Glucose and Insulin Levels are Increased in Obese and Overweight Mothers’ Breast-Milk

Abstract

Objective: To analyze the relationships between mothers’ pre-pregnancy body mass index (BMI) and levels of glucose and insulin in breast-milk. Methods: Participants were 32 breast-feeding mothers who were assigned to either normal weight (group 1: n = 21, BMI between 18.5 and 24.9 kg/m2) or overweight/obese (group 2: n = 11, BMI ≥ 25 kg/m2) based on their pre-pregnancy BMI. Breast-milk samples were collected at six weeks postpartum. Glucose and insulin concentrations were measured in the breast-milk samples. To control for any extreme dietary influences on breast-milk glucose concentrations, mothers completed 24-hour food recalls. Results: Mean milk-glucose values of groups 1 and 2 were 32.6 ± 21.8 mg/dL and 51.9 ± 20.5 mg/dL respectively. Milk-borne insulin values were 4.5 ± 7.6 µIU/mL and 30.1 ± 56.3 μ IU/mL, respectively. Independent-samples t tests found that glucose levels of group 2 were greater than those of group 1, t(30) = 2.43, p = 0.02; and milk-borne insulin was greater in group 2 than in group 1, t(30) = 2.075, p = 0.05. Mothers’ pre-pregnancy BMI was found correlated with both breast-milk glucose (r = 0.483, p = 0.005) and insulin (r = 0.565, p = 0.001). Conclusion: This study found that in comparison with normal weight mothers, over-weight/ obese mothers have higher concentrations of glucose and insulin in their breast-milk. Further studies are needed to explain the underlying mechanisms, and possible consequences of infant exposure to higher levels of glucose and insulin in breast-milk

Associations between human breast milk hormones and adipocytokines and infant growth and body composition in the first 6 months of life

“…Specifically, breast milk insulin was 229% higher in obese mothers nursing female infants than in normal weight mothers nursing female infants and 179% higher than obese mothers nursing male infants. Two other studies have reported positive associations between maternal BMI and HBM insulin concentrations (12,13), while others have found no association (7,14).…”

Relationship of Maternal Weight Status Before, During, and After Pregnancy with Breast Milk Hormone Concentrations

“…Leptin is an appetite-regulating hormone produced in the adipose tissue (27) as well as epithelial cells of the mammary gland (28), and it has been found in much higher concentrations in human serum compared with breast milk (20) and in serum of women with obesity than those with normal weight (29). Milk leptin's positive association with maternal BMI (with a small number of exceptions) (19,30) has been well established (11,13,16,31). Our results confirmed this association in exclusively breastfeeding women and extended it by documenting that milk leptin concentration is responsive to dynamic aspects of weight change in pregnancy and lactation.…”

Biological Determinants Linking Infant Weight Gain and Child Obesity: Current Knowledge and Future Directions

“…In rats, the fatty acid composition and insulin concentrations of milk from genetically obese dams differs from those of the milk of lean dams (73), and diet-induced obesity impairs mammary lipid metabolism and milk fat production and results in reduced milk triglycerides (74). HM from overweight and obese women also has higher total fat, glucose, and insulin concentrations than HM from lean mothers (75,76). The concentrations of the hormonally active adipokines leptin and adiponectin in HM vary by maternal BMI (77)(78)(79)(80).…”

“…Furthermore, obesity in adults is often characterized by leptin resistance, and how early exposure to elevated leptin concentrations in HM may affect leptin sensitivity also remains unknown. Insulin is another powerful anabolic hormone present in HM that differs based on maternal phenotype (75). Variation in these hormones resulting from maternal obesity and/or diabetes could affect the metabolic programming and growth/adiposity trajectory of the newborn (108).…”