Plant Sterols and Stanols

December 7, 2007



Consumers may not always know the difference between sterols and steroids, but that hasn't stopped them from turning to heart-healthy foods and beverages in record numbers. According to a new survey from the International Food Information Council (IFIC; Washington, DC), 53% of Americans list heart disease as their top health concern.

While nearly 80% of shoppers believe that choosing the right foods and beverages can improve cardiovascular health, shoppers are more familiar with some heart-healthy ingredients than others. For instance, 76% of the survey respondents noted that omega-3s may lower the risk of heart disease, but only 30% said the same for sterols. However, consumer awareness of sterols is still significant. The IFIC survey went on to point out that 37% of Americans already buy sterol-enriched products, and 50% say they are either likely or somewhat likely to use them in the future.

"More than ever, consumers are taking control of their health through diet," IFIC advisory committee member Roger Clemens, PhD, an adjunct professor at USC's (Los Angeles) department of pharmacology and pharmaceutical sciences, said on October 9. "Food plays an important role in our health and that of our families. It is encouraging to see that consumers are able to identify specific diet and health relationships."

WHAT ARE STEROLS?

Plant sterols are naturally occurring molecules found in fruits and vegetables, especially vegetable oils. In plants, sterols perform some of the same functions as cholesterol in animals, and the chemical structures of sterols and cholesterol are similar. Closely related compounds called stanols also share structural similarities to cholesterol. Researchers believe that this structural similarity enables sterols and stanols to block the absorption of harmful low-density lipoprotein (LDL) cholesterol. Sterol and stanol esters, which consist of sterols and stanols attached to fatty-acid molecules, also act the same way.

Although the evidence is still evolving, sterols are among the most well-studied dietary ingredients. The American Dietetic Association (ADA; Chicago) notes that more than 140 studies have examined the effects of sterols on cholesterol; in 2000, FDA authorized a cardiovascular health claim for sterol and stanol esters. In 2003, FDA expanded the claim to include free sterols. To qualify for the health claim, foods must be low in fat and contain at least 0.65 g of sterol esters, 1.7 g of stanol esters, or 0.4 g of free sterols per serving.

Research suggests that a daily sterol intake of 2 g can lower both LDL and the risk of heart disease by 10%. The average daily intake, however, is in the range of 0.2 to 0.4 g. One reason is that while sterols are found in a wide range of foods, they only exist in small amounts. Using the old Total cereal analogy, it takes 140 apples, 11 cups of peanuts, or 70 slices of whole-wheat bread to yield 2 g of sterols, according to Unilever's (Rotterdam, The Netherlands) Promise Institute for Heart Health Nutrition.

QUITE A SPREAD

Consumers have a growing array of options to choose from. Although the first sterol products available to Americans were supplements and spreads, sterol-enriched juices, yogurt drinks, breads, and even snack foods now line store shelves.

One of the latest signs that sterols have hit the mainstream was the June 28 announcement that one of the country's top grocery retailers, Kroger Co. (Cincinnati), launched a cholesterol-reducing fat-free milk. Each serving of the milk, dubbed Active Lifestyle, contains 0.4 g of CoroWise sterols supplied by Cargill (Minneapolis). When Kroger announced the launch earlier this summer, the company's vice president of corporate brands, Linda Severin, proclaimed that "the war against high cholesterol just got stronger and easier."

Cargill highlighted Active Lifestyle along with several other CoroWise-enriched products during a media briefing at this year's ADA Food and Nutrition Conference and Expo, held on September 30 in Philadelphia. In addition to introducing Active Lifestyle, Cargill also displayed Wyeth's (Madison, NJ) new Centrum Cardio and Vitalicious Inc.'s (New York City) VitaTop muffin tops.

During a panel discussion at the Cargill briefing, former ADA president Rebecca Reeves, PhD, RD, noted that with fortified products like milk, bread, and cheese, it's relatively easy to help consumers consume sterols. "It's almost like stealth nutrition," she said. "All of us are aware that plant sterols are clearly shown to lower cholesterol. The science behind these products is tremendous."

Medical journalist Robert Kowalski, who also spoke at the briefing, added that most sterol-enriched foods don't cost much more than conventional items. Unfortunately, consumers aren't as familiar with sterols as they could be. "What bothers me is that the public still hasn't gotten this story," Kowalski said.

According to Pam Stauffer, global marketing programs and communications manager at Cargill, the company will continue to develop new applications for CoroWise. "There are many additional opportunities for cholesterol-lowering functional foods, and we remain committed to helping our customers develop new products that address unmet consumer needs for heart health," Stauffer said on September 25. In fact, at this year's Food Ingredients Europe show in London, Cargill exhibited a new grade of CoroWise, CoroWise ES101-a free plant sterol that requires less processing than other similar ingredients.

Another sterol-enriched product, Corazonas Heart-Healthy Tortilla Chips, is the product of a fruitful collaboration between Corazonas Foods Inc. (Los Angeles) and Brandeis University (Waltham, MA). The chips, which come in six flavors, address two hot consumer trends: ethnic flavors and cardiovascular health. Using sterol technology licensed from Brandeis, Corazonas developed the chips and also plans to expand the line to include other snacks like cookies and crackers. The Brandeis license effectively enables manufacturers to create sterols in concentrations of 2–25%. The chips provide 0.4 g of sterols per serving.

