(David Longstreath/Associated Press)

Imagine incorporating an inexpensive, single supplement into your life that forces you to get a little sunshine and promises to strengthen your bones, thwart different forms of cancer, stave off multiple sclerosis and autoimmune disorders and fight infections.

New research into the preventive benefits of vitamin D has raised hopes that the sunshine vitamin, which is produced naturally in the body through exposure to the sun's ultraviolet rays, could extend and improve people's lives.

In September 2007, an analysis of 18 randomized controlled trials involving people over the age of 50 found that people who took at least 500 international units (IU) of vitamin D daily had a seven per cent lower risk of death compared with those given a placebo.

Lead researcher Dr. Philippe Autier said it was not clear how the supplements lowered risks of mortality, but he suggested that Vitamin D may block cancer cell proliferation or improve blood vessel and immune system functions. The study, published in the Archives of Internal Medicine, reviewed research involving 57,311 participants.

The new findings are part of a growing body of research regarding vitamin D's benefits. In June 2007, the Canadian Cancer Society said that based on current research adults should consider increasing their daily dosage of vitamin D. The society said Canadians should now consume 1,000 IU of vitamin D daily during the fall and winter months, in consultation with a health-care provider.

The society noted, however, that more research on appropriate dosage levels is needed and said it would update its recommendations as new studies are released.

In making its recommendations, the society referred to new research including a study published in the June issue of the American Journal of Clinical Nutrition. Researchers at Creighton University School of Medicine in Omaha found a 60 to 77 per cent decrease in cancer rates in postmenopausal women who took a daily dose of 1,100 IU of vitamin D combined with calcium over women who were given a placebo or calcium alone. The double blind clinical study, conducted over four years, tested healthy women over the age of 55 living in rural Nebraska. Critics of the study cautioned that a larger study would have yielded more reliable and conclusive results.

But Reinhold Vieth, a nutritional scientist at the University of Toronto, said the new study is the last piece of evidence for which many in the field have been waiting. Vieth said that many cells in the body use vitamin D to produce a signaling molecule that allows the cells to communicate with each other.

"Those signals do things like helping cells to differentiate to recognize what kind of cell they should be becoming or they can signal cells to stop proliferating and those are good things in terms of cancer, you want differentiation so they become good well-behaved cells and you don't want them to keep replicating all the time," he said.

Other researchers have begun studying how the sunshine vitamin affects other forms of cancer. Researchers at the University of California, San Diego, suggested in the March 2007 issue of the American Journal of Preventive Medicine that taking 2,000 IU of vitamin D daily along with 10 to 15 minutes in the sun and a healthy diet could reduce the incidence of colorectal cancer by two-thirds. The same authors found that breast cancer rates were 50 per cent lower in people with high levels of vitamin D in their blood, and suggested that the average person could maintain those levels by taking 2,000 IU of vitamin D daily and spending 10 to 15 minutes in the sun.

Similarly, a December 2006 study in more than seven million people found that white members of the U.S. military who had high blood levels of vitamin D were 62 per cent less likely to develop multiple sclerosis than those with the lowest levels of the vitamin. Researchers noted the findings were still too preliminary to suggest that a lack of vitamin D could trigger the nerve disorder.

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.

In 2004, researcher Kenneth Saag of the University of Alabama at Birmingham suggested that Vitamin D might quell the onset of rheumatoid arthritis in older women. His preliminary study found that women who had a dietary intake of 290 IU daily were 28 per cent less likely to develop the disease.

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.

Vitamin D: The Sunshine Vitamin

Vitamin D: One Big Reason We Need Sun Exposure

The ‘Sunshine Vitamin’ is linked to lowering your risk of several forms of cancer and many other diseases.

Exposure to UVB present in sunshine and in most tanning beds is the body’s natural way to produce vitamin D, accounting for 90 percent of vitamin D production.1 Dietary “supplements” are just that: Supplemental ways to produce vitamin D.

