Scientists prescribe the best diet to fight cholesterol

2011-08-24 16:57

High cholesterol levels, particularly the low density kind (LDL), have been plaguing the Western world for decades, and individuals with elevated LDL have been given many dietary guidelines over the years, mostly outlining an “avoidance” diet focused on lowered levels of saturated fat and animal products. Now a new study published in the Journal of the American Medical Association has changed the usual focus towards the dietary do’s.

Researchers found that eating cholesterol-lowering foods like nuts, soy protein, and certain fiber-rich items results in bigger drops in “bad” LDL cholesterol than simply avoiding high-fat meat, eggs, and dairy foods. “Doctors tend to focus on telling patients what to avoid instead of what to add,” said study co-author Cyril Kendall, a research scientist at the University of Toronto.

The study involved 345 individuals with high cholesterol in two comparison groups. They were assigned either to a group which received advice on cholesterol-lowering foods such as oats, barley, soy milk, tofu, nuts, and legumes, or to a group advised to reduce fat intake by eating low-fat dairy products, whole-grain cereals, and fruits and vegetables, guidelines which are also endorsed by the American Heart Association.

The first group had nearly a 14 percent drop in LDL cholesterol -- the average level dropped from 171 milligrams/deciliter to 145 mg/dL -- while the control group had only a 3 percent decline, a drop from 171 to 163. (A level above 160 mg/dL is considered high.) The study didn’t address whether health outcomes, like heart attack prevention, would be affected by this level of decline.

The diet which brought about the dramatic decrease in cholesterol is summarized below:

-- Soy products. Eat four servings a day; each serving is equivalent to 4 ounces of firm tofu, 1 cup of soy milk, 1/2 cup of soybeans, 3/4 cup of soy yogurt, or 1/3 cup roasted soy nuts.
-- Nuts. Eat about 1.5 ounces per day of any kind of nuts, including almonds, peanuts, and cashews.
-- Foods fortified with plant sterols. Eat four servings a day of products fortified with plant sterols, including an 8-ounce glass of orange juice, cup of yogurt, and tablespoon of margarine. The US Food and Drug Administration allows such fortified foods to be labeled “cholesterol-lowering”.
-- Fiber-rich foods. Eat four to five 4-ounce servings a day of foods rich in viscous fiber, a kind of sticky fiber found in beans, legumes, oats, barley, and cereals that contain psyllium. Wheat bran and produce rich in insoluble fiber -- for all their nutritional benefits -- don’t contain much viscous fiber.

Although cholesterol usually gets bad press, it is an essential structural component of many of our bodily functions, such as the maintenance of cell membranes; it is also required to establish proper membrane permeability and fluidity. In addition, cholesterol is an important component for the manufacture of bile acids, steroid hormones (our sex hormones as well as adrenaline and cortisol, necessary for proper metabolism), and Vitamin D. In very young children, it is crucial for the proper development of the brain and nervous system, which is why infants and toddlers are almost always advised to drink full-fat milk and yogurt.

In aging adults, high cholesterol is frequently associated with plaque buildup in the cardiovascular system, and thereby with heart disease. Given that well-known link, researchers are stumped by the inverse correlation between cholesterol levels and mortality in some studies. A 2009 study of patients with acute coronary syndromes found an association of hypercholesterolemia (high cholesterol) with better mortality outcomes. In the Framingham Heart Study, in subjects over 50 years of age scientists found an 11% increase overall and 14% increase in cardiovascular disease mortality per 1 mg/dL per year drop in total cholesterol levels. However, low cholesterol levels seem to be a consequence of an underlying illness, rather than a cause. For example, many cancer patients suffer from hypocholesterolemia (low cholesterol).

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