One of the things I’ve learned after writing about health for three decades is that there are a lot of assumptions out there about what’s good for us that, upon closer look, have very little good scientific evidence behind them.

Or, at the very least, there's a very strong other-side-to-the-story behind the assumption.

Take antioxidant vitamin supplements. Or, perhaps, you shouldn’t take them. (Quick, short, slightly technical definition: Antioxidants are substances that inhibit oxidation in cells caused by highly reactive chemicals known as free radicals. Well-known antioxidants include vitamins A, C and E, and the mineral selenium.)

In an article published earlier this week in the British newspaper The Guardian, reporter Justine Davies explains why the phrase "rich in antioxidants" may be a food advertiser’s dream slogan, but a consumer’s waste of money — or worse.

Although studies had shown the link between eating fruit and veg and a lower risk of disease, randomised controlled trials — where one group given antioxidant vitamins were compared with a similar group given a placebo — were needed to prove antioxidants actually worked. These trials involved thousands of patients. Although a small number showed antioxidants can be beneficial in diseases such as macular degeneration, the findings on antioxidants and diseases such as cancer, heart disease and strokes have been shocking. A paper combining the results of all previous studies showed antioxidant vitamins were not beneficial, and some even made diseases worse.

Davies describes recent research that suggests a small amount of oxidative stress may actually prolong rather than cut short the aging process. If this science holds up, taking antioxidant supplements might be counterproductive.

Nothing is simple when it comes to biology and human health. And the ground under scientific thinking is constantly shifting. Anyway, for the other-side-to-the-story about antioxidant supplements, I recommend you look at the article.