Breast milk is nutritious at any time, but its nutritional value will gradually decrease with the passage of time. Generally, breast milk half a year ago contains various immune antibodies, which are rich in protein, fat, sugar, vitamins and trace elements. After six months, the immune antibodies in breast milk will all disappear, and the nutrients such as protein and fat will gradually decrease. After ten months, the protein content in breast milk will reach the lowest, and at this time, breast milk basically contains only trace elements, sugars and vitamins.