Meaty Matters

When it comes to knowing what is good for them, Americans seem to spend as much time grinding their teeth in frustration as actually chowing down. Almost as soon as they are comfortable with one dietary dictum, out comes a new nugget of nutritional wisdom at odds with the first. Last week consumers got just such a confusing jolt. For years they have been told that burgers and steaks are high in dreadful compounds, called saturated fats, that boost the body's supply of cholesterol and thus increase the risk of heart disease. Now researchers have demonstrated that one type of saturated fat that is plentiful in beef can actually lower cholesterol.

In a study published in the New England Journal of Medicine, Dr. Scott Grundy and Dr. Andrea Bonanome, both of the University of Texas at Dallas, placed eleven men on three different liquid diets, each for three weeks. The low-cholesterol liquids derived 40% of their calories from fat. One preparation used stearic acid; a second, another saturated fat called palmitic acid; and the third, oleic acid, a monounsaturated fat in olive oil. The results, which may apply only to men since no women were studied, showed that blood levels of cholesterol dropped 10% with the oleic-acid diet and a more impressive 14% on the stearic-acid formula.

Does this mean that Americans can safely gorge on mounds of meat? Emphatically not, says Dr. Grundy: "The simple message is that moderate portions of lean beef are O.K." A slab of beef may be high in stearic acid, but it is also full of palmitic acid, which raised blood cholesterol by a startling 21% in the study. Thus while the "good" fatty acid can mitigate the effect of the "bad," it cannot wholly overcome it. Americans are advised to stick to a prudent diet: no more than 30% of daily calories should come from fat, and only a third of that from saturated fat.

Still, the findings are likely to have some beneficial impact for consumers. Food manufacturers could create margarine and shortenings rich in stearic acid, which would improve taste by adding texture but without raising cholesterol. Even better, cattle breeders and ranchers may eventually hit on a way of raising animals that are high in the "good" saturated fat and low in the "bad."