Vitamin D: Public Service Announcement
Aug. 30th, 2009 12:06 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
deirdreIf you're one of my celiac readers, this should be of particular interest as a) celiac disease prevents absorption of vitamin D, and b) for that reason (and perhaps others), even asymptomatic celiacs are substantially more prone to colorectal cancer.
I'm not one of those people who believes in taking mega-doses of vitamins, however I know a bunch of people going through cancer right now, and there's been a whole bunch of research about the link between low levels of vitamin D and certain cancers.
So here's a few references:
Model of how Vitamin D works in cancer. (from which the above quote is taken)
Science Daily article has the following key points:
For those who already have colon cancer:
The question is, then, how much Vitamin D? It's an oil-based vitamin, thus you don't want to take too much. Some people can take ten times (or more) than the RDA and not have problems, but some have problems at 5x the RDA. Beware of doctors who prescribe literally crazy-making quantities of Vitamin D.
My suggestion would be to supplement take at least the RDA of 400 IU, though the number some people seem to be settling on is 1000 IU (2.5x the RDA). I currently take 800 IU, but I also drink a lot of milk.
What form of Vitamin D?
What's made in the skin as a result of sun exposure is Vitamin D-3, Calcitriol, usually supplemented as Cholecalciferol.
There's also D-2, which is supplemented as Ergocalciferol, and the process for doing this is currently (or was until recently) patented by Eli Lilly.
The NIH factsheet says:
In other words, which is better in the long run is not known at present.
I'd also suggest that if you're high risk (e.g. celiac, family history of this cancer), you ask your doctor to check your serum levels of vitamin D when other bloodwork is done. It's not a bad thing to check every few years anyway.
I'm not one of those people who believes in taking mega-doses of vitamins, however I know a bunch of people going through cancer right now, and there's been a whole bunch of research about the link between low levels of vitamin D and certain cancers.
According to Garland, other scientists have found that the cells adhere to one another in tissue with adequate vitamin D, acting as mature epithelial cells. Without enough vitamin D, they may lose this stickiness along with their identity as differentiated cells, and revert to a stem cell-like state.
So here's a few references:
Model of how Vitamin D works in cancer. (from which the above quote is taken)
Science Daily article has the following key points:
"[P]revious research has shown that higher levels of vitamin D reduce the risk of developing colon and rectal cancer by about 50 percent...."
For those who already have colon cancer:
The results showed that individuals with the vitamin D levels in the highest quartile were 48 percent less likely to die (from any cause, including colon cancer) than those with the lowest vitamin D measurements. The odds of dying from colon cancer specifically were 39 percent lower, the scientists found.
The question is, then, how much Vitamin D? It's an oil-based vitamin, thus you don't want to take too much. Some people can take ten times (or more) than the RDA and not have problems, but some have problems at 5x the RDA. Beware of doctors who prescribe literally crazy-making quantities of Vitamin D.
My suggestion would be to supplement take at least the RDA of 400 IU, though the number some people seem to be settling on is 1000 IU (2.5x the RDA). I currently take 800 IU, but I also drink a lot of milk.
What form of Vitamin D?
What's made in the skin as a result of sun exposure is Vitamin D-3, Calcitriol, usually supplemented as Cholecalciferol.
There's also D-2, which is supplemented as Ergocalciferol, and the process for doing this is currently (or was until recently) patented by Eli Lilly.
The NIH factsheet says:
Vitamin D3 could be more than three times as effective as vitamin D2 in raising serum 25(OH)D concentrations and maintaining those levels for a longer time, and its metabolites have superior affinity for vitamin D-binding proteins in plasma [6,32,33]. Because metabolite receptor affinity is not a functional assessment, as the earlier results for the healing of rickets were, further research is needed on the comparative physiological effects of both forms.
In other words, which is better in the long run is not known at present.
I'd also suggest that if you're high risk (e.g. celiac, family history of this cancer), you ask your doctor to check your serum levels of vitamin D when other bloodwork is done. It's not a bad thing to check every few years anyway.