Role of Nutrition in Overall Growth and Development of Children and Adolescents

The dietary intake of infants, children and adolescents should not only maintain the current body weight but should be adequate enough to support their normal growth and development.1  A healthy diet is the one which meets the energy requirements and supplies essential macro and micronutrients for supporting the functioning of all vital processes.1  Growth during infancy is rapid. During this period, the requirements for energy and nutrients are highest relative to body size when compared with other growth periods. Also, this period is critical for neurocognitive development.1

The table below shows the major physical and cognitive milestones in normal children2:

Age Physical Skills Cognitive skills
2 years Jumps with both feet, throws the ball overhead, Can dress itself under supervision and can use zippers, buckles, and buttons Has the understanding of how to avoid simple obstacles like stoves and stairs etc.
3 years Most children can stand on one foot for 5 seconds. They can also hop on one foot and can broad-jump as well Can count up to 3, can tell its age, first and last name, can answer simple questions
4–5 years Most children can hop and balance on one foot, can do forward heal-toe walking, and can catch the bounced ball Can count 5–10 objects, asks questions, has a vocabulary of more than 200 words, understands the concepts of opposite and consecutive
6–11 years The complex gross and fine motor and perceptual skills are improved through practice and refinement Thinking becomes logical and rational, concrete operational thinking develops
12–17 years Rapid growth and development of sexual organs as well as secondary sex characteristics Develop formal operational thinking during early adolescence which becomes well developed during the latter part of adolescence

 

Physical effects

Inadequate nutrition during infancy, childhood or adolescence can restrict growth, weaken immunity and increase the incidence of infections and diseases.1 Undernutrition can begin with conception itself due to maternal undernutrition. This may lead to the delivery of low birth-weight babies. In India, although <1% preschool children suffer from severe forms of protein energy malnutrition (PEM), sub-clinical undernourishment is prevalent in almost half of <5-year-old children with symptoms such as underweight, stunting and wasting.3 Poor or insufficient diet can also cause catabolism of body tissues and failure to provide energy substrate. Continuous undernutrition during the childhood years leads to short stature in adults.3

Effect on the nervous system

The central nervous system (CNS) is most susceptible to nutritional impact during the period starting from 3rd trimester of pregnancy until 2 years of age.4

Diet has a dual role in cognitive development4:

  • It provides substrates from which the brain is constructed
  • It provides energy for the adequate functioning of the brain

Both intrauterine and extra-uterine malnutrition have a great impact on brain function as well as brain structure composition. The adverse effects of malnutrition on the brain during early life include: decrease in brain cells, number of synapses, dendritic arborisation and myelin production, leading to smaller brain size and changes in neurotransmitter systems. The hippocampus, cerebellum and neocortex are the most affected brain parts.4

All these changes are associated with4:

  • Delay in cognitive and motor functions
  • Lower IQ scores
  • Impaired school performance
  • Learning disorders
  • Poor memory
  • Reduced social skills

A nutritionally adequate and balanced diet is crucial to prevent the above mentioned physical and psychological ill-effects and for the optimum growth, development and boosting of the immune function in children.3 The overall nutritional requirements for growing children are briefly discussed below.3

Macronutrients

Carbohydrates: A major energy source for all cells are carbohydrates which are the primary source of energy for erythrocytes and the CNS.1 They should provide 45% to 65% of total calories in a diet. Complex instead of simple carbohydrates should contribute to a greater extent in the diet. A higher intake of simple sugars in children can displace essential macro- and micronutrients, thereby increasing the risk of nutrient deficiencies.  Fruits are a good source of simple carbohydrate and are also rich sources of vitamins and fibre. Whole fruits instead of fruits juices should preferably be given to children.1,5

Protein: Protein energy malnutrition hampers brain, immune system and intestinal mucosal functions.1 Protein requirement is greater for infants and growing children than for adults.3 It is important that all the essential amino acids be provided through dietary intake.1 For children who are vegetarians or vegans, a variety of food sources including legumes and corn should be incorporated to meet the requirement of essential amino acids. Breast milk is considered the optimal source of proteins for infants.1For children and adolescents, milk is an important source of good quality proteins in addition to other animal and vegetables food sources.3 Overall, for children around 10% to 35% of total calories should come from proteins.

