Pregnancy energy requirements

Because the isotope method is noninvasive, nonrestrictive, and does not expose the subjects to radiation, the H2 0 method is considered the method of choice by the nutrition conununity for the estimation of energy requirements during infancy, growth, pregnancy, and lactation. 

Butte NF, et al. Energy requirements during pregnancy based on total energy expenditure and energy deposition. Am J Clin Nutr. 2004 79(6) 1078-87. 

Advisory Committee to Revise the Canadian Dietary Standard (1983), with the same assumptions about requirement variance. As in the Canadian report, the CV for the requirement was taken as 15 percent. One further assumption is necessary the correlation between nutrient and energy requirements across individuals within a class. Beaton and Swiss (1974) examined this assumption for protein and concluded that in all age groups, except early infancy and perhaps pregnancy and lactation, the correlation was likely to be very low (a maximum of 0.2). Table VI assumes a correlation of zero. 

Daily energy expenditure is the sum of BMR, thermic effect of food eaten, occupational activities and non-occupational activities. Energy requirements increase with growth, pregnancy and lactation, (as does... 

The RDA values are not requirements they are recommended daily intakes of certain essential nutrients. Based on available scientific knowledge, they are believed to be adequate for known nutritional needs for most healthy people under usual environmental stresses. The recommended allowances vary for age and sex, with extra allowances for women during pregnancy and lactation. The most commonly used RDA values (the reference male and reference female ) are those of adults 23 to 50 years of age. With the exception of energy (kilocalories), the RDA provide for individual requirement variations and prevent symptoms of clinical deficiency of 97% of the population. 

Protein turnover is not completely efficient in the reutilization of amino acids. Some are lost by oxidative catabolism, while others are used in synthesis of non-protein metabolites. For this reason, a dietary source of protein is needed to maintain adequate synthesis of protein. During periods of growth, pregnancy, lactation, or recovery from illness, supplemental dietary protein is required. These processes are affected by energy supply and hormonal factors. An overview of amino acid metabolism is presented in Figure 17-1. 

Fig. 21.1 Estimated energy and protein requirements for each trimester of pregnancy [22]...

---