Optimum diet and exercise in childhood and adolescence promote health. Poor nutrition during periods of intense exercise can impair skeletal growth and maturation.
Children’s metabolisms are less efficient and mechanically more inefficient than adults and therefore may use more energy during training. A negative energy balance can increase the risk for menstrual irregularities, poor bone health and eating disorders.
Due to growth, children and adolescents have higher protein requirements than adults, but the requirement should be easy to meet with adequate energy intake.
Children seem to have lower carbohydrate storage capacity than adults and possibly rely more on fat as fuel source during moderate intensity exercise. Consumption of a low concentration carbohydrate drink during prolonged exercise periods can possibly be of benefit due to limited carbohydrate stores. Carbohydrate loading in young athletes is currently discouraged. Whole grains, fruits, vegetables and milk/yoghurt are nutritious sources of carbohydrate. Adding refined carbohydrates (e.g. sports drinks) can be useful to achieve energy needs, but should be limited.
Children and adolescents have an increased reliance on fat as a fuel source. Restriction of fat intake can contribute to inadequate energy intake, impaired growth and development and insufficient intake of fat-soluble vitamins.
It is likely that by meeting energy demands, vitamin and mineral needs will also be met. Minerals of concern are calcium, iron and zinc.
Calcium must be provided in sufficient quantity from ingested foods to optimize skeletal growth. The easiest way to achieve adequate calcium intake is to consume 3 servings of dairy products per day (4 servings for adolescents). Most vegetables also contain some calcium and breakfast cereals are frequently fortified with calcium.
Iron is a key component of haemoglobin and iron deficiency can impair cognitive function, mood, motivation and attention span and may contribute to an impaired aerobic and anaerobic performance. To avoid deficiency, the young athlete should regularly include poultry, lean red meat, iron-enriched breakfast cereals and green vegetables in their diet.
Hydration
Compared to adults, children have less efficient thermoregulatory mechanisms, a faster influx of heat and a lower sweat rate. Children and adolescents exercising in the heat are therefore advised to maintain adequate hydration by drinking periodically “until they are not thirsty any more, and then another few gulps”. For the child younger than 10 years, the suggestion is half a glass (100 – 125 ml) beyond thirst and for an older child or adolescent a full glass (200 – 250 ml) beyond thirst.
- Children and adolescents may have a higher cost of motor activities, greater fat oxidation and a less efficient thermoregulation compared to adults.
- Young athletes have increased requirements for energy, protein and probably carbohydrate compared with their non-athletic peers.
- Young athletes should start exercise well hydrated and should aim to maintain hydration status during training or competition by drinking if necessary.
References
Bass S & Inge K. Nutrition for special populations: Children and young athletes in Bourke Clinical Sports Nutrition
Meyer F, O’Connor H & Shirreffs M. (2007) Nutrition for the young athlete. Journal of Sports Sciences 25 (S1), S73-S82.
Nemet D & Eliakim A. (2009) Pediatric sports nutrition: an update. Current Opinion in Clinical Nutrition and Metabolic Care 12,304-309.
Petrie HJ, Stover EA & Horswill CA. (2004) Nutritional concerns for the child and adolescent competitor. Nutrition 20,620-631.
Greer FR & Krebs NF. (2006) Optimizing bone health and calcium intakes of infants, children and adolescents. American Academy of Pediatrics (117),578-585.
Montfort-Steiger V & Williams CA. (2007) Carbohydrate intake considerations for young athletes. Journal of Sports Science and Medicine 6,343-352.
Burrows M. (2007) Exercise and bone mineral accrual in children and adolescents. Journal of Sports Science and Medicine 6,305-312.
Heaney RP & Weaver CM. (2005) Newer perspectives on calcium nutrition and bone quality. Journal of the American College of Nutrition 24,574S-581S.
Markou KB, Theodoropoulou A et al. (2010) Bone acquisition during adolescence in athletes. Annals of the New York Academy of Sciences 1205,12-16.
Georgopoulos NA, Roupas ND et al. (2000) The influence of intensive physical training on growth and pubertal development in athletes. Annals of the New York Academy of Sciences 1205,39-44.
Unnithan VB & Baxter-Jones ADG. (2000) The young athlete. In Nutrition in sport Volume VII of the encyclopaedia of sports medicine. (edited by Ronald J Maughan). 429-441. Blackwell Science Ltd. London.
Aucouturier J, Baker JS & Duche P. (2008) Fat and carbohydrate metabolism during submaximal exercise in children. Sports Medicine 38(3), 213-238.