Department of Anthropology, Washington University in St. Louis
Friday All day, Park Concourse
Despite considerable research looking at milk macronutrients, energy, and hormones in milk, there remains virtually no published data looking at macronutrients, energy, and metabolic hormones from the same milk samples. While many of these metabolic hormones, especially leptin, have been implicated in the establishment of feeding self control and satiety, there is no available research testing for an association between milk nutritional composition and the quantity of hormones such as leptin. This study hypothesized that as a satiety signal, milk leptin levels would be positively associated with fat, protein and energy and inversely associated with sugar in milk.
These proposed associations were tested in 135 milk samples from 103 individuals from Cebu, Philippines. Milk samples were collected as part of a larger study of reproductive health (Adair et al., 2011) and substudy of lactation and milk (Quinn et al., 2012). Individuals had been nursing from 7-1300 days. Milk fat, protein, and total sugars were measured using standard procedures. Milk leptin was measured in skimmed milk using EIA and was within the range reported for other populations (287 ± 257 pg/mL).
There were no significant associations between individual macronutrients and leptin in this sample except for total sugars (r=-0.35, p<0.005). Milk leptin declined as milk sugar increased. As increasing milk sugar is usually associated with decreased caloric density of milk, this provides a new source of evidence linking milk leptin with infant satiety by providing an actual measure of the nutritional composition of the milk relative to leptin content.
National Science Foundation DCS 0746320