Adolescents and Young Adults

CLARA A. STORVICK AND MARGARET L. FINCKE.

THE girl and boy in adolescence grow at a faster rate than at any other time except in infancy. A boy's nutritional requirements during the time he is becoming a man are higher than at any other time in his life. Those of a girl are exceeded only during pregnancy and lactation.

Preparation begins a little before adolescence. The child stores energy in the form of body fat the most concentrated form of fuel. The coming spurt of growth will take enormous amounts of energy too much to take in while the most active growth is going on.

The year after that, the boy suddenly shoots up and may gain as much as 4 inches in height and 15 pounds in weight in a year. The girl also grows fast, but her total gain in height may not be quite so large.

The girl generally experiences this spurt in growth before the boy and usually is taller than he is at about 12 to 14 years. Then the more mature boy begins to surpass the girl in height, and by 15 years the average boy is taller than the average girl. She starts her increased rate of growth sooner, but she does not attain so great a final height or continue to grow for so many years.

This pattern of growth is an individual matter. Some adolescents start increased growth early and stop soon. Others do not show the real increase in height until 2 or 3 years after others of the same chronological age. Chronological age and physiological age thus may not always coincide.

Growth is more complex than increase in height alone. While fat is lost, bones increase in density and muscles in size and strength, especially among boys.

Endocrine systems the glands that secrete internally are growing and developing also, perhaps at their own rates, which may be somewhat different from the rate of growth of bone and muscle.

The whole body takes on additional size and development except the nervous system (including the brain) and the lymphatic system.

Adolescence, then, is a period of stress--physical, physiological, psychological, emotional, and social. Rapid growth alone causes strain and stress. But the period of rapid. growth is relatively short-2 or 3 years while the other maturing developments go on for 8 years or more. Gain in weight continues as growth of muscle and greater hardness of bone occur.

INTEREST in adequate nutrition of adolescents and young adults is reflected in the number and kind of studies to determine their nutritional requirements.

Research workers in universities and colleges, hospitals, health agencies, the United States Public Health Service, and the Department of Agriculture have used various methods in their investigations. Surveys of large numbers of children have been designed to obtain information on nutritional status based on food habits and the intake of nutrients and calories. Some of the surveys have included biochemical tests to determine the concentration of nutrients in blood and urine.

More detailed studies have been made of smaller groups, who have been maintained for definite periods on diets of known nutrient content to determine the actual requirements of specific nutrients for various age groups.

The nutrient requirements thus determined include those for protein and the constituent amino acids, calcium, iron, vitamin A, vitamin C (ascorbic acid), vitamin B, (thiamine), vitamin B₂ (riboflavin), niacin, and calories.

Not all nutrient requirements have been established for all age groups, because generally it is not possible or feasible to determine the requirement for more than one nutrient at a time.

FUNDAMENTAL to the understanding of what constitutes an adequate diet is the recognition of the physiological role of various nutrients in the body.

Energy requirement is expressed in calories, and our need for them is affected by age, size, activity, rate of growth, and such physiological stress as recovery from certain severe illnesses.

Protein is a constituent of all body cells. The nutritional value of a protein is determined by the amino acids that compose it, for from them we must build all of the proteins required for the growth and maintenance of our various tissues.

Fat is our most concentrated source of calories and is essential to the transport and absorption of the fat-soluble vitamins. Many fats are rich sources of these vitamins and of the nutritionally essential fatty acids, linoleic and arachidonic.

Carbohydrate may furnish 50 percent or more of the calories. In general, it provides energy in a form quickly available to the body and is essential for the complete metabolism of fat.

Fruit and vegetables, which we generally classify by carbohydrate content, and breads and cereals, which are among our richest and cheapest sources of carbohydrate, also provide some minerals and vitamins.

In planning the adolescent's diet, attention should be given to the needs for calcium, iron, and iodine, since they are the ones most likely to be present in insufficient amounts. If the diet is planned to provide adequate amounts of them, the same foods will provide enough of the other minerals.

THE RECOMMENDED dietary allowances are guides to the maintenance of good nutrition. You can calculate your own intakes of the different nutrients by referring to the tables of composition of foods that begin on page 243.

