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Cholesterol-lowering foods most effective when combined, U of T study

March 08, 2006

Soy protein, almonds, plant sterol enriched margarines, oats and barley among most effective foods

Cholesterol-lowering foods such as soy protein, almonds, plant sterol enriched margarines, oats and barley may reduce cholesterol levels more effectively when eaten in combination, says a new University of Toronto study by Professor David Jenkins. The study, which appears in the current issue of the American Journal of Clinical Nutrition, also found that among the subjects who adhered to the diet (one third of test group), this combination of foods reduces low-density lipoprotein cholesterol ("bad" cholesterol) in similar ways as a first generation statin.

"The benefit of statins to individuals at high risk for cardiovascular disease is not in question here," says Jenkins, a professor in the Department of Nutritional Sciences and a Canada research chair in nutrition and metabolism. "Previous studies have demonstrated that statins can reduce heart disease risk between 25 and 50 per cent. We don't, however, know the long-term effects of these drugs when used on a large section of the broader population who are at low risk in primary prevention. Taking a pill may give people the false impression that they have nothing further to do to protect their health and prevent them from making serious lifestyle changes. Emphasizing diet changes in general can boost the success rate of statins while providing additional health benefits and a possible alternative for those for whom drugs are not a viable option."

Jenkins and his colleagues prescribed a seven-day menu high in viscous fibres, soy protein, almonds and plant sterol margarine to 66 people - 31 men and 35 women with an average age of 59.3 and within 30 percent of their recommended cholesterol targets. For the first time, 55 participants followed the menu under real-world conditions for a year. They maintained diet records and met every two months with the research team to discuss their progress and have their cholesterol levels measured.

"The participants found it easiest to incorporate single items such as the almonds and margarine into their daily lives," says Jenkins, who is also staff physician of endocrinology at St. Michael's Hospital. "The fibres and vegetable protein were more challenging since they require more planning and preparation, and because these types of niche products are less available. It's just easier, for example, to buy a beef burger instead of one made from soy, although the range of options is improving. We considered it ideal if the participants were able to follow the diet three quarters of the time."

After 12 months, more than 30 per cent of the participants had successfully adhered to the diet and lowered their cholesterol levels by more than 20 per cent. This rate is comparable to the results achieved by 29 of the participants who took a statin for one month under metabolically controlled conditions before following the diet under real-world conditions.

"The study's findings suggest that the average person can do a lot to improve their health through diet," Jenkins says. "People interested in lowering their cholesterol should probably acquire a taste for tofu and oatmeal, keeping in mind that portable alternatives fit best with a modern lifestyle. Save the experimenting for the evening, when you have more time to prepare more complicated meals."

Jenkins is a leading researcher in the nutritional sciences who developed the glycemic index. His previous studies explored the connections between high-fibre diets, soy foods and heart disease prevention, and meal frequency, vegetarian diets and almonds in reducing cholesterol levels.

In future studies, he and his colleagues plan to directly compare the benefits of diet against statins over longer periods among individuals at risk for cardiovascular disease across Canada. They will also investigate the effects of incorporating more mono-unsaturated fats into the diet.

University of Toronto