Shira Santos, age 9, of Santa Cruz, Calif., for her question:

IS MILK THE PERFECT FOOD?

Many food experts tell us that milk is the most nourishing of all foods. In fact, many say that it is the most nearly perfect food that is available today. But it is not totally "perfect."

The body needs five kinds of nutrients for energy, growth and the replacement of worn out tissues: carbohydrates, fats, minerals, proteins and vitamins. Milk is an outstanding source of all these nutrients.

Technically, however, milk cannot be called the "perfect food" because it does not have enough iron and it does not provide all necessary vitamins.

Cows provide most of the milk used in the United States and Canada and in many of the world's countries. But also popular, especially in Europe, Africa, Latin America and Asia, is goat milk.

Camels provide milk in the deserts of Arabia while some South Americans drink llama milk. Reindeer milk, sheep milk and water buffalo milk are also popular in some areas.

Cow's milk is made up of 87 percent water and 13 percent solids. The solids provide nourishing substances that are needed for growth and good health. Best of all, the nutrients are provided in large amounts and in such proportions that they can work as a team to help keep the body healthy.

Doctors disagree on exactly how much milk a person should drink. Many say that teen agers and younger children should have at least three eight ounce glasses each day and adults should have one glass.

However, many people cannot drink milk because they are allergic to it.

Also, many doctors recommend that patients who have large amounts of cholesterol in their bloodstreams should avoid drinking whole milk because of its cholesterol content. Milk fat appears as tiny globules and each drop of milk contains about 100 million of such globules.

Fats in milk, however, provide energy. They also supply certain fatty acids that the body must have.

Some medical experts report that children who drink milk grow faster than other children who eat the same kinds of food but do not drink milk.

In the U.S., the federal government requires that milk sold as food must meet certain standards. It must contain at least 3.25 percent milk fat and 8.25 percent nonfat milk solids. Most cow's milk has about 3.5 percent fat, 5 percent lactose, 3.5 percent protein and 0.7 percent minerals.

Many of the nutrition experts say that milk serves as a protective food since it gives the nutrients that might be missing from an average diet.

Other experts say that while milk may be fine for children, it is not recommended for adults since they will obtain all their required nutrients from other foods in the normal diet.