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Research seeks evidence of vitamin D benefits

By Laura Wershler

Canadian women have been invited to participate in an international study to determine if achieving optimal vitamin D levels will prevent breast cancer.

The GrassrootsHealth Breast Cancer Prevention Study in Canada aims to prospectively examine breast cancer occurrence among women 60 and over who achieve and maintain a designated vitamin D serum level in the bloodstream.

"We are hoping the study will solidify and quantify the case that vitamin D experts have been building for years: that increased vitamin D levels in women will significantly reduce breast cancer," says Dr. Robert Banner, President of the Ontario Society of Physicians for Complementary and Integrative Medicine.

When the study launched in the United States in August 2011, Dr. Cedric F. Garland of the Moores Cancer Center and University California San Diego School of Medicine, said that "75 per cent of breast cancer could be prevented with higher vitamin D serum levels. This will potentially be the most important study ever conducted toward prevention of breast cancer."

GrassrootsHealth, a non-profit public health research organization, extended the study to include Canadian women in October 2011. They hope to enrol 1000 women who will be able to achieve optimal vitamin D levels through their choice of UVB exposure, fortified food or supplements.

In addition to monitoring breast cancer outcomes, the short-term effects of vitamin D on high blood pressure, colds, flue and falls will also be tracked.

Carole Baggerly, director of GrassrootsHealth and a breast cancer survivor, says, "It is essential Canadian women be included in our drive to demonstrate the medical benefits of vitamin D. When you can project that fully 75% of breast cancer cases could be prevented with higher optimal vitamin D serum levels, there is no justification for waiting to take preventive measures."

Canadian women who are 60 years of age and older, have no current cancer and are not currently being treated for cancer can participate.

Study participants will be asked to achieve a vitamin D serum level of 100-150 nanomoles/litre, or nmol/L, the range recommended by vitamin D researchers as optimal for disease prevention in a Scientist's Call to Action issued in January 2011.

The call to action states that achieving this level is inexpensive and safe. In the United States, blood serum levels are measured in nanograms/millilitre, with the recommended optimum range being 40-60 ng/ml

Another GrassrootsHealth research project is determining what amount of vitamin D supplementation is required to achieve these levels. To date, research results suggest that supplementation of almost 10,000 IU of vitamin D3 per day is required to get 97.5% of the population over 100 nmol/L or 40 ng/ml.

Baggerly says previous studies that have failed to show that vitamin D can prevent breast cancer, or breast cancer reoccurrence, used between 400 IU and 2000 IU of vitamin D supplementation, and that in some of these studies, blood serum levels were not measured.

She says it's a case of "not-enough-D" type research.

Such research continues. A new U.S. study by the National Institute of Health called the Vitamin D and Omega-3 Trial (VITAL)is in the process of recruitment.

According to the online notice the study is "investigating whether taking daily dietary supplements of vitamin D3 (2000 IU) or fish oil (1 gram of omega-3 fatty acids) reduces the risk of developing cancer, heart disease, and stroke in people who do not have a prior history of these illnesses."

Baggerly notes several challenges to the design of this trial. She says it is not providing calcium as did the Lappe trial of 2007 which demonstrated a clear reduction in cancer incidence. Also, she says that 2000 IU/day will not be enough to get serum levels high enough and it will be hard to maintain a placebo group.

"There is too much knowledge about vitamin D in the U.S. to keep a placebo group going."

GrassrootsHealth has seed funding to get the vitamin D and breast cancer prevention study started but is actively looking for more sources of funding to expand the five-year study. Baggerly says they welcome financial support from any Canadian organization interested in contributing to this research.

GrassrootsHealth depends on public support of its research projects and does not take funding from government sources.

Individual women who want to help sponsor the research can do so by joining the Breast Cancer Prevention International Study. Details are available on the group's website. Baggerly says all women 60 and over will be automatically enrolled.

"Ultimately we want women to know how they can proactively help prevent breast cancer before it is discovered at a screening clinic," she adds.

"The more women who participate in this study, the greater the chance that we will defeat breast cancer within our lifetimes."

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