eileen

Vitamin D from sunshine can reduce the risks of breast, colon and endometrial cancers as well as heart attacks
Tom SpearsVancouver Sun; Canwest News Service

Saturday, January 26, 2008
If you are reading this newspaper, chances are you are overdressed. Biologically speaking, you should be next to naked and on a beach a long way south of Canada. Your skin should be soaking up sunshine and manufacturing vitamin D -- something it doesn't do for people who live in a land of limited sun, long sleeves and indoor jobs.
For years medical researchers didn't see the picture this way. Since the 1950s they've known that sunshine causes skin cancer. But in the past year, a second picture has emerged in mainstream medical conferences and journals. The vitamin D from sunshine helps prevent some cancers that are generally seen as more dangerous -- among them breast, colon and endometrial cancers. It appears to have a role in fighting infection and in preventing such immune-system diseases as multiple sclerosis. Most recently, evidence suggests it prevents heart attacks.
It's not a miracle pill. But early indications suggest when it comes to health measures you can control, taking vitamin D may rank up there with quitting smoking.
Yet nearly all Canadians are probably deficient in this so-called "sunshine" vitamin, the only vitamin you can't get in large amounts from a good diet.
And much of this information has been staring scientists in the face, generally unrecognized, for 40 years or more.
The breakthrough came last year from rural Nebraska. Some 1,200, aged 55 and up, volunteered to take either vitamin D or a placebo, a "dummy pill," for four years. Neither the women nor their doctors knew who was getting which pill -- an approach called "double-blind."
Joan Lappe, who teaches and studies bone health at Creighton University in Omaha, organized the study. Vitamin D is essential for building strong bones. It acts as a hormone to help bones absorb calcium; without the vitamin, you can swallow a mountain of calcium and it won't do much good.
For the past five years, though, Lappe has been trying to determine if vitamin D prevents other disease -- especially cancer. That's why she recruited the Nebraska women.
The results this June bowled over long-term medical researchers. Women who took vitamin D and calcium had 60 per cent less breast, lung and colon cancer at the end of the trial than women who took the dummy pill. And when she dropped the cases discovered in the first year, assuming those cancers had been present but unnoticed when the trial began, the reduction in cancer in her vitamin D group was an astonishing 77 per cent.
This one study alone would have been big news, but it wasn't alone. It was followed by a river of findings.
Lappe answers questions cheerfully about the Nebraska study that caused so much excitement last June.
"I can always talk about vitamin D!" she says. The basics: We make vitamin D in our skin, but only when direct sunlight strikes it. In this form it's called D3, or cholecalciferol. The liver, and later the kidneys, transform it into closely related chemical compounds that the body uses in various ways.
No one anywhere in Canada can manufacture D3 in the fall or winter because the sun is too low in the sky to start this reaction.
There's a problem in summer, too. The part of sunshine that does this is ultraviolet (UV) B, which also causes skin cancer. Sunscreens that block UVB also prevent it from making vitamin D.
Food, the source of most vitamins, is a lousy source of vitamin D. Fatty fish has a little, and there's some added to milk.
Lappe's group was giving women 1,100 "international units" or IU each day -- 11 times what is in a glass of milk. It's nearly triple the 400 a day that Health Canada recommends for middle-aged people. (It recommends a 400-IU daily supplement for breastfed infants, but suggests older children get enough from milk.)
Typical vitamin D pills range from 400 to 1,000 IU. By comparison, the body can manufacture 20,000 IU in just a few minutes when you wear a swimsuit outdoors on a summer day. A typical multivitamin -- such as Centrum for adults or Flintstones for children -- contains 400 IU.
Lappe, like many researchers today, believes the old rules for the vitamin are wrong. (She takes 2,000 IU a day.)
And as the summer and fall of 2007 progressed, major medical groups in Canada started to fall in line. In late September, the Canadian Paediatric Society announced that pregnant women should consider taking 2,000 IU a day, and that newborns should also get a vitamin supplement -- not just for strong bones, but to build their immune systems.
Dr. John Godel of the Paediatric Society said he believes the vitamin is implicated in protection again everything from cancer to multiple sclerosis. "There's been a lot of anecdotal evidence to suggest all these effects, but it's only in the last two years that there's been experimental evidence," he said in an interview. "It's quite an exciting concept, really."
The Canadian Cancer Society joined the action, telling all adults in Canada to take 1,000 IU a day in the fall and winter -- or year-round if they live in the north or have dark skin. (Dark-skinned people make less vitamin from sunshine.) In a show of confidence, it made the announcement the same day Lappe's study appeared.
It also adds: Keep wearing sunscreen.
