KANSAS CITY, Mo. (AP) _ A type of margarine that contains a wood pulp extract proved effective in lowering cholesterol levels, according to a Mayo Clinic study.

The spread, called Benecol, has been eaten in Finland since 1995. It is expected to be on U.S. grocers' shelves in January. The study was funded by the company that plans to introduce the product, McNeil Consumer Products.

The active ingredient in the margarine, plant stanol ester, can lower people's LDL, or ``bad cholesterol,'' by 14 percent, the study found. Stanol ester is flavorless and odorless.

Lowell C. Dale, one of the study's researchers, reported the preliminary findings Wednesday at a meeting of the American Dietetic Association.

The stanol ester works by inhibiting the transportation of cholesterol from the digestive tract to the liver, decreasing the amount of total cholesterol and LDL cholesterol in the blood, researchers said.

A recent study in the New England Journal of Medicine found that Finns who ate three pats of the margarine a day without otherwise changing their diet lowered their total cholesterol by 10 percent.

The Mayo study focused on about 300 healthy American men and women ages 19 and up with borderline or mildly elevated cholesterol levels.

Participants given margarine three times a day lowered their LDL cholesterol by about 14 percent after eight weeks. Six weeks after they stopped eating the margarine, their cholesterol shot back up to where it was when the study began.

The product has already been approved by as a dietary supplement and does not need approval from the Food and Drug Administration, a McNeil spokesman said. Company officials said that salad dressings containing stanol esters and other products will be introduced next year.

Another cholesterol-lowering food additive, plant sterol, which is derived from soybeans, will be introduced in February by Lipton. It will marketed under the name Take Control and will also be introduced as a margarine. Studies show it can lower cholesterol by about 10 percent.