The Sunshine Vitamin D and Breast Cancer

Rhonda Abrams sees the sun in a new light. For years she was afraid of it. Skin cancer had killed hermother at the age of 49. The sun became her mortal foe and Abrams protected herself by wearing hats and long sleeves, seeking shade whenever possible.

But when she was diagnosed with breast cancer at the age of 45, Abrams started to reconsider her ideals and decided she had been misguided in her fears.

By hiding from the sun, she deprived herself of an important vitamin she now credits as being pivotal in her recovery from cancer: The sunshine vitamin, D.

“I avoided the sun because when a parent dies of cancer, you do all you can to avoid the same situation,” said Abrams, a media studies instructor in Toronto. “But I realized that vitamin D was one of the things I may not be getting enough of.”

The importance of vitamin D in battling chronic diseases has gained increased interest in the scientific community, which has been churning out studies about its role in regulating cell growth.

Canadians should be particularly concerned, experts say, as the majority of the population is vitamin D deprived at some point in the year, mostly during the grey winter months. Between October and March, not only are the sun’s rays too weak for the body to synthesize, Canadians tend to hibernate from the cold and stay indoors. And this widespread vitamin D deficiency is what ails us, according to the experts, from heart disease and diabetes to multiple sclerosis and cancer.

“Vitamin D helps the body’s cells to communicate, sending different messages to different cells,” said Reinhold Vieth, a nutritional sciences professor at the University of Toronto. “When you’re vitamin D deficient, this breaks down the communication. That doesn’t mean the body will collapse but the problem is that the incidents of things going wrong goes up.”

The theories are based on worldwide patterns, Vieth said. The farther north (or south) you move up in the world, the higher the rates of cancer and other chronic diseases.

“We’re presuming that the farther north you are, the less sunshine and vitamin D there is. It’s a chain of logic.”

Not only does vitamin D help keep cells in sync, studies have shown that it also plays a defensive and offensive role in and against 17 varieties of cancer including prostate, colon and breast cancer. The sunshine vitamin works by identifying cancerous cells and inducing, what one expert described as, “suicide.” William Grant, director of the Sunlight, Nutrition and Health Research Centre in San Francisco, said vitamin D has also been shown to prevent cancerous cells from spreading to other organs in the body, or metastasize.

“Cancer patients with high levels of vitamin D also have longer survival rates,” he added.

In a 2008 study out of Mount Sinai Hospital, researchers found vitamin D deficiency was common among the 512 breast cancer patients and associated with higher grade tumours. The study, published by the American Society of Clinical Oncology, also found an increased risk of recurrence and lower overall survival rates compared to those with sufficient vitamin D levels.

By the time Abrams discovered the grape-sized lump on her left breast, she was already in Stage IV cancer and it had spread to her lymph nodes. Doctors told her that with chemotherapy, surgery and radiation, she would have two years left to live. But after her diagnosis, Abrams did her own research and with the help of a naturopath, followed an alternative plan that included vitamin D supplements in addition to her medical treatments. That was five years ago.

“I think it made a big difference because I think a lot of people get weakened from the treatment itself,” said Abrams, whose cancer is now in remission.

She blogs about her experience at whatididtosurvive.com.

A 2008 study out of the University of California in San Diego used data from the World Health Organization to chart breast cancer patterns in 175 countries along a horizontal axis for latitude. The result was a parabolic curve that resembled a smile, showing that breast cancer incidence was greatest at the highest latitudes in both hemispheres, where the sun is also the weakest. That’s because in evolutionary terms, humans weren’t meant to live in the colder climes, Vieth said.

“All species were designed to match the environment where they evolved, it’s survival of the fittest,” he said. “Humans are all primate and fittest to survive in tropical environments … we’re living a strange form of lifestyle for primates.”

That logic extends to skin pigmentation and varying vitamin D needs.

In a 2008 study published online at BioMed Central Public Health, Vieth, a co-author, found that while vitamin D deficiency was common among 107 U of T students in the winter months, those of East Asian and South Asian descent had significantly lower concentrations than those of European descent. “There’s been a lot of migration in the world,” Vieth said. “And now you’ve got people with dark skin packing up and moving to North Bay for which their skin is not optimized.”

Cultural and lifestyle habits can also exacerbate the deficiency. Women who cover up head-to-toe year-round in traditional clothing like burkas leave little skin exposed to the sun. The deficiency is widespread among youngsters as well.

In a study out of SickKids Hospital last year, Dr. Jonathon Maguire, now a staff physician at St. Michael’s Hospital, found that vitamin D levels in 92 Toronto toddlers between the ages of 2 and 3 were lower than in similar aged toddlers in the U.S., outside of Alaska. One-third of the toddlers also had less than the recommended levels of vitamin D, for reasons scientists have yet to fully understand.

“One possibility could be that children are drinking less milk,” Maguire said. “Or it could be because of our winters and that parents are using more sunscreen in the summer. We’re not sure what it means but we’re trying to tease things apart.”

Sunscreen blocks the production of vitamin D, a deficiency that could put children at a higher risk of developing medical problems like Type 1 diabetes, multiple sclerosis and cancer.

Grant bristles when asked about the conflicting messages lobbied at the public between the importance of seeking sunshine vitamin and the dangers of skin cancer.

Vitamin D levels changed in the U.S., Australia and England over the last three decades because dermatologists taught the public to fear the sun, he said. “Dermatologists don’t study the entire body like cardiovascular disease and other cancers,” he said. “They don’t see the whole picture.”

The Canadian Cancer Society, meanwhile, upped the recommended vitamin D intake for adults from 200 IU (international units) in 2006 to 1,000 IU in 2007 after reviewing the evidence.

The society maintains that a few minutes of unprotected sun exposure in the summer is enough to produce sufficient vitamin D, saying that skin cancer is still the most frequently diagnosed cancer. While Grant says that 20 minutes in the summer sun should be enough and also warns against burning, he counters that mortality rates from low levels of vitamin D are higher than skin cancer.

“You have to weigh the risks.”