
If you want me to explain the science you won’t understand, milk has a different solute concentration than water. Solutes are the substances dissolved in water. Milk’s solute concentration is closer to that of a baby’s body. Water’s solute concentration is too low. Drinking it will dilute the sodium in their blood because their livers cannot process straight water. A low blood solubility causes cells to dangerously expand, which is really bad in brain cells.