Lactating people can have caffeinated products, such as coffee, tea and chocolate. Caffeine passes into human milk. The breastfed or human milk fed infant who is exposed to high levels of caffeine may have jitteriness, fussiness and trouble sleeping. It is ideal to limit the amount of caffeine to the equivalent of 5 cups of coffee a day, or 300-500mg of caffeine a day. Younger infants such as newborns and premature infants may be more sensitive to caffeine because they don’t metabolize the caffeine as quickly.