Why do some people say that milk is harmful?

Milk contains insulin growth factor, which is secreted by the human body during its growth and development. But it will stop secreting this substance in adulthood. But if this substance is ingested from the outside, it will do great harm to the human body.

Lactose in milk can't be digested and absorbed by human body, and most infant allergic reactions are caused by milk powder. The really useful substance in milk is whey protein, but the content is quite low. The proportion of calcium and magnesium in milk is also unreasonable.

Milk is actually designed for calves, not humans.

If you want to drink, try to reduce your intake. Drink fresh raw milk.