Thursday, February 21, 2008

Vitamin E supplements to be discouraged.....

Preamble - by the way, all these posts are, as much as anything, me recording things that I find of which I want to keep track . Often it is about me "thinking out loud" around these things. I am not prescribing anything for anyone - you can make your own mind up!

I have posted one or two things before that I have found interesting that - at first sight - seem to call into question the perceived wisdom of taking lots of supplemental antioxidants:

and from Emma's blog:
Here is another interesting one:

Vitamin E May Increase Tuberculosis Risk In Male Smokers With High Vitamin C Intake

Six-year vitamin E supplementation increased tuberculosis risk by 72% in male smokers who had high dietary vitamin C intake, but vitamin E had no effect on those who had low dietary vitamin C intake, according to a study published in the British Journal of Nutrition.......
.......... Vitamin E had no effect on participants who had dietary vitamin C intake less than 90 mg/day. Unexpectedly, vitamin E supplementation increased tuberculosis risk by 72% in those who had dietary vitamin C intake over 90 mg/day. The most dramatic increase in tuberculosis risk by vitamin E was restricted to a one-year period after the initiation of supplementation.

The researchers concluded that "the consumption of vitamin E supplements by the general population should be discouraged because there is evidence of harm for some people."

Interesting also that Vitamin C is mentioned here. In a previous post I quoted a study that found that :

Conclusion: Vitamin C supplementation decreases training efficiency because it prevents some cellular adaptations to exercise.
and mentioned that:

So don't take that Vitamin C - exercise itself is an antioxidant and taking antioxidants prevents useful benefits to training! I told you it was heresy!

I have said before that:

It is also worth pointing out that Vilhjalmur Stefansson lived for years on the traditional Eskimo diet of fat and veggies.......and was, like the Eskimos he was living with, exceptionally healthy. Gary Taubes in his new and excellent book Good Calories, Bad Calories suggests that scurvy and other vitamin deficiency diseases are actually only found when people are eating diets low in meat, eggs and dairy. It seems to be the high levels of carbs that prompt the need for all the vitamins in the veggies.....

The full study is here:

Vitamin E supplementation may transiently increase tuberculosis risk in males who smoke heavily and have high dietary vitamin C intake

Vitamin E and β-carotene affect the immune function and might influence the predisposition of man to infections. To examine whether vitamin E or β-carotene supplementation affects tuberculosis risk, we analysed data of the Alpha-Tocopherol Beta-Carotene Cancer Prevention (ATBC) Study, a randomised controlled trial which examined the effects of vitamin E (50 mg/d) and β-carotene (20 mg/d) on lung cancer. The trial was conducted in the general community in Finland in 1985–93; the intervention lasted for 6·1 years (median). The ATBC Study cohort consists of 29 023 males aged 50–69 years, smoking at baseline, with no tuberculosis diagnosis prior to randomisation. Vitamin E supplementation had no overall effect on the incidence of tuberculosis (risk ratio (RR) = 1·18; 95 % CI 0·87, 1·59) nor had β-carotene (RR = 1·07; 95 % CI 0·80, 1·45). Nevertheless, dietary vitamin C intake significantly modified the vitamin E effect. Among participants who obtained 90 mg/d or more of vitamin C in foods (n 13 502), vitamin E supplementation increased tuberculosis risk by 72 (95 % CI 4, 185)%. This effect was restricted to participants who smoked heavily. Finally, in participants not supplemented with vitamin E, dietary vitamin C had a negative association with tuberculosis risk so that the adjusted risk was 60 (95 % CI 16, 81) % lower in the highest intake quartile compared with the lowest. Our finding that vitamin E seemed to transiently increase the risk of tuberculosis in those who smoked heavily and had high dietary vitamin C intake should increase caution towards vitamin E supplementation for improving the immune system.


scott said...

Agree with the overuse of anti-oxidants being unhelpful. Regarding E, though, I have approached this from a standpoint of using it to stabilize potentially volatile fats as they are metabolized. This would include fish oil. So there may still be some value there from that perspective...not adding to the anti-oxidant load, but mitigating other potentially harmful substances.

Thoughts on Alpha Lipoic Acid? Supposed to help the body regenerate its own glutathione. In that regard, may serve a similar role to COQ10.

Great blog, appreciate the work that you put into it.

Chris said...

Thanks Scott

There may be an issue here about the source of the Vitamin E.. I am about to post something which questions the use of synthetic vitamins.

I've not really looked at Alpha Lipoic Acid.