Not long ago there was a snippet on the evening news about how B vitamins DON'T lower homocysteine, and don't really help prevent heart attack, based upon a recent study.
Well, after being told on a forum in which I participate that B12 is dangerous and should not be taken except under careful doctor supervision, because in Norway doctors consider it a threat, I looked into the NORVIT study, which was the basis of the snippet I heard.
This is the conclusion drawn from the NORVIT study, "Lowering plasma homocysteine levels by as much as 28% does not result in any reduction in the risk of myocardial infarction (MI) or stroke in patients who have already had an MI, according to the results of the Norwegian Vitamin Trial (NORVIT). [1] The study also suggests that administration of combination B vitamins with the aim of reducing plasma homocysteine may actually increase the risk of cardiovascular disease and that folic acid alone may increase the risk of cancer."
That sounds really worrying, right?
Well, take a close look at what the study says:
www.medscape.com/viewarticle/512905
For instance, it says,
"Study and Rationale"
"NORVIT was designed as a randomized, controlled, double-blind, multicenter, secondary prevention trial, testing the hypotheses that long-term (3.5-year) treatment with a folate/vitamin B12 combination or vitamin B6 would lower the incidence of MI and stroke by 20% each. A substudy was also set up to test the hypothesis that vitamin B therapy protects against loss of cognitive function."
That sounds good, but when it comes to listing the vitamins actually administered, it says,
"Treatment"
"Patients were randomized into 4 groups in a 2 x 2 factorial design:
Folic acid + vitamin B6
Folic acid alone
Vitamin B6 alone
Placebo"
Do you see B12 in the list? I don't.
It goes on, in the less noticeable print, to include B12, "Doses of drugs were folic acid 0.8 mg/day (+ vitamin B12 at a dosage of 0.4 mg/day) and vitamin B6 at a dosage of 40 mg/day; 90% of participants reported adherence to the study medication protocol."
Okay, so the flaw that jumps out at me is that B12 was included at the rate of 400 mcg. That's a pretty tiny amount. Anyone having the most basic B12 replacement therapy has 1000 mcg a day.
At the same time, the amount of B6 that was administered was relatively huge, 40 mg. (That's a hundred times more.)
Significantly, none of the tables provided even mentions B12.
I found this at TheHeart.org, "As Bonaa reported here today, the combination of vitamin B6 and folic acid, as well as folic acid alone, effectively lowered homocysteine levels by 28% but did not have the expected beneficial effect on cardiovascular risk. At follow-up, the risk of stroke and MI was 18% in the placebo group, roughly the same as that seen in both the folic-acid-only group and the vitamin-B6-only group. By contrast, in the combination group, 23% of patients had a fatal or nonfatal stroke or MI, a statistically significant absolute increase of 5%, compared with the other treatment arms (p=0.029)."
Interestingly enough, the group receiving the most B12 had the most reduction in homocysteine,