suntanning

[Guest guest]

After reading an article on vitamin D at http://

www.nutritionalwellness.com/archives/2005/jun/06_vasquez.php that

proclaimed

High-Dose Vitamin D - One of the Best Nutritional Supplements on the

Market, I was a little confused. I thought high does vitamin D was

toxic. but even more controversial, the author advises fullbody

suntanning in real sunlight 20 minutes per day with no sunscreen. He

does not even mention the issue of skin cancer once in his article.

I was immediately reminded of an article I read many years ago in

Mother Jones magazine about the apparent epidemiological correlation

between sunscreen use and malignant melanoma (I abstracted two

studies from medline that share this concern below). Thanks to the

wonders of technology, you can see the Mother Jones article at

http://www.motherjones.com/news/outfront/1998/05/wellbeing.html

 

If melanoma is not prevented by sunscreen, then the only benefit is

against the nonmalignant skin cancers, which are mainly cosmetic

problems. THere are several reasons why sunscreen would promote

melanoma. One is that white folks spend much more time in the sun

when they are not burning quickly. This ability to withstand the

pain of the sun may be a major factor in melanoma. Since sunscreen

blocks vitamin D formation and Vitamin D deficiency may predispose to

cancer, the double whammy of increased sun with no vitamin D

protection may be a key variable here. As the author of the MJ

article notes, most white folks just do the sensible thing. They

cover up. In fact, if you have ever traveled to hot places around

the world, the locals always try to AVOID the sun, regardless of skin

color. Only tourists lie about nude in the sand. Is it possible

that if one tries to avoid the sun in general, but does get that 20

minutes per day fullbody exposure or the equivalent, then sunscreen

is not only unnecessary, but actually unhealthy.

 

And for those who like to tan for hours, you are defying evolution.

But the same is probably true for those who get no directly absorbed

UV. Humans evolved in subsaharan africa on what was likely a vitamin

D deficient diet. While they ate meat, early humans were scavengers,

not hunters, and could not depend on steady supplies of foods like

liver. Thus, they evolved powerful mechanisms for creating vitamin D

from sunlight. Light skin absorbs more sunlight to create this

vitamin due to this racial feature evolving in cold northern climates

where sun was scarce. so while white folks need a good shot of

sunlight, they really must be careful to get what they need and no

more. Darker skin folks like mediterraneans, jews, arabs, africans

can tolerate much more. A nice tan is at least some reward after the

centuries of oppression, no doubt. :-)

 

 

 

 

Clin Exp Dermatol. 2000 Sep;25(6):459-63.

Epidemiology of melanoma.

 

Marks R.

 

University of Melbourne, Department of Medicine, St Vincent's

Hospital Melbourne and Skin and Cancer Foundation of Victoria,

Austrialia.

 

Melanoma incidence and morality rates are increasing in most

countries throughout the world where they are being recorded. The

annual incidence rates have increased in the order of 3-7% in fair-

skinned populations in recent decades. The mortality rates have

increased at a rate lower than for incidence. This has been

attributed to educational programs designed to improve the early

detection of melanoma, as the treatment of melanoma has not changed

substantially in recent decades. There has been a decrease in the

thickness of melanoma with an increasing proportion of thin melanomas

at diagnosis. Causation of melanoma is a combination of

constitutional risk factors of which skin colour is the major factor.

The presence and number of common acquired and dysplastic melanocytic

naevi is also a major constitutional risk factor in fair-skinned

people. The only environmental risk factor that has been shown

consistently is exposure to sunlight, particularly large doses of

sunlight sufficient to cause sunburn in childhood that will be

remembered many years later. However, recreational activity leading

to sunburn in adulthood is also associated with risk. To date, no

other environmental factors have been shown epidemiologically to be

clearly associated with risk of melanoma. Recent epidemiological data

from some studies suggesting that there is an increased risk of

melanoma in sunscreen users requires further explanation.

 

Br J Dermatol. 2002 Apr;146 Suppl 61:24-30.

 

Cutaneous malignant melanoma, sun exposure, and sunscreen use:

epidemiological evidence.

 

Bastuji-Garin S, Diepgen TL.

 

Public Health Department, Paris XII University, Henri-Mondor

Hospital, 51 avenue du Marechal de Lattre de Tassigny, 94000 Creteil,

France. sylvie.bastuji-garin

 

BACKGROUND: Cutaneous malignant melanoma is the most serious form of

skin cancer and accounts for about three-quarters of all skin cancer

deaths. Over the last few decades the incidence and mortality rates

of melanoma have been increasing worldwide. The risk of melanoma is

higher in individuals with both phenotypic susceptibility and a

history of sun exposure. Therefore, recommended sun protection

behaviours include wearing long-sleeved clothing, seeking shade,

avoiding the sun when it is strongest, and using sunscreen lotion

with a sun protection factor of 15 or higher. It has been reported,

however, that the use of sunscreens does not protect against melanoma

and seems to increase the duration of recreational sun exposure.

METHODS: Published epidemiological studies examining sunscreen use

and melanoma have been reviewed from an epidemiological point of

view, taking into account potential biases. We have classified case-

control studies into four categories: (1) inconclusive studies

because of major bias in control population and/or the lack of

multivariate analysis; (2) no association between sunscreen use and

melanoma after controlling for confounders; (3) negative association

(i.e. protective effect of sunscreen); and (4) positive association.

Various other epidemiological studies were also analysed. RESULTS:

These results are controversial. Two case-control studies show a

protective effect of sunscreen use, while three studies showed a

significant risk associated with sunscreen use. However, the

discordant results, the low relative risks, the lack of dose-effect

relationship and the numerous biases, especially the uncertainty that

exposure (sunscreen use) preceded melanoma do not suggest a causative

association between sunscreen use and melanoma. Several hypotheses

could partly explain these contradictory results.

[Guest guest]

He

does not even mention the issue of skin cancer once in his article.

>>>> D3 is not toxic. Also, sun exposure while increasing skin CA reduces

mortality from many other CA.It is not a straight forward as it looks. There is

now a debate between the dermatologist and some oncologists regarding sun

exposure

 

 

 

 

Oakland, CA 94609

 

 

 

[Guest guest]

People also tend to accumulate many chemicals during their lives. It

becomes quite noticeable upon cadaver dissection if someone was given chemo,

for example. Logic would tend to support a chemical interaction along with

intense uv radiation. We do not tend to hear about this problem in

immigrant workers, who spend lots of time under direct sun during the heat

of the day.

 

 

Mike W. Bowser, L Ac

 

 

 

> " " <alonmarcus

>

>

>Re: suntanning

>Sun, 19 Jun 2005 10:07:35 -0700

>

>He

>does not even mention the issue of skin cancer once in his article.

> >>>> D3 is not toxic. Also, sun exposure while increasing skin CA

>reduces mortality from many other CA.It is not a straight forward as it

>looks. There is now a debate between the dermatologist and some oncologists

>regarding sun exposure

>

>

>

>

>Oakland, CA 94609

>

>

>

[Guest guest]

Here are a couple of summary reports from Ralph Moss's newsletter about the Vit

D and sun controversy.

 

http://www.cancerdecisions.com/061205.html

 

http://www.cancerdecisions.com/061905.html