Cancer society calls for major vitamin D trial

Organization lobbying medical research agencies in North America to find out what dosage, if any, prevents the disease

MARTIN MITTELSTAEDT
www.GlobeandMail.com
October 25, 2007

Intrigued by the possibility that taking vitamin D may be an easy way to prevent cancer, the Canadian Cancer Society has taken the unusual step of writing to major medical research agencies in North America to tell them that it is time to fund a large-scale clinical trial that will find out for sure.

Society officials don't think the organization has ever before indicated to the research community in such a high-profile way the need for a clinical trial. The move reflects a recent flurry of scientific papers that have come to the surprising conclusion that half of cancers, or even more, in a country like Canada could be prevented if all adults are encouraged to take the "sunshine vitamin."

If further experiments bear out the tantalizing findings, it would mean that vitamin D could be a magic bullet for cancer prevention on par with tobacco control, healthy eating and active lifestyles.

Heather Logan, the society's director of cancer control policy, said the organization acted because it thinks the vitamin may offer a way to "make dramatic inroads in terms of the burden of cancer."

But the society says scientific uncertainties hamper the current understanding of how to use it. Researchers have not yet run the kind of large-scale experiments that would uncover the levels people needed, and how doses would have to be adjusted for variable factors, such as a person's skin colour.

"The body of evidence around the impact of vitamin D ... now requires the rigours of a comprehensive research program to address the gaps in knowledge," the society said in the letter, sent last week.

Determining whether vitamin D prevents cancer is particularly important for Canadians. People in high latitude countries such as Canada cannot make it the natural way, by exposing naked skin to strong sunlight for about half of each year.

That is because sunlight doesn't get intense enough in northern areas of the world from about now until early March for production of the vitamin.

Researchers have found that during this so-called vitamin D winter, levels of the nutrient in people's bodies plunge, which they theorize increases vulnerability to cancer and other serious ailments. Most cells in the body - including those from such areas as the colon, prostate and breast - have receptors for the vitamin, suggesting it's needed for proper functioning.

A large trial would probably need thousands of participants, take years to complete, and cost millions of dollars. However, if the experiment confirmed dramatic health benefits, it could ultimately save governments and health insurance companies billions of dollars.

Besides the society, the letter was endorsed by a section of the World Health Organization that deals with sun protection and the American College of Rheumatology.

Among others, the letter was sent to the National Cancer Institute of Canada, the U.S. National Institutes of Health and the Canadian Institutes of Health Research, bodies that have available government and other funding for medical studies.

The letter has received a positive response. "There is enough evidence around to suggest that vitamin D ... could be of interest in terms of reducing cancer," said Phil Branton, scientific director of the Institute of Cancer Research at the CIHR.

The society said any experiment would need to use at least 1,000 international units of vitamin D a day to be clinically relevant. This amount is up to five times higher than Health Canada recommends. The society suspects the federal guideline, developed in 1997, needs to be raised. It said researchers should also look at health risks of taking vitamin D above Health Canada's 2,000 IU daily safety limit.

The society recommended that any experiment include people from a variety of backgrounds, because blacks and South Asians, who have more protection against ultraviolet light, are most at risk of having low vitamin D levels.

Medical researchers welcomed the cancer society's call.

Reinhold Veith, a University of Toronto professor in the department of nutritional sciences, said the investigation is needed because of the vitamin's low-cost and wide availability and the plausible scientific basis for why it might work at the cellular level.

"In terms of all of those features, I don't think there is anything else that can beat the vitamin D story," he said.

Researchers began investigating vitamin D because of the finding that those with low levels in their bodies were most likely to develop cancer. Frank Garland, a professor at the department of family and preventive medicine at the University of California in San Diego, published a study in August suggesting that the vitamin could prevent half of breast and colon cancers in North America.

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The D list

A chronology of vitamin D and cancer prevention:

1941 A U.S. researcher postulates that something about strong sunlight prevented cancer, based on observations of a south to north trend of increasing mortality for many cancers in North America.

