Betty Crowley, age 9, of Hutchinson, Kan., for her question:
HOW DO OUR BODIES USE FOOD?
Food gives our bodies energy to do work. It provides materials to grow and repair body tissues and chemicals to regulate the organs and systems of the body.
All food is made up of nutrients, or chemical building blocks. There are two kinds of nutrients: organic and inorganic. Organic nutrients include carbohydrates, fats, proteins and vitamins while water and minerals are inorganic nutrients.
Food restores used up energy, rebuilds tissue cells that constantly need repair and develops bones, muscles and teeth. It keeps the body healthy, strong and vigorous.
Proper food also protects the body against disease. Without food, a person could live for only a few weeks.
Food nutrients must be digested, or broken down to a few simple chemicals, before they can be used in the body. When digested food reaches the cells of the body, it is oxidized, or slowly burned.
The oxidation process releases energy that our bodies use when we eat, dress, run, play, swim, walk, write and even breathe and think. Our glands, hearts, muscles and nerves use energy for their specialized work.
Oxidation also produces heat that keeps our body cells at a temperature of 98.6 degrees Fahrenheit. Without this heat, no cell can perform its work or even stay alive.
Carbohydrates serve as our chief fuel foods, but fats are a more concentrated source. Fat furnishes two and a quarter times as much energy as an equal weight of carbohydrates. We store extra carbohydrates and fats as fatty tissue that serves as a reserve energy source.
We get carbohydrates from such starch foods as bread, macaroni, potatoes and rice as well as from sweet foods such as cake, candy, chocolate and cookies. Food high in fats include bacon, butter, cream, ice cream, margarine and many salad dressings.
We need food to build new tissue. Food also is used to repair worn out tissues and the damage from wounds, infections and broken bones. The body uses food that contains nitrogen for building and repairing. Nitrogen is found only in the amino acids that make up protein nutrients.
Protein rich foods include eggs, fish, legumes, meats, milk, nuts and poultry.
Not all protein rich foods are equally effective for building and repairing tissue. Animal proteins contain more of the amino acids that the body uses for building than plant proteins do.
A balanced diet should include at least one third animal protein, many nutrition experts suggest.
Our bodies do not store extra proteins. If we eat more proteins than we need for building and repair, we burn them as fuel.
Regulation of body processes is carried on chiefly by the vitamins and minerals that we receive from such foods as berries, citrus fruits, eggs, fish, lean meat, liver, milk, salad greens, sea foods, green and yellow vegetables and whole grain breads and cereals.