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Prevent Cancer With The
Sunshine and Vitamin D


Unlike fads that sizzled and fizzled, the evidence for Vitamin D's health benefits is now strong and keeps growing. If it bears out, it will challenge one of medicine's most fundamental beliefs: that people need to coat themselves with sunscreen whenever they're in the sun. Doing that may actually contribute to far more cancer deaths than it prevents, some researchers think.

The vitamin is D, nicknamed the "sunshine vitamin" because the skin makes it from ultraviolet rays. Sunscreen blocks its production, but dermatologists and health agencies have long preached that such lotions are needed to prevent skin cancer. Now some scientists are questioning that advice. The reason is that vitamin D increasingly seems important for preventing and even treating many types of cancer.

In the last few years alone, dozens of separate studies found vitamin D helped protect against lymphoma and cancers of the prostate, lung and, ironically, the skin. The strongest evidence is for colon cancer.

A study published in the Archives of Internal Medicine on May 28, 2007, suggested that women who consume higher amounts of calcium and vitamin D may have a lower risk of developing breast cancer before menopause. The study followed more than 31,000 women aged 45 and older for 10 years. It found that intake of calcium and vitamin D was moderately associated with a lower risk of breast cancer before — but not after — menopause.

Yet another study — released on May 15, 2008 — found that women with low levels of vitamin D may have a poorer prognosis than those with sufficient vitamin D. The study by Toronto researchers also found that women with too little of the vitamin had a greater chance of recurrence and lower overall survival rates than those with healthier amounts.

The study involved 512 women, aged 35 to 69, who were diagnosed with breast cancer between 1989 and 1996. Their health was followed until 2007, on average for almost 12 years. The researchers found that 37.5 per cent of the patients were vitamin D deficient and 38.5 per cent had levels that were considered insufficient for good bone health. Only 24 per cent had sufficient levels of vitamin D in their blood.

The researchers say their study shows there is an association between vitamin D levels and breast cancer outcome. They say it's too early to tell whether vitamin D deficiency can cause the disease.

But less than two weeks later, another study suggested the cancer-fighting properties of vitamin D may be not be universal. The study, published in the Journal of the National Cancer Institute, found that a higher level of vitamin D in men is not associated with a lower risk of developing prostate cancer. And in some cases, it may be linked to a higher risk of developing a more aggressive form of the disease.

Meanwhile, a study published in the June 9, 2008 issue of the Archives of Internal Medicine found that men with low levels of vitamin D may have an increased risk of heart attack. The study followed the medical records and blood samples of 454 men who had non-fatal heart attacks or fatal heart disease from January 1993 and January 2004. They compared the data from those men with records and blood samples of 900 living men who had no history of cardiovascular disease. The researchers also recorded diet and lifestyle factors.

The researchers found that after adjusting for several factors — including family history of heart trouble, body mass index, alcohol consumption, physical activity and hypertension — men with low levels of vitamin D (less than 15 nanograms per millilitre of blood) had a higher risk for developing heart disease than men with sufficient levels of vitamin D (30 nanograms per millilitre of blood or more).

Dr. John Cannell, the executive director of the U.S. Vitamin D Council, in 2006 published a study in the Journal of Epidemiology and Infection suggesting among other things that children who are exposed regularly to sunlight are less likely to catch colds and respiratory infections. A separate 2006 study published in the journal Science suggested that Vitamin D might boost the body's production of naturally occurring antibiotics.

Bolstered by the benefits the sunshine vitamin offers, many public health officials are encouraging people to include vitamin D in their diets as researchers continue to investigate how it helps the body.

Many people aren't getting enough vitamin D. It's hard to do from food and fortified milk alone, and supplements are problematic.

So the thinking is this: Even if too much sun leads to skin cancer, which is rarely deadly, too little sun may be worse.

No one is suggesting that people fry on a beach. But many scientists believe that "safe sun" - 15 minutes or so a few times a week without sunscreen - is not only possible but helpful to health.

One is Dr. Edward Giovannucci, a Harvard University professor of medicine and nutrition who laid out his case in a keynote lecture at a recent American Association for Cancer Research meeting in Anaheim, Calif.

His research suggests that vitamin D might help prevent 30 deaths for each one caused by skin cancer.

"I would challenge anyone to find an area or nutrient or any factor that has such consistent anti-cancer benefits as vitamin D," Giovannucci told the cancer scientists. "The data are really quite remarkable."

