How Effective Are Phytosterols In Lowering Cholesterol?

Phytosterols, a family of naturally occurring chemical compounds made by plants, have a chemical structure similar to cholesterol and work to lower blood cholesterol by competing for absorption. Benefits range from 5 to 15 percent lowering of low-density lipoprotein cholesterol, the "bad" cholesterol, in your blood. Effectiveness depends primarily on how much you use.

Significance

Cholesterol is essential to life, yet a health risk when too much accumulates in arteries. Your daily diet, if it mirrors a typical American diet, contains about 300mg of cholesterol. Roughly two-thirds of that is absorbed in your small intestine. In addition, your body makes about 600mg per day of cholesterol. Cholesterol circulates in the blood to get to where it is needed, but if there too much, it gets taken up into the cells that line the insides of your arteries, resulting in a thickening called "plaque" and an increased risk of heart attack.

Phytosterol Theory

Note that phytosterols and phytostanols, similar molecules, are all included in "phytosterols." To understand the critical part of phytosterol function, envision fat and cholesterol in your digestive system as being broken down into progressively small blobs. When small enough, these blobs, now called micelles, are taken up into the absorbing cells that line the inside of your intestine. Cholesterol inside the micelles is absorbed. If the cholesterol is displaced by phytosterols, so that it is outside the micelles, absorption is less effective. The end result is a one-third lowering of cholesterol absorption, notes the August 2003 issue of "Mayo Clinic Proceedings."

Evidence

In February 2009, Isabelle Demonty published a review of 84 human trials on phytosterols in "The Journal of Nutrition." Most of the trials resulted in LDL cholesterol decreases of 5 to 15 percent. The average for all trials was 8.8 percent. There was also a clear dose-response effect, with 5 percent achieved at 1,000mg per day and 10 percent at 2,000mg per day. Above 2,000mg per day there were only small additional gains.

FDA-Approved Health Claim

In 2003, the Food and Drug Administration approved a health claim for phytosterol products. Labels can show a statement that these products may reduce the risk of heart disease if the products contain at least 400mg per serving and are used twice a day with meals. As noted, newer evidence has shown more is better. Kevin Maki, Ph.D., chief science officer for Provident Clinical Research and author of peer-reviewed articles on phytosterols, said "In 2011 the FDA will be considering raising the minimum amount of phytosterols to qualify for the health claim from 800mg per day to 2,000mg per day. Supplements providing only the current minimum will either have to give up the label health claim or reformulate."

Putting this into Practice

For an LDL cholesterol blood test over 160mg/dL your doctor is likely to recommend a prescription cholesterol-lowering drug, but for a result between 100 and 160mg/dL may instead recommend a collection of lifestyle changes that include weight loss, diet changes, exercise and adding phytosterols to your diet. The staff at your supermarket should be able to help you find phytosterol-containing foods, such as margarine or salad dressing. Remember that adding phytosterols to your daily regimen is not a magic shield allowing you to consume saturated fat and cholesterol-containing foods with impunity.