Dear Sasquatch: Do Antioxidants Prevent Disease?
My mom is trying to get us all to eat healthier, so she stopped buying junk food (sob!) and she bought a bunch of supplements. I can understand the vitamins, but aren’t antioxidants for aging? I’m only 17. She said they prevent all kinds of diseases. Is that true?
First, it’s worth noting that some vitamins, like E and C, actually are antioxidants, and that so far, in healthy people, even vitamin supplementation is not clearly of benefit and could even be harmful. When in doubt, the safest route is usually not to ingest something until you have more evidence to do so.
As I’ve mentioned here before, studies showing health benefits of vitamins usually find them in people with deficiencies. Also, the results of research in adults do not necessarily apply in the same way (or at all) in children and teenagers.
As for antioxidants specifically, there is no evidence that taking supplements will benefit you or your mom (and some studies show potential harm). The hype began with a common phenomenon—researchers hypothesize that something might be true and some preliminary research seems to support the hypothesis. The media report the hypothesis as fact but do not report the follow-up studies or criticisms of the flaws in the initial studies that call the hypothesis into question or even disprove it.
This is a particular problem in biological studies because our bodies are so complex that even in a well-designed study, it’s difficult to rule out the many possible variables that could contribute to the results. The situation is even worse when companies develop products based on the initial hypothesis, spreading the misinformation even further through advertising, which is in the public eye more consistently and long term than most news stories.
I recently read about a multi-level marketing company called MonaVie that is releasing an “antioxidant scanner” to the distributors of its products. Basically, you stick your finger in the scanner and get a score, and if it is low (which of course it will be), the company representative just happens to have a catalog full of antioxidant supplements to sell you.
Antioxidants, and supplements in general, are big business.
What makes the situation even trickier for the consumers is that the scientific explanations given for why antioxidants “work” do contain some factual information, and on the surface, it seems to make perfect sense. Our bodies do contain free radicals (a.k.a. reactive oxygen species, or ROS) that are associated with cell damage, and cell damage is linked to aging and some diseases. Antioxidants, which our bodies naturally produce, do indeed neutralize ROS.
But that’s not the whole story. ROS perform necessary functions in our bodies, in cell signaling and as neurotransmitters, for example. Our bodies produce antioxidants to keep the ROS in balance. And even though higher levels of free radicals are often associated with cell damage, such as in degenerative diseases, it’s actually still not clear that they are causing the damage rather than proliferating as a result of the damage or as a result of whatever else may be damaging the cell.
More research needs to be done on antioxidants, ROS, aging, and disease before we can be confident about making the huge leap from how these are associated (i.e., correlation) to any certainty about actual cause and effect. We do know that eating plenty of fruits and vegetables is healthy, but how much of that is due to the foods’ antioxidant content and not other factors is unknown.
The research that has been done, however, does not support the claims that healthy people need supplemental antioxidants beyond what we get from foods and what our bodies produce.
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Image credit: Tsahi Levent-Levi