Pea plants are commonly used for food. When almost at full maturity, the seeds of pea plants are harvested. The vegetables are then consumed fresh, generally as shell peas. In some cases, the pods are allowed to mature and then used dried. Both the peas and the pod are edible. The tips are known as "pea shoots" and can also be harvested and then cooked. Peas contain many different nutrients. They are excellent for keeping good bone health. They are a source for vitamin K1, which activates the noