Does exercise boost beneficial hormone transfer in lactating women?

Breast milk contains adiponectin, a hormone impacting glucose and fat metabolism. It can influence infant metabolism by crossing the intestinal barrier. Adiponectin is primarily secreted by white adipose tissue. Its low levels are linked to insulin resistance and type 2 diabetes. Maternal lifestyle, including smoking, BMI, gestational diabetes, and diet, has been shown to affect the composition of breast milk. Aerobic exercise, either as moderate-intensity continuous training (MICT) or high-intensity interval training (HIIT), may increase circulating levels of adiponectin.

The study involved exclusively breastfeeding participants with 6–12 week-old term infants undergoing three laboratory conditions:

Moderate-intensity continuous training (MICT)

High-intensity interval training (HIIT)

and No activity (REST)

Breast milk samples were collected before, immediately after, 1 hour after, and 4 hours after each condition, and adiponectin concentrations were measured. Researchers then compared adiponectin concentration changes post-MICT and HIIT.

The results showed that adiponectin concentrations increased 1 h after HIIT, from 4.6 μg/L to 5.6 μg/L. This change was 0.9 μg/L greater than the change between these two time points in the REST condition. There were no other statistically significant changes in adiponectin concentrations.

“One of the reasons why the WHO recommends breastfeeding during the first six months of life is that breast-fed children are less likely to be overweight and obese than formula-fed children. However, new research shows that the composition of breast milk varies between mothers who have high and low body mass indexes, and that differences in breast milk composition can play a role in the transfer of obesity from mother to child” said Trine Moholdt, researcher, Norwegian University of Science and Technology.

Reference: Holmen, M., et al. (2023). High-intensity exercise increases breast milk adiponectin concentrations: a randomised cross-over study. Frontiers in Nutrition. doi.org/10.3389/fnut.2023.1275508.