Milk is packed with protein, carbs, fats, and vitamins, making it the perfect nutrition source for babies. However, America’s massive dairy industry is proof that adults, too, can’t get enough of the creamy beverage. In the TED-Ed video below, narrator Addison Anderson provides milk lovers with an in-depth look at their favorite drink, explaining how mammals produce milk, why humans prefer milk produced by animals like cows, and how we use technology to prolong milk’s shelf life and make it safer to drink.

Keep in mind, however, that many humans aren't milk-drinkers: An estimated 65 percent of the human population has some form of lactose tolerance after infancy, meaning they aren’t able to digest lactose, a.k.a. the sugar in milk and dairy products. Cells in the small intestine produce an enzyme called lactase, which breaks down the lactose; some people produce less of it as they grow out of infancy. As a result, they suffer from stomach pain, bloating, gas, nausea, and diarrhea after consuming dairy. This condition is very common among individuals of East Asian descent, West African, Arab, Jewish, Greek, and Italian descent, according to the National Institutes of Health.

[h/t TED-Ed]

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