Saturday, April 16, 2011

ARE ANTIOXIDANTS UGLY?




We know that a diet high in fruits and vegetables can help you avoid heart disease as well several different types of cancers. We also know that a diet rich in fruits and vegetables can help you avoid Alzheimer's disease. But what is it, exactly, that's so protective? If that's true, then it would be reasonable to believe that antioxidant supplements in pill form would help protect you from illness or even make you better, right? We in medicine know, however, that it's always wise to check our assumptions and look for evidence - that's why we call it "evidence-based medicine."

The Newsweek piece quotes a British "chemist and science writer" named David Bradley as saying that "oxidizing agents," also known as free radicals, are a "front-line of immune defense against pathogens and cancer cells." He goes on to claim that because antioxidants eliminate these free radicals, they are damaging to health. “antioxidants” cancel “oxidizing agents” in a straight-line, one-on-one, hand-to-hand-combat manner. But the foundational science behind both antioxidants and the oxidative agents they target completely contradicts.

Chemistry professor, Louis Feiser of Harvard, told us, “oxidation” and “reduction” are two inseparable sides of the same coin. When a molecule loses electrons, it has been “oxidized”; when it gains electrons, it has been “reduced.” Since one molecule’s loss is always another molecule’s gain, the oxidation/reduction must always occur simultaneously, and the whole electron-exchange transaction is called a “redox reaction.”

NATURE: Dietary components presently termed “antioxidants” can work on both sides of the “redox reaction,” sometimes donating electrons, sometimes gaining them, as needed. To describe their functions more accurately, including both aspects of electron flow, antioxidants might best be termed “redox reaction regulators.

NEWSWEEK: “antioxidant” supplements are used to combat “free radicals,” molecules which have lost electrons (have been “oxidized”) and—in a manner of speaking—roam around the body stealing electrons back from other molecules in an indiscriminate manner, causing damage as a result. “free radicals are generated by normal metabolism, though dietary fat and iron-rich foods such as red meat generate more of them”.

Newsweek concludes as writing, “It is time to reevaluate the tumorigenic detrimental effect of PAO [phyto-antioxidants], especially those exhibiting prooxidant bioactivity.”

In a 2008, the Cochrane Collaboration, an international consortium of scientists who assess medical research, scrutinized 67 studies with nearly 400,000 participants. The goal: to determine whether antioxidant supplements reduce mortality in either healthy people or in people with cardiovascular, neurological, rheumatoid, renal, endocrine, or other diseases. Cochrane reviewers wrote: “We found no evidence to support antioxidant supplements for primary or secondary prevention, [and] Vitamin A, beta-carotene, and vitamin E may increase mortality.” In analyses of antioxidant supplements and Lou Gehrig’s disease, Alzheimer’s or mild cognitive impairment, and lung cancer, their verdict was the same.: no, no, no, and no. And each analysis had an alarming refrain about increasing overall mortality. One report said that NF-E2-Related Factor 2 might promote atherosclerosis.

A paper to appear in an upcoming issue of the Proceedings of the National Academy of Sciences finds that antioxidants might impair fertility. Experiments show that administration of broad-range scavengers of oxidative species into the ovarian bursa of mice, hormonally induced to ovulate, significantly reduced the rate of ovulation.”

It’s also mentioned in the Physician’s Desk Reference (PDR), an unlikely target for Newsweek. It’s N-acetylcysteine, which the PDR accurately reports will raise glutathione levels, not at all a bad thing, but of course injecting it into one’s ovaries isn’t usually the way it’s taken as a supplement. N-acetylcysteine also has other entirely non-antioxidant actions, such as binding zinc—essential, along with folate and vitamin B12 to DNA replication, and fertility—and copper, so not using N-acetylcysteine. if someone trying to get pregnant is a actually a good idea. Low levels of zinc have been linked—just as are low levels of folate and vitamin B12—with spina bifida and birth defects, too. But these effects have nothing at all to do with any “antioxidant” effect.

