Final answer:
For a 1-month-old infant fed human milk, a daily 4)supplement of 400 IU of vitamin D is recommended to prevent deficiency and support healthy bone development.
Step-by-step explanation:
To prevent vitamin D deficiency in a 1-month-old infant fed human milk, it is recommended to supplement with 400 IU vitamin D per day.
Breast milk may not provide enough vitamin D, especially if maternal intake is inadequate or if the infant has limited sun exposure. While vitamin D can be produced by the action of sunlight on the skin.
Infants are often protected from direct sunlight exposure, necessitating dietary supplementation to support bone health and prevent conditions such as rickets.