(Slate) - So much for toasting to your health. A meta-analysis published yesterday in Biology Letters casts doubt on the claim that resveratrol, which is found in the skin of red grapes and therefore red wine, may help you lead a better life. Researchers from New Zealand’s University of Otago performed a meta-analysis of 19 studies that looked at whether resveratrol extended life in six species: yeast, nematodes, mice, fruitflies, Mexican fruitflies, and turquoise killifish. They found that at first glance, resveratrol seemed on aggregate to delay death. But it turns out that the effect was pronounced only in yeast, turquoise killifish, and nematodes—basically, species that are less applicable to human beings.