NOW Lactose Details Extract of Sweet and Sour Whey Assists in the Growth of Beneficial Gut Bacteria Naturally Sweet Did you know that the first carbohydrate you and every other mammal on Earth consumed was Lactose? Also known as “milk sugar”, Lactose is a natural sugar found in milk. Extracted from sweet or sour whey, NOW Real Food Pure Lactose is about 20% the sweetness of sugar and is used in unique food applications and as a sweet addition to children’s milk. Lactose is also a good way to support the growth of beneficial gut bacteria such as acidophilus.