The study, published in the July 23 issue of the Journal of the American Medical Association, compared a diet of known cholesterol-lowering, vegetarian foods to a standard cholesterol-reducing drug called lovastatin. The special diet lowered levels of LDL cholesterol - the "bad" cholesterol known to cause clogging in coronary arteries - in subjects by almost 29 per cent, compared to a 30.9 per cent decrease in the lovastatin subjects. The special diet combined nuts (almonds), soy proteins, viscous fibre (high-fibre) foods such as oats and barely and a special margarine with plant sterols (found in leafy green vegetables and vegetable oils).
Lead author David Jenkins, a professor in U of T's Department of Nutritional Sciences and director of the Clinical Nutrition and Risk Factor Modification Centre at St. Michael's Hospital, believes the reason these foods work so well to reduce cholesterol is that humans may be evolutionarily adapted to what has been called the "ape diet," a diet very high in fibre, nuts, vegetable proteins and plant sterols.
He adds the study could have far-reaching implications for public health. "As we age, we tend to get raised cholesterol, which in turn increases our risk of heart disease. This study shows that people now have a dietary alternative to drugs to control their cholesterol, at least initially." Jenkins notes the diet can also be used to maintain normal cholesterol levels.
In this month-long study, a follow-up to one released December 2002, 46 men and women with raised cholesterol were randomly assigned to one of three vegetarian diet groups. The control group ate meals low in saturated fats (such as those found in animal products like beef and butter). The second group had the same low fat diet, plus a daily 20 mg treatment of lovastatin. The last group had a diet high in four foods known to have cholesterol-lowering properties. This special diet, designed to be easy to prepare and eat, included foods such as oat bran bread and cereal, soy drinks, fruit and soy deli slices. A typical dinner for people on the special diet was tofu bake with eggplant, onions and sweet peppers, pearled barley and vegetables.
"The Food and Drug Administration has approved these cholesterol-lowering foods as having legitimate health claims for heart disease risk reduction," says Jenkins, who also holds the Canada Research Chair in Vascular and Metabolic Biology. "They're also being recommended by the American Heart Association and the National Cholesterol Education Program as foods that should be incorporated into the diet. And we have now proven that these foods have an almost identical effect on lowering cholesterol as the original cholesterol-reducing drugs." Jenkins points out that large numbers of people with high cholesterol are being put on medication before they are able to give diet an adequate trial. He adds that while many people may still require drugs to lower their cholesterol, his team has demonstrated an effective alternative for those who are prepared to control their food choices.
The study received funding from the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chair program, the Almond Board of California, Loblaws Brands Ltd., Yves Fine Foods (now Hain-Celestial Group) and Unilever Canada. Other Department of Nutritional Sciences researchers participating in the study included research associate Cyril Kendall, graduate students Augustine Marchie and Azadeh Emam, technician George Koumbridis, and research dieticians (also of St. Michael's Hospital) Russell de Souza, Julia Wong, Dorothea Faulkner and Tina Parker. The research team also included Professors Robert Josse, Lawrence Leiter and Philip Connelly of the Faculty of Medicine and St. Michael's Hospital; statistical consultant Edward Vidgen; Elke Trautwein of Unilever R&D, Vlaardingen, The Netherlands; and Karen Lapsley of the Almond Board of California.
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