1980 U.S. researchers Cedric and Frank Garland issue the hypothesis that low levels of vitamin D play a role in causing colon cancer. They found an inverse relationship between the amount of sunlight and colon cancer mortality in the United States. The finding touches off 15 years of research that suggests vitamin D insufficiency plays some kind of a role in many other cancers, including breast, prostate and ovary.

1997 A report on vitamin D for Health Canada and the U.S. Dept. of Health dismisses as "premature" the idea "that vitamin D deficiency increases cancer risk." It calls for more studies to test the hypothesis.The report sets the current recommended vitamin D intake standard for Canada and the United States based on the low vitamin D levels needed to prevent rickets and bone health.

June, 2007 U.S. researchers at Creighton University in Nebraska find that vitamin D supplementation of 1,100 international units daily reduced the relative risk of cancer in a group of women by 60 per cent. It is the first clinical trial to find such a result. Their study is criticized because it had a small number of participants and was originally designed to look at bone health.

The Canadian Cancer Society recommends 1,000 IU of vitamin D a day during fall and winter as a cancer preventive for those with white skin. It says blacks should take 1,000 IU year round.

October, 2007 The Canadian Cancer Society calls for a large clinical trial to find out the best vitamin D dose for cancer prevention.

Martin Mittelstaedt

Canadian pediatricians recommend more vitamin D for pregnant, nursing women

The Canadian Press

TORONTO - Pregnant women and nursing mothers should talk to their doctors about taking a daily supplement of 2,000 international units of vitamin D, the Canadian Paediatric Society said Monday.

The vitamin D intake mentioned by the pediatricians' group is significantly higher than Health Canada's current recommendation of 200 IUs for adults 19 to 50 years of age, which includes pregnant and lactating women.

Health Canada also released a statement Monday, saying that it believes a number of independent recommendations issued by various organizations on vitamin D are coming too soon.

"Health Canada believes these recommendations are premature and that a comprehensive review that looks at both benefits and safety needs to be undertaken before the department can issue a revised recommendation," it said.

Vitamin D deficiency can pose serious dangers to the development of a fetus and infant, yet can be prevented through taking supplements, the society argues.

The focus isn't just on preventing bone-disfiguring rickets these days because vitamin D can also help protect babies against other illnesses in childhood and later in life, it says.

"There are lots of studies that suggest that a lot of mothers, particularly aboriginal mothers in the north, have been vitamin D deficient," Dr. John Godel, principal author of the Canadian Paediatric Society's statement, said Monday from Quadra Island, B.C.

"And this means that the breast milk that they have is also deficient."

It's the latest call by a major health or medical organization for Canadians to boost their intake of what's often called the sunshine vitamin. In June, the Canadian Cancer Society caused a stir when it suggested that adults consider taking a vitamin D supplement of 1,000 IUs daily during fall and winter, while darker-skinned and older people should think about taking the little white pills year-round.

Health Canada noted that it's aware of the growing body of evidence on the role of vitamin D in relation to health. But it also reminded Canadians that there are health risks associated with taking too much vitamin D and they should not exceed 2,000 IUs per day from all sources, including milk and supplements.

The department is working with the United States Institute of Medicine (IOM), which recently held a workshop looking at the process for updating daily recommended intakes, including those for vitamin D.

Godel said he suspects Health Canada will have to change its basic criteria.

"It's a bit of a problem because Health Canada has a big influence on what is recommended and given in native communities, particularly in the north, so that it might be difficult for a nurse in an outlying community to give 2,000 international units when Health Canada hasn't come on board with the higher dose," he said.

"So it's going to take a while."

A lot of research has been done since the IOM last established recommendations in 1997, Godel noted.

Carol Wagner, a professor of pediatrics at the Medical University of South Carolina, is among those conducting research on vitamin D deficiency. She has been studying pregnant women for about four years and lactating women since 2001.

"We've really just found even in sunny South Carolina, where we live, a silent epidemic, especially in our darker-pigmented individuals," she said from Charleston, S.C.

"Why do we care about it? We care about vitamin D because it's not just about bones. It's about your innate immune system, your ability to fight infections, long latency diseases such as multiple sclerosis and cancers, all sorts of things like that."

