Scientists say most people in North America are not taking enough vitamin D, and that could increase their risk for developing cancer quite significantly.
In a study conducted by researchers at Creighton University School of Medicine, researchers followed 1,179 healthy, postmenopausal women from rural eastern Nebraska for a four-year period between 2000 and 2005.
The women were all 55 years or older and free of known cancers for at least 10 years prior to entering the Creighton study; they were randomly assigned to take daily dosages of 1,400-1,500 mg supplemental calcium, 1,400-1,500 mg supplemental calcium plus 1,100 IU of vitamin D3, or placebos.
The research team found that those taking calcium, as well as a quantity of vitamin D3, at nearly three times the U.S. government's Recommended Daily Amount (RDA) for middle-age adults, showed a 60 percent or greater reduction in cancer risk than women who did not get the vitamin.
Lead investigator Joan Lappe, Ph.D., R.N., Creighton professor of medicine says vitamin D is a critical tool in fighting cancer as well as many other diseases.
Dr. Lappe believes the findings confirm what many have suspected for some time and supports a growing body of evidence that a higher intake of vitamin D may be helpful in the prevention and treatment of cancer, high blood pressure, fibromyalgia, diabetes mellitus, multiple sclerosis, rheumatoid arthritis and other diseases.
As a rule people make their own vitamin D3 when they are exposed to sunlight and just 10-15 minutes a day in a bright summer sun creates large amounts of the vitamin.
The researchers found that over the course of four years, women in the calcium/vitamin D3 group experienced a 60 percent decrease in their cancer risk than the group taking placebos.
Working on the premise that some women entered the study with undiagnosed cancers, the researchers then eliminated the first-year results and looked at the last three years of the study and the results appeared even more dramatic with the calcium/vitamin D3 group showing a remarkable 77 percent cancer-risk reduction.
In the three-year analysis, there was no statistically significant difference in cancer incidence between participants taking placebos and those taking just calcium supplements.
Through the course of the study, 50 participants developed non skin cancers, including breast, colon, lung and other cancers.
Lappe says more research is needed to determine whether the research results apply to other populations, including men, women of all ages, and different ethnic groups as all the study participants were Caucasian.