Adolescent Years

Adolescence Years
A child’s body begins a period of rapid change in size and shape approximately around the age of 10 years in girls and 12 years in boys. This is called the “adolescent growth spurt.” During the next four years, an average girl may grow 10 inches taller and gain 40 to 50 pounds. An average boy may grow 12 inches taller and gain 50 to 60 pounds. At the same time, their body shape begins to change, too.
The nutritional requirements of young people are influenced primarily by the spurt of growth that occurs at puberty. The peak of growth is generally between 11 and 15 years for girls and 13 and 16 years for boys. The nutrient needs of individual teenagers differ greatly, and food intake can vary enormously from day to day, so that those with deficient or excessive intakes on one day may well compensate on the next. In this period of life, several nutrients are at greater deficiency risk including iron and calcium.
Iron
Among adolescents, iron-deficiency anemia is one of the most common diet-related deficiency diseases. Adolescents are particularly susceptible to iron deficiency anaemia in view of their increased blood volume and muscle mass during growth and development. This raises the need of iron for building up hemoglobin, the red pigment in blood that carries oxygen, and for the related protein myoglobin, in muscle. The increase in lean body mass (LBM), composed mainly of muscle, is more important in adolescent boys than in girls. In preadolescent years, LBM is about the same for both sexes. Once adolescence starts, however, the boy undergoes a more rapid accumulation of LBM for each additional kilogram of body weight gained during growth, ending up with a final LBM maximum value double that of the girl. The iron needs of adolescents are relatively high; this is because iron is needed to replace the blood lost during menstruation in girls and to support the growth of muscle mass in boys. The RDA for iron for boys is 11 mg/day, while the RDA for girls is 15 mg/day. If energy intake is adequate and adolescents consume food sources of heme iron such as lean meat/fish/poultry each day, they should be able to meet the RDA for iron. All these factors should be taken into account when assessing iron needs in this group of age.
One of the most important diet considerations during adolescence is an increase in the intake of iron-rich foods such as lean meats and fish as well as beans, dark green vegetables, nuts and iron-fortified cereals and other grains. Iron from animal foods is much better absorbed than iron from non-animal sources. Adolescents following vegetarian diets are therefore at an increased risk of iron-deficiency. However, vitamin C (e.g. from citrus fruits) and animal proteins (meat & fish) assist in the absorption of heme iron.
Calcium
The skeleton accounts for at least 99% of the body stores of calcium and the gain in skeletal weight are most rapid during the adolescent growth spurt. About 45% of the adult skeletal mass is formed during adolescence, although its growth continues well beyond the adolescent period and into the third decade. All the calcium for the growth of the skeleton must be derived from the diet. The largest gains are made in early adolescence, between about 10-14 years in girls and 12-16 years in boys.
The AI for calcium from age 9 through adolescence is 1,300 mg/day. This amount of calcium can be difficult for many adolescents to consume because the quality of foods they select is often less than optimal to meet their nutrient needs. However, this level of calcium intake is easily achieved by eating at least 3 servings of dairy foods or calcium-fortified products daily. The achievement of peak bone mass during childhood and adolescence is crucial to reduce the risk of osteoporosis in later years. By eating several servings of dairy products, such as milk, yogurt and cheese, the recommended calcium intake can be achieved.
As well as a good dietary supply of calcium, other vitamins or minerals, like vitamin D and phosphorous, are needed for building up bones. Physical activity is also essential, particularly weight-bearing exercise, which provides the stimulus to build and retain bone in the body. Activities such as cycling, gymnastics, skating, ball games, dancing and supervised weight training for at least 30-60 minutes a day, three to five times a week can help build bone mass and density. Making the right dietary and lifestyle choices early in life will help young people develop health-promoting behaviors’ that they can follow throughout life.
Encouraging Healthy Foods
Dietary habits that affect food preferences, energy consumption and nutrient intakes, are generally developed in early childhood and particularly during adolescence. The home and school environments play a major role in determining a child 's attitude to, and consumption of individual foods.
Teenagers, as well as being exposed to periodic food fads and slimming trends, tend to skip meals and develop irregular eating habits. One of the most frequently missed meals is breakfast. Studies show that breakfast plays an important role in providing needed energy and nutrients after an overnight fast and can aid in concentration and performance at school.
Snacks generally form an integral part of meal patterns for both children and teenagers. Younger children cannot eat large quantities at one sitting and often get hungry long before the next regular mealtime. Mid-morning and mid-afternoon snacks can help to meet energy needs throughout the day. Fast-growing and active teenagers often have substantial energy and nutrition needs and the teaching of food and nutrition in the school curricula will enable children to have the knowledge to make informed choices about the foods in their regular meals and snacks.
Energy Needs
Normally, the energy requirements of adolescents tend to parallel their growth rate, and individuals meet their energy needs by means of their appetite with adequate precision. As a result, the majority of adolescents maintain energy balance, and a varied food intake provides sufficient nutrients to ensure optimal growth and development.
Stress and emotional upsets however can seriously affect the energy balance in adolescents, resulting in the consumption of too little or too much food. Mild or severe infections, nervousness, menstrual, dental or skin problems (acne) can result in alterations of appetite, and those adolescents on marginal diets are the most vulnerable. Emotional stress is often associated with food faddism and slimming trends, both of which can lead to eating disorders such as anorexia nervosa.
On the other hand, the prevalence of overweight and obesity in children and adolescents is now a major nutritional problem and the condition is likely to persist into adulthood. Developing adolescents are particularly concerned about their body image and excessive weight can have profound effects on their emotional well being as well as on their physical health. The cause of obesity is multifactorial and socio-economic, biochemical, genetic, and psychological factors all closely interact.
Lack of activity plays an important role in the development, progression and perpetuation of obesity in adolescence. Surveys of young people have found that the majority is largely inactive and health professionals and governments are now encouraging higher levels of physical activity among children and adolescents. Physical inactivity does not only have a prime role in the development of overweight and obesity, but also on the development of chronic diseases such as heart disease, certain cancers, diabetes, hypertension, bowel problems and osteoporosis in later life. In addition, physical activity is related to improvements in body flexibility, balance, agility and co-ordination and strengthening of bones. The current recommendation is for children to try to be physically active for at least 60 minutes daily.
The adolescent growth spurt requires many different nutrients. Calcium is especially important for bone growth and health because 45% of the bone an adult has is built up during adolescence. Although some teenagers become concerned that they are not changing as rapidly as their friends or other classmates in school, there is wide variation in the age at which the adolescent growth spurts starts. It is generally more dependent on the hereditary characteristics than on being a certain age.
It is important to emphasize that changes in body size and shape are part of normal adolescent development. Females gain proportionally more body fat during this time, while males gain proportionally more muscle and bone mass.One of the changes taking place during adolescence is the varying hormonal levels in the body. These hormones are responsible for the changes seen in the physical development of the body and secondary characteristics such as facial hair growth and deepening voices.
For most micronutrients, recommendations are the same as for adults. Exceptions are made for certain minerals needed for bone growth (calcium and phosphorus). Dieting is not appropriate at this stage of life, it is important for teens to stick to a healthy diet and get lots of physical activity. A healthy diet consists of fruits, vegetables, whole grains, nuts, lean proteins, low-fat dairy products, beans, lentils and healthy fats from olive oil, avocado, nuts and fish. It is also important for teens to stay hydrated and drink water throughout the day.

