Is some sun exposure good for me? Will moderate and daily alcohol consumption actually extend my life? Is the risk of breast, ovarian, and uterine cancer in women reduced by minimizing the frequency of menses? With the barrage of health claims that come at us on a daily basis, it can sometimes be impossible to distinguish fiction from fact. Doctors, being simply human, fall into this trap as well – eager to sound cutting-edge and knowledgeable to patients, many are willing to base medical advice on interpretations of research that are either immature or only partially informed. Scientists, eager for a headline and desperately needed funding, may drop a quote to a journalist that is overly extrapolative, leading to confusion between evidence and best guess. We are certainly all capable of hyperbole when describing something fascinating or full of potential. It is forgivable. What seems far more insidious is financial exploitation under the guise of good science, that is, taking this otherwise innocuous human flaw to the marketplace wholesale. One of the most widespread examples of this abuse is proudly labeled on products contained in most refrigerators in the US: the beneficial effects of antioxidants.
This one is pretty entrenched. ”Antioxidant Rich!” has become the advertising slogan of so many foods that are considered healthy, that the confirmation bias is near insurmountable. So what is an antioxidant anyway? When something gets burned, it oxidizes, and part of that process produces oxidants, some of which are highly reactive atoms and ions called free radicals. This happens around a campfire in a very similar way to how it occurs in our bodies. The food we eat is slowly heated during the digestive process and exposed to oxygen delivered by red blood cells. During the oxidation process, the free radicals let loose in our cells are like tiny bullets, damaging tissue and knocking proteins out from within DNA molecules. Free radicals may be associated with neurological and nervous system diseases like Alzheimer’s, Parkinson’s, and schizophrenia, and there is a clear link between them and the formation of some cancers. Despite this, free radicals are critical to living a healthy life. They are one of the body’s most capable weapons, employed by white blood cells to safeguard the bloodstream from unwanted bacteria and viruses. By oxidizing the invaders, the immune system effectively destroys them through the use of free radicals. To curb the widespread damage that occurs from these cellular-sized Uzis, the body synthesizes antioxidants like vitamins A, C, and E as well as selenium and melatonin. While these all serve other important roles within the body, one of their chief duties is to neutralize excess free radicals.
It’s at this point that our original problem took hold. Leaping to conclusions, many adopted the free radical theory of aging, and determined that taking abnormally high doses of supplements rich in antioxidants would greatly slow the aging process and drastically reduce incidences of cancer and many other diseases. The berry and bean growers out there, as well as their secondary and tertiary markets, could now trumpet anti-aging and anti-cancer benefits on their product labels – which they promptly did. A couple of nightly newscasts and a season of Oprah later, and everyone was on board with antioxidants as a source of life extension and general wellness. The problem is that there wasn’t much good science regarding whether the average person benefited from supplementing their antioxidant intake.
Over the years, the findings of more and more research surface. One large study geared towards determining whether beta-carotene supplements decreased the risk of lung cancer in patients was stopped after the returning data indicated that subjects were developing lung cancer at a significantly increased rate. Then in 2007, the Journal of the American Medical Association published this exhaustive and utterly damning meta analysis of all available studies on the effectiveness of antioxidant supplements. They examined 68 reliably conducted scientific trials (some with low-bias risk others with high) that covered 232, 606 participants. What they discovered is best summed in quote:
“We did not find convincing evidence that antioxidant supplementshave beneficial effects on mortality. Even more, beta carotene,vitamin A, and vitamin E seem to increase the risk of death.Further randomized trials are needed to establish the effectsof vitamin C and selenium.”
The particulars of the survey methodology are interesting and make for a good read, and they inspire confidence in the reliability of the results. I also tend to trust the American Medical Association over Welch’s when it comes to my health.
Not that I’m saying that antioxidants are bad or that free radicals are good, but rather that they work best in their natural balance. A normal diet, or even a crappy fast food and prepackaged meals diet, gives the body all of the antioxidants it needs. That’s also not to say that fruits and vegetables aren’t really important for other reasons as well. The great botanist and writer, Michael Pollan has said, “Eat food. Mostly plants. Not too much.” I think that sums it up best.
Oh – didn’t want anybody left wondering:
Is some sun exposure good for me (absolutely, don’t get too much if you’re really pastey)?
Will moderate and daily alcohol consumption actually extend my life? (yep by 10-15% on average - unless you drink more than two beers a day or the equivalent)?
Is the risk of breast, ovarian, and uterine cancer in women reduced by minimizing the frequency of menses (yes, considerably)?
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