If a foodstuff has a positive effect on our well-being then it follows, more of that foodstuff will endow us with even greater positive effects, yes? – Probably not. As with most things in life, more is not always better.

This from Medical Xpress:

For decades, health-conscious people around the globe have taken antioxidant supplements and eaten foods rich in antioxidants, figuring this was one of the paths to good health and a long life.

Yet clinical trials of antioxidant supplements have repeatedly dashed the hopes of consumers who take them hoping to reduce their cancer risk. Virtually all such trials have failed to show any protective effect against cancer. In fact, in several trials antioxidant supplementation has been linked with increased rates of certain cancers. In one trial, smokers taking extra beta carotene had higher, not lower, rates of lung cancer.

Full Medical Xpress Article: How antioxidants can accelerate cancers, and why they don't protect against them.