Fats: In addition to being energy dense, fats provide essential fatty acids and have important structural and functional roles.1 Fatty acids are needed for nervous system myelination in children younger than 2 years of age.5 Cholesterol moieties act as precursors for cell membranes, hormones, and bile acids. Fats also facilitate absorption of fat-soluble vitamins. These functions of fats are important for neurological and ocular development.1For children younger than 2 years, 25% to 40% of total calories should come from fat, and for older children 10% to 35% calories should come from fat.

Micronutrients

Calcium: During childhood and adolescence, adequate calcium intake is important for bone health during growing years as well as later years of life. Milk and dairy products are a good source of calcium.3,5  Although recommended dietary allowances for calcium are about 600 to 800 mg/d, higher calcium intakes during adolescence helps to achieve peak bone mass.3  For children who do not consume adequate milk products, calcium requirements can be met through other sources such as tofu, green leafy vegetables, ragi, sesame seeds and calcium-fortified food products.5

Iron: Iron deficiency is very common among children and is associated with anemia and neurocognitive deficits. Iron present in animal food sources is more bioavailable than that present in plant sources.1 Vitamin C rich foods promote the absorption of iron in the body.3

Vitamin A: Vitamin A is an important micronutrient as it is required for clear vision in dim light, and maintenance of the integrity of epithelial tissues. It also plays a role in maintaining resistance against common infections.3  Yellow, orange and dark green fruits and vegetables are rich sources of beta-carotene, which is the precursor of retinol.1,3

Vitamin D: Vitamin D is critcial for calcium and bone metabolism, and its adequeate intake is important for long-term bone health. In infants vitamin D deficiency can cause rickets and very severe deficiency can also lead to hypocalcemic seizures.5  Breastfeeding, darker skin, little sun exposure and fat malabsorption are the risk factors for Vitamin D deficiency. Breastfed infants and children who do not get at least 400 IU of vitamin D through diet should receive Vitamin D supplement.5

The Indian Council of Medical Research (ICMR) recommended dietary allowances of macronutrients and important micronutrients for infants, children and adolescents are listed below:

Recommended Dietary Allowances3

Group Particulars Net energy

(kcal/d)

Protein

(g/d)

Visible fat

(g/d)

Calcium (mg/d) Iron

(mg/d)

Vitamin A

(mg/d)

Retinol Β-carotene
Infants 0-6 months 92 kcal/kg/d 1.16 g/kg/d 500 46 µg/kg/d
6–12 months 80 kcal/kg/d 1.69 g/kg/d 19 350 2800
Children 1–3 years 1060 16.7 27 600 9 400

 

3200

 

4–6 years 1350 20.1 25 13
7–9 years 1690 29.5 30 16 600 4800
Boys 10–12 years 2190 39.9 35 800 21  

 

 

 

 

600

 

 

 

 

 

4800

Girls 10–12 years 2010 40.4 35 800 27
Boys 13–15 years 2750 54.3 45 800 32
Girls 13–15 years 2330 51.9 40 800 27
Boys 16–17 years 3020 61.5 50 800 28
Girls 16–17 years 2441 55.5 35 800 26

 

References

  1. Parks EP, Maqbool A, Shaikhkhalil A, Groleau V, Dougherty KA, Stallings VA. Nutritional requirements. In: Kliegman RM, Stanton BF, St Geme JW, Schor NF, editors. Nelson textbook of paediatrics. Chapter 44. Philadelphia, PA: Elsevier. p. 268-286.e1.
  2. Queensland Government. Physical and Cognitive Developmental Milestones. 2017. Brisbane Qld: The State of Queensland (Department of Communities, Child Safety and Disability Services) [cited December 5, 2017]. Available from https://www.communities.qld.gov.au/childsafety/child-safety-practice-manual/chapters/2-investigation-assessment/resources.
  3. National Institute of Nutrition. Dietary guidelines for Indians: a manual. 2011. Hyderabad, India: National Institute of Nutrition [cited October 30, 2017]. Available from http://ninindia.org/dietaryguidelinesforninwebsite.pdf.
  4. Escolano-Margarit MV, Campoy C. Nutrition and the developing brain. In: Swaiman KF, Ashwal S, Ferriero DM, Schor NF, Finkel RS, Gropman AL, et al., editors. Swaiman’s pediatric neurology. Chapter 47.  Philadelphia, PA: Elsevier. p. e952-59.
  5. Daymont C, Rezet B. Nutritional requirements and growth. In: Florin TA, Ludwig S., editors. Netter’s paediatrics. Chapter 13. Philadelphia, PA: Saunders. p. 82-87.

 

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