While American dietary problems usually come from overconsumption rather than underconsumption, there are a few nutritional deficiencies that continue to plague this country.

Often nutrient problems correspond to select groups within the population. Girls from the ages of 14 to 18 years seem to have the greatest need for diets higher in vitamin A, for instance. Iron deficiency may be more widespread. Results from the 1978 Nationwide Food Consumption Survey show iron defiencies among infants 1 to 2 years old, children 3 to 5 years old and women 12 to 50 years old.

That mineral combines with other chemicals to create hemoglobin, the red, and oxygen-carrying constituent, in blood. Yet dietary iron consistently eludes even those with otherwise balanced diets. Not only do few foods contain large amounts of iron, iron absorption is a tricky business. Even when the mineral is present in the diet, it may be tied up by some other substance, making it unavailable to the body. Some foods containing the mineral contain other substances that could inhibit iron absorption in the body. On the other hand, vitamin C, protein and copper may enhance iron absorption.

Because the liver stores iron, it also provides a good source of the mineral. This explains why many nutritionists encourage people -- especially pre-menopausal women -- to consume at least one serving of liver a week.

Ah, but will they do it? Liver suffers from a well-earned reputation of being a strong-tasting food with a rather peculiar texture. Even adults who have been primed for eating foods good for them often are no more eager to indulge in liver than are expressive and vociferous children uninhibited by good manners.

Liver haters might feel more inclined to indulge in a little liverwurst (with onions and rye bread, the flavor seems a little less overpowering) or pa te'. Finely chopped chicken liver can top a chef's salad. Chicken liver appeals to many who blanch at the thought of calves' liver -- especially if it's deep-fried (add seasonings to the breading for the especially squeamish).

Liver lovers also preach proper cooking. Do not overcook the meat, as this seems to concentrate the flavor and does nothing to enhance texture. Some cooks even propose serving liver rare.

Those who loathe liver (which contains 5 milligrams of iron for every 2 ounces) would do well to consume other organ meats, such as beef heart or brains or even red meat in general. Beans also provide a good source of iron, so chili with kidney beans might be an appealing alternative. Oysters and clams are full of iron, as are nuts (almonds, cashews and black walnuts), legumes (peanuts, lima beans and peas), dark green vegetables and dates, dried peaches and prunes.

One more time, it is assumed that every kitchen has salt, pepper, vegetable oil, and for this express lane, also olive oil.

EXPRESS LANE LIST: chicken livers, honey, soy sauce, white wine, garlic, rice, spinach, shallots.

CHINESE CHICKEN LIVERS (2 servings) 1 pound chicken livers 2 tablespoons honey 1 tablespoon soy sauce 1 tablespoon white wine 1/4 cup vegetable oil 1 or 2 cloves garlic, minced

Wash chicken livers and pat dry. Combine other ingredients, adding oil last. Marinate livers in the honey mixture in shallow pan, overnight if possible. Bake at 375 degrees for 15 to 20 minutes, turning once. Serve with hot rice, preferably white, cooked according to package directions.

SAUTEED SPINACH (2 servings) 3 tablespoons olive oil 1 shallot, minced 3 cloves garlic, minced 1/2 pound fresh spinach

In a large skillet, heat olive oil. Add shallot and garlic and saute' until golden. Add spinach and saute' for 3 or 4 minutes, stirring, until spinach wilts.