Pregnancy imposes a substantial metabolic burden on women through weight gain and increased insulin resistance. Accordingly, women have an increased risk of diabetes after repeated deliveries. Various factors, including a history of gestational diabetes, maternal age, and obesity, affect women’s risk of progressing to diabetes.
Among these factors, lactation has been reported to reduce the risk of maternal postpartum diabetes in a dose-dependent manner. Parous women who did not lactate have an increased risk of diabetes compared to nulliparous women, but lactation for more than 3 months appears to reduce this risk comparable to nulliparous women
Epidemiological studies have shown that this beneficial effect of lactation in preventing postpartum diabetes can last up to 30 years after delivery. Lactation increases energy consumption and improves insulin sensitivity, but the mechanisms underlying the long-term beneficial effects of lactation have not been elucidated.
Feeding with benefits
In addition to providing health benefits for infants, breastfeeding has also been reported to offer metabolic benefits for mothers, but the underlying biology explaining this observation has remained elusive.
By studying both human and murine mothers over time, Moon et al. identified long-term improvements in pancreatic β cell mass and function, as well as glucose tolerance, all associated with lactation. The authors linked the hormone prolactin to serotonin production and proliferation of the β cells, providing a mechanistic explanation for the beneficial effects of lactation.
Pregnancy imposes a substantial metabolic burden on women through weight gain and insulin resistance. Lactation reduces the risk of maternal postpartum diabetes, but the mechanisms underlying this benefit are unknown. Here, the study identified long-term beneficial effects of lactation on β cell function, which last for years after the cessation of lactation. The study analysed metabolic phenotypes including β cell characteristics in lactating and non-lactating humans and mice.
Lactating and non-lactating women showed comparable glucose tolerance at 2 months after delivery, but after a mean of 3.6 years, glucose tolerance in lactated women had improved compared to non-lactated women.
In humans, the disposition index, a measure of insulin secretory function of β cells considering the degree of insulin sensitivity, was higher in lactated women at 3.6 years after delivery.
lactation benefits women’s metabolic health by improving β cell mass and function and glycemic control. 5-hydroxytryptamine plays a critical role in achieving the necessary β cell mass during lactation by stimulating β cell proliferation and exerting an antioxidant activity to protect β cells against oxidative stress.
Future studies on the modulation of the serotonergic pathway in accordance with the management of maternal metabolic risk factors would provide additional insights into maternal physiology.