The people eating the trans fats ended up with higher total and LDL ("bad") cholesterol than those eating the cis fats, though not as high as those eating the saturated fats.
Since polys lower cholesterol levels, margarine's impact may not be so bad.
"I'd like to see a five to six week study, because it takes a little longer than three weeks for cholesterol levels to stabilizeM," says Emken.
But don't switch back to butter--it's saturated fat and cholesterol are known arterycloggers.
If your cholesterol is below 200, most doctors--and the government--say you needn't worry about getting a heart attack.
"These people have galloping proression of their cholesterol deposits, which will eventually lead to heart disease, and the average physician is not picking it up."
Q: The National Cholesterol Education Programs says that your risk of heart disease isn't high if your cholesterol is less than 200.
Called the Cholesterol-Lowering AtherosclerosisStudy, the two-year test included 162men -- nonsmokers and ex-smokers aged 40 to 59 years -- who at the beginning of the study had blood cholesterol levels ranging from relatively low (185 milligrams per deciliter) to high (350 mg/dl) levels.
In the drug-treated group, there was a26 percent reduction in total cholesterol, a 43 percent reduction in low-density lipoprotein (LDL) cholesterol and a 37 percent increase in high-density lipoprotein (HDL) cholesterol.
When given in large doses, niacin, which is one of the B complex vitamins, lowers total blood cholesterol and LDL cholesterol, while raising HDL cholesterol.