Study Shows Vitamin D Reduces Cancer Risk
Published by Staff June 8th, 2007 in Health.
Most Americans and others are not taking enough vitamin D, a fact that may put them at significant risk for developing cancer, according to a landmark study conducted by Creighton University School of Medicine.
The four-year, randomized study followed 1,179 healthy, postmenopausal women from rural eastern Nebraska.* Participants taking calcium, as well as a quantity of vitamin D3 nearly three times the U.S. government’s Recommended Daily Amount (RDA) for middle-age adults, showed a dramatic 60 percent or greater reduction in cancer risk than women who did not get the vitamin.
The results of the study, conducted between 2000 and 2005, were reported in the June 8 online edition of the American Journal of Clinical Nutrition.
“The findings are very exciting. They confirm what a number of vitamin D proponents have suspected for some time but that, until now, have not been substantiated through clinical trial,” said principal investigator Joan Lappe, Ph.D., R.N., Creighton professor of medicine and holder of the Criss/Beirne Endowed Chair in the School of Nursing. “Vitamin D is a critical tool in fighting cancer as well as many other diseases.”
Other Creighton researchers involved in the study included Robert Recker, M.D.; Robert Heaney, M.D.; Dianne Travers-Gustafson, M.S.; and K. Michael Davies, Ph.D.
Research participants were all 55 years and older and free of known cancers for at least 10 years prior to entering the Creighton study. Subjects 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. National Institutes of Health funded the study.
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.
On the premise that some women entered the study with undiagnosed cancers, researchers then eliminated the first-year results and looked at the last three years of the study. When they did that, the results became even more dramatic with the calcium/vitamin D3 group showing a startling 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 nonskin cancers, including breast, colon, lung and other cancers.
Lappe said further studies are needed to determine whether the Creighton research results apply to other populations, including men, women of all ages, and different ethnic groups. While the study was open to all ethnic groups, all participants were Caucasian, she noted.
There is 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, and rheumatoid arthritis and other diseases.
Humans make their own vitamin D3 when they are exposed to sunlight. In fact, only 10-15 minutes a day in a bright summer sun creates large amounts of the vitamin, Lappe said. However, people need to exercise caution since the sun’s ultraviolet B rays also can cause skin cancer; sunscreen blocks most vitamin D production.
In addition, the latitude at which you live and your ancestry also influence your body’s ability to convert sunlight into vitamin D. People with dark skin have more difficulty making the vitamin. Persons living at latitudes north of the 37th parallel – Omaha is near the 41st parallel – cannot get their vitamin D naturally during the winter months because of the sun’s angle.
Experts generally agree that the RDA** for vitamin D needs to be increased substantially, however there is debate about the amount. Supplements are available in two forms – vitamin D2 and vitamin D3. Creighton researchers recommend vitamin D3 , because it is more active and thus more effective in humans.
Source: Creighton University
Dear Sir/Madam,
The problem of low vitamin D levels affects people everywhere. In Spain, a sunny country with outdor social life, more than half of the population have inadequete (low) levels of 25-hydroxyvitamin.
A few days ago (June 1 and 2), there was a scientific Summit about Vitamin D at Valencia. Some comments may be read (sorry, in Spanish) at http://www.lacoctelera.com/gineblog.
There is a need for new recomendations about vitamin D supplements to prevent cancer as well as other severe diseases.
Sincerely
Prof. Faustino Perez
http://www.unizar.es/gine/cvi.htm
This research was conducted around Omaha. While 1,100 IU of vitamin D3 may be sufficient to raise the Vit D3 status of women at Latitude 42 and below, to optimal, it will not be sufficient in areas significantly North of Omaha lat 42.
Everyone living North of Latitude 42 must recognise the amount of vitamin d you get from sunlight will be less because the sun is progressively weaker as move further North. There are also fewer days when it is suitable for sunbathing.
“Human serum 25-hydroxycholecalciferol response to extended oral dosing with cholecalciferol” shows your body uses 4000iu Vit D3 daily so, as the input sunlight lessens progessively as you move further from the Equator, so the contribution from supplements, towards that daily input target, needs to be raised incrementaly.
Readers from UK/Europe may also need to take into account that the Omaha women would have been getting 200iu/d from fortified milk. As our milk is not fortified we must also increase our intake by this additional 200iu to compensate.