Vitamins and Minerals in Milk
Milk contains vitamins A and D, riboflavin (B2) and tryptophan, an amino acid important in the formation of the B vitamin niacin. It is low in vitamins C and E. Milk exposed to ultra-violet light loses riboflavin, so it is packaged in cardboard or opaque plastic containers to prevent the degradation of this vitamin by light.
Many milks are fortified with vitamins A and D. Vitamin D is found naturally in very few foods and was initially added to milk, a staple food, to reduce the incidence of rickets, a bone-softening condition in children that was at one time endemic in North America. Before the fortification of milk was widely practiced, many children grew up with severely bowed legs and other effects of vitamin D deficiency. Because vitamins A and D are fat-soluble, they are found in the milk fat of whole milk. For this reason, whole milk is not required to be fortified with either vitamin, although many milk manufacturers add both. In reduced fat (2 percent fat) and fat-free (nonfat) milks, however, the vitamin A has been diminished, so these milks are required to be fortified with that vitamin. Fortification with vitamin D in reduced fat (2 percent) and fat-free (nonfat) milks is optional, but a lot of milk processors add it anyway. Vitamin A fortification is also required in dried whole milk and evaporated skim milk, while fortification with vitamin D is required in evaporated whole and fat-free (nonfat) milk.
Minerals in Milk
The major mineral in milk is calcium, with 1 cup of milk containing, on average, 300 mg of the nutrient. Two servings of milk a day provide a substantial portion of the 1000 mg RDI for adults. Milk can also provide calcium in the form of other foods such as yogurt, pudding, ice cream, custards, hot chocolate, and cheese.
Other primary minerals found in milk and milk products include phosphorous, potassium, magnesium, sodium chloride, and sulfur. Although milk is rich in many minerals, it is low in iron.