What’s more, research has shown that people who utilize indoor tanning equipment that emits UVB – which most tanning equipment does – also produce vitamin D. And studies have also shown that indoor tanning patrons have higher vitamin D blood levels than non-tanners.2

While the North American indoor tanning industry promotes itself as a cosmetic service, one undeniable side-effect of that cosmetic service is vitamin D production. Even though it may not be necessary to develop a tan to produce vitamin D, this should also be considered: There is growing consensus that humans may not be able to get enough vitamin D through dietary supplements alone (especially if recommended vitamin D levels are raised, as is widely anticipated, from 200-600 IU daily to 1,000-2,000 IU) and growing acceptance of moderate sun exposure as the best, cheapest, most widely available and most natural source. (In comparison, an 8-ounce glass of whole milk is fortified with just 100 IU of Vitamin D). Further, because research suggests that the risks associated with sun exposure are most likely related to intermittent sunburns, it is credible to believe that the benefits of regular, moderate non-burning exposure outweigh the easily manageable risks associated with overexposure.

New research has shown that vitamin D deficiency is epidemic in American adults today, suggesting that up to 90 percent of North Americans are vitamin D deficient and that vitamin D deficiency has significant implications on human health.3 Indeed, two world-wide conferences on Vitamin D were convened in 2006 in North America, with universal consensus that Vitamin D deficiency is a real problem. As a result of those conferences, the American Cancer Society and the Canadian Cancer Society – which had both preached sun abstinence for years – both recognized for the first time in May 2006 that some sunlight is necessary for human health.

It is likely that over-usage of sunscreen in climates and seasons when sunburn is not a possibility — sunscreen almost completely prevents vitamin D production — has contributed to this problem. This is especially significant because:

• A 2006 systematic review of 63 studies on vitamin D status in relation to cancer risk has shown that vitamin D sufficiency may reduce one’s risk of colon, breast and ovarian cancers by up to 50 percent.4
• Additionally, vitamin D deficiency is a leading cause of osteoporosis, a disease affecting 25 million Americans which leads to 1 million hip and bone fractures every year.3 In elderly individuals, such fractures are often deadly. Encouraging everyone to wear sunscreen all year long in any climate undoubtedly is contributing to this problem, as vitamin D is necessary for the body to properly process calcium.
• Vitamin D deficiency most likely plays a role in the development of muscular sclerosis, according to the Calgary based charity Direct-MS. (You can learn more about this by visiting www.direct-ms.org.
• Vitamin D deficiency is also believed to be linked to an increased risk of prostate cancer and even heart disease.

Four additional resources for more information and research on vitamin D are:

• www.uvadvantage.com
• www.vitaminDcouncil.com
• www.sunarc.org
• www.qualitycounts.com/fpvitamind.html

Additionally, a new Canadian Group, the Vitamin D Society, has been launched in 2006 to educate Canadians about Vitamin D deficiency and fund new Vitamin D research. Its web site is www.vitaminDsociety.org.

“Current research indicates vitamin D deficiency plays a role in causing 17 varieties of cancer, heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects and periodontal disease,” the Vitamin D Council writes on its web site. “This does not mean that vitamin D is the only cause of these diseases, or that you will not get them if you take vitamin D. What it does mean is that vitamin D, and the many ways in which it affects a person’s health, can no longer be overlooked by the healthcare industry nor by individuals striving to maintain, or achieve, a greater state of health.”

While public health officials have floundered at how to craft a message that recognizes the both the benefits of sunlight and the risks of overexposure, the professional indoor tanning industry has for more than a decade promoted a balanced message about sunlight. The tanning industry’s core belief: Moderate tanning, for individuals who can develop a tan, is the smartest way to maximize the potential benefits of sun exposure while minimizing the potential risks associated with either too much or too little sunlight.

Sunburn prevention — not sun avoidance — is the key.