INFS Health Series: Nutrition for Adolescents Part 2: Understanding the nutritional demands

Author: Aditya Mahajan, Assessment Advisor (INFS)

Key points
• Adequate caloric intake is necessary to facilitate growth and development in the adolescents. The caloric demand depends basically on age, gender, body composition and activity levels.
• Protein intake plays a significant role in supporting the normal growth along with maintenance and addition of lean body mass in the adolescents.
• There are significant differences in the energy metabolism during the exercises between the adolescents and the adults. This can play a crucial role in determining the nutrient requirements of the young athletes.
• Consumption of dietary fiber is associated with a number of health benefits including prevention of chronic conditions like obesity, Type II diabetes, cancer etc.

Keywords: nutrition, adolescent, protein, calories, health

Introduction
The risk factors for various serious conditions start developing during the adolescent stage. With the increase in the prevalence of adolescent obesity, cardiovascular diseases, diabetes etc, it is becoming increasingly important to shift the focus on adolescent nutritional status and eating habits. Also, the numbers of young adolescents are involved in competitive sports. Good performance requires right nutrition, along with the training.

The aim of this article is to explore the relevant data on the nutritional demands of the adolescents to determine the energy and different macro-nutrient needs of the adolescents.

Energy intake
The energy requirement represents the total energy needed to maintain health, support the growth and an appropriate level of activity.

The energy demands in the normal healthy adolescents are determined by:

  1. Total Energy expenditure (TEE): This includes the following two components:
    ▪ Basal Metabolic rate: Basal metabolic rate is closely related to the height, weight as well as the amount of the lean body mass.
    ▪ Activity level: There are significant differences in the activity level of children and adolescent living in different societies. For example, in general, the activity level of an adolescent living in a rural area is relatively higher than the one living in an urban society. Also, the activity levels are found to vary with the age. Additionally, many adolescents participate also participate in competitive sports. These differences in the activity level result in the different energy requirements to maintain energy balance (i.e. to prevent obesity and malnourishment) and sustain adequate growth.
  2. Discretionary calories: This represents the additional calories required to meet the demands of the normal growth. It was found that the adolescent growth spurt ( the period during which most of the growth in height is achieved; refer to the previous article) is sensitive to the caloric intake. Adequate caloric intake is necessary to support the normal growth and insufficient energy intake may even result in serious consequences such as growth retardation, delayed puberty etc.

Considering the above factors, the suggested energy requirements are:
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Protein intake
Protein requirements are determined by the amount of protein required to maintain the existing lean body mass and to support the growth of additional lean body mass during the growth spurt. Inadequate protein intake can lead to a reduction in growth, reduced accrual of lean body mass, sexual maturation delay etc.

Several studies have recommended the protein intake of 0.8-1g/kg/day in adolescents, however, it was found that for active individuals, protein requirements were substantially higher. The Recommended daily allowance (RDA) of protein for active adolescents, involved in the regular intensive activity, was 1.4g/kg/day.

Fat and carbohydrate intake
There is no accounted data supporting a specific distribution of carbohydrates and fats. However, studies show that during the exercise (endurance as well as short-term, intense exercises), adolescents derive a greater proportion of energy from fats rather than glucose. This suggests that majority of the energy demands (>30%) in the diet should be derived from fats, however, that remains to be established.

Consumption of complex carbohydrate should also be encouraged as they have higher fiber content and generally rich in micro-nutrients. Increased fiber intake (from fruits and vegetables) was found to be associated with the lesser probability of onset of obesity, cardiovascular diseases, some cancers and type II diabetes in the adolescents.

Conclusion
The nutrition plays a central role in maintaining the optimal health, supporting the normal growth and the demands of the optimal sports performance. Optimal caloric intake and protein play a significant role. The consumption of complex carbohydrates was found to be associated with several health benefits in the adolescents. As suggested in the previous article also, the nutritional demands were found to be sensitive to several factors including age, gender, and activity level. Coaches, parents, and trainers must be sensitive to these changing demands of the young athletes.

Read Part 1 of INFS Health Series: Nutrition for Adolescents

References

1. Gidding, Samuel S., et al. “Dietary recommendations for children and adolescents: a guide for practitioners.” Pediatrics117.2 (2006): 544-559.
2. Torun, Benjamin. “Energy requirements of children and adolescents.” Public health nutrition 8.7a (2005): 968-993.
3. The story, Mary, and Jamie Stang. “Nutrition needs of adolescents.” Guidelines for adolescent nutrition services. Minneapolis, MN: Centre for Leadership, Education, and Training in Maternal and Child Nutrition Division of Epidemiology and Community Health, School of Public Health, University of Minnesota (2005): 21-34.
4. Beaufrère B, Briend A, GhisolW J, Goulet O, Putet G, Rieu D, Turck D, Vidailhet M, Vermorel M (2001) Infants, children, and adolescents. In: Martin (ed) Nutritional requirements for the French population. Tec & Doc, Paris, pp. 255–291.
5. Boisseau, Nathalie, et al. “Protein requirements in male adolescent soccer players.” European journal of applied physiology 100.1 (2007): 27-33.
6. Bolster, D. R., et al. “Exercise affects protein utilization in healthy children.” The Journal of Nutrition 131.10 (2001): 2659-2663.
7. Hebestreit, H., F. Meyer, Htay-Htay, G.J.F. Heigenhauser, and O. Bar- O(1996). Plasma metabolites, volume, and electrolytes following 30-s high-intensityexercise in boys and men. E ur. J. Appl. Physiol. 72: 563-569.
8. Williams, Christine L., Marguerite Bollella, and Ernst L. Wynder. “A new recommendation for dietary fiber in childhood.” Pediatrics 96.5 (1995): 985-988.

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