The Indian Council of Medical Research (2010) recommends an increase of 350 kcals per day during the second and third trimester of pregnancy. This takes into consideration additional energy needed to support the growth of the foetus, placenta and maternal tissues, as well as to meet the increased metabolic rate. BMR increases by about 5% during the first and second trimester and about 12% during the third trimester. As growth of the foetus is very rapid during this period, it is important that the increased need for energy is met. Enough energy containing food should be supplied to ensure that the dietary protein is used for building new tissues, and not to meet energy requirements. During first trimester of pregnancy, the demand for extra energy is small and is taken care of by the reduced activity.
Additional protein is necessary for growth of the foetus, new maternal tissues and to prepare the mother for lactation. The ICMR recommends additional 23g per day during the second half of pregnancy. The protein should be of good quality.
Fats and Essential Fatty Acids
ICMR Expert Committee has suggested an intake of 30g of visible fat/day during pregnancy to meet essential fatty acid requirement. This level of fat intake would also provide necessary energy density to the diet.
During pregnancy additional calcium is needed for growth and development of bones as well as teeth of the foetus. ICMR (1990) has therefore, recommended a total of 1200mg of calcium which takes care of the total calcium needs of the mother and the additional needs of pregnancy. If these requirements are not fulfilled, then the mother’s bones is mobilized resulting in demineralization of maternal bones leading to easy fractures.
Zinc has an important role to play in pregnancy. Apart from being a component of several enzyme systems it participates in the synthesis of nucleic acids – DNA and RNA highlighting its significance in the process of reproduction. Recent studies indicate that deficiency of zinc affects adversely the course and outcome of pregnancy.
Iron is needed for the additional volume of blood and other tissues formed during development of foetus. The store for iron is built during prenatal period, because milk, the infant’s main food during first three to four months is deficient in iron. It is now a common practice for the doctor to give expectant mothers a prescription for an iron supplement. Though this is true, foods rich in iron should be emphasized in the diet. The iron intake during this period is recommended at 35 mg per day, considering an 8% absorption.
There is an additional need for iodine at this stage in life. If mother’s iodine intake is low, the infant may suffer from creatinism, a disease characterized by retarded physical and mental development. Due to increase in BMR, iodine requirement are enhanced.
Additional intake of 200mcg of vitamin A has been recommended during this period. No additional intake has been recommended for vitamin D, in the absence of any experimental data. However, the requirement for vitamin D may be higher during pregnancy, when calcium metabolism is under physiological stress. Since vitamin C allowances for adults includes a sufficiently safe margin, the requirements being small, only 20 mg extra allowance has been recommended. The additional intake of thiamine, riboflavin and niacin has been recommended to the tune of 0.2 mg, 0.3 mg, and 2.0 mg, per 1000 kcal respectively, correlating with the increased calorie intake. Increased energy allowance will provide the increased B Complex vitamins. An increased level of vitamin B6 at 2.5 mg/day is recommended. Folic acid intake is increased to 500 mcg/day. It is difficult to provide this amount through food and the additional needs may have to be met through supplements of medicinal folate. Information regarding additional needs of vitamin B12 during pregnancy is limited. However, on the basis of various studies, ICMR has suggested a daily intake of 1.2 mcg vitamin B12 during pregnancy.
It, therefore, is clear that the nutritional needs during pregnancy are increased.