A newborn on day 2 of life receives the first feeding. Which milk phase and composition most likely describe what the infant receives at this time, and what is its principal functional significance?

• A. Mature milk: clear, watery, high in fat and carbohydrate—primarily serves to hydrate and provide long-term energy stores while supplying the majority of fat-soluble vitamins.
• B. Foremilk: viscous and yellow with very high iron and immunoglobulin content—serves mainly to protect the newborn from bacterial translocation across the gut mucosa during the first week.
• C. Colostrum: yellow, thick, high in protein and antibodies—provides immune protection and concentrated micronutrients while the infant’s gut is immature.
• D. Hindmilk: watery, low fat, secreted in early feedings—primarily to quench thirst and supply simple sugars and electrolytes to stabilize neonatal blood glucose.

Answer: (C)