Lactose (a sugar)
From Proteopedia
Lactose is a sugar found in milk and other foods. It is formed by a condensation reaction (also called dehydration synthesis) of the building blocks glucose and galactose. A large part of the human adult population is lactose intolerant. Because they are unable to efficiently digest lactose into its building blocks, lactose builds up and causes symptoms such as stomach pain. Lactose-intolerant individuals either have to limit lactose intake or take supplements to help digest it.
This page assumes basic textbook knowledge of carbohydrate chemistry. For a refresher, see the relevant section in the first chapters of any college biology textbook, e.g. this one.
Structure
| |||||||||||
Function
Lactose is one of the main sources of energy (calories) in human breast milk and milk from other animals. As hunter-gatherers, adult humans had no significant source of lactose in their diet, and no need for the ability to digest it. This has changed in societies that include dairy as significant part of their diet. Some adults produce sufficient quantities of the enzyme lactase, enabling them to digest substantial amounts of lactose in their diets by hydrolyzing it, while others don't.
