Why is introducing whole milk during the first year of life not advisable?

Introducing whole milk during the first year of life is not advisable because it could cause bleeding in the digestive tract. Infants have immature digestive systems, and whole milk contains higher levels of protein, sodium, and potassium than breast milk or formula, which can be difficult for them to handle. Additionally, the proteins in whole cow's milk can irritate the lining of an infant's gut, increasing the risk of gastrointestinal issues, including the potential for gastrointestinal bleeding.

In contrast, the other concerns listed—high blood pressure, high blood lipids, and rickets—while they are considerations in the dietary management of older children and adults, do not directly relate to the immediate dangers of introducing whole milk too early for infants. The focus on digestive tract health highlights the unique vulnerabilities of infants during their first year of development. Therefore, it is critical to rely on breast milk or iron-fortified infant formula during this stage of life.