Medical practitioners often recommend replacing saturated fat with vegetable oil when cooking to decrease cholesterol and prevent heart disease. However, a new study published in BMJ shows that the reduce saturated fats in vegetable oil can only lessen cholesterol but does not help in the prevention of heart disease.

The belief that replacing saturated fats such as butter, cream and lard with plant-based oil from corn, soybean, canola and olives can reduce the risk heart of heart disease came from the Minnesota Coronary Experiment (MCE) and was conducted from 1968 to 1973, according to Medical Daily.

To better understand the diet-heart hypothesis, researchers re-analyzed the data of more than 9,400 people who participated in the MCE. The MCE was conducted with 9,423 men and women, aged between 20 and 97, from one nursing home and state mental hospitals in Minnesota.

Nursing homes and mental hospitals were chosen for the MCE due to meal policies that lessen the chance of participants missing their meal.

Upon further scrutiny of the available data, researchers discovered that swapping saturated fats with vegetable oils helps lower cholesterol but does not result in the effective prevention of heart disease and survival.

In a report from Reuters, Dr. Christopher Ramsden, researcher at the National Institutes of Health and the University of North Carolina at Chapel Hill and author of the study, noted that participants who have greater reduction in their cholesterol during the course of MCE present higher risk of dying.

Dr. Lennert Veerman of the University of Queensland in Australia wrote an editorial accompanying the study. He told Reuters that more research is needed to identify which fats are best used to prevent heart disease.

In a separate report, researchers has also disprove the claim that low-fat dairy products are better than full-fat dairy products, explaining that full-fat dairy products are more effective in preventing the on-set of diabetes and obesity.