What are the most important nutritional considerations for adolescents? 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.

5.1. Iron Among adolescents, iron-deficiency anaemia 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 haemoglobin, 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.

Other factors contributing to elevated iron needs are increased body weight and the beginning of menstruation for girls. 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 (known as haem iron) is much better absorbed than iron from non-animal sources (non-haem iron).

Adolescents following vegetarian diets are therefore at an increased risk of iron-deficiency. However, vitamin C and animal proteins assists in the absorption of non-haem iron.

A glass of citrus juice taken with an iron-fortified breakfast cereal or a squeeze of lemon or bits of chicken on a salad can help with the amount of iron absorbed from these foods.

5.2. Calcium The skeleton accounts for at least 99% of the body stores of calcium and the gain in skeletal weight is 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.

During peak adolescent growth, calcium retention is, on average, about 200mg/day in girls and 300 mg/day in boys.

The efficiency of calcium absorption is only around 30% so it is important that the diet supplies an adequate calcium intake to help build the densest bones possible

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, yoghurt 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 behaviours that they can follow throughout life. To know more about physical activity.

Bibliography * Calvo, E. B.; Galindo, A. C.; Aspres, N. B. (1992). Iron status in exclusively breast-fed infants. Pediatrics, 90(3):375-379.

* Department of Health and Social Security (1988). Present day practice in infant feeding: 3rd Report. Report on Health and Social Subjects 32. HMSO, London.

* EEC Commission Directive on infant's formulae and follow-on formulae (1991). Official J. European Communities No. L175/35-/49.

* Freedman, D. S.; Dietz, W. H.; Srinivasan, S. R.; Berenson, G. S. (1999). The relation of overweight to cardiovascular risk factors among children and adolescents to cardiovascular risk factors among children and adolescents: the Bogalusa Heart Study. Pediatrics, 103:1175-1182.

* Gregory, J.; Lowe, S.; Bates, C. J., Prentice, A., Jackson, L.V., Smithers, G., Wenlock, R., Farron, M., (2000). National Diet and Nutrition Survey: young people aged 4-18 years, vol. 1. Report of the Diet and Nutrition Survey, TSO, London.

* International Life Sciences Institute (2000). Overweight and Obesity in European Children and Adolescents. Causes and consequences-prevention and treatment. pp. 1-22. ILSI Europe, Brussels, Belgium.

* James, J. (1991). Iron deficiency in toddlers. Maternal and Child Health, 16:309-315.

* Stordy, B. J.; Redfern, A. M.; Morgan, J. B. (1995). Healthy eating for infants-mothers' actions. Acta Paed, 84:733-741.

* Walter, T., Dallman, P.R., Pizarro, F., Velozo, L., Pena, G., Bartholmey, S.J., Hertrampf, E., Olivares, M., Letelier, A., Arredondo, M., (1993). Effectiveness of iron-fortified infant cereal in the prevention of iron deficiency anaemia. Pediatrics, 91(5):976-982.

* Wardley, B. L.; Puntis, J. W. L.; Taitz, L. S. (1997). Handbook of Child Nutrition. 2nd Edition. Oxford University Press, Oxford.

* Weaver, C. M. (2000). The growing years and prevention of osteoporosis in later life. Proceedings of the Nutrition Society, 59:303-306.

* World Health Organisation (1990). Prevention in childhood and youth of adult cardiovascular disease: time for action. WHO, Geneva.

References: European Food Information Council (EUFIC) Date last updated: 17 November 2006

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