Butylated hydroxyanisole (BHA) a waxy solid used as a food additive, which according to a National Institutes of Health report is “reasonably anticipated” to be a human carcinogen based on evidence of carcinogenicity in experimental animals. When administered as part of their diet, BHA causes papillomas and squamous cell carcinomas of the forestomach in rats and Syrian golden hamsters. In this case Newsweek says: don’t go buy BHA to inject into your ovaries! This particular “antioxidant” is likely dangerous.

even though the Association of American Poison Control Centers 2008 report noted that not even one death from use of vitamins, minerals, or botanical supplements for that entire year—check with a physician skilled and knowledgeable in nutritional and natural medicine. And lastly, for likely the next decade at least, be very skeptical of “health advice” offered by Newsweek or any of the “mainstream” media, particularly if it’s about the natural approach to healthcare.

Antioxidants on Heart: During the last two years, a number of randomized trials using antioxidant vitamin supplements have finally been reported, and the results have generally been disappointing. Both the American Heart Association and the Institute of Medicine have released recent statements saying that, while a diet rich in antioxidant vitamins seems prudent, there is insufficient evidence to recommend using supplements of vitamin C, vitamin E, beta-carotine, selenium, or other antioxidants to prevent heart disease. The study from the University of Washington, reported last month, brings up the possibility that antioxidant therapy may do more than merely fail to halt the progression of coronary artery disease. This new study suggests the possibility of harm.

Antioxidants- Vitamins: A range of different vitamins and minerals have been identified as having antioxidant properties. Even Linus Pauling, noted Nobel Laureate, spent the latter years of his career claiming that vitamin C was a panacea for just about every complaint he could think of. However, a new meta-analysis of existing studies published in JAMA regarding the use of antioxidant supplements shows that far from prolonging longevity, beta carotene, vitamin A, and vitamin E usage were associated with increased mortality.

A paper to appear in an upcoming issue of the Proceedings of the National Academy of Sciences finds that antioxidants might impair fertility. Further experiments confirmed it: a type of free radical called reactive oxygen species is produced in response to luteinizing hormone, the physiological trigger for ovulation. That suggests that luteinizing hormone triggers ovulation through an intermediary—namely, reactive oxygen species. If reactive oxygen species are being mopped up by antioxidants, there’s no ovulation.

• A 2010 study in lab rats found that two popular antioxidants, quercetin and ferulic acid aggravated and possibly triggered kidney cancer. As the scientists put it in the Journal of Agricultural and Food Chemistry, “It is time to reevaluate the tumorigenic detrimental effect of” antioxidants.

• Finally, a new study in lab mice finds that a natural protein that boosts antioxidant levels in the blood may actually promote atherosclerosis, or clogging of the arteries. The study, in the January issue of Arteriosclerosis, Thrombosis, and Vascular Biology, offers clues about why taking antioxidants has not been shown to improve heart health. The protein Nrf2 indeed boosts antioxidants, but in the study it also raised blood-cholesterol levels, as well as cholesterol content in the liver—both of which are excellent ways to get atherosclerosis.

A Chicago study of 68 existing studies on Beta carotene and vitamins A and E have been found to increase the risk of death. Synthetic supplements have higher concentrated levels of antioxidants and can therefore be more problematic. Antioxidants fight free radicals that can cause cell damage. The study explained that by wiping out the free radicals from our bodies, we are interrupting important defense mechanisms needed to fight disease. According to the study, using antioxidants Beta carotene and vitamin A and E, can increase the chance of mortality by 5 %. Vitamin C, which is thought to increase longevity, was shown to have no real effect on longevity at all.

“It’s not clear why antioxidants in supplement form might be so dangerous. One idea holds that at high doses they become pro-oxidants, stimulating the harmful DNA- and cell-damaging reactions they’re supposed to prevent. But a more likely explanation is that we are seeing the human version of what scientists are finding in studies of lab animals: antioxidants interfere with immune-system cells that fight against infection and cancer. So it’s the time to reevaluate the effect of antioxidants in disease state as well as in normal condition to assess the actual effect of Antioxidants in our body.”

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2 comments:

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Unknown said...

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