Lactose, or milk sugar, is the primary carbohydrate in cow's milk. Made from one molecule each of the simple sugars glucose and galactose, it's known as a disaccharide. People with lactose intolerance for one reason or another (age, genetics, etc.), no longer make the enzyme lactase and so can't digest milk sugar (20). This leads to some unsavory symptoms, which, needless to say, the victims find rather unpleasant at best. Raw milk, with its lactose-digesting Lactobacilli bacteria intact, may allow people who traditionally have avoided milk to give it another try.
The end-result of lactose digestion is a substance called lactic acid (responsible for the sour taste in fermented dairy products). Besides having known inhibitory effects on harmful species of bacteria (21), lactic acid boosts the absorption of calcium, phosphorus and iron, and has been shown to make milk proteins more digestible by knocking them out of solution as fine curd particles (22)(23).