Plant sterols resemble cholesterol but have been shown to block cholesterol's absorption and lower blood cholesterol beyond diet. They are minimally absorbed by the intestines, write McGill University's Peter J.H. Jones and colleagues.
Jones added a plant sterol mixture to margarine for the study. The sterol mix came from Forbes Medi-Tech Inc. Jones is a consultant for that company, says the journal.
Plant sterols are already on the market in various products, including cholesterol-lowering margarines such as Take Control and Benecol.
Cholesterol is a waxy, fat-like substance found in the body. The body makes and uses it, and cholesterol is also found in many animal-based foods. Excess cholesterol settles in the walls of blood vessels, including those of the heart, which can reduce blood flow and lead to heart disease.
The CDC estimates that 105 million Americans have cholesterol levels that are above desirable levels, which puts them at risk for heart disease. Desirable or optimal levels for people with or without heart disease are as follows, says the CDC:
Jones' study was small, with 29 participants. All had high cholesterol, and 14 also had type 2 diabetes and were slightly overweight. Participants were 40-80 years old, averaging in their mid-50s. None exercised.
The lab-based breakfasts were important. They included toast with margarine containing a secret ingredient. The researchers added a plant sterol or a placebo powder (cornstarch) to the margarine. For 21 days, participants got one or the other spread on their morning toast.
Doable in the Real World?
The plan didn't totally mirror real life. For one thing, the participants didn't have to cook or select their meals. They also didn't have to worry about portion size, since the food was provided for them.
Plus, alcohol and coffee were banned. So were snacks, except for decaf, calorie-free sodas, and herbal teas made by McGill's kitchen staff.
Calories were adjusted, when needed, to keep everyone at their starting weight. Sterols in commercial products may or may not match the amounts used in the study.
Benefit Seen With and Without Diabetes
Follow up blood tests showed drops in "bad" LDL cholesterol with the sterol mix. The diabetes patients had a greater reduction, but significant improvements were also seen in nondiabetic participants.
The results showed that plant sterols are [effective] in lowering LDL cholesterol in both diabetic and nondiabetic persons, says the study. The plant sterols also lowered levels of non-HDL cholesterol, which can also contribute to heart disease.
Lowering Heart Risk
The risk of developing heart disease is two to seven times higher in people with type 2 diabetes compared with those without diabetes, say the researchers. "This study showed that plant sterol consumption decreases the risk of cardiovascular disease in this population," they write.
"One out every two men and one out of every three women will develop heart disease sometime in their life. Whether you have heart disease or want to prevent it, you can reduce your risk for having a heart attack by lowering your cholesterol level."