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Sunshine cuts risk of breast cancer

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Published Date: 05 August 2007
By MARC HORNE
SUNSHINE could help women in the fight against breast cancer, according to new research.
For years, experts have warned that spending too much time in the sun can increase the risk of developing skin cancer. But now it seems that women who avoid sunlight altogether are putting themselves at greater risk of being diagnosed with breast can
cer.

The majority of vitamin D comes from exposure of the skin to sunlight but many women - exposed less in winter and reluctant to bare themselves in summer because of the dangers - are deficient.

There has been anecdotal evidence to suggest that breast cancer is less common among women who live closer to the Equator, where the sunshine is stronger.

But a new study provides the firmest evidence yet that the lower the levels of vitamin D in a woman's blood-stream, the greater the risk of her developing breast cancer if she has passed the menopause.

Of more than 1,000 women who took part in a trial, those who were given both calcium and vitamin D supplements had less than half the chance of developing breast cancer than those given a placebo.

A team from Creighton University in Omaha, Nebraska, enrolled 1,179 women all 55 or older, who had no history of cancer.

The women were divided randomly into groups and given either supplements of calcium alone, calcium plus vitamin D or a placebo for four years.

When the researchers repeated the analysis for those women who were free of cancer after the first year of the study, the results were even more striking, with the risks being reduced by more than three-quarters.

"Our findings of decreased all-cancer risk with improved vitamin D status are consistent with a large and still growing body of data showing that cancer risk, cancer mortality, or both are inversely associated with solar exposure, vitamin D status or both," the researchers said.

"Findings from this study suggest that higher intakes of calcium and vitamin D may be associated with a lower risk of developing premenopausal breast cancer."

Vitamin D is also present in foods including milk, eggs, oily fish, green vegetables and fortified margarines.



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  • Last Updated: 04 August 2007 6:19 PM
  • Source: Scotland On Sunday
  • Location: Scotland
  • Related Topics: Breast cancer
 
1

Charles Linskaill,

Edinburgh 05/08/2007 00:47:30

I think this sun thing is a bit hearsay, its more like diet factors come into it, and lets face it we all eat more healthy when its bright and cheerful sunlight, i.e. salads olive dressings etc!
Oestrogen related factors are the ones that cause Breast Cancer, that would be more diet related than sun related, hence our diet changes big style on sunny days hence less risk Breast Cancer.
Off-course sunlight is good for all but not to much!
And I don't believe for one-minute exposing your Breasts to the sun will help you avoid Breast Cancer.

2

tedhutchinson,

Louth 05/08/2007 08:47:28

To work out how much sunshine you need to meet your body's daily requirement you first need to understand you body uses between 3000 and 5000iu Vitamin D3 daily. Google "Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol" for Heaney's paper on the topic.

You require UVB rays to be present in the sunlight and because of the angle of the sun required to enable UVB to reach the earth your shadow has to be shorter than your height. The process is heat driven so the minimum erythemal index needed is 3.

It takes 5 minutes for one side of your naked (or as near to as possible) body, laying down, to raise 1000iu, so turning over every 5 minutes for 20 minutes will create 4000iu. Sufficient for one day.

If you want to rectify an insufficiency situation, and as most people in the UK remain insufficient throughout the year, (google "Hypovitaminosis D in British adults at age 45 y:") you probably need to, then you have to understand that further heat simply turns the vitamin D your skin has just made into suprasterols for which the body has no use.
So to build up stores for the Winter or to raise your current status, you need to cover up/go inside and allow your skin to cool down and the Vitamin d to be absorbed before another 20 minute session.

The newly proposed safe upper limit for Cholecalciferol Vitamin D3 has suggested that as 10,000iu/daily is the maximum amount your skin usually is able to make on a sunny day this should also be the amount for safe supplementation. (Adverse events have only occurred above 40,000iu/d has been taken for some time) Risk Assessment Vitamin D.

Those areas least often exposed to direct sunlight will be the most efficient Vitamin D producers so do try to expose as much untanned skin as possible.

Sunblock, sunscreen SPF cosmetics all largely prevent UVB rays from reaching the skin so prevent Vitamin D synthesis.

You can boost your

3

tedhutchinson,

Louth 05/08/2007 08:53:21

http://www.whfoods.com/genpage.php?tname=george&dbid=...
The World's Healthiest foods website article on How diet can protect from sunburn may be helpful but do remember this isn't an instant solution. The Tomato puree research required daily consumption over 12 weeks to show improved UVB tolerance.

The information on Calcium is also worth considering as http://www.whfoods.com/genpage.php?tname=nutrient&dbi... it has been shown that calcium from food-sources is used more effectively than calcium from supplements.

