Polenta Has Potential as a Source of Protein

Several years ago, we started seeing polenta on trendy menus. Sometimes it was an appetizer, sometimes a main course, sometimes even a dessert. It’s a new treat that is quite old.

An American Indian product, polenta is basically ground cornmeal; in Italy, however, it is cornmeal that is cooked slowly, spread out, cooled and topped with sauces, cheese, vegetables, even powdered sugar.

By itself, corn--and thus polenta--is only moderately nutritious. A two-thirds-cup serving of fresh corn kernels provides just over 10% of the recommended daily allowance for vitamin C and about a quarter of the RDA for folacin.

Yellow corn contains about 6% of the RDA for vitamin A (in the form of beta carotene), but white corn has none.

Corn is fairly high in protein but low in the essential amino acids lysine and tryptophan. However, as with most other vegetables and grain products, by combining corn with legumes or animal products, you can obtain a fairly complete protein mix.

Although corn is high in the B vitamin niacin, it is in a form that the human body cannot use. When American Indians ground their corn to make tortillas or cornmeal, they added an alkaline substance, such as lime (the mineral, not the fruit), that released the niacin from the corn. Thus, they were able to rely on corn as a dietary staple. However, in populations that did not do this--in the Southern United States during the 19th and 20th centuries, for example--the rate of pellagra, or niacin deficiency, became epidemic.

If you have ever noticed a bitter taste when you make something from cornmeal, it is because the polyunsaturated oil in the corn becomes rancid quickly after the corn is ground. If you want your corn bread or polenta to be good and sweet, and you don’t grind your own, buy the freshest cornmeal you can find and keep it airtight in the refrigerator.

Polenta is available in many forms. The specially ground coarse meal is available prepackaged or in bulk. Quick-cooking varieties are available, but polenta is usually cooked slowly (about 30 minutes) with 4 cups of liquid to 1 cup of cornmeal.

Ready-to-slice polenta is also available commercially, and recipes abound in cookbooks. As with many simple foods, it is possible to dress up polenta to make it as high-fat as many meats, but there are also fat-free ways to prepare it.

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Dr. Sheldon Margen is a professor of public health at UC Berkeley; Dale A. Ogar is managing editor of the UC Berkeley Wellness Letter. Send questions to Dale Ogar, School of Public Health, UC Berkeley, Berkeley, CA 94720-7360, or e-mail to daogar@wellnessletter.com. Eating Smart appears occasionally in Health.