Considerable research continues to focus on cholesterol-lowering foods. Indeed, food industry executives polled by Reuters Business Insight last year predicted that by 2009, cholesterol-lowering foods would be the most profitable health food, far ahead of recently trendy products such as low-carb foods.
Plant sterol (PS) or stanol-enriched foods were originally incorporated into fat-based foods like margarine because of increased solubility of the PS ester. Some low-fat and non-fat foods containing PS however are now commercially available, although some studies have suggested that the cholesterol-lowering activity is reduced in such formats.
"Ingesting PS in the form of a single-dose, low-fat yoghurt-type drink is a new concept in view of being a concentrated source of PS delivered in a small volume as compared to multiple intakes of larger servings of dairy-type foods or fruit juices," explained the researchers, led by Elke Trautwein from Unilever Food and Health Research Institute.
The new results, based on a randomised, double-blind, placebo-controlled, parallel intervention study of 181 subjects with mildly elevated cholesterol levels for four weeks, are said to be the first to systematically investigate the effect of PS-containing foods in a feeding or fasting setting.
High cholesterol levels, hypercholesterolaemia, have a long association with many diseases, particularly cardiovascular disease (CVD), the cause of almost 50 per cent of deaths in Europe, and reported to cost the EU economy an estimated €169bn ($202bn) per year.
The study, published in the European Journal of Clinical Nutrition (Vol. 60, pp. 325-333), divided the subjects into five groups to receive one of five drinks and timing instructions: drink A (0.1 per cent dairy fat, 2.2 per cent total fat) with a meal; drink A without a meal; drink B (1.5 per cent dairy fat, 3.3 per cent total fat) with a meal; drink B without a meal; placebo with a meal. Both drinks contained about three grams of PS per 100 grams.
After the four week PS intervention, the researchers found that total cholesterol levels for both drink A and B taken with a meal decreased by about 10 per cent compared to placebo, while taking both drinks between meals decreased total cholesterol levels by about 7.5 per cent.
The reduction of LDL-cholesterol levels was also more significant when the drinks were taken with a meal (14 per cent versus 10 per cent without a meal).
"[These results] suggest that a fed state is crucial for an optimal cholesterol-lowering efficacy," wrote the researchers.
Liquid foods pass more rapidly through the gastrointestinal tract than solid foods, yet by ingesting the PS-enriched yoghurt with a slow emptying solid food gives the active ingredients "more time to be mixed with the intestinal contents."
The results also suggest that the effect of plant sterols is less dependent on the fat content of the food matrix. When taken into account with other studies however the researchers suggest that the fat content of the food must be above two grams to achieve an effect.
"Similar cholesterol lowering effects can be achieved irrespective of a low or high amount of fat eaten with a meal, provided it is above a certain threshold level, probably in the range of a few grams," said the researchers.
Fatty meals stimulate the production of bile, which leads to an increase release of cholesterol from the body. Plant sterols displace cholesterol from both dietary and bodily sources from the micelles that are formed during digestion. This results in less cholesterol being absorbed.
"Incorporating PS into a low-fat yoghurt single-dose drink seems an attractive, convenient and easy concept to lower modestly elevated cholesterol concentrations by dietary means," concluded the researchers.
The Unilever team also pointed out that the reductions found were similar to those reported by Raisio scientists who tested a single-dose intake of stanols in the form of a yoghurt drink.
Heikki Ruska, COO of Raisio's Ingredients Division, told NutraIngredients.com that the company's single-dose yoghurt drinks had indeed produced good results.
"We are continuing to grow the Benecol family, and are always looking for product categories and applications for the stanols," said Ruska.
The company already markets stanol-containing capsules in the Finland, said Ruska, that are virtually fat-free.
In 2003, the European phytosterol market was worth €61m ($75m), according to new data from Frost & Sullivan, and it will continue to grow by 15 per cent each year to 2010.