Phytosterol Superstars

Eating for a healthy ticker continues to appeal to consumers. After all, heart disease is the underlying cause for 37.3% of all deaths, making it the No. 1 killer in the United States. People are on the lookout for alternative ways to achieve cardiovascular health beyond cutting down on saturated and trans fats, placing heart-healthy phytosterol ingredients in a advantageous position.

According to the 2007 Food & Health SurveyConsumer Attitudes Toward Functional Foods/Foods for Health from the International Food Information Council Foundation, Washington, D.C., 80% of consumers believe in the heart-health benefits foods and beverages offer. Functional foods that help lower low-density lipoprotein (LDL) cholesterol levels can decrease the risk of developing coronary heart disease. A survey conducted by National Consumers League in 2007 found that 82% of Americans at moderate risk for high cholesterol would prefer a nonprescription alternative to statins, says J. J. Mathieu, ADM Technical Services, Decatur, IL.

Phytosterols are becoming honored among the health community as superstars due to their LDL-lowering potential. The National Cholesterol Education Programs third report of the expert panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults calls for adults with elevated LDL cholesterol to consider plant stanols and/or sterols (2 grams per day) as a therapeutic option to lower LDL. FDA granted the following health claim for food labels about plant sterols: Diets low in saturated fat and cholesterol that include at least 1.3 grams of plant sterol esters or 3.4 grams of plant stanol esters, consumed in two meals with other foods, may reduce the risk of heart disease.

The power of phytosterols

Phytosterols are plant-derived compounds with a similar structure and function to cholesterol. They occur naturally in some vegetable oils, nuts, grain products, fruits and vegetables. The early human diet was probably once rich in phytosterols, in the neighborhood of 1 gram per day. But current dietary patterns only provide about 150 to 450 mg per day of phytosterols.

There are two classes of phytosterols: sterols with a double bond in the sterol ring, and stanols that lack a double bond in the sterol ring. The most-plentiful sources of plant sterols are sitosterol and campesterol. Stanols make up only 10% of the total dietary phytosterols.

Plant phytosterols work to lower LDL cholesterol levels by blocking its absorption. They compete with cholesterol in the formation of mixed micelles, mixtures of bile salts, lipids and sterols formed in the small intestine after a fatty meal is consumed. Research on phytosterols and cholesterol management has been growing since the 1950s, culminating in a strong body of evidence. A meta-analysis of randomized controlled intervention trials that investigated people with a family history of hypercholesterolemia found that consuming spreads fortified with 1.8 to 2.8 grams per day of sterols and/or stanols over a period of four weeks to three months significantly lowered total cholesterol by 7% to 11% (Journal of the American College of Nutrition, 2006;25(1):41-48).

Phytosterols are also studied for other health benefits. Some epidemiological data suggest that higher intakes of plant foods containing phytosterols are linked with lower cancer risk. A few clinical trials indicate phytosterol supplementation might improve benign prostatic hyperplasia-related urinary-tract symptoms. Preliminary data suggests phytosterols may attenuate inflammatory activity of immune cells. But more research needs to occur in these areas before specific recommendations can be made regarding phytosterols role.

Phytosterols in the food supply

A great deal of evidence specifically relates phytosterol-enriched foods with LDL cholesterollowering benefits. In a meta-analysis published in Mayo Clinic Proceedings (2003;78(8):965-978), researchers analyzed data from 23 clinical trials of plant sterolenriched foods, and 27 clinical trials of plant stanolenriched foods, determining that plant sterols, as well as stanols, decreased LDL-cholesterol levels by about 10% at doses of at least 2 grams per day. Higher doses did not show substantial improvements in cholesterol-lowering ability. Although the FDA health claim notes that plant sterols and stanols should be consumed in two meals, recent research suggests that similar benefits occur when 2.5 grams of plant stanols are consumed at lunch, instead of divided into three meals (American Journal of Cardiology, 2005;96(1A):15D-22D).

Sterol- and stanol-enriched foods seem to have similar cholesterol-lowering effects in short-term studies, but a 2004 study (Annals of Medicine, 36(2):126-134) found that, at one year, plant sterolenriched spread showed inconsistent effects compared with plant stanolenriched spread. The study favored plant stanolenriched spread for long-term lowering of serum cholesterol. More research is needed to better understand the differences between sterol- and stanol-enriched foods in long-term cholesterol reduction.

While phytosterol-enriched spreads seem to be the bread and butter of the phytosterol functional-food business, a more-diverse range of products is making its way to shelves. It is estimated that the U.S. market for retail sterol products was $80 million in 2006, says Mathieu.

Liza Pepple, product manager, ADM Natural Health & Nutrition, reports that the companys plant sterols are GRAS in 19 different categories, including pasta and noodles, salty snacks, milk-type products, processed soups, puddings, soymilk, ice cream, cream substitutes, adult confections, edible vegetable oil (home use), adult ready-to-eat breakfast cereals, baked goods and fruit and/or vegetable juices, as well as vegetarian meat analogues, cheese and cream.

Plant sterols could potentially save many thousands from premature death and significantly reduce health-care costs, Mathieu says.

Sharon Palmer is a registered dietitian with 16 years of experience in health-care and foodservice management. She writes on food and nutrition for newspapers, magazines, websites and books. Palmer makes her home in Southern California and can be reached at [email protected].