Normal and Therapeutic Nutrition

Normal and Therapeutic Nutrition 3(2+1)

Lesson 16:Nutritional requirements for Adolescence

Nutritional Requirements

Table: Recommended Dietary Allowances of adolescents

NUTRIENT	7-9 YEARS	10-12 YEARS
		BOYS	GIRLS
Weight (kg)	25.9	35.4	31.5
Energy (k.cal)	1850	2199	1970
Protein (g)	41	54	57
Fat (g)	25	22	22
Calcium (mg)	400	600	600
Iron (mg)	26	34	19
Vitamin A (µg)	600	600	600
? Carotene (µg)	2400	2400	2400
Thiamin (mg)	1.0	1.1	1.0
Riboflavin (mg)	1.2	1.3	1.2
Nicotinic acid (mg)	13	15	13
Pyridoxine (mg)	1.6	1.6	1.6
Ascorbic acid (mg)	40	40	40
Folic acid (µg)	60	70	70
Vitamin B12 (µg)	0.2-1	0.2-1	0.2-1

Energy:

• Energy needs increase with metabolic demands of growth and energy expenditure.
• Girls consume fewer kilo calories than boys.
• Increase in appetite leads to satisfying their hunger with snack foods that are high in sugar and fat and low in protein
• Difference in calorie intake of boys and girls starts from 10 years and boys take higher calories than girls.

Proteins:

• Protein needs represent 12 – 14% of energy intake
• Protein intake exceeds 1g/kg body weight for pubertal changes in both the sexes and for developing muscle mass in boys.
• The protein requirements for both boys and girls are the same up to the age of ten years. But there is a gradual difference in their requirements from the age of 10 years where the boys have a higher requirement compared to girls. Between 10-12 years the requirement of protein for girls is higher compared to boys. Later boys requirement is more than girls of the same age.

Minerals:

Calcium: Adolescents need more calcium than adults to meet their skeletal growth. About 150 mg of calcium must be retained each day to allow for the increase in bone mass.

Iron:

Iron is needed for haemoglobin synthesis for increased blood volume and for myoglobin which is needed for muscle growth.

Girls need to ensure adequate intake of iron as they lose 0.5 mg/day during menstruation. During adolescence there is an increase in body mass corresponding to about 4.3 kg/year in the female. With a further increase in haemoglobin by 2g/dl in boys and 1g/dl in girls, the respective requirement for growth alone is 0.7 mg/day in boys and 0.45 mg/day in girls while the obligatory losses also increase with age.

Zinc:
Zinc deficiency is not normally seen in adolescents. Zinc supplements have been shown to increase the pubertal growth in adolescents suffering from pubertal delay.

Vitamins:

• Vitamin – B- thiamine, riboflavin and niacin increase as per the requirement of calories
• Folacin and B12 are essential for DNA and RNA synthesis
• Vitamin B6: is essential for transamination to synthesise non essential amino acids. The requirement for B6 is increased. Premenstrual tension can be reduced if adolescent girls consume 100mg/day of vitamin B6.
• Vitamin – D: is essential for skeletal growth
• Vitamin A, C, and E: The structural and functional integrity of newly formed cells depend on the availability of these vitamins.