Lactation performance of rural Mesoamerindians

Abstract

Anthropometry, body composition and dietary intake of 30 lactating Otomi Indians of Capulhuac, Mexico, were studied to identify maternal factors which potentially limit lactation and thereby infant growth. Human milk production, milk composition, and maternal dietary intake, body weight, skinfold thicknesses, and body composition were measured at 4 and 6 months postpartum. The 2H2O dose-to-mother method was used to estimate milk production and maternal total body water (TBW). Fat-free mass (FFM) was calculated as TBW/0.73. Body fat was computed as body weight minus FFM. Human milk samples were analyzed for energy, nitrogen, lactose and fat using standard analytical methods. Maternal diet was assessed by three 24-h intake recalls. Mean (SD) milk production was 885 (146) and 869 (150) g/d at 4 and 6 months, respectively. Milk concentrations of protein nitrogen (1.23 (0.17) mg/g) and lactose (66.6 (2.8) mg/g) were comparable to, but the concentrations of fat (22.2 (6.7) mg/g) and energy (0.54 (0.06) kcal/g) were lower than, values observed in economically privileged populations. Maternal height, weight, and BMI were 1.47 (0.06) m, 50.3 (6.0) kg, and 23.4 (3.1) kg/m2, respectively. Maternal TBW, FFM and body fat were 55.8 (4.6)%, 76.4 (6.3)%, and 23.6 (6.4)%, expressed as a percentage of body weight, respectively. Maternal energy and protein intakes averaged 1708 (338) kcal/d and 40 (10) g/d, respectively. Milk production was negatively correlated with maternal body fat (P = 0.006). Energy and fat concentrations in the milk of the Otomi women were positively related to their weight (P = 0.002), BMI (P = 0.05), and body fat (P = 0.004). Energy concentrations in milk were not related to rates of milk production (r = 0.24; P = 0.23). Nor was milk production or composition significantly associated with maternal dietary intake. Lactation performance of these Otomi women correlated significantly with maternal body size and composition, but not current dietary intake.

PIP: Researchers analyzed data on 30 postpartum women from the Otomi Indian community living in rural Capulhuac, Mexico to examine interrelationships among lactation performance, maternal body size/composition, and dietary intake to learn which maternal factors limit lactation and thus infant growth. Infant food supplementation was minimal. Current diet did not affect milk production or levels of energy and fat in milk. Even though the body mass index (BMI) was lower than the normal range (19.8-26 kg/sq meter) for only 2 women, 8 women had 20% body fat indicating considerable undernutrition. Women consumed a mean of 68% and 80% of energy and protein requirements. Mean energy intakes (kcal/kg/day) at 4 and 6 months postpartum were 33.8 and 35.1 respectively, compared with the recommended 51. Mean protein intakes (g/kg/day) were 0.75 and 0.84 respectively compared with the recommended 1.1 3-day intake records based on memory, estimation of portion sizes, food preparation, and food composition data led to the above energy intake results, but they may not have been accurate since a mean of 35 would not allow much physical activity. Fats and carbohydrates mainly from maize made up 17% and 76% respectively of the Otomi diet suggesting a suboptimal diet. Yet human milk production rates (885 g/day at 4 months and 869 g/day at 6 months) tended to equal or be higher than those of women of higher socioeconomic status (711-925 g/day) and other poor women (525-789 g/day). The greater the levels of maternal body fat the smaller the amount of milk women produced (p=.006). Total nitrogen, protein nitrogen, lactose, and nonprotein nitrogen levels fell within the range of that of privileged women. Fat and energy levels in the milk were lower than those of privileged women, however heavy women (p=.002) with high BMI (p=.05) and body fat (p=.004) levels tended to have high levels of energy and fat in the milk. Energy levels in milk were not linked with milk production. Neither milk production nor composition were related to dietary intake.