Body Composition From Birth to 4.5 Months in Infants Born to Non-Obese Women

Abstract

Infant body composition is affected by maternal obesity, which results in increased % body fat in the infant. With the rapidly increasing incidence of obesity, it is important that normative data are available for infant body composition that is not affected by this trend in maternal obesity. This study assessed body composition in infants born at term to women with a BMI between 18.5 and 25. Infant % body fat, fat mass (FM), and fat free mass (FFM) were assessed at birth, 6 wk, 3 mo, and 4.5 mo of age by air displacement plethysmography, using the PEA POD body composition system. The effects of age, gender, GA, and feeding mode on these parameters were assessed. The % body fat doubled between birth and 6 wk of age and then increased at a slower rate. FFM was higher in male infants at all ages, whereas % body fat was higher in female infants at 4.5 mo. There was a trend to increased % fat and decreased FFM in breastfed (BF) infants. The study provides unique data regarding changes in infant body composition and growth in infants born to women in the healthy weight range. (Pediatr Res 68: 84-88, 2010) B ody composition in early life may play a key role in the programming of a variety of health outcomes, including hypertension, stroke, type 2 diabetes, obesity, and cardiovascular disease (1). The Barker hypothesis states that undernutrition and small size at birth are associated with increased risk of cardiovascular disease and type 2 diabetes later in life (2). Observational evidence also suggests that faster growth during infancy is associated with an increased risk of obesity (2-5). This is an area of very active research, and in this environment, it is important to establish normal values for infant body composition and growth. In addition, the assessment of feeding interventions for preterm infants may be improved by measuring changes in fat free mass (FFM) vs. fat mass (FM). Deviations from normal developmental patterns of body composition may program these infants for later health problems (2-5). Again, it is critical that normative data be established for infant body composition.Historically, growth has been monitored by serial measurements of weight, length, and head circumference, with little information available on the compositional nature of infant growth. Early data were based on chemical analysis of a small number of stillborn infants (6,7). More recently, body composition has been measured using dual-energy x-ray absorptiometry (DXA) (8,9), total body electrical conductivity (TOBEC) (10), magnetic resonance imaging (11), or multicompartment models based on total body water, total body potassium, and bone mineral content measurements (12). However, many of these studies did not measure body composition at birth, and no studies have taken maternal body composition into account. Because it has been shown that maternal overweight/obesity is associated with increased body fat in the newborn infant (13,14), and the prevalence of maternal obesity is increasing, there is a need to establish norma...

Is body fat percentage a better measure of undernutrition in newborns than birth weight percentiles?

“…For neonates up to 6-d-old, this fat-free mass density calculation allows for the greater hydration of fat-free mass in the first week of life (21). FM and fat-free mass were computed from weight and BF% (13).…”

“…Recently, a new technology using air displacement plethysmography (ADP) has become available to noninvasively, accurately, and quickly measure BF% in infants from birth to 6 mo of age. ADP has been validated against the four-compartment model and biological and physical phantoms (13) and is considered the criterion method for determining BF% in neonates (14)(15)(16)(17)(18). Several studies have investigated the BF% as the indicator of neonatal nutritional status using ADP (13,(19)(20)(21).…”

Invited review: Pre- and postnatal adipose tissue development in farm animals: from stem cells to adipocyte physiology

“…The first IM adipocytes appear during the first postnatal month (Hauser et al, 1997). Although fetal fat gain in the body accelerates from 69 days post-conception onwards, pig neonates like sheep are characterized by a small amount of total body fat at birth (1% to 2% of the live weight; Frondas-Chauty et al, 2012), contrasting with the situation in human neonates (~10%; Carberry et al, 2010). At birth, the percentage of multilocular adipocytes is very high, but by day 3 postpartum, many unilocular adipocytes (one major central lipid droplet) are already observed (Hauser et al, 1997).…”

Body composition of parents and their infants : methodological, anthropometric, metabolic and genetic studies

“…Since the measurement procedures in Bod Pod and Pea Pod are standardised and relatively robust, these devices may be suitable for multicentre studies. Also, it is possible that some of the data obtained by cohort studies using ADP (17,19,44,79,87) may be useful in meta-analyses.…”