What is the osmolality recommendation for infant formulas?

• A. Less than 500 mOsm/kg
• B. Less than 460 mOsm/kg
• C. Less than 400 mOsm/kg
• D. Less than 360 mOsm/kg

Answer: (B)

Osmolality measures how concentrated a formula is with dissolved particles. In infants, especially newborns and those with immature guts, a higher osmolality can pull water into the intestinal lumen and irritate or injure the gut, increasing the risk of feeding intolerance and serious conditions like necrotizing enterocolitis.

The recommended ceiling for infant formulas is less than 460 mOsm/kg. This threshold balances providing complete nutrition with minimizing osmotic stress on the immature gut. Most standard-term formulas stay well below this limit, while formulas with added nutrients or fortifiers approach it but should remain under it to reduce risk. If the target were set much lower, many commonly used formulas would be excluded, potentially compromising nutrition or requiring larger volumes or alternative feeds.