Low saturated fat diets have been recommended as a means of reducing blood cholesterol levels for decades. However, for many years it has also been recognized that reducing the saturated fat content of the diet alone isn’t sufficient to markedly lower blood cholesterol levels. To this point, since 2002, Dr. David Jenkins of the University of Toronto and his colleagues have published a series of studies showing that the combination of cholesterol-lowering foods called the portfolio diet lowers cholesterol to a much greater extent than any single food. Not surprisingly, soyfoods have been an integral part of this combination since they are low in saturated fat and soy protein itself lowers blood cholesterol levels. Subjects following the test diet are instructed to consume 22 grams of soy protein from soymilk, tofu and soy meat analogues per 1000 calories or about 35 grams per participant. Other components of the portfolio diet included nuts, soluble fiber and phytosterols.
In the latest study from this group of researchers, 300 men and women with elevated cholesterol consumed either a low saturated fat control diet, or the portfolio diet. Those following the portfolio diet received either two or seven counseling sessions during the trial period.. These sessions were aimed at helping the participants consume the appropriate foods.
At the end of the study, LDL-cholesterol decreased by only 3 percent in the control group. In contrast, LDL-cholesterol decreased by 13 percent in subjects following the portfolio diet. The results not only confirm that a combination of cholesterol-lowering foods is superior to a low saturated fat diet alone, but also that only two counseling sessions are needed for maximum benefit. Since estimates are that a one percent reduction in cholesterol can lower heart disease risk by as much as two percent over time, adopting the portfolio diet can theoretically reduce risk of heart disease by 25 percent. The added benefit to the portfolio diet is that the foods that make up this way of eating, such as soy, are thought to be protective against other chronic diseases as well.
Jenkins DJ, Jones PJ, Lamarche B, Kendall CW, Faulkner D, Cermakova L, Gigleux I, Ramprasath V, de Souza R, et al. Effect of a dietary portfolio of cholesterol-lowering foods given at 2 levels of intensity of dietary advice on serum lipids in hyperlipidemia: a randomized controlled trial. JAMA. 2011; 306: 831-9.