The following menu provides approximately 2,500 calories and is broken down into three meals and two snacks. Since you don 't have control over how many calories your teen eats, here are some ways you can encourage them to eat healthy. Encourage them to eat snacks between meals and to try not to go over 4 hours without eating. This will help keep their energy up and help them to stay focused in school. Encourage them to include a fruit or vegetable with every meal and snack. This will help to ensure they are eating adequate vitamins, minerals and fiber.
Breakfast
Breakfast should include 2 servings of fruit, 1 serving of protein and 3 servings of whole grains. An example meal is 1/2 cup of berries, 6 oz. orange juice, 1 whole grain bagel and 2 tbsp. peanut butter
Mid-morning Snack
A mid-morning snack should include1 dairy or dairy substitute serving, 2 whole grains and 1 fruit. An example snack is string cheese, 8 whole grain crackers and ½ cup of grapes.
Lunch
Lunch should include 2 servings of vegetables, 3 whole grains, 3 servings of protein and 2 servings of dairy or dairy substitute. An example meal is a turkey sandwich with 2 slices of whole grain bread, 3 oz. of turkey, 2 slices of cheese, 10 whole grain pretzel sticks, ½ cup baby carrots. Bring a separate bag of veggies like tomatoes and lettuce to add to the sandwich.
Mid-afternoon Snack
A mid-afternoon snack should include 1 whole grain, 1 protein and 1 fruit. An example snack is to make trail mix and mix together ½ cup whole grain cereal and 1/4 cup nuts and dried fruit.
Dinner
Dinner should include 3 servings of vegetables, 4 whole grains, 3 servings of protein, and 1 serving of low-fat dairy or dairy substitute. An example meal is 1.5 cups of whole grain pasta topped with ¼ cup tomato-based pasta sauce; 1 slice of garlic toast; 3 oz. of chicken breast; 1 cup salad topped with carrots, tomatoes, cucumbers and olives; 1 tbsp. salad dressing; and 1 cup of skim or 1-percent milk.

References

Pruitt, Sheila Tucker B.E., Stein, Jane J., Cummings, Benjamin, Blake, Joan Salge, Thompson, Janice, Mel .
Nutrition, Health, and Wellness An Applied Approach VitalSource eBook For DeVry University [1] (http://devry.vitalsource.com/books/9781256323273/id/ch20tab01

Purdue University. (2002). Nutrition through the lifecycle. Retrieved from http://www.four-h.purdue.edu/foods/Nutrition through the lifecycle.htm

References: Pruitt, Sheila Tucker B.E., Stein, Jane J., Cummings, Benjamin, Blake, Joan Salge, Thompson, Janice, Mel . Nutrition, Health, and Wellness An Applied Approach VitalSource eBook For DeVry University [1] (http://devry.vitalsource.com/books/9781256323273/id/ch20tab01 Purdue University. (2002). Nutrition through the lifecycle. Retrieved from http://www.four-h.purdue.edu/foods/Nutrition through the lifecycle.htm