Evolutionary Perspectives

  • The Barker Hypothesis (also known as the Developmental Origins of Health and Disease hypothesis)- The environment experienced during early development, including during fetal development and infancy, can have long-lasting effects on health and disease risk later in life. Studies have found that individuals who were breastfed as infants have a lower risk of obesity, diabetes, and cardiovascular disease in adulthood compared to those who were formula-fed. Breastfeeding may contribute to the programming of metabolic processes and immune function during early development due to the effect it has on the gut microbiome. This may influence longterm health outcomes. 
  • The Hygiene Hypothesis- This hypothesis proposes that decreased exposure to microbes in early childhood due to improved sanitation and hygiene practices may lead to an increased risk of developing immune-related diseases. Breast milk contains an array of beneficial bacteria, prebiotics, and immune factors that promote the growth of beneficial gut microbes and support immune system development, which may confer protective effects against immune-mediated disorders later in life.
  • Mismatch Theory- This theory proposes that certain health conditions arise from a discrepancy between the environment in which our bodies evolved and the modern environment in which we currently live. For much of human history, breastfeeding was the primary method of infant feeding, and it played a crucial role in supporting infant immune development.  When infants are not breastfed,  the theory suggests that they may experience mismatches between the nutrients and immune factors they receive and what their bodies expect based on evolutionary adaptation. These mismatches could may lead to different health conditions later in life, like obesity.