dime wrote:Unlike vitamin A or D, levels of vitamin E are well controlled by the liver as it seems.
Level of all vitamins are well controlled, co-depending on so many other factors.
As we have seen in the vitamin D and sunshine exposure thread, (even) at high level sunexposure,
serum vitamin D may remain relatively low (Indian farm workers), or not (a proportion of Israeli lifeguards).
The issue, in my opinion, is that in between (high) intake and elimination, there may be a timespan that any extra may have an effect.
The level of toxicity is of a different magnitude; what cannot nearly be constituted as toxic,
may very well have adverse biological effects.
That the body tries to maintain a certain level of vitamin E, actually advocates against taking supplementary vitamin E, in my opinion.
If it needs more vitamin E, the body
will increase its level (as it does in patients with breast cancer
Gerber M et al Free full text)
So, we should not enforce an elevated level.
a new review concludes that biological mechanisms exist to routinely eliminate excess levels of the vitamin, and they make it almost impossible to take a harmful amount.
Before excess is (routinely) eliminated, its there.
Sure, a 'toxic' vitamin E level may never be reached, but any elevation may disrupt a delicate balance,
having some impact anyway.
Maret Traber wrote:I believe that past studies which have alleged adverse consequences from vitamin E have misinterpreted the data
He may be referring to this:
In 29,133 male smokers 50 to 69 years of age from southwestern Finland, more deaths from hemorrhagic stroke (without an effect on total mortality) were observed among the men who received supplemental vitamin E. (50 mg / day).
The Alpha-Tocopherol Beta Carotene Cancer Prevention Study Group - April 1994
"
3570 deaths occurred during the trial. Among participants receiving alpha-tocopherol, there were fewer deaths caused by ischemic heart disease and ischemic stroke than there were among those who did not receive alpha-tocopherol, but more deaths due to cancers other than lung cancer or due to hemorrhagic stroke (Figure 3). Overall mortality was 2 percent higher in the alpha-tocopherol groups than in the groups that received no alpha-tocopherol (95 percent confidence interval, -5 to 9 percent; P = 0.6). ... Alpha-tocopherol has effects on platelet function (25,26) that could conceivably underlie this observation."
Full text results
Fact is: supplementary vitamin E
does increase serum vitamin E.
In a pilot study, the level went up from 17.3 to 52.6 (and back to 28.1 one week after the study),
and in the subsequent trial it went up from 15.2 to 43.7 (and back to 22.1 one week after the study)
(daily dosage: 400 mg dl-alpha-tocopheryl acetate)
increasing interleukin 1f3 (IL-l f3) production of peripheral blood mononuclear cells from 1.05 to 1.53
and increasing tumor necrosis factor a (TNF-a) production from 1.06 to 1.26
Jeng KC et al
There are so many factors influenced by elevated serum vitamin E.
Vitamin E is an effective scavenger of radicals, but therefore also influences the feedback mechanisms controlling this scavenger system.
Extra vitamin E may decrease catalase activity, which may lead to a lipoperoxidative process in specific cells.
Grammatico, P et al
