SCIENCE BEHIND SECOND GROWTH SPURT

What is growth spurt?

It is that time of life when rapid increase in height and weight is observed.

When does it occur?

It occurs mainly twice in a person’s life hence referred to as the 1^st and the 2^nd growth spurt.

1^st growth spurt: Occurs from birth to 12 months of life wherein the birth weight increases up to 3 times and 50%increase in length is observed.

2^nd Growth Spurt: Occurs during adolescence. Adolescence is the transitional phase of life from childhood to adulthood. A rapid increase in the velocity of height and weight, psychological and sexual maturity with cognitive development are observed among adolescents.

• Age of onset of growth spurt in Girls: around10 years
• Age of onset of growth spurt in Boys: around 12 years

Adolescence represents the last window of opportunity to gain optimal height and to prepare for a healthy adult life.

Changes occurring during adolescence:

The beginning of growth and development during adolescence is signified by the onset of puberty. Biological changes occur during puberty include:

• Sexual maturation,
• Completion of skeletal growth (marked increase in skeletal mass, changes in body composition). ^[i]
• 50% of adult weight and muscle mass gained
• 20% of adult height is attained
• Completion of over 80% of adolescent growth is completed in early adolescence (10–15 years)

Nutrition Requirement during Adolescence

Nutrient requirements increase during adolescence to support rapid growth. Inappropriate nutrition can create a lasting impact on the growth, development and physical fitness of an adolescent. Nutrients of significance during this period are:

• Proteins: To support increase in muscle mass and promotes the hormone Insulin like Growth Factor-1 (IGF-1) concentrations which aids in growth.
• Calcium: To support bone growth
• Vitamin D: To facilitate absorption of calcium in bones
• Iron: To support blood formation and improve physical performance of child.

Role of IGF-1: IGF 1 is essential for longitudinal bone growth (leading to increase in height), skeletal maturation and bone mass acquisition. Adequate levels of IGF-1 are required to for attainment of optimal peak bone mass (Locatelli V and Bianchi VE, 2014). There is a strong association between IGF-1 and body size during infancy and childhood (Rolland-Cachera, 1995).

Role of Proteins, IGF-1 during Adolescence:

It has been suggested that protein intakes below the physiological needs result in reduced growth (Hoppe 2004). Reports suggest that there is an association between protein intake, growth and IGF-I concentrations. The dietary depletion of proteins has been shown to have a marked negative effect on IGF-I concentrations in malnourished children (Smith et al, 1989). Further, the quality of protein may also have a regulatory effect on growth (Hoppe, 2004).

Taken together, adolescence is a period of rapid growth with increased nutritional requirements. Growth during this period is faster than at any other time in an individual’s life except in the first year. It offers a window of opportunity to prepare nutritionally for a healthy adult life and to cover the nutritional deficits encountered during childhood. Meeting up with the increased nutritional demand during this period helps in attainment of optimal growth.

References

1. Stang J, Story M. 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.

2. Vittorio Locatelli and Vittorio E. Bianchi, “Effect of GH/IGF-1 on Bone Metabolism and Osteoporsosis,”International Journal of Endocrinology, vol. 2014, Article ID 235060, 25 pages, 2014. doi:10.1155/2014/235060

3. Jacob JA, Nair MK. Protein and micronutrient supplementation in complementing pubertal growth. The Indian Journal of Pediatrics. 2012 Jan 1;79(1):84-91.

4. Rolland-Cachera MF, Deheeger M, Akrout M, Bellisle F. Influence of macronutrients on adiposity development: a follow up study of nutrition and growth from 10 mo to 8 y of age. Int J Obes 1995;19:573-8.

5. Smith IF, Taiwo O, Payne-Robinson HM. Plasma somatomedin-C in Nigerian malnourished children fed a vegetable protein rehabilitation diet. Eur J Clin Nutr 1989;43:705–13.

6. Hoppe C, Udam TR, Lauritzen L, Mølgaard C, Juul A, Michaelsen KF. Animal protein intake, serum insulin-like growth factor I, and growth in healthy2.5-y-old Danish children. Am J Clin Nutr. 2004 Aug;80(2):447-52.