Effect of Fats on Cholesterol levelsFa

A study in New England Journal of Medicine looked at how harder, processed fats such as stick margarine, butter and lard affect cholesterol levels when compared with softer products like tub margarine and oil.
The softer products were found to be healthier because the harder ones have more of what are called trans fatty acids, which raise cholesterol and the risk of heart disease. Trans fatty acids are created during a production process called hydrogenation, which transforms vegetable oil into a more solid substance so that it will resist spoiling.

In the study, 18 women and 18 men over 50 were each fed one of six diets for five weeks. Each diet provided 30 percent of calories from fat. Participants were given either soybean oil, semiliquid margarine, soft margarine, shortening, stick margarine or butter. Participants eventually were fed all six diets, and the researchers measured the effects on their cholesterol levels after each five-week period.

Researchers checked the participants' levels of two opposing cholesterol forces in the bloodstream: LDL, or bad, cholesterol, which can clog arteries, and HDL, or good, cholesterol, which protects against heart disease.

People who consumed soybean oil reduced their levels of LDL cholesterol by an average of 12 percent compared with those who ate butter.
Those given semiliquid margarine lowered their levels 11 percent.
Among those who ate soft margarine, the level dropped 9 percent, and
for shortening, the level fell 7 percent.
Those who ate stick margarine reduced their LDL cholesterol only 5 percent.
Conversely, those who ate the softer fats had smaller reductions in HDL cholesterol.