4

tedhutchinson,

Louth 05/08/2007 09:13:17

Research shows the lowest levels of breast cancer occur around 52 ng/ml 130nmol/L, so this is the level associated with reduction by 50% in incidence of breast cancer.

Most UK white adults (because it takes darker skins longer to make Vitamin d the situation will be worse for those with brown/black skins) have levels below 75nmol/L see
http://www.ajcn.org/cgi/content/abstract/85/3/860

So to get from 75nmol/L to above 125nmol/L requires a raise of 50nmol/L. Each 400iu Vitamin d3 cholecalciferol tablet daily raised status by between 7-12nmol/L http://www.ajcn.org/cgi/content/full/85/3/649
So 2000iu/d D3 or more will be required by most UK readers to achieve optimal status on those days when laying nearly naked in the sun at midday for 20 minutes or so isn't an option.

5

Yane,

Melbourne 05/08/2007 12:20:33

loved readin that tedhutchison but the truth is that if I lay naked in the sun here in the height o summer fur 20 minutes I definitely couldn't get breast cancer cos ma tits wid be be burnt aff

6

tedhutchinson,

Louth 05/08/2007 13:41:02

Well Yane Melbourne Australia is Latitude 37 the same latitude as Seville Spain or San Fransisco USA that is 1300mls nearer the Equator and yes the sun is hotter nearer the Equator. So consequently the amount of exposure needed at midday midsummer is shorter.
For Glasgow reader of the Scotsman 20 minutes is a reasonable maximum time to out in the sun whereas in Melbourne, depending on skin type between 5 and 15mins should be sufficient.
You must never burn or allow your skin to become red as not only have you damaged your skin but you've also turned the Vitamin D3 into supra sterols which are no use at all. These animated diagrams explain the synthesis of Vitamin d3 http://www.uvguide.co.uk/vitdpathway.htm and show what happens if you overdo the sun exposure.

One interesting aspect of the Northern-Southern hemisphere divide is that even at the same latitude the sun shines 10% brighter in the Southern part. This is partly due to the fact that there is less land and more sea in the Southern hemisphere therefore fewer cities/factories and less pollution allowing more UVB to penetrate to ground level but also the orbit of the earth is such that when it is Winter in Melbourne the tilt of the Earth in it's orbit brings it physically nearer the Sun than when it's Winter in Glasgow. These 2 reasons together account for the extra power of the sun at your end of the world but of course being 1300mls nearer the Equator makes a big difference.
However, research on Vitamin D insufficiency in Australia reports "Vitamin D insufficiency is common over a wide latitude range in Australia. Season appears to be more important than latitude, but both accounted for less than one-fifth of the variation in serum 25(OH) D levels, highlighting the importance of behavioral factors. Current sun exposure guidelines do not seem to fully prevent vitamin D insufficiency, and consideration shoul

7

Lynn,

Madison, Wisconsin, USA 05/08/2007 18:32:56

Damned if we do, damned if we don't, eh?

8

tedhutchinson,

05/08/2007 20:37:57

Damned if we do, damned if we don't, eh?

But when looking at risks we have to use our common sense.
People need to understand the cancer risk of having low vitamin d status increases significantly the chances of getting the most common deadly cancers, breast, prostate, lung colon so much that for each skin cancer caused by excessive sun exposure more than 30 people die needlessly from those cancers that thrive in Vitamin D depleted bodies.
But the advantages of having optimal vitamin d status don't end with cancer. When the UVB rays hit the skin it's the cholesterol in the skin that is converted to Vitamin D so raising your vitamin d status inevitably reduces your cholesterol level, it also reduces your blood pressure and thus impacts on your heart disease risk. Not to mention diabetes, oseotarthritis, osteoporosis, obestiy, and hyperparathyroidism.
Having optimal Vitamin D status also impacts on your feelings of well being. Having sufficient Vitamin D to see you through the winter will reduce your chances of SAD or other mental illness.
So for each skin cancer caused by excessive burning sun exposure well over 600 lives are damaged by the effects of low vitamin d status.
Our bodies evolved to live naked in the sunlight. If we ate more healthily and used MODERATION in limiting our sun exposure we really can enjoy the health benefits of a high vitamin d status and significantly lower cancer total incidence including fewer skin cancers as sunlight actually primes the skin to attack skin cancer cells. http://www.sciencentral.com/articles/view.php3?type=artic...

9

Yane,

Melbourne 05/08/2007 23:32:24

Well, I sincerely thank you for all that information.
I never knew that the feeling ya get from running along the sand & hurling yerself into the sea could have a scientific explanation.


 

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