A pregnant woman who has a lactase deficiency and cannot tolerate milk in her diet is concerned that she will not be able to produce milk of sufficient caloric value to nourish her baby. The best advice to her is which one of the following?

The woman will be able to breastfeed her baby because she can produce lactose from amino acids and other carbohydrates. She will not have to eat pure galactose, or even lactose, to do so. Glucose, which can be provided by gluconeogenesis or obtained from the diet, can be converted to UDP-galactose (glucose-glucose-6-phosphate-glucose-1-phosphate-UDP-glucose-UDP-galactose). UDP-galactose reacts with free glucose to form lactose. a-Lactalbumin is a protein that serves as the modifier of galactosyl transferase, which catalyzes this reaction. The amino acids of a-lactalbumin can be used to produce glucose, but the immediate products of a-lactalbumin degradation are not lactose. Carbohydrates cannot be synthesized from fats.