Vitamins & Minerals in Milk
This page describes the Vitamins and Minerals present in milk, and the Effects of Heat Treatments and Light Exposure on the Vitamin and Mineral Content in Milk. A description of the nutritional function of vitamins and minerals is provided on the Nutritional Components in Milk page in the Nutrition Facts section. For more details on the vitamins and minerals in milk, see references by Flynn et al. (1997), Fox and McSweeney (1998), Holt (1995), and Öste et al. (1997).
Vitamins in Milk
Vitamins have many roles in the body, including metabolism co-factors, oxygen transport and antioxidants. They help the body use carbohydrates, protein, and fat. The specific content of vitamins in milk is listed in the Nutrient Content Tables in the Nutrition Facts section.
Milk contains the water soluble vitamins thiamin (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), pantothenic acid (vitamin B5), vitamin B6 (pyridoxine), vitamin B12 (cobalamin), vitamin C, and folate. Milk is a good source of thiamin, riboflavin and vitamin B12 . Milk contains small amounts of niacin, pantothenic acid, vitamin B6, vitamin C, and folate and is not considered a major source of these vitamins in the diet.
Milk contains the fat soluble vitamins A, D, E, and K. The content level of fat soluble vitamins in dairy products depends on the fat content of the product. Reduced fat (2% fat), lowfat (1% fat), and skim milk must be fortified with vitamin A to be nutritionally equivalent to whole milk. Fortification of all milk with vitamin D is voluntary. Milk contains small amounts of vitamins E and K and is not considered a major source of these vitamins in the diet.
Minerals in Milk
Minerals have many roles in the body including enzyme functions, bone formation, water balance maintenance, and oxygen transport. The specific content of minerals in milk is listed in the Nutrient Content Tables in the Nutrition Facts section.
Milk is a good source of calcium, magnesium, phosphorus, potassium, selenium, and zinc. Many minerals in milk are associated together in the form of salts, such as calcium phosphate. In milk approximately 67% of the calcium, 35% of the magnesium, and 44% of the phosphate are salts bound within the casein micelle and the remainder are soluble in the serum phase. The fact that calcium and phosphate are associated as salts bound with the protein does not affect the nutritional availability of either calcium or phosphate.
Milk contains small amounts of copper, iron, manganese, and sodium and is not considered a major source of these minerals in the diet.
Effects of Heat Treatments & Light Exposure on the Vitamin & Mineral Content in Milk
The mild heat treatment used in the typical high temperature short time (HTST) pasteurization of fluid milk does not appreciably affect the vitamin content. However, the higher heat treatment used in ultra high temperature (UHT) pasteurization for extended shelf combined with the increased storage life of these products does cause losses of some water-soluble vitamins. Thiamin is reduced from 0.45 to 0.42 mg/L, vitamin B 12 is reduced from 3.0 to 2.7 µg/L, and vitamin C is reduced from 2.0 to 1.8 mg/L (Potter et al., 1984). Riboflavin is a heat stable vitamin and is not affected by severe heat treatments.
Calcium phosphate will migrate in and out of the casein micelle with changes in temperature. This process is reversible at moderate temperatures. This does not affect the nutritional properties of milk minerals. At very high temperatures the calcium phosphate may precipitate out of solution which causes irreversible changes in the casein micelle structure.
Exposure to light will decrease the riboflavin and vitamin A content in milk. Milk should be stored in containers that provide barriers to light (opaque plastic or paperboard) to maximize vitamin retention.