Human Nutrition 3(3+0)

Lesson 3 : Recommended Dietary Allowances for Nutrients

Iron

Iron requirements are computed mainly by the factorial method. Iron lost in urine, sweat and in menstruation is estimated. Iron requirements for growth are calculated from the retention in the body during growth. An average absorption of 10% of food iron is assumed in computing iron requirements.

During early infancy where little change occurs in storage iron and haemoglobin (Hb) levels, a full term infant of 2.7 kg body weight needs only 0.3 mg/day to maintain its Hb at the normal concentration of 11 g/ deciliter and to replace excretory loss. During the second year of life, when growth rate slows down and the body mass increases by 2.5 kg, 80 mg of iron is needed. Added to basal losses, the total requirement during this period is about 0.4mg/ day.

Iron requirements during pregnancy can be calculated from a knowledge of iron needs for foetal growth, expansion of maternal tissue including the red cells mass, the content of iron in the placenta and the blood loss during parturition. These additional requirements should be added to the basal requirement.

Iron requirement during lactation is the sum of the requirement of the mother and that required making up the iron lost in breast milk.

The daily iron requirements recommended by ICMR Nutrition Expert Group are as follows:

Table 5: RDA for Iron

Group	Iron( mg/d)
Adult: Men Women	17 21
Pregnant woman Lactating woman	35 25
Infants 0-6 months 6-12 months	- 46 µg/kg/day
Children: 1-3 years 4- 6 years 7-9 years	09 13 16
Adolescents: 10-12 years Boys Girls 13-15 years Boys Girls 16-17 years Boys Girls	21 27 32 27 28 26

Ref: Nutrition Expert group, ICMR (2010)