Cooks shunning strong onions in favor of sweeter varieties may want to reconsider based on a new study. When Cornell scientists compared strong-flavored onions with more mild varieties, they found that those with the boldest taste harbor the highest antioxidant activity, and appear to be the most effective in inhibiting the growth of colon cancer and liver cancer cells.
Shallots, and onions like the Western Yellow, New York Bold and Northern Red, boasted the most powerful antioxidant profile, while more mild varieties like the popular Vidalia, lagged far behind in potency.
Until further study, the scientists won't venture to say how many servings of onions a person would have to eat for the maximum benefit, but they do suggest that people consider cooking with stronger onions for an extra surge of health.
J. Ag. Fd. Chem. 52:22, Nov. 2004