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Should You Put Stock in This Portfolio?

The Portfolio diet, so called because it puts a lot of cholesterol-lowering foods together in one meal plan (like stocks in a portfolio), has been making news. Three well-designed studies by Canadian researchers supported the benefits of the diet. One study, recently published in the Journal of the American Medical Association, compared this diet with a more conventional cholesterol-lowering, low-fat diet, as well as with a cholesterol-lowering drug. The Portfolio diet, in these studies, worked as well as the drug and much better than the low-fat diet, reducing total cholesterol by about one-third in only a few weeks. The studies were small and short, however, and the researchers called for more studies. So nothing is yet definite.

Still, this came as good news for people who know they need to lower their cholesterol levels, but for one reason or another resist taking cholesterol-lowering drugs.

The Portfolio diet is a good one, though limited in the food choices it offers. It is vegetarian: no meats or dairy products are allowed. Thus, it is very low in saturated fat. It is also designed to be high in fiber—especially soluble fiber, the kind that lowers cholesterol. The fiber comes from foods such as soy and other legumes, oats, eggplant, okra, barley, almonds, and cauliflower. Special cholesterol-lowering margarines containing plant sterols (Benecol, for example) are also included. And to really boost the fiber intake, you must consume three daily doses of psyllium, a seed grain sold as a fiber supplement and laxative (Metamucil is the best known brand, but there are many others, including inexpensive store brands). Soy foods, such as tofu and/or soy milk, are part of every meal. No sweets are allowed (except fruit jam) and no dairy products. It’s not a starvation diet—you get 2,000 calories a day, and while some people would lose weight on that, many would not.

Besides lowering cholesterol, the diet may well offer other health benefits, such as a reduced risk of diabetes.

Pluses and minuses

So should you try this diet? Your decision should be based on your own circumstances, as well as consultation with your physician. If your total cholesterol level is high, you should try to reduce it though a combination of diet and exercise—and if these don’t work you should consider medication. If you are a vegetarian, the Portfolio diet may seem easy; if you are accustomed to eating meat, poultry, fish, and dairy, it could be hard. And fish and low-fat or nonfat dairy products have their own cardiovascular benefits.

While low-fat diets help lower total cholesterol, they may also lower HDL ("good") cholesterol. The Portfolio diet apparently does not lower HDL, which is a plus. But it doesn’t raise it, either (no diet raises it significantly). So if you have low HDL—below 40 for a man, 50 for a woman—this diet won’t solve the problem. In contrast, some cholesterol-lowering drugs do raise HDL by 10% or so. Regular aerobic exercise also boosts HDL.

And keep in mind that while cholesterol-lowering drugs have been shown to reduce the risk of a heart attack and death, we don’t actually know if this diet will do so.

Words to the wise: Can you stick to a diet consisting chiefly of soy, okra, eggplant, beans, and the like, with a dose of psyllium at every meal? If your answer is yes, this may be the eating plan for you. But if your cholesterol level is high, make this decision after seeking professional advice—and make exercise a part of the program. Psyllium may interact with certain drugs; discuss this with your doctor or pharmacist if you take medication. For more details on the diet, click here.

UC Berkeley Wellness Letter, November 2003