Although we know them as “vegetable oils,” they’re actually pressed mainly from seeds: cottonseeds, rapeseeds, safflower seeds, sunflower seeds, sesame seeds, and corn, as well as from soybeans. We’ve seen how these oils started to become popular for culinary use when the AHA endorsed them for “heart health” in 1961. Having the backing of the country’s highest medical authority on heart disease gave them an enormous boost. “The rush to get aboard the polyunsaturated bandwagon has become a stampede,” gushed the trade publication Food Processing in that same year. New products containing “higher and higher amounts of polyunsaturated oils” included salad dressings, mayonnaise, and margarine. Even breads and rolls were promoted for containing these new oils. Mazola was just one of the manufacturers enthusiastically advertising the potential health benefits of its oils. “Polyunsaturates are the plus in Mazola,” said a magazine ad in 1967.