Antioxidants: Good or bad?
A recent news story suggested that taking antioxidants might not be a good idea when you want to reap the most benefit from exercise. In this study, antioxidant vitamins C and E blocked the increase in insulin sensitivity normally seen after exercise.
But for years, people have been telling us that antioxidants are good. What's going on here? Should we take antioxidants or not?
The simple answer is that no one knows for sure.
The exercise study was just one study, and it was performed in nondiabetic young men. Other studies in animals have shown that antioxidants can be beneficial. However, I know of no major study showing major benefits of antioxidants in people with diabetes.
Why do we want antioxidants in the first place?
The theory behind the antioxidants is that when we burn food to convert it into energy we can use, that process is not 100% efficient, and one by-product is something called reactive oxygen species (ROS).
The ROS are very destructive, and in excess, they can kill cells.
Because of this, our bodies normally produce antioxidants that neutralize the ROS before they can cause much damage. But people with diabetes tend to have less endogenous antioxidants than other people. So it makes sense that supplementing with antioxidants would be a good thing.
The problem is that just as the ROS can kill our own cells, they can also kill "bad" cells like cancer cells and bacteria. You can think of the ROS as bullets. Used against foreign invaders like bacteria or defective cells like cancer cells, the bullets are good. When the bullets are turned on our own healthy cells, they're bad. Antioxidants can't differentiate.
Furthermore, we're now learning that ROS can function not just as destructive bullets but also as signaling molecules. In fact, ROS can increase the production of insulin when the beta cells are stimulated by glucose.
So taking too much antioxidant might abolish these beneficial effects of ROS along with the detrimental ones.
But how do we know how much is too much? As noted previously, we don't.
I think we need to use common sense. When we can, it's best to get our antioxidants from food. That's how nature intended, and food contains fiber and other compounds that may help the natural antioxidants do their job.
But if have diabetes, we probably have less antioxidants than normal, and if we're trying to eat less food, perhaps we're not getting enough antioxidants in our food to overcome the deficit. Hence I think it makes sense to take reasonable amounts of common antioxidants.
But I think taking gobs of antioxidant pills is probably not a good idea. We really don't know the long-term effects.
For more details about antioxidants and diabetes, see here.