Milk provides vitamins and antioxidants that help keep your body healthy. Vitamins A, D, E and vitamin K are all fat-soluble, and thiamine, niacin, riboflavin are water-soluble. Milk also contains vitamin B-5, B-6 and B-12, folate and vitamin C, which are also water-soluble. What you may not realize is that milk also contains sugar.
What is Lactose and Saccharose
Lactose and saccharose are both naturally occurring sugars. According to Prince George's Community College, they are both disaccharides, which, simply put, are sugars that contain two monosaccharide molecules. Lactose, also known as milk sugar, gives cow's milk its sweet taste. Saccharose, also known as sucrose, is ordinary, white table sugar derived from sugar beets or sugar cane plants. Lactose and saccharose are both carbohydrates, which require digestion before they can supply cellular energy.
Mammal's Milk
A lactose sugar molecule forms when a single glucose and a single galactose molecule combine during a chemical process known as a dehydration reaction. The only natural source of lactose sugar molecules is mammal's milk. Lactose sugar molecules also develop during the manufacture of processed cheese as a byproduct. Elmhurst College explains that approximately 4 percent to 6 percent of cow's milk is lactose and 5 percent to 8 percent of human milk is lactose.
Soy and Flavored Milk
Unlike lactose, saccharose is not a natural ingredient in mammal's milk. It is however, an added sugar used to sweeten and flavor soy milk. The Alabama Cooperative Extension System explains that soy milk does not have the same level of sweetness as mammal's milk; the addition of saccharose makes the taste of soy milk more appealing. Saccharose is also an added non-nutritive sweetener in flavored milks such as chocolate or strawberry. Because of the added saccharose, soy and flavored milks have higher carbohydrate contents than unflavored milk.
Milk Intolerance and Allergies
In order for your body to digest the lactose in milk, it must separate the glucose and galactose molecules. The enzyme responsible for this split is lactase. According to Colorado State University, insufficient amounts of lactase result in lactose intolerance, which causes diarrhea, abdominal pain and gas. Lactose is sometimes confused with casein, but the two are actually quite different. While you may be lactose intolerant, it does not mean that you are allergic to milk. A true milk allergy is an allergy to casein, a milk protein.
References
- Prince George's Community College: Exploring the Molecules of Life: Carbohydrates
- Elmhurst College: Lactose
- Alabama Cooperative Extension System; Soymilk May Become Staple School Menu Item; Jim Langcuster; December 2003
- Colorado State University; Lactose Intolerance (Lactase Non-Persistence); R. Bowen; April 2009
- Cornell University: Vitamins and Minerals in Milk
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