Scientists have shed new light on how the phytosterol esters found in products such as Flora pro.activ help lower blood cholesterol. A major clinical study has tracked the interaction of phytosterol esters with digestion and metabolism of cholesterol directly in the intestine and its subsequent levels in the blood after eating.

The cholesterol-lowering effect of plant sterols has been known since the 1950s and repeatedly demonstrated in clinical trials. However, a recent study sponsored by Unilever, and in partnership with the French INSERM institute that conclusive proof that plant sterols esters markedly reduce free cholesterol availability in the intestine has been obtained. Previously, the precise mechanism by which plant sterol esters lower cholesterol was not fully understood.

The clinical study was carried out in Marseille, France and involved 12 male subjects. Each subject drank 500mL of liquid meal which contained deuterium enriched cholesterol and in the test product phytosterol esters. Samples were then taken at fixed time points from a tube in their small intestine and blood from their arm. These samples were then analysed for their lipid composition. In-Vitro, experiments were also carried out to corroborate the clinical results.

The results showed that plant sterol esters reduced the presence of meal-derived hepta-deuterated cholesterol in the circulation, and reduced the accumulation of cholesterol in the intestinal phase of digestion. This resulted in reduced cholesterol incorporation into micelles and vesicles, hence less cholesterol was absorbed.

The results have recently been published in the Journal of Lipid Research, and Guus Duchateau (Science leader Bioavailability & ADME*, Nutrition & Health) from Vlaardingen was one of the authors. Speaking about the research he said "To the best of our knowledge this was one of the most invasive clinical trials ever carried out by Unilever R&D. It took a lot of preparation but what a success! Even now we are submitting a second, follow up paper from the same data set".

The World Health Organisation has estimated that 80% of coronary heart disease (CHD) and stroke cases could be prevented by implementing positive diet and lifestyle changes.1 Such changes include the uptake of a healthier diet, increasing physical activity and cessation of smoking.Elevated LDL cholesterol is widely accepted as one of the key modifiable risk factors associated with CHD.2

Wendy Duncan, Senior Nutrition & Health Nutrition Manager at Unilever says: "We have a long history of supporting scientific research into cholesterol and being at the forefront of its management through diet and lifestyle. This study was carried out as part of the ongoing support of science by Unilever. Our scientists will continue to closely monitor developments in cholesterol and plant sterol and stanol research, and will continue to progress our products and ranges accordingly."

1. World Health Organisation (WHO). WHO Technical Report Series 916, Geneva, 2003

2. Tolonen H et al. Int J Epidemiol 2005; 34(1): 181-192

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