We must remember in using the table of recommended allowances that all of these nutrients can be stored in the body, at least for a short time. It is therefore not necessary to ingest quite all these amounts every day. Sometimes it is possible to average several days' intakes to reach the recommended daily amounts. For instance, one day we may eat a serving of turnip greens, which provide 10 thousand I.U. (International Units) of vitamin A; the next day, a serving of peas with 900 I.U.; and the third day, green beans;which have 800 I.U. These, together with other vegetables and fruit, milk fat, and eggs easily can provide the 5 thousand I.U. recommended.

Likewise the adolescent girl who is predisposed to simple iron-deficiency anemia and needs to be especially concerned about her iron intake may find that if she eats liver occasionally, along with eggs and green vegetables, she will increase her average intake of iron to the amount recommended.

BOYS 13 TO 15 YEARS OLD need no more calories than they will as moderately active young men and no more vitamin A, thiamine, or niacin.

They do need more protein, calcium, iron, riboflavin, and ascorbic acid.

The boy who is between 16 and 19 years old needs somewhat more calories than his older or younger brother, but his needs for protein, thiamine, riboflavin, niacin, and ascorbic acid are considerably greater.

The teen-age girl likewise has increased nutritional needs over her moderately active older sister. As the girl starts her growth spurt earlier than the boy and stops sooner, she needs more calories when she is 13 to 15 and fewer in the later teens as she approaches the adult level. Her requirements for protein, calcium, iron, riboflavin, and ascorbic acid all through the teens continue to stay well above the adult level.

The diet has to be planned carefully then, for both boys and girls. Both have such great needs for protein, the B vitamins, and vitamin C that they cannot afford to let many of their calories come from foods that do not contribute those three.

A boy usually manages to make a better selection of food than a girl, Probably because his appetite is so great that if the food is available be will eat it. He may be inclined to neglect the foods containing vitamin C, however.

A girl's appetite is more capricious and varies from day to day. She is more likely to get enough vitamin C because of her liking for salads and fruit, but her protein and iron intakes may be low.

Foods containing calcium, vitamin A, and riboflavin often are neglected by both boys and girls.

SOME SORT OF FOOD PLAN seems necessary in order to avoid the haphazardness of blind choice.

The younger child who eats all his meals at home is influenced by the family's habits.

The adolescent, however, usually eats at least one meal a day away from home. He must now exercise his own choice, and his good choice or bad choice will have far-reaching effects on his good health, stamina, and mental stability.

The girl who exercises her choice wisely gains in attractiveness and the good looks that come from an inner glow that we can attribute to a healthy body and mind. Even at home, differences in choice are possible and often are made.

Adolescents need more than three meals a day, especially while the greatest growth is taking place.

Much of this food is eaten as snacks, away from home or at home after school, while preparing the next day's lessons, or before bedtime. The snacks can contribute to the overall nutritive needs, or they can provide empty calories with little else in the way of nutrients.

There is no one set of menus which will suit everybody. Certain general guides can be offered, however. If the adolescent chooses from the following food groups, his choices will probably add up to a good whole.

For the teen-age boy or girl, the following are suggested:

Milk group four or more cups a day;

meat group two or more servings a day;

vegetable-fruit group four or more servings a day including a dark-green or a deep-yellow vegetable at least every other day; a citrus fruit or other fruit or vegetable important for vitamin C one or more every day; other fruits and vegetables, including potatoes;

bread-cereals group four or more servings each day.

The milk group consists of whole milk, skim milk, buttermilk, cheese, ice cream, milk sherbet, and milkshakes. Milk contributes liberal amounts of riboflavin and good-quality protein and a large share of the calcium.

The meat group contains meats of all kinds, poultry, fish, eggs, dry beans, peas, and nuts. It is well to use pork in some form, including sausage or ham, two or three times a week because it is an outstanding source of thiamine. All meats are good sources of iron, niacin, and riboflavin, but the organ meats liver, heart, kidney supply much more of these nutrients than muscle meats and can well be used sometimes. Pea soup, baked beans, peanuts or peanut butter, chili and lima beans, garbanzos, black-eyed peas, and other legumes belong in this group, too, even though they do not supply quite so much protein or protein of as good quality as meat, poultry, fish, and eggs.