Want to strengthen your bones, thwart certain cancers, avoid multiple sclerosis and other autoimmune disorders, fight infection and live longer? Then let some sunshine into your life!

An explosion of recent research has found that vitamin D, produced naturally by your body through exposure to the sun's ultraviolet rays, could greatly improve the quality – and length – of your life.

In September 2007, analysis of trials involving more than 55,000 people over the age of 50 found that people who took at least 500 international units (IU) of vitamin D daily had a 7% lower risk of death compared with those given a placebo.

While it’s not clear why vitamin D supplements lowered mortality, the suggestion is that it may block cancer cell proliferation or improve blood vessel and immune system functions.

The results of another 2007 study by Creighton University School of Medicine in Omaha found a 60–77% decrease in cancer rates in postmenopausal women who took a daily dose of 1,100 IU of vitamin D combined with calcium over women taking calcium alone.

In the March 2008 issue of the American Journal of Preventive Medicine, researchers at the University of California, San Diego, suggested that taking 2,000 IU of vitamin D daily, along with 10–15 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% lower in women with high levels of vitamin D in their blood.

Yet another study, this one from December 2006, found that Caucasian members of the U.S. military who had high blood levels of vitamin D were 62% less likely to develop multiple sclerosis than those with the lowest levels of the vitamin.

And it doesn’t end there.  Earlier this year, a study by Toronto researchers stated that women with breast cancer who also have low levels of vitamin D have a greater chance of recurrence and lower overall survival rates than those with higher amounts. It’s still too early to tell if vitamin D deficiency can actually cause the disease. Unfortunately for men, vitamin D seems to have no effect on prostate cancer, although it does seem to play a role in reducing the risk of heart attacks in males.

The Canadian Cancer Society recommends Canadians take in 1,000 IU of vitamin D every day (after first consulting their doctors). That’s no problem during the spring and summer when normal exposure to the sun’s rays does the job. But it is a problem during Canada’s sun-deprived winters. So public health officials are now advising that people take Vitamin D supplements during the winter months.

It’s also advised that those over 50 take vitamin D supplements year round, as the skin's ability to produce the vitamin decreases with age. People with darker skin tones are also advised to take a supplement, as they have more difficulty producing natural vitamin D from the sun's ultraviolet rays.

What is vitamin D?

Vitamin D helps the body absorb calcium, thus making bones stronger. A deficiency of vitamin D in children can trigger rickets, a bone disease that leaves children with soft bones and skeletal deformities. As breast milk doesn’t contain sufficient levels of vitamin D, public health officials recommend that infants who are exclusively breastfed should be given a supplement to prevent vitamin D deficiency.

In adults, low levels of vitamin D can cause osteoporosis. As well, patients with a reduced ability to absorb dietary fat, including people suffering from Crohn's disease, cystic fibrosis or liver disease, often have low vitamin D levels.

So now we all have the more reason to play another game of golf, work longer in our gardens or just go for leisurely strolls – and take a daily vitamin D pill to keep healthier longer.