits of sunlight are denied by current public
health policy in the UK, written by Oliver Gillie.
It may be obtained as a free download from www.healthresearchforum.org.uk
* Oliver Gillie is a former medical correspondent of the Sunday Times
and medical editor of the Independent.
He founded Health Research Forum to promote public health policy based
on scientific evidence.
Phone: 0207 561 9677, 07774 995 805
Dr William Grant of
Sunarc is an expert on cancer and sunlight.
He is available on 001 415 441 7663 or 001 415 776 5274
E-mail: [email protected]
to sunbathe safely and build up your D stores
In Australia and New Zealand short daily exposures of the arms, hands
and face to sunlight are now recommended in order to maintain healthy
supplies of vitamin D 26. Recommended exposure varies
from five to seven minutes outside midday hours in summer in the sunniest
northern parts of Australia to 40 minutes at the middle of day in winter
in Christchurch, New Zealand.
In the UK the sun is only strong enough to make vitamin D in exposed skin
between April and September. So it is important to sunbathe in the summer
months to establish a store of vitamin D which will last over the winter.
In the UK the summer sun is generally much weaker than in northern Australia
and so for the UK similar exposures, five to ten minutes, might be recommended
at midday except perhaps on a clear day in the height of summer.
The sun is strongest in the middle of the day and so this is the best
time to sunbathe in the UK, although care must be taken to stop as soon
as the skin feels at all uncomfortable or hot. Another advantage of sunbathing
in the middle of the day is that sunlight at this time contains more beneficial
UVB and less UVA which is now thought to be more damaging.
Wear as few clothes as possible. Begin with only a few minutes exposure
and build up gradually. A person with a white skin will get maximum vitamin
D after 10-20 minutes sunbathing in the middle of the day in midsummer
in the UK. Up to an hour is needed by people with dark skins. Longer times
are needed in April and September because even in the middle of the day
the sun is still low in the sky and much of the ultra-violet rays are
absorbed by the longer journey through the atmosphere.
When abroad take care to avoid sunburn which is a special hazard when
light is reflected from snow, sand or water, or when a breeze cools the
skin and covers up any hot or burning sensation. Avoid the sun midday
midsummer in the Med.
1. Pritchard, R. S., Baron, J. A. & Gerhardsson de Verdier, M. Dietary
calcium, vitamin D, and the risk of colorectal cancer in Stockholm, Sweden.
Cancer Epidemiol Biomarkers Prev 5, 897-900 (1996).
2. White, E., Shannon, J. S. & Patterson, R. E. Relationship between
vitamin and calcium supplement use and colon cancer. Cancer Epidemiol
Biomarkers Prev 6, 769-74 (1997).
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due to inadequate doses of solar ultraviolet-B radiation. Cancer 94, 1867-75
9. Luscombe, C., Fryer, A., French, M. & al, e. Exposure to ultraviolet
radiation: association with susceptibility and age at presentation with
prostate cancer. Lancet 358, 641-2 (2001).
10. Gillie, O. Sunlight Robbery: Health Benefits of sunlight are denied
by current public health policy in the UK. Health Research Forum Occasional
Reports 1, 1-41 (2004).
11. Kennedy, C., Bajdik,
C. D., Willemze, R., de Gruijl, F. R. & Bouwes Bavinck, J. N. The
influence of Painful Sunburns and Lifetime Sun Exposure on the Risk of
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13. Kaskel, P. et al. Outdoor activities in childhood: a protective factor
for cutaneous melanoma? Results of a case-control study in 271 matched
pairs. Br J Dermatol 145, 602-9 (2001).
14. Hakansson, N., Floderus, B., Gustavsson, P., Feychting, M. & Hallin,
N. Occupational sunlight exposure and cancer incidence among Swedish construction
workers. Epidemiology 12, 552-7 (2001).
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18. National Service Framework for Older People. Department of Health
19. Trivedi, D., Doll, R. & Khaw, K. Effect of four monthly oral vitamin
D3 (cholecalciferol) supplementation on fractures and mortality in men
and women living in the community: randomised double blind controlled
trial. British Medical Journal 326 (2003).
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Journal of the American Medical Association 291, 1999-2006 (2004).
21. Munger, K., Zhang, S., O'Reilly, E. & al, e. Vitamin D intake
and incidence of multiple sclerosis. Neurology 62, 60-5 (2004).
22. Willer, C., Dyment, D., Sadovnick, A., Rothwell, P. & Ebers, G.
Timing of birth influences multiple sclerosis susceptibility: the Canadian
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26. Statement by Cancer
Council Australia, Osteoporosis Australia and other health organisations.
See website: www.cancer.org.au/documents/Risks_Benefits_Sun_Exposure_MAR05.pdf
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