Metabolisable energy consumption in the exclusively breast-fed infant aged 3–6 months from the developed world: a systematic review

Abstract

The present study aimed to evaluate evidence on metabolisable energy consumption and pattern of consumption with age in infants in the developed world who were exclusively breast-fed, at around the time of introducing complementary feeding. We carried out a systematic review aimed at answering three questions: how much milk is transferred from mother to infant?; does transfer increase with the age of the infant?; and what is the metabolisable energy content of breast milk? Thirty-three eligible studies of 1041 mother-infant pairs reported transfer at 3-4 months of age, the weighted mean transfer being 779 (SD 40) g/d. Six studies (99 pairs) measured transfer at 5 months, with a weighted mean transfer of 827 (SD 39) g/d. Five studies (72 pairs) measured milk transfer at 6 months, reporting a weighted mean transfer of 894 (SD 87) g/d. Nine longitudinal studies reported no significant increases in milk transfer after 2-4 months. Twenty-five studies on breast-milk energy content were based on 777 mother-infant pairs. The weighted mean metabolisable energy content was 2·6 (SD 0·2) kJ/g. Breast-milk metabolisable energy content is probably lower, and breast-milk transfer slightly higher, than is usually assumed. Longitudinal studies do not support the hypothesis that breast-milk transfer increases markedly with age. More research on energy intake in 5-6-month-old exclusively breast-fed infants is necessary, and information on the metabolisability of breast milk in mid-infancy is desirable. This evidence should inform future recommendations on infant feeding and help to identify research needs in infant energy balance. Infant nutrition: Breast feeding: Complementary feeding: Energy metabolismThe evidence base for many infant-feeding recommendations is currently limited (Michaelsen et al. 2000;Lanigan et al. 2001;Kramer & Kakuma, 2002). For example, a review on the possible adequacy of breast milk to meet energy and nutrient requirements up to the age of 6 months noted a lack of published evidence on infant energy intake with which to address this question and called for further research (Butte et al. 2002). We were also aware that many implicit but important assumptions (about breast-milk transfer, metabolisability and energy content, for example) have commonly been made in the literature, and these assumptions have been repeated and widely used in infant-feeding recommendations. The assumptions have not generally been formally tested, and it is widely recognised that more evidencebased approaches to the issue would be helpful (Michaelsen et al. 2000;Lanigan et al. 2001;Kramer & Kakuma, 2002).Before embarking on a new research project on energy balance in infancy, we had the opportunity to test the evidence base on critical energy-balance variables by conducting a systematic review of studies on exclusively breast-fed infants over the period when complementary feeding is usually introduced. 'Exclusive breast-feeding' is defined in WHO terms as feeding exclusively with breast milk (World Health Organization, 1995), wit...

Randomized controlled trial of 4 compared with 6 mo of exclusive breastfeeding in Iceland: differences in breast-milk intake by stable-isotope probe

“…We calculated energy consumption with the assumption that the metabolizable energy content of breast milk at age 6 mo is 62.1 kcal/100 g (4). Current WHO guidelines for energy requirements in breastfed infants at age 6 mo are 78 kcal Á kg 21 Á d 21 (35), which in this study would equate to 625 kcal/d for the average EBF infant in this study.…”

“…According to published data on breast milk (intake, energy content) and infant energy requirements, average intakes would fail to meet energy requirements in the average 6-mo-old infant (4), although this approach relied on various assumptions about breast-milk energy content. However, insufficient relevant evidence is available, particularly in EBF infants.…”

Field and laboratory methods in human milk research

“…The cost of analyzing samples is considerable-often several hundred dollars per participant. In addition, doubly labeled water may also under-or over-estimate intake, with ranges (15% over to 5% under) similar to those seen in test weighing protocols (Haisma et al, 2003;Reilly et al, 2005;Scanlon et al, 2002;Wells et al, 1996).…”

Breast milk nutrient content and infancy growth

“…It is unclear whether the slower infancy weight gain in breast‐fed babies is a result of lower total calorie intake or related to the nutrient composition of human breast milk (HM). Previous studies documenting HM energy or macronutrient contents have been recently reviewed 7, 8. Most were performed in small sample sizes, and few attempted to assess the influence of HM composition on subsequent infancy growth outcomes.…”