Because of the rapid growth spurt during adolescence energy and nutrient requirements are greatly increased. The peak period of growth is between 11 and 15 years of age for girls and between 13 and 16 years for boys. Girls accumulate relatively more fat and boys more lean body mass. Overall boys increase their total body mass much more dramatically than girls and so RNI values deviate increasingly from about 11 years of age. The amount of energy required will depend on the degree of physical activity in which the individual is engaged and this varies considerably. Many adolescents have low dietary intakes of calcium and iron and other possible ‘at risk nutrients’ include zinc and folate.
Adolescent eating patterns
Adolescents are eating more away from the home environment and there is an increasing tendency towards snack foods, some of which are high in fat. Those who do not eat school lunch and eat out of the school environment have been seen to have diets of poor nutritional quality. Adolescence is a time in which a transition occurs from child to adult eating behaviour and experimentation with new eating habits is common. Some adolescents may opt for vegetarianism out of serious principle and should be given every assistance in establishing their new way of life on a sound nutritional footing.
Food faddism based on misconceptions about food may lead to poor food choice and suboptimal nutrition. Fortunately most fads are short term and have no lasting ill effects. Nutrition education is important because of its role in preventing adult disease and because it provides a sound basis for future parenthood. However, due to the nature of adolescence this is difficult as suggestions made by an adult are likely to be viewed with suspicion and ignored, at least at first.
‘Nutrients at risk’
The two main nutrients at risk during adolescence are iron and calcium and low intakes of these nutrients are common. Iron requirements increase in adolescence particularly in girls with the onset of menstruation. Foods high In Iron and vitamin C are not usually found in preferred snack foods and convenience meals and therefore the intake of these nutrients is likely to be low. Adolescents who consume milk and dairy products are unlikely to have a calcium deficiency, but those who do not may fail to meet their increased needs for this nutrient.
Other nutrients which may be low in the diets of adolescents include zinc (a nutrient found in many of the foods containing iron) and folate which is found in dark green vegetables and citrus fruits.
Adolescents should be encouraged to eat a well-balanced diet based on the Balance of good health and health promotion in schools should include nutrition education.