International Board of Certified Lactation Consultant (IBCLC) Practice Exam

Which hormone regulates appetite, food intake, and energy metabolism in breastfed babies?

1. Insulin

2. Leptin

3. Ghrelin

4. Cortisol

The correct answer is: Leptin

Leptin is the hormone that plays a crucial role in regulating appetite, food intake, and energy metabolism, particularly in breastfed infants. It is primarily produced by adipose (fat) tissue and informs the brain about the body's energy status, helping to balance hunger and satiety signals. In breastfed babies, leptin levels in breast milk are significantly associated with the infant's body fat stores. This allows the baby to receive not only nutrition but also signals related to energy expenditure and appetite regulation. As the baby consumes breast milk, the transfer of leptin can influence their hunger cues and metabolic processes, prompting a response that aligns with their growth and developmental needs. In contrast, insulin primarily regulates glucose levels and metabolic processes rather than appetite directly. Ghrelin, a hunger hormone, stimulates appetite but does not directly regulate energy metabolism in the same complex way as leptin does in infants. Cortisol, often referred to as the stress hormone, affects metabolism and can influence appetite but is not the main regulator of hunger and energy balance in breastfed babies. Therefore, leptin is specifically recognized for its significant role in appetite regulation, making it the correct choice in this context.