7/19/2004 - Myriam Richelle and colleagues from the Nestle ResearchCentre, Switzerland, have discovered that adding plant sterols to foods toreduce the absorption of cholesterol, also reduces the absorption ofbeta-carotene and vitamin E (alpha-tocopherol). However, the sterols didnot significantly reduce the absorption of vitamin A (retinol) andvitamins D and K.

The study involved 26 men with normal cholesterol levels in a doubleblind, randomised, crossover. The men were divided into three groups andgiven a standard diet designed to provide a constant daily intake of 250 -260 mg cholesterol. In addition, the subjects consumed daily, for 1 wk,either a low-fat milk-based beverage alone (control) or the same beveragesupplemented with 2.2 g plant sterol equivalents provided as either freesterols or sterol esters. The groups were crossed over so that each groupwas on each treatment for one week.

On day four subjects received 45 mg of cholesterol radioactively labelledwith carbon-13 isotopes intravenously and an oral dose of 15 mg ofcholesterol labelled with hydrogen-2 isotopes. The two differentlylabelled cholesterols allowed the team to determine how much cholesterolwas metabolised in vivo and how much was absorbed from the gut. On theseventh day the subjects were given a meal consisting of 15 mg ofbeta-carotene and 30mg of vitamin E both labelled with hydrogen 2isotopes. Blood samples were collected to determine how much cholesteroland vitamins had been absorbed.

The team found that both types of plant sterols reduced cholesterolabsorption by 60% compared to the control. Both plant free sterols andplant sterol esters reduced the bioavailability of beta carotene byapproximately 50% and that of vitamin E by approximately 20%. However thereduction in bioavailability was less with the free sterols than with theplant sterol esters. The authors therefore suggest that when plant sterolsare introduced to the diet to block absorption of cholesterol, it shouldbe counterbalanced by an increase in the dietary intake of these vitamins.(From the American Journal of Clinical Nutrition , 2004, 80 (1): 171 -177).

RSSL's Lipids Laboratory has expertise in all aspects of fat analysis andfatty acid profiling, including the determination of plant sterol andstanol esters. The Vitamin Team offers a full analytical service forbeta-carotene and vitamins A, B, C, D and E. For more information contactCustomer Services Freefone on 0800 243482 or e-mail enquiries@rssl.com

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