There appears to be a continued public misconception (encouraged by the supplement industry) that free radicals are bad, and that antioxidants are good. Of course, like most phenomena affecting our health, it’s not that simple.
Free radicals are molecules or atoms containing an unpaired electron. Unpaired electrons are attention seekers. They really don’t like being alone, so are always searching out other electrons. This makes them highly reactive. Free radicals are like the unstable friend who shows up drunk to the party and starts breaking things. Antioxidants are molecules that are able to donate an electron to the free radical, thus stabilizing it. They’re like the patient friend who is able to convince the free radical not to drive home, takes him to the back room to calm him down, and brings him water and a bucket once he starts throwing up.
Needless to say, without the presence of antioxidants, free radicals can really ruin the party. The cellular damage that results is called oxidative stress, and is associated with ageing, heart failure, cancer, Alzheimer’s, and many other health problems.
Until recently, the thinking had been that the more antioxidants, the less oxidative stress, because all of those lonely electrons would quickly get paired up before they had the chance to start mucking things up in our cells. But that thinking has changed.
Drs. Cleva Villanueva and Robert Kross published a 2012 review titled “Antioxidant-Induced Stress” in the International Journal of Molecular Sciences. We spoke via Skype about the shifting understanding of antioxidants.
source: scientific american