Sunday, November 4, 2007

Vitamin D May Not Cut Cancer Deaths

Study Shows No Link Between Vitamin D Level and Cancer Deaths -- Except for Colorectal Cancer

Oct. 30, 2007 -- Cancer researchers today reported that blood levels of vitamin D -- whether high or low -- may not help prevent adults from dying of cancer over a dozen years.

But colorectal cancer may be the exception, according to the scientists, who included D. Michal Freedman, PhD, MPH, of the National Cancer Institute.

Vitamin D has attracted attention from researchers for its possible anticancer effects.

Freedman's team studied data on more than 16,800 people aged 17 and older who participated in U.S. health studies between 1988 and 1994.

In those studies, participants got a blood test to measure their blood level of vitamin D.

Freedman and colleagues followed the participants through 2000. During those 12 years, 536 participants died of cancer.

Participants' vitamin D levels at the study's start didn't appear to affect cancer mortality in general, regardless of age, sex, race, or other factors.

However, people with high levels of vitamin D at the study's start were 72% less likely than those with low levels of vitamin D to die of colorectal cancer.

Death rates for the other cancers that were studied, including lung cancer, breast cancer, prostate cancer, other digestive cancers, non-Hodgkin's lymphoma, and leukemia, weren't linked to vitamin D blood levels.

The study's limits include the fact that participants only had their vitamin D level checked once. So it's not clear if their vitamin D level rose or fell over the years.

Freedman's team had lots of data including which participants smoked and exercised. But they can't rule out the possible influence of other factors.

The study appears in next week's edition of the Journal of the National Cancer Institute.

An editorial published with the study states that "the relationship between nutritional factors and colorectal as well as other cancers is complicated" and that the findings "must be put into the context of total diet and lifestyle."

The editorial was written by experts including Johanna Dyer, DSc, RD, of the Office of Dietary Supplements at the National Institutes of Health (NIH).

2 comments:

TedHutchinson said...

But that report was based on one blood test over 10years.
If I observed your motorway driving speed on one occasion would that be a good basis to estimate your speed related driving accidents/mortality over the next ten years? I think if you really wanted to estimate someones normal driving speed then several observation through the year would be needed. Similarly to assume from one sample at age 17 that person was driving (or vitamin d acquisition) was similar aged 27, without any evidence on which to base that conclusion is somewhat misguided.
Apart from that aspect of this research being naive, they also took the southern latitude blood draws in the cooler winter months and the northern latitude blood in the summer months, thus blurring any distinction between them.
Whenever you read any research you have to use your brains to work out what they are really saying and why they may be spinning the results. In this case the longer people continue to be vitamin d deficient the more money the cancer industry can make.

Anonymous said...

This is an interesting view point. I just read another article that describes how Vitamin D can reduce many diseases at Here Comes The Sun