The key findings of the Harvard Medical School study on butter and margarine are that margarine may increase the risk of heart disease in women by 70 percent. The results of the study suggest that margarine isn't always a healthy alternative to butter.
In 1993, Harvard Medical School compared women who ate 3 to 4 teaspoons of margarine with those who ate 2 to 3 teaspoons of margarine each day. The study focused on both tub and stick margarine. Approximately 90,000 women aged 34 to 59 participated over an eight-year period. Women who ate increased amounts of margarine were 70 percent more likely to suffer from heart disease. Additionally, the study found that those who want to reduce their risk of heart disease and some forms of cancer should cut down on their overall fat consumption.
Dr. William Connor, who was leading the study, stated that its results shouldn't be interpreted to mean that butter is healthier than margarine. Instead, people who want to stay healthy should eat vegetable oils in their natural states. This includes soybean, soy and canola oil, which are all used in cooking. According to the study, when manufacturers turn hydrogenated fats from their liquid to their solid forms, they become more saturated and increase cholesterol levels. As such, those who want to stay healthy should also avoid hydrogenated vegetable oils.