I have a background in model organism aging research*, so I have a bit of knowledge on the topic. Accumulated oxidative damage is one of they hypothesized causes of aging. The damage certainly occurs, and it certainly isn’t helpful. So, the thinking goes, if we give you antioxidants, they will prevent oxidative damage and perhaps slow the damage that leads to aging.
One problem is that “antioxidant” is a broad and (IMO) not very useful descriptor. There are antioxidants that are made by your body, and are essential for all sorts of biochemistry. There are antioxidants that happen to be essential nutrients. There are yet other antioxidants that are found in food, and may have beneficial properties that are unrelated to their antioxidant properties. And there are antioxidants that are harmful, though we usually don’t refer to them as such.
Your body also makes antioxidant enzymes. I’m aware of a number of studies that have genetically engineered various model organisms to increase the production of these enzymes. Off the top of my head, in these experiments huge amounts of antioxidant enzymes have little (if any) effect on life span or health. Some dietary antioxidants do increase life span or health of various critters, but there’s often conflicting evidence. IMO, when there is an effect, it is due to drug-like properties of that particular molecule, rather than antioxidant properties.
Now, there is very strong epidemiological evidence that diets high in antioxidants are correlated with health and longevity. My semi-WAG is that this is not simply due to antioxidant properties. There may be some antioxidants that happen to have (unrelated) benefits. I think, however, that much of the correlation is due to underlying causes. Really, diets high in antioxidants are high in fruits and vegetables, and low in big macs and pancake-wrapped-sausages and corn syrup. And there are probably all sorts of other confounding factors – life style, activity, income, etc.
Basically, I think oxidative damage is just one of many things that contribute to disease and aging, and simple antioxidants won’t do much to reduce oxidative damage.
- mostly related to worms and flies and the like, though I’m also somewhat familiar with work done with rodents. Though we really don’t know how much of this research is relevant to humans…