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Nov 23, 2009


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I agree with you David. I don't even measure vitamin D levels in my patients. There is a big planned trial, planned by Harvard, of vitamin D and omega-3 fatty acids in primary prevention, but the results will not be available for at least 5 years.

At least the mortality numbers seem to be in the right direction, but we've seen off-target effects for so many of the vitamins now - vitamin C and hemorrhagic stroke, folic acid and cancer, vitamin A and cancer, etc. It makes you shiver. I tell all my patients that the vitamin cocktail they are consuming is really a drug cocktail, and we try to pare it back from there.

Welcome to medical blogging.How we gather and use evidence and put it all together are things I have pondered about for quite a while and still manage to confuse myself with some regularity but I keep plugging away.

What kinds of levels are we talking about? I do take some vitamin D for bone health with my calcium and magnesium supplement. I'm also almost never in the sun. That's not a mega dose or anything.

I'm also curious as to whether there are any studies on vitamin D and seasonal affective disorder. No evidence yet, but I think it could be interesting.

I am amazed how naive educated physicians can be about supplements. In case most of you don't know, vitamins cannot function without mineral cofactors. Minerals, vitamins, amino acids & fatty acids & physiological & biological functions are dependent on each other. Balance, is that such a hard concept to understand? I see studies which use single vitamins, or combinations of a few or others that use synthetic forms of vitamins, some with the inorganic forms of minerals, both of these types of studies prove absolutely nothing if it isn't what the body needs. Take for instance calcium. Calcium supplementation alone will do absolutely nothing for something like osteoporosis. All minerals that make up bone & bone matrix & their cofactors are need for the body to rebuild bone density. Another is chromium supplementation for diabetes. There are 23 other cofactors essential for chromium to work. So when the author questions supplementation via studies he is correct since those studies are inadequate because of the focus on the targeted vitamins. There are other factors which are clearly not considered. Perhaps there should be more focus on the macro effect of a balanced supplementation program rather than piece mealing a few of the nutrients without the necessary cofactors.

I've always been weary of megadoses of vitamins, especially vitamin B supplements that give 40,000% of the recommended daily value. I know they're water soluble, but that's still a bit much to swallow.

Many questions have been raised over the Norway folic acid study:

Then there was this new folic acid study, which has gotten virtually no media attention:

Dan Hackam: "At least the mortality numbers seem to be in the right direction, but we've seen off-target effects for so many of the vitamins now - vitamin C and hemorrhagic stroke"

Don't you mean vitamin *E* and hemorrhagic stroke?

"we are talking about administering a therapy to enormous numbers of healthy people with the hope of preventing disease"

Ironically, this exactly what is happening with skin cancer sun avoidance advice - SPF 15, seek shade, avoid tanning etc.

A therapy of hormone depletion for enormous numbers of healthy people with the hope of preventing skin cancer, based solely on correlation and without trials to determine efficacy and side-effects.

I understand the point that you are making (although the innuendo - failed supplement - is a bit under-hand), however there is now a mountain of evidence that vitamin D (or rather pre-hormone D) is lot more than just a maybe.

Epidemiological, longitudinal and prospective studies (1) provide strong correlation and in vivo/vitro experiments show plausibility. There's even an analysis using Hill's criteria for causality (2).

The glaring omission in the evidence trail is the lack of large scale, large dosage, serum measured RCTs. NIH's upcoming 5 year VITAL trial should settle a few things.

Your caution about fat-soluble vitamins is probably warranted though. An analysis of NHANES II data (3) found low levels of 25(OH)D "was associated with a 26% increased rate of all-cause mortality" with an optimal 25(OH)D level between 30 and 49 ng/mL. However, levels above 50ng/ml increased mortality.

1. Giovannucci, E. et al. Prospective study of predictors of vitamin d status and cancer incidence and mortality in men. J. Natl. Cancer Inst. 98, 451-459 (2006). URL http://dx.doi.org/10.1093/jnci/djj101.
2. Grant, W. B. How strong is the evidence that solar ultraviolet b and vitamin d reduce the risk of cancer? an examination using hill's criteria for causality. Dermato-Endocrinology 1, 17-24 (2009). URL http://dx.doi.org/10.4161/derm.1.1.7388.
3. Melamed, M. L., Michos, E. D., Post, W. & Astor, B. 25-hydroxyvitamin d levels and the risk of mortality in the general population. Archives of internal medicine 168, 1629-1637 (2008) (http://view.ncbi.nlm.nih.gov/pubmed/18695076)

Thanks for the report... I'm probably going to do like you mention in your conclusion and wait a bit for more studies before "jumping the bandwagon." Too many studies keep poping up about how x helps you do x. I like to wait that other studies re-comfirm those discoveries...

Some people just don't care about evidence, they still want to do what they "Feel" is right. They still want to experience the vitamins, or drugs, or other natural remedies on their own.

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