She said that 2,000 IUs "really is quite safe."

"And to go through a pregnancy and be insufficient is really, I think, not the way to have a pregnancy progress."

The Canadian Paediatric Society repeated its urging that babies who are exclusively breastfed receive a supplement of 400 IUs a day, and that babies in the north, above 55 degrees latitude, should get twice that recommended amount from October to April.

The society's statement also recommends that babies with dark skin, those who have limited exposure to the sun or whose mothers are vitamin D deficient also get extra vitamin D during the winter, no matter where they live.

Wagner said vitamin D intake could also be considered from the point of view of a per-kilogram basis.

"An infant who weighs three kilos gets 400 international units," she observed. "So you have a woman who's 60, 70, 80 kilos, who's only getting 400 and think about that per kilo - it's really negligible."

Vitamin D increases life expectancy, study finds

Angela Mulholland, CTV.ca News
Sep. 10 2007 4:12 PM ET

An intriguing new study finds that those who take vitamin D supplements can increase their life expectancies by one to two years.

The study, published in the Archives of Internal Medicine, is just the latest to add to the growing body of evidence that "the sunshine vitamin" is not just good for strengthening bones but also appears to increase survival.

Past studies have suggested that vitamin D deficiencies might be associated with a higher risk of death from cancer, heart disease and diabetes -- illnesses that account for 60 to 70 per cent of deaths in high-income nations.

This study finds that taking extra vitamin D brings health benefits, even in the short term.

This study looked at the results of 18 previously published studies involving a total of 57,311 participants.

Dr. Philippe Autier, of the International Agency for Research on Cancer, Lyon, France, and Sara Gandini, of the European Institute of Oncology, Milano, Italy, analyzed the studies and evaluated doses of vitamin D ranging from 300 to 2,000 international units, with an average dose of 528 international units.

Most commercially available supplements contain between 400 and 1,000 international units.

After an average of 5.7 years, those participants who took vitamin D had a seven per cent lower risk of death than those who did not.

"We had a reduction in all-cause mortality after a follow-up of about six years. So it means that may represent something like an increase of two to three years of your life expectancy," Autier told CTV News.

"With vitamin D, you could say yes, finally, if there is one supplement to take, with all the evidence so far, the best is to take vitamin D -- ordinary doses of vitamin D, not high doses."

The editorial that accompanies the article points out that the study did not consider specific causes of death. The studies were generally short, so the impact of vitamin D was seen on diseases that express themselves in a shorter period of time. For chronic diseases that have a long period of time to develop, the impact of vitamin D would be underestimated by this analysis.

The authors note that it's not clear how vitamin D supplementation lowers death risk. They say it could be that the vitamin inhibits some mechanisms by which cancer cells multiply and grow. Or, it may boost the function of blood vessels or the immune system, they note.

Where the sun don't shine

The editorial notes that vitamin D supplements may simply be compensating for a deficiency that many people appear to have.

"In recent years, an increasing number of researchers from various fields have been arriving at the conclusion that the levels of vitamin D in many people are inadequate for optimal health," the editorial reads.

Heather Chappell of the Canadian Cancer Society says this latest study supports the growing body of evidence of the health benefits of vitamin D. It also supports their recommendations, issued earlier this year, that the entire adult population of Canada begin taking vitamin D supplementation.

"We want to remind Canadians that in Canada, the sun is not strong enough in the fall and winter to produce enough vitamin D. So the Cancer Society recommends that adults start talking 1,000 IU of vitamin D daily.

"The sun's rays become less strong as we move into the fall, so people should start taking a supplement in the fall and winter... probably near the end of September."

Toronto physician, Dr. Linda Rapson says she finds that many of her patients with chronic pain and other ailments are also deficient in vitamin D.

"I have seen people with levels so low that their muscles are weak and they can't get out of a chair easily. After a couple of weeks of taking vitamin D, there is a huge change," she says.

"I think people should be aware vitamin D is essential, that you have to take it. And you don't just take it for a while and you are fine; you have to keep taking it."

With a report from CTV medical specialist Avis Favaro and producer Elizabeth St. Philip