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June 18, 2010

Vitamin D won't reduce cancer risk, study finds

Researchers have long considered the possibility that Vitamin D might be used to prevent cancer, but a new study shows that is not the case.

The large-scale study looked at whether increased Vitamin D would reduce the risk in seven cancers - non-Hodgkin lymphoma and cancers of the endometrium, esophagus, stomach, kidney, ovary or pancreas.

 Kathy J. Helzlsouer, director of the Prevention & Research Center at Mercy Medical Center, chaired the study. Other institutitions, including the National Institutes of Health and National Cancer Institute, were also involved. Details will appear in the July 1 issue of the American Journal of Epidemiology.

Researchers took samples of Vitamin D levels from about 12,000 men and women before they were diagnosed with cancer. They followed the people for more than three decades.

They then compared the samples to those participants who were eventually diagnosed with cancer during that time period to those who didn't get the disease. There was no significant variation of Vitamin D levels between the two groups, meaning higher levels didn't make a difference in cancer risk.

Vitamin D is made naturally by the body when the skin is exposed to sunlight. It can also be obtained by the body in foods, fortified foods and nutritional supplements. The vitamin is used for healthy bones, calcium absorption and immune function.

Posted by Andrea Walker at 12:01 AM | | Comments (6)
Categories: Cancer


This is a flawed study. The group started out vitamin D deficiendt and ended up vitamin D deficient.

There needs to be a group who takes a vitamin D supplement, and a control group.

All this this study proves is that the study group was vitamin d deficient.

Controlled studies that were not flawed found otherwise.

The abstract presents no data so it is difficult to judge the validity of the work. However it does also say

The mortality rate ratio was statistically significantly higher for those with vitamin D concentrations in the deficient range, defined as <45nmol/L.

which you did not bother to mention.

There is a placebo controlled study that shows the opposite and led the Canadian Cancer Society to start recommending that everyone take vitamin D to prevent cancer. The study quoted above is poor science and should be ignored. you can see the relevant data at

As a long term cancer survivor, that carefully monitors Vitamin D 25-hydroxy levels, this story was of personal interest. I tracked down the complete study and was struck by the fact that all the data points (cancer patients and healthy) were Vitamin D insufficient. The study means nothing if healthy individuals with sufficient (above 125 nmol/L or 50 ng/ml) Vitamin D 25-hydroxy levels are used for the non-cancer group. Since everyone in the study was insufficient (below 31 ng/ml 25-hydroxy)in Vitamin D it is totally meaningless. NCI is guilty of misinformation and poor research.

Where did you find this study? I've been looking for it. I read that they took a single blood test and then followed the subjects for 20 years. Could that be possible? What a waste of time and money. That would make the paper this study is printed useful for only TP.

The work is here
in Advance Access. It is free to access.

Look in the methodology paper. The study was never intended for this use and therefore the data is unsuitable. The referees do not seem to have pointed this out.

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About Picture of Health
Meredith CohnMeredith Cohn has been a reporter since 1991, covering everything from politics and airlines to the environment and medicine. A runner since junior high and a particular eater for almost as long, she tries to keep up on health and fitness trends. Her aim is to bring you the latest news and information from the local and national medical and wellness communities.

Andrea K. WalkerAndrea K. Walker knows it’s weird to some people, but she has a fascination with fitness, diseases, medicine and other health-related topics. She subscribes to a variety of health and fitness magazines and becomes easily engrossed in the latest research in health and science. An exercise fanatic, she’s probably tried just about every fitness activity there is. Her favorites are running, yoga and kickboxing. So it is probably fitting that she has been assigned to cover the business of healthcare and to become a regular contributor to this blog. Andrea has been at The Sun for nearly 10 years, covering manufacturing, retail , airlines and small and minority business. She looks forward to telling readers about the latest health news.

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