By this point, most of us have heard that high levels of low-density lipoproteins (LDLs, the “bad" cholesterol) in our blood contributes to a risk cardiovascular disease. We have also been told that a heart-healthy, low fat diet can reduce LDL-cholesterol levels.

Unfortunately, the truth is that most dietary changes recommended to help reduce blood cholesterol levels are only moderately effective (4% to 13%). And many people struggling to lower their cholesterol levels must resort to a combination of dietary changes and statins, a class of drugs that have repeatedly been shown to dramatically reduce LDL levels in the blood (28% to 35%) and to lower cardiovascular risk.

Recently, in an effort to improve the effectiveness of diet in the prevention of cardiovascular disease, the Adult Treatment Panel (ATP III) of the National Cholesterol Education Program has recommended the addition of plant sterols (fats found in leafy green vegetables and vegetable oils) and viscous fibers (such as oats, barley, and psyllium) to the more traditional cholesterol-lowering diet. The American Heart Association (AHA) has also recently drawn attention to the cholesterol lowering benefits of nuts (particularly almonds) and soy proteins. In fact, the U.S. Food and Drug Association (FDA) now allows all of these foods (except nuts) to make health claims regarding their cholesterol-lowering benefits (a health claim for nuts is currently under consideration). In an effort to determine the efficacy of these new dietary recommendations, a recent study, published in the July 23, 2003 issue of the Journal of the Americal Medical Association, compared a diet of known cholesterol-lowering, vegetarian foods (the “portfolio” diet) to a popular cholesterol-reducing drug called lovastatin . The study concluded that a vegetarian diet made up of specific cholesterol-lowering foods lowered serum LDL levels equally as well as the popular drug treatment.

About the Study

The study enrolled 46 healthy adults (25 men and 21 women) who all had high LDL cholesterol levels (more than 158 milligrams per deciliter [mg/dl])(3.9 mmol/L). The participants were randomly assigned to one of three study groups: the “portfolio” diet (which was high in plant sterols, viscous fibers, nuts, and soy proteins), a more traditional low-fat vegetarian diet (the control diet), or the control diet plus lovastatin (20 milligrams [mg]). Each of the participants followed the diet for one month.

The Findings

The researchers found that participants in all three study groups (control diet, control diet plus lovastatin, and the portfolio diet) significantly reduced their serum LDL levels. However, these reductions were significantly higher among those on the portfolio diet (28.6%) and the control diet plus lovastatin (30.9%) than among those on the control diet alone (8%).

Significant reductions were also seen in the levels of C-reactive protein, a substance believed to play an important role in the development of atherosclerosis . These reductions were 10% in the control diet group, 33% in the control diet plus lovastatin group, and 28.2% in the portfolio diet group.

How Does This Affect You?

The study concluded that following a low-fat, vegetarian diet high in plant sterols, viscous fibers, nuts, and soy proteins significantly improved the efficacy of diet alone as a method of reducing serum LDL cholesterol levels. Indeed, the researchers concluded that following the portfolio diet was as effective as taking lovastatin.

Another benefit of the portfolio diet seems to be its ability to lower C-reactive proteins in the blood. This effect has been associated with statins in the past, but never before reported in connection with a conventional cholesterol-lowering diet. However, more research is required in this area.

According to one of the researchers conducting the study, the reason for the success of this diet (sometimes referred to as the “ape diet”) may be evolutionary, that is, a diet high in fiber, nuts, vegetable proteins, and plant sterols may more closely resemble the diet followed by our more primitive (and presumably heart-healthier) ancestors than our modern diet rich in saturated fat and calories.

Although the portfolio diet is apparently effective at reducing LDL-cholesterol in the short term, the study was unable to address whether or not it can actually reduce cardiovascular risk over the long term. This is in contrast to statin medications, which have been shown to do just that. It is also unlikely that intensive dietary modifications, which are difficult to adhere to, will ever completely replace the convenience and popularity of simply taking a pill.

Nonetheless, the portfolio diet is clearly a promising option for those who would prefer to avoid drugs and take a more ancestral approach to their elevated cholesterol instead.