Breast Milk and Infant Growth Among Lean, Overweight and Diabetic Mothers (MIG)

Childhood obesity is a critical global public health concern. Breastfeeding is the ideal choice for infant nutrition. However, rapid and excess weight gain during infancy predicts later, even among breastfed infants. This risk is higher if mothers are obese and/or diabetic. Composition of bioactive components of breast milk may differ based between mothers who are normal weight (NW), overweight, or who have diabetes. Obesity and Type 2 Diabetes are associated with overall increases in inflammation and oxidative stress, but how breast milk composition is affected remains unknown. Our overarching goal is to determine how maternal obesity and Type 2 Diabetes impacts human breast milk composition and how differences in composition may impact infant growth and fat development. We are undertaking a study that follows 20 Normal Weight, 20 Obese, 20 Gestational Diabetic, and 20 Type 2 Diabetic mothers and their infants over the first 4 months of life. We will track infant weight and fat gain and monitor maternal glucose control. We will also collect breast milk samples over the first 4 months and measure concentrations of growth and appetite hormones, cytokines, markers of oxidative stress and nutrient composition in milk. We predict that concentrations of growth-regulatory hormones (insulin and leptin) in addition to the inflammatory cytokines and markers of oxidative stress will be lowest in breast milk from NW mothers, higher in breast milk from obese and gestational diabetic mothers, and highest in Type 2 Diabetic mothers' breast milk. We expect these differences will be most pronounced in the first 2 weeks after birth. We also predict that breast milk concentrations of these biomarkers will be associated with infant fat gain. What we find will help us understand how early infant nutrition and growth may affect that child's later risk of obesity.