Nutrition During Adolescence
The transition from childhood to adulthood is called adolescence. This period (13-18 years) is characterized by rapid growth and development at all levels i.e., physical, physiological, psychological and social as described below.
RECOMMENDED NUTRIENT ALLOWANCES
The metabolic demands of growth and energy expenditure increases the calorie needs. The ICMR committee has suggested that energy should be provided on the basis of ideal weight for age. The energy requirements for boys is more than that of girls which is 2450 k.cal. and 2640 k.cal for boys 13-15 years and 16-18 years respectively and 2060 k.cal for girls of 13 to 18 years. The difference in energy requirements can be attributed to the rapid increase in weight for boys.
The protein requirements are computed in the same way as for adults. The protein needs represent 12-14 percent of the total energy requirements. This meets the need for growth, for pubertal changes in both sexes and for developing lean body mass in boys.
Bone growth requires calcium. Calcium requirements are based on calcium accretion during the period of growth. About 150 mg of calcium should be retained for increasing bone mass. Hence the allowance for boys is more than girls because of their increased skeletal growth.
The increase in body mass during adolescence correspond to 4.3 kg/year in boys and 4 kg/year in girls. The haemoglobin concentration increases by 2g /dl in boys and 1g/dl in girls. Therefore the iron required for growth alone is 0.7 mg / day in boys and 0.45 mg/day in girls. Moreover there is additional loss of iron in girls during menstruation which is significant from 13 years onwards which amounts to 0.45 to 0.5 mg/day. Hence considering the additional requirement for
1. growth spurt
2. expansion of blood volume
3. increase in haemoglobin concentration
4. additional iron to compensate menstrual losses in girls and
5. adding the basal loss of iron,
the requirements for iron have been arrived at 41 mg/day and 28 mg/day for boys and girls 13 - 15 years of age, and 50 mg /day and 30 mg / day for boys and girls 16-18 years of age respectively. The higher requirement of iron for boys than girls may be attributed to the low percentage of iron absorption in adolescent boys (3 percent) than adolescent girls (5 percent).
The requirement for B vitamins namely thiamine, riboflavin and niacin increases in direct proportion with increase in calorie intake. Folic acid and vitamin B12 requirements also increase when there is rapid tissue synthesis as they participate in synthesis of DNA and RNA.
Transamination to synthesize non-essential amino acids requires more vitamin B6. The structural and functional integrity of newly formed cells depends on the availability of vitamins A, C and E.
Balanced diet for adolescents (13 - 18 years)
S.No. Food Groups Quantity (g) : Boys Girls
1. Cereals and Millets : 420 300
2. Pulses : 60 60
3. Milk (ml) : 500 500
4. Roots and Tuber : 200 100
5. Green leafy vegetables : 100 100
6. Other vegetables : 100 100
7. Fruits : 100 100
8. Sugar : 35 30
9. Fats / oils (visible) : 25 25