Let's talk lactose

Italian Cream Sodas, Agora, Houston, TX

With a hat tip to @EatingOurWords on Twitter, I learned about the creation of the capriccino- basically, a cappuccino made with goat's milk as a way of accommodating lactose intolerant cappuccino drinkers. Except, well, goat's milk has lactose, too. Almost as high as in cow's milk. But not as high as in human milk - which is nearly double the concentration in cow's milk

So, how did lactose-intolerant humans survive being breastfed?

Breakfast custard, Peppersoup Cafe, Houston, TX

Let's clear up some of misunderstanding about the basic chemistry and biology of lactose in the diet. What is lactose? It is the primary carbohydrate in milk - the milk sugar so to speak. Lactose itself is a disaccharide, that is a sugar made up of two simple sugars connected together - those two are galactose and glucose. Glucose, you may have heard of - it's the primary sugar in corn syrup (the regular kind, not the high fructose kind). Galactose is an isomer of glucose - has the same basic atoms, but arranged differently.

The first step in digesting lactose is breaking it into these two simpler sugars, and that is accomplished by the enzyme lactase. Most human babies produce lactase to help digest lactose while being breastfed, but progressively stop making lactase as they mature, and milk becomes less a part of the diet. So, in fact, lactose intolerance is the normal state of most humans - it is the condition of lactase persistence that is the novel evolutionary event that permitted the creation of milk-based cuisines in Europe.

A lot of folks falsely think that any kind of digestion problem is due to the lactose, as lactose intolerance is quite common, but more than likely, if goat's milk can be digested, it's due to some other sensitivity that is specific to cow milk.