Antioxidants and Health, a Cautionary Tale

Health care is a good reminder of the limits of knowledge and science and that human fallibility pervades all professions and activities.  We will all recall the advice we have been getting for a number of years about eating more anti-oxidants or even taking supplements to that end.  Well, think again, a new paper outlines the change in recommendations caused by further research.  The original recommendation came about because oxidative damage is a common cellular process.  Antioxidants that might limit this damage are present in a normal diet.  Some research suggests that taking more might actually have bad health effects, with a recent Canadian study even suggesting that taking supplements may increase mortality.  Meanwhile a multi-billion dollar business has of course come into being to sell antioxidant supplements and foods.  Here is one paper that reviews the issues surrounding antioxidant use.    (AO Paper)   You can find others if you Google the term.  One thing the article points out is that initial enthusiasm was based on in vitro, or outside the body, research, and in the body, antioxidants just didn’t work the same.  Some “experts” claimed just giving higher doses could overcome these limitations, but of course, like most chemicals, high doses of antioxidants have clear toxic effects.  The author is sympathetic to the value of antioxidants, while recognizing that there are misconceptions, both positive and negative about their use. My review of several articles would lead me to believe that the only recommendation that currently makes sense is to eat a healthy diet; if you do, you will probably get all the antioxidants you need and you can avoid the cost and risk of supplements.

The important thing from the antioxidant example, however, is to understand how critical it is to be, well, skeptical about health recommendations.  There are many examples of this; changing blood sugar and hypertension guidelines are ones that come to mind.  The human body is a complex system.  Understanding the effect of one variable or factor is very difficult in such a system.  The body has a variety of responses to perturbations of any one parameter or factor.  Those responses may elicit further responses.  Feedbacks and other responses may be non-linear.  So any treatment that impacts human biochemistry is always likely to have unseen consequences.  Even the largest clinical trials may not be long enough or sophisticated enough to catch all those unexpected consequences.  The desire for economic gain and recognition of oneself are powerful human motivators that tend to lead even supposed scientists and experts to make recommendations and pronouncements that are unsupported by truly valid research findings.  Our health is a serious matter, we all need to be on guard against poor advice, and the scientists and experts we are relying on should be especially vigilant for errors in their own thought and analytic processes.  And the same is true for matters outside of health care–climate change come to mind for anyone?  Another complex and poorly understood system.