Humans can eat acorns that are properly prepared. Only high-quality acorns can be used, and they must first be leeched of their bitter tannins in water.
In some ancient cultures, such as Iberia, acorns were a staple food. American Indians also consumed many of them. Over time, ground acorns have been used as a coffee during coffee shortages, and acorn meal has been used in place of grain flour in recipes.
Acorns are a dietary staple for certain wildlife, including some birds, squirrels, pigs, bears and deer. The large size makes them appealing because they are efficiently consumed, and they are high in nutrients.