"Brandeis University has been a dream partner," Corazonas CEO Ramona Cappello said on October 8. "We've been able to take an American favorite, tortilla chips, and produce them with healthy ingredients to create a crunchy, good-for-you, and absolutely delicious snack. In the United States, half the population suffers from borderline-to-high cholesterol. It's very rewarding for our Corazonas team to be providing a product that we know can make a real difference in people's heart health."

Irene Abrams, executive director of Brandeis University's Office of Technology Licensing, added the school is confident that that expanded product line will be as successful as the initial chip product launch. "Brandeis is thrilled that Corazonas is successfully turning our basic discovery into products that have a positive health benefit and are gaining broad acceptance by consumers," Abrams said.

One of the drawbacks of many sterol products on the market is that to qualify for FDA's health claim, a food or beverage must provide at least 0.8 g of sterols per day. Since most items only provide 0.4 g of sterols per serving, consumers need to eat multiple servings per day to obtain a product's full benefits. In July, Unilever (Englewood Cliffs, NJ) took aim at this problem by launching Promise Activ SuperShots. Each 3-oz shot provides 2 g of plant sterols. Unilever's Promise product line previously included only spreads.

"Promise Activ SuperShots represent a significant expansion of the Promise brand in the United States," Promise brand director Eric Berman said on July 11. "Our mission is to deliver delicious foods that can aid in the overall improvement of heart health. We're particularly excited with this latest innovation, as it represents a first not only for the Promise brand, but for the American marketplace as well."

ACTION OVERSEAS

American consumers aren't the only ones benefiting from new sterol technology, however. In October, Forbes Medi-Tech (Vancouver, BC, Canada) announced that the Dutch supermarket chain Albert Heijn (Zaandam, The Netherlands), a division of Ahold (Amsterdam), will sell a private-label organic skim-milk beverage containing Forbes' sterol/stanol ingredient Reducol.

Meanwhile, in Poland, consumers now have access to supplements containing CardiaBeat, a combination of sterols and omega-3 fatty acids developed by Enzymotec (Migdal Ha'Emeq, Israel). Distributed in Poland by Genexo Pharmaceuticals (Warsaw, Poland), CardiaBeat recently received European approval as a novel food and also received a NutrAward prize at SupplyExpo in March in Anaheim.

CLINICAL DATA

As mentioned earlier, researchers have studied sterols extensively. Two of the latest studies involving plant sterols and sterol esters appeared in the September 2007 issue of the American Journal of Clinical Nutrition and the April 2007 issue of Lipids in Health and Disease. While both studies involved relatively small numbers of people and were of a short duration, they seem to build on the previous body of evidence suggesting that sterols may help reduce the risk of cardiovascular disease.

In the American Journal of Clinical Nutrition study, French researchers divided 194 people with high cholesterol into two groups. One group drank two daily servings of low-fat fermented milk enriched with 0.8 g of plant sterols per serving, while the other group drank two daily servings of regular low-fat fermented milk. After three weeks, LDL concentrations dropped by 9.5% in the treatment group compared to the control group, and after six weeks, LDL levels dropped by 7.8%, while plasma triaclyglycerol and HDL levels remained unchanged.

In the Lipids in Health and Disease trial, 16 people with high cholesterol entered into a four-week placebo phase, followed by a two-week washout and a four-week treatment phase in which they received capsules containing 1.3 g of Vegapure plant sterol esters supplied by Cognis Corp. (La Grange, IL). The researchers instructed the participants to follow their normal diet and exercise patterns for the duration of the study.

By week three, LDL in the treatment group dropped by 7% while high-density lipoprotein (HDL) rose by 9%. By week four, LDL in the treatment group dropped back to 4% while HDL rose by 4%. Other markers, such as the ratios of total cholesterol to HDL, and LDL to HDL, also dropped significantly by weeks three and four.

According to study author David Cai, PhD, senior scientist at Cognis, one of the reasons the trial was important was while previous research measured the effects of sterol-enriched foods and tablets, this was the first to measure the effects of sterols in capsules. Manufacturers can use VegaPure in a number of applications, including foods, beverages, and capsules.

"This is the first study to demonstrate that plant sterol esters in capsules are equally as effective as in foods, and esters are a better sterol form for soft gel capsules than free sterols or stanols," Cai said after the study's release on April 26.

Cai added that the results were "a dramatic finding," considering the small amounts of sterol esters consumed during the study and the lack of dietary or physical intervention. "It's reasonable to surmise that the drop in LDL cholesterol would have been closer to 15% had the subjects combined a healthy lifestyle with daily consumption of 3 g of plant sterol esters, the amount used in other published research," Cai said.

CONSUMER EDUCATION

At this year's ADA Food and Nutrition Conference, a key theme was the fact that while consumers usually say they want to improve their diets, what they say and what they do are often two different things. The "diet disconnect" problem is one that perhaps can best be addressed through a combination of consumer education and the development of convenient, tasty products that appeal to shoppers.

In the recent IFIC survey, 70% of the respondents said they were making changes to their diets to improve their overall well-being. While taste (88%) and price (72%) were the two most important food criteria identified by consumers in the survey, healthfulness came in third, at 65%. The IFIC survey did not focus specifically on cardiovascular health or sterols. However, manufacturers can still take away some important insights from the survey results.

"The majority of Americans are interested in learning more about food and health relationships, and in consuming components, such as antioxidants, whole grains, fiber, probiotics, omega-3 fatty acids, soy, among others for their health benefits," Wendy Reinhart Kapsak, RD, director of health and nutrition for IFIC, said on October 9. "That's a good thing. The next step is motivating consumers to fit these foods into their diet so that they improve their health and sustain it for a lifetime."