One of the world’s most widely used vegetable oils may contribute to memory loss and learning challenges. And it also could make your residents gain more weight. At least, those are the suggestions in a new study by researchers at Temple University.

“Canola oil is appealing because it is less expensive than other vegetable oils, and it is advertised as being healthy,” explained Domenico Praticò, M.D., a senior investigator on the study. “Very few studies, however, have examined that claim, especially in terms of the brain.”

Using mice as subjects, Praticò and colleagues found participants on a canola oil-enriched diet weighed significantly more than those on a regular diet. Maze tests to assess working memory, short-term memory, and learning ability uncovered additional differences. Most notably, mice that had consumed canola oil over a period of six months suffered impairments in working memory.

Critics note that many vegetable oils — including canola oil — may pose health risks because they contain high levels of polyunsaturated fats. Such fats can cause inflammation and cell mutation, which can lead to heart conditions and other ailments, they claim.