All this pleases Lappe no end; she wishes her own country would follow suit. (The U.S. National Institutes of Health says adults should get 200 IU a day until age 50 and 400 IU a day between 50 and 70, since our bodies makes vitamin D less efficiently as we age. For people older than that, it recommends 600 IU.)
Bruce Hollis, who teaches pediatrics at the Medical University of South Carolina is also thrilled with Canada's lead. "The Canadian Cancer Society and the (Canadian) Paediatric (Society) made remarkable suggestions, especially the pediatric people. They're basically saying: We've seen enough evidence. We're not waiting for the government. And governments have been just abysmal" in not recommending more vitamin D. "It's a tragedy, and so I look at these societies, and they make these recommendations, but unfortunately in our country (U.S.) they haven't."
Health Canada has not endorsed the higher vitamin doses; it continues to suggest 200 IU/day for adults up to age 50, 400 IU/day for those aged 51 to 70, and 600 IU/day for anyone older than 70.
"We're aware of the growing body of evidence for vitamin D," said Health Canada spokesman Paul Duchesne. "But the process both for us and for the U.S. is to go through the Institute of Medicine, and they establish reference values which are used both by Canada and the U.S. So that's where we're at; the Institute of Medicine (is) in the process of review." (The Institute of Medicine is part of the U.S. National Academy of Sciences.)
The vitamin D story, says Hollis, is about to expand even beyond cancer.
A Harvard study is likely to show in a few months that the vitamin reduces heart attacks, he says -- "which will just stun the cardiologists." He believes the vitamin is also used in processing glucose, suggesting a role in preventing diabetes.
Last year he was part of a team that reported the vitamin kills tuberculosis in the lab. The study ran in Science, a major research journal.
Studies of U.S. soldiers also show a link -- though it's not proof of cause-and-effect -- between low levels of vitamin D and multiple sclerosis, another disease more common in northern countries.
It could be an "environmental trigger," Hollis says. "In Scotland the incidence (of MS) is horrible, just awful. And the climate's so gloomy and the diet's so bad."
He takes 4,000 IU a day. His fellow researcher in the TB story is John White of McGill University in Montreal, though White cautions the evidence regarding TB and other infections isn't as strong as for colon cancer.
"Tuberculosis is the classic," he says. "You will see papers in the (research) literature about tremendously high rates of tuberculosis among immigrants in London (England) from the Indian subcontinent" -- people with dark skin who move to a northern country with grey skies. Their dose of sunlight plummets; their infections spread.
He too takes 4,000 IU a day.
But just as everyone was trading stories this summer about the wonderful things this little pill can do, the U.S. National Cancer Institute waded into the love-in -- on the other side. "No relationship was found between vitamin D levels and the overall risk of dying from cancer, according to a study published online Oct. 30 in the Journal of the National Cancer Institute," it announced. "However, higher vitamin D levels were associated with a decreased risk of colorectal cancer death."
The NCI took a different approach. Where Lappe gave people pills and worked forward in time, the NCI did what's called a "retrospective" study.
It combed back through records of more than 16,000 people, and compared their blood levels of vitamin D with whether they developed cancer. Mostly, it concluded, there wasn't a link -- except for colon cancer. (That's already a big exception. About 20,460 cases of colorectal cancer will be diagnosed in Canada this year; 8,700 deaths are forecast, making it the second-leading cause of cancer-related deaths behind lung cancer.)
In any case, such arguments are common in science. People legitimately use different methods and may get very different results. In the end, a growing number of studies will probably pile up evidence mostly on one side.
The NCI stopped short of saying the vitamin D claims are wrong. Instead, it says that "not enough is known."
There's still a lot to study, McGill's White cautions. So far, he believes, the link with colon cancer is "probably the strongest."
The map showing colon cancer death rates closely match the maps showing how much UVB radiation reaches the Earth's surface. "It's really quite striking."
But he says experimental data in controlled labs, in cell cultures or whole animals, is starting to add up.
"I'm not saying the sun is good. It still does the bad things," he says. "If you take vitamin D supplements, you don't all of a sudden feel 20 years younger and energetic. You basically feel nothing. I think any effects of supplementation are going to be felt over an extended period of decades," as with changes in numbers of people who smoke.
Will it turn out to be as important to health as smoking? "I wouldn't be surprised, to be honest. For the simple reason that it's something that the general public can deal with on their own, either through diet or moderate sun exposure... or supplementation."

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"under exposure to UV rays is as dangerous as overexposure....this is D life" eileen