In recents years, some studies have questioned the usefulness of anti-oxidants in fruit and vegetables. This is more or less in line with what Ray wrote about caffeine being the only real anti-oxidant in the typical diet. I sometimes wonder about whether that extends to the fat solubles A/E - whether those should be taken long term for maintenance, as opposed to only when needed like Alzheimer's, acne... When Ray writes about them, it's often for a specific purpose rather than for maintenance. I think the question should extend to all supplements - hormones, vitamins, drugs etc: should you take them in times when there's no acute problem? The work below suggests A/E/C and selenium aren't magic as there isn't even a positive on average. No surprise for C and beta carotene. I wish caffeine was included in the study.
http://jama.jamanetwork.com/article.aspx?articleid=205797
The study was referenced in a Wiki paragraph on oxidative stress:
http://en.wikipedia.org/wiki/Oxidative_stress
http://jama.jamanetwork.com/article.aspx?articleid=205797
Context Antioxidant supplements are used for prevention of several diseases.
Objective To assess the effect of antioxidant supplements on mortality in randomized primary and secondary prevention trials.
Data Sources and Trial Selection We searched electronic databases and bibliographies published by October 2005. All randomized trials involving adults comparing beta carotene, vitamin A, vitamin C (ascorbic acid), vitamin E, and selenium either singly or combined vs placebo or vs no intervention were included in our analysis. Randomization, blinding, and follow-up were considered markers of bias in the included trials. The effect of antioxidant supplements on all-cause mortality was analyzed with random-effects meta-analyses and reported as relative risk (RR) with 95% confidence intervals (CIs). Meta-regression was used to assess the effect of covariates across the trials.
Data Extraction We included 68 randomized trials with 232 606 participants (385 publications).
Data Synthesis When all low- and high-bias risk trials of antioxidant supplements were pooled together there was no significant effect on mortality (RR, 1.02; 95% CI, 0.98-1.06). Multivariate meta-regression analyses showed that low-bias risk trials (RR, 1.16; 95% CI, 1.05-1.29) and selenium (RR, 0.998; 95% CI, 0.997-0.9995) were significantly associated with mortality. In 47 low-bias trials with 180 938 participants, the antioxidant supplements significantly increased mortality (RR, 1.05; 95% CI, 1.02-1.08). In low-bias risk trials, after exclusion of selenium trials, beta carotene (RR, 1.07; 95% CI, 1.02-1.11), vitamin A (RR, 1.16; 95% CI, 1.10-1.24), and vitamin E (RR, 1.04; 95% CI, 1.01-1.07), singly or combined, significantly increased mortality. Vitamin C and selenium had no significant effect on mortality.
Conclusions Treatment with beta carotene, vitamin A, and vitamin E may increase mortality. The potential roles of vitamin C and selenium on mortality need further study.
The study was referenced in a Wiki paragraph on oxidative stress:
http://en.wikipedia.org/wiki/Oxidative_stress
Antioxidants as supplements[edit]
The use of antioxidants to prevent disease is controversial.[38] In a high-risk group like smokers, high doses of synthetic beta carotene increased the rate of lung cancer.[39] In less high-risk groups, the use of vitamin E appears to reduce the risk of heart disease, although more recent evidence may in fact suggest the opposite.[40] In other diseases, such as Alzheimer's, the evidence on vitamin E supplementation is mixed.[41][42] Since dietary sources contain a wider range of carotenoids and vitamin E tocopherols and tocotrienols from whole foods, ex post facto epidemiological studies can have differing conclusions than artificial experiments using isolated compounds. However, AstraZeneca's radical scavenging nitrone drug NXY-059 shows some efficacy in the treatment of stroke.[43]
Oxidative stress (as formulated in Harman's free radical theory of aging) is also thought to contribute to the aging process. While there is good evidence to support this idea in model organisms such as Drosophila melanogaster and Caenorhabditis elegans,[44][45] recent evidence from Michael Ristow's laboratory suggests that oxidative stress may also promote life expectancy of Caenorhabditis elegans by inducing a secondary response to initially increased levels of reactive oxygen species.[46] This process was previously named mitohormesis or mitochondrial hormesis on a purely hypothetical basis.[47] The situation in mammals is even less clear.[48][49][50] Recent epidemiological findings support the process of mitohormesis, with a 2007 meta-analysis indicating studies with a low risk of bias (randomization, blinding, follow-up) find that some popular antioxidant supplements (Vitamin A, Beta Carotene, and Vitamin E) may increase mortality risk (although studies more prone to bias reported the reverse)