Antioxidants just took a hit that could threaten their place upon the throne of nutritional impeccability. Up until recently, nary a bad thing could be said about antioxidants — we have been told that they protect cells, prevent disease, enhance the skin, and even lead to longer life. But now, a study out of the Weizmann Institute of Science in Israel has found something to blemish these superstars — at least if you’re a female hoping to get pregnant.

Antioxidants, it seems, may hinder female fertility. In case you’ve been holed up in a cave and have missed the news reports for the last decade, antioxidants are substances found in rich supply in fruits and vegetables. Among the antioxidants are vitamins A, C and E, as well as selenium and flavonoids, found in red wine and chocolate. Because antioxidants have proven so helpful in other applications, the Israeli research team explored how they might affect ovulation, hoping to discover some benefit. They fed antioxidants directly to the ovaries of female mice, and to their surprise, they discovered that the ovaries of the affected mice produced very few eggs, and those eggs that did get produced had little viability. There was a significant drop compared to ovulation rates before exposure to the antioxidants.

The finding is rather ironic in light of the fact that little over a month ago, researchers in New Zealand concluded that men taking antioxidant supplements upped their chances of impregnating their partners by fourfold. Also, earlier studies found that antioxidant supplementation could reverse some of the conditions that cause female infertility — conditions like endometriosis and polycystic ovary disease. Other studies linked a woman’s low antioxidant intake with repeated miscarriage.

Antioxidants work because they neutralize destructive molecules called “reactive oxygen species.” Under stress, the body tends to overproduce these molecules, which then damage DNA and cause illness and aging. For most purposes, limiting the spread of these molecules confers a huge boon to health, reducing inflammation and damage to cells, but the researchers discovered that the ovulation process actually needs the reactive oxygen species in order to succeed. In other words, this very molecule that promotes aging and disease — the reactive oxygen species–simultaneously triggers ovulation; thereby, promoting both the start of life and, it would seem, death. It’s a strange-but-true, counterintuitive phenomenon, like taking poisons to cure diseases in homeopathic applications.

The scientists discovered that ovulation relies on reactive oxygen species by treating ovarian follicles first with luteinizing hormone, which triggers ovulation, and then with hydrogen peroxide, a reactive oxygen species. Sure enough, the peroxide triggered the same effect as the hormone: ovulation.

Do these findings mean that if you want to get pregnant, you need to avoid vegetables and eat junk in order to create conditions ripe for conception? That’s doubtful. Remember that other studies did find that antioxidants benefit male fertility and minimize some of the female problems that typically block conception. In fact, it’s hard to know just what the results of the latest study mean. The fact that the ovary reacts negatively to a direct application of antioxidants doesn’t necessarily indicate that oral antioxidants will overall reduce conception rates or infant survival rates…unless you’re planning to inject your ovaries directly through your abdominal wall. It would seem that a woman low in antioxidants might suffer from other health impacts that would be detrimental to conception and the birthing process. The researchers plan to undertake further study.

Until all the facts are in, though, you might as well join forces with the glass half-full folks and not use megadoses of antioxidants. At worst, the new data brings confusing news for those women wanting to get pregnant while maintaining good health, but for those looking for cheap and safe contraception, that glass may be filled to the brim. As research director Professor Nava Dekel says, “On the one hand, these findings could prove useful to women who are having trouble getting pregnant. On the other, further studies might show that certain antioxidants might be effective means of birth control that could be safer than today’s hormone-based prevention.”

But until those studies are in, I wouldn’t count on it to prevent unwanted pregnancies.