Mono and polyunsaturated fats were hailed for their ability to lower the levels of bad cholesterol in the blood, and reduce the risks for heart disease and stroke. Unsaturated oils are, however, more susceptible to degradation under ... a fishy flavor, says John Radcliffe, Ph.D., R.D., professor of nutrition and food sciences, Texas Womans University, Denton. The real problem with canola and soy oils is the high levels of linolenic acid, an unsaturated fatty acid. ...