The talk so impressed the American Cancer Society's chief epidemiologist, Dr. Michael Thun, that the society is reviewing its sun protection guidelines. "There is now intriguing evidence that vitamin D may have a role in the prevention as well as treatment of certain cancers," Thun said.

Even some dermatologists may be coming around. "I find the evidence to be mounting and increasingly compelling," said Dr. Allan Halpern, dermatology chief at Memorial Sloan-Kettering Cancer Center in New York, who advises several cancer groups.

The dilemma, he said, is a lack of consensus on how much vitamin D is needed or the best way to get it.

No source is ideal. Even if sunshine were to be recommended, the amount needed would depend on the season, time of day, where a person lives, skin color and other factors. Thun and others worry that folks might overdo it.

"People tend to go overboard with even a hint of encouragement to get more sun exposure," Thun said, adding that he'd prefer people get more of the nutrient from food or pills.

But this is difficult. Vitamin D occurs naturally in salmon, tuna and other oily fish, and is routinely added to milk. However, diet accounts for very little of the vitamin D circulating in blood, Giovannucci said.

Supplements contain the nutrient, but most use an old form - D-2 - that is far less potent than the more desirable D-3. Multivitamins typically contain only small amounts of D-2 and include vitamin A, which offsets many of D's benefits.

As a result, pills might not raise vitamin D levels much at all.

Government advisers can't even agree on an RDA, or recommended daily allowance for vitamin D. Instead, they say "adequate intake" is 200 international units a day up to age 50, 400 IUs for ages 50 to 70, and 600 IUs for people over 70.

Many scientists think adults need 1,000 IUs a day. Giovannucci's research suggests 1,500 IUs might be needed to significantly curb cancer.

How vitamin D may do this is still under study, but there are lots of reasons to think it can:

_Several studies observing large groups of people found that those with higher vitamin D levels also had lower rates of cancer. For some of these studies, doctors had blood samples to measure vitamin D, making the findings particularly strong. Even so, these studies aren't the gold standard of medical research - a comparison over many years of a large group of people who were given the vitamin with a large group who didn't take it. In the past, the best research has deflated health claims involving other nutrients, including vitamin E and beta carotene.

_Lab and animal studies show that vitamin D stifles abnormal cell growth, helps cells die when they are supposed to, and curbs formation of blood vessels that feed tumors.

_Cancer is more common in the elderly, and the skin makes less vitamin D as people age.

_Vitamin D gets trapped in fat, so obese people have lower blood levels of D. They also have higher rates of cancer.

_Diabetics, too, are prone to cancer, and their damaged kidneys have trouble converting vitamin D into a form the body can use.

During short winter days, the sun's rays come in at too oblique an angle to spur the skin to make vitamin D. That is why nutrition experts think vitamin D-3 supplements may be especially helpful during winter, and for dark-skinned people all the time.

But too much of the pill variety can cause a dangerous buildup of calcium in the body. The government says 2,000 IUs is the upper daily limit for anyone over a year old.

On the other hand, D from sunshine has no such limit. It's almost impossible to overdose when getting it this way. However, it is possible to get skin cancer. And this is where the dermatology establishment and Dr. Michael Holick part company.

Thirty years ago, Holick helped make the landmark discovery of how vitamin D works. Until a few years ago, he was chief of endocrinology, nutrition and diabetes and a professor of dermatology at Boston University. Then he published a book, "The UV Advantage," urging people to get enough sunlight to make vitamin D.

"I am advocating common sense," not prolonged sunbathing or tanning salons, Holick said.

Skin cancer is rarely fatal, he notes. The most deadly form, melanoma, accounts for only 7,770 of the 570,280 cancer deaths expected to occur in the United States this year.

More than 1 million milder forms of skin cancer will occur, and these are the ones tied to chronic or prolonged suntanning.

Repeated sunburns - especially in childhood and among redheads and very fair-skinned people - have been linked to melanoma, but there is no credible scientific evidence that moderate sun exposure causes it, Holick contends.

"The problem has been that the American Academy of Dermatology has been unchallenged for 20 years," he says. "They have brainwashed the public at every level."

The head of Holick's department, Dr. Barbara Gilchrest, called his book an embarrassment and stripped him of his dermatology professorship, although he kept his other posts.

