Little is known about human milk (HM) composition in T2 diabetes (T2DM) and data support that HM insulin may be absorbed from the immature newborn gut and be metabolically active. We characterized HM composition and measured fasting and 90 min postprandial insulin and glucose (gluc) in HM (mid-feed) and plasma in 12 T2DM mothers (BMI 32± 4) after a 60 g carb meal at 2 weeks postpartum. We compared fasting HM samples with 12 normoglycemic (NGT) and 10 GDM mothers who were matched by BMI and infant sex. The study was powered on our hypothesis that fasting HM insulin would be higher in T2DM (2 insulin requiring). All macronutrients and energy density (Miris) in HM of T2DM were in the expected range (mean fat 4.1; protein 1.6; carbs 7.2 g/100mL; energy 74 kcal/100ml) and did not differ postprandially. Notably, paired fasting HM insulin in T2DM was 30.2 and 16.1 μIU/mL higher in the NGT (p<0.01) and GDM groups (p<0.05), respectively (Figure A). HM gluc did not differ by groups. In T2DM, HM gluc (p<0.001) and insulin (p<0.05) increased after the meal. Strikingly, mean fasting insulin was 4-fold higher in T2DM HM vs. plasma (p<0.005; Figure B). These are the first data to show that while HM macronutrients and calories from mothers with T2DM are reassuringly in expected quantities, HM insulin is higher and concentrated in T2DM milk. Given that the newborn gut may be permeable to insulin, potential effects on the newborn pancreas, growth, and the microbiome deserve further study.
R. Rodel: None. J. Martin Carli: None. N. Hirsch: None. K.P. Heiss: None. T.L. Hernandez: None. N.F. Krebs: None. L.A. Barbour: None. B. Young: None.
Colorado Clinical and Translational Sciences Institute (UL1TR000154); National Center for Advancing Translational Sciences (UL1TR002535); National Institutes of Health (T32DK007658-28), (R01DK101659 to T.L.H.), (F32-HD0978068), (T32-DK007658-21); Thrasher Research Fund; University of Colorado Center for Women’s Health Research
