Why is vitamin A reduced in skimmed and semi skimmed milk?

Vitamin A is reduced in skimmed and semi-skimmed milk because it is a fat-soluble vitamin, meaning it is primarily found in the fat component of milk. When milk is processed to remove fat, such as in the making of skimmed or semi-skimmed varieties, a significant portion of the vitamin A is also removed. This reduction can lead to lower overall nutrient content in these milk types compared to whole milk, which retains the fat and associated vitamins. To address this, some manufacturers fortify skimmed and semi-skimmed milk with vitamin A to restore its nutritional value.