She also faulted his industry ties. Holick said the school has received $150,000 in grants from the Indoor Tanning Association for his research, far less than the consulting deals and grants that other scientists routinely take from drug companies.

In fact, industry has spent money attacking him. One such statement from the Sun Safety Alliance, funded in part by Coppertone and drug store chains, declared that "sunning to prevent vitamin D deficiency is like smoking to combat anxiety."

Some time ago, the dermatology academy launched a "Don't Seek the Sun" campaign calling any advice to get sun "irresponsible." It quoted Dr. Vincent DeLeo, a Columbia University dermatologist, as saying: "Under no circumstances should anyone be misled into thinking that natural sunlight or tanning beds are better sources of vitamin D than foods or nutritional supplements."

That opinion is hardly unanimous, though, even among dermatologists.

"The statement that 'no sun exposure is good' I don't think is correct anymore," said Dr. Henry Lim, chairman of dermatology at Henry Ford Health System in Detroit and an academy vice president.

Some wonder if vitamin D may turn out to be like another vitamin, folate. High intake of it was once thought to be important mostly for pregnant women, to prevent birth defects. However, since food makers began adding extra folate to flour in 1998, heart disease, stroke, blood pressure, colon cancer and osteoporosis have all fallen, suggesting the general public may have been folate-deficient after all.

With vitamin D, "some people believe that it is a partial deficiency that increases the cancer risk," said Hector DeLuca, a University of Wisconsin-Madison biochemist who did landmark studies on the nutrient.

About a dozen major studies are under way to test vitamin D's ability to ward off cancer, said Dr. Peter Greenwald, chief of cancer prevention for the National Cancer Institute. Several others are testing its potential to treat the disease. Two recent studies reported encouraging signs in prostate and lung cancer.

As for sunshine, experts recommend moderation until more evidence is in hand.

"The skin can handle it, just like the liver can handle alcohol," said Dr. James Leyden, professor emeritus of dermatology at the University of Pennsylvania, who has consulted for sunscreen makers.

"I like to have wine with dinner, but I don't think I should drink four bottles a day."

Facts about Vitamin D:

1. Vitamin D is produced by your skin in response to exposure to ultraviolet radiation from natural sunlight.
2. The healing rays of natural sunlight (that generate vitamin D in your skin) cannot penetrate glass. So you don't generate vitamin D when sitting in your car or home.
3. It is nearly impossible to get adequate amounts of vitamin D from your diet. Sunlight exposure is the only reliable way to generate vitamin D in your own body.
4. A person would have to drink ten tall glasses of vitamin D fortified milk each day just to get minimum levels of vitamin D into their diet.
5. The further you live from the equator, the longer exposure you need to the sun in order to generate vitamin D. Canada, the UK and most U.S. states are far from the equator.
6. People with dark skin pigmentation may need 20 - 30 times as much exposure to sunlight as fair-skinned people to generate the same amount of vitamin D. That's why prostate cancer is epidemic among black men -- it's a simple, but widespread, sunlight deficiency.
7. Sufficient levels of vitamin D are crucial for calcium absorption in your intestines. Without sufficient vitamin D, your body cannot absorb calcium, rendering calcium supplements useless.
8. Chronic vitamin D deficiency cannot be reversed overnight: it takes months of vitamin D supplementation and sunlight exposure to rebuild the body's bones and nervous system.
9. Even weak sunscreens (SPF=8) block your body's ability to generate vitamin D by 95%. This is how sunscreen products actually cause disease -- by creating a critical vitamin deficiency in the body.
10. It is impossible to generate too much vitamin D in your body from sunlight exposure: your body will self-regulate and only generate what it needs.
11. If it hurts to press firmly on your sternum, you may be suffering from chronic vitamin D deficiency right now.
12. Vitamin D is "activated" in your body by your kidneys and liver before it can be used.
13. Having kidney disease or liver damage can greatly impair your body's ability to activate circulating vitamin D.
14. The sunscreen industry doesn't want you to know that your body actually needs sunlight exposure because that realization would mean lower sales of sunscreen products.
15. Even though vitamin D is one of the most powerful healing chemicals in your body, your body makes it absolutely free. No prescription required.


Dr. William Grant and Dr. Mercola
discuss Vitamin D and Cancer Link Part 1

Dr. William Grant and Dr. Mercola
discuss Vitamin D and Cancer Link Part 2

CTV Newsnet Report on Vitamin D and Cancer Link

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