Vitamin D is a steroid hormone precursor that has recently been found to play a role in a wide variety of diseases. Current research indicates vitamin D deficiency plays a role in causing seventeen varieties of cancer as well as heart disease, stroke, hypertension, autoimmune diseases, diabetes, depression, chronic pain, osteoarthritis, osteoporosis, muscle weakness, muscle wasting, birth defects and periodontal disease.

A new study made by researchers from Toronto comes to support the idea that vitamin D is essential to our health, especially women’s health. According to their findings, breast cancer patients with low levels of vitamin D are nearly twice as likely to have the disease spread to other parts of their bodies and are 73 percent more likely to die from it.

The findings are the first to link lack of vitamin D to the progression of breast cancer and the fate of those with the disease.

Vitamin D is found in many dietary sources such as fish, eggs, fortified milk, and cod liver oil. The sun also contributes significantly to the daily production of vitamin D, and as little as 10 minutes of exposure is thought to be enough to prevent deficiencies. This is the reason why the vitamin is also called the “sunshine vitamin.”

The study, sponsored by the Breast Cancer Research Foundation, especially involved Canadian women because the country’s weak winter sunlight is not strong enough for nearly half the year to create the nutrient the natural way, through the action of strong ultraviolet light on skin. In fact, vast amount of evidence indicates that people living in the northern regions of the globe have higher cancer rates than those living closer to the equator, possibly because of less sunshine and vitamin D.

The study followed 512 women diagnosed with breast cancer at the University of Toronto hospitals between 1989 and 1995. Only one in four women in the study had sufficient blood levels of D at the time they were first diagnosed with breast cancer. Those who were deficient were nearly twice as likely to have their cancer recur or spread over the next 10 years, and 73 percent more likely to die of the disease.

“These are pretty big differences. It’s the first time that vitamin D has been linked to breast cancer progression,” said study leader Dr. Pamela Goodwin of Mount Sinai Hospital in Toronto, as quoted by the Associated Press.

There is insufficient research to show that vitamin D supplements can help women already diagnosed with breast cancer or that supplements can prevent cancer, Dr. Goodwin said. She also warned women not to take excessive amounts of vitamin D because high amounts of vitamin D are also not good for the organism, leading to increased cancer risk.

What Dr. Goodwin recommends is women get tested for vitamin D deficiency and to correct low levels with the help of a physician.

The findings of the study are the more worrisome as more and more dermatologists urge people to stay away from the sunlight or to use sunscreen as a way to lower risks of skin cancer. However good this advice is, it has its negative side too, as staying away from the sunlight leads to lower vitamin D levels, studies show.

Although death rates from breast cancer have been declining, possibly due to earlier detection and diagnosis, on a national level, breast cancer still represents the second leading cause of cancer death for women after lung cancer. According to the American Cancer Society, more than 180,000 American women are diagnosed with breast cancer every year, and almost 41,000 will die because of it. In Canada, breast cancer is expected to strike about 22,400 women this year and an estimated 5,300 will die from it.

The study, released by the American Society for Clinical Oncology on Thursday, will be presented in Chicago at the society’s annual meeting later this month.