Sunday, January 17, 2010

Vitamin D and Prostate Cancer

This is interesting... Peter Frost questions the evidence supporting high oral doses of vitamin D:
"What effects, then, can we expect from artificially raising the vitamin D levels of black Americans? Keep in mind that we are really talking about a hormone, not a vitamin. This hormone interacts with the chromosomes and may gradually shorten their telomeres if concentrations are too low or too high. Similarly, cancer risk increases if concentrations are too low or too high. Prostate cancer is least likely when vitamin D levels vary between 16 and 24 ng/mL -- a range of values below the current recommended minimum of 30 ng/mL."
- Black-White Differences in Cancer Risk and the Vitamin D Hypothesis, Journal of the National Medical Association, December 2009
The reference for that highlighted text above was...
"Calcidiol* serum concentrations show a U-shaped risk of prostate cancer suggesting an optimal serum concentration of 40-60 nmol/L [16-24 ng/mL] for the lowest cancer risk."
- Vitamin D and Aging, The Journal of Steroid Biochemistry and Molecular Biology, December 2009
*Calcidiol, 25(OH)D, is vitamin D3 that has been hydroxylated by the liver. Serum calcidiol is an indicator of vitamin D status.

It will be interesting to see what recommendations the IOM makes regarding vitamin D intake. They've been holding a series of meetings on it. (The IOM is the Institute of Medicine of the National Academies. They publish the DRIs/RDAs.)

Here are the current recommendations for vitamin D that are likely to go up:



Jim Purdy said...

Interesting. Many of the blogs I follow are jumping on the Vitamin D bandwagon.

Nigel Kinbrum BSc(Hons)Eng said...

It could be the fluctuation that's the problem rather than the level itself.

See Vitamin D and UV fluctuations and Vitamin D and UV fluctuations (2).


Bix said...

It will be interesting to see how the IOM deals with the oral vitamin D and liver issue.

I'm disappointed to see that "At least two members of the committee proposed by the Institute of Medicine to reevaluate intake guidelines for calcium and vitamin D have potential conflicts of interest, a Center for Science in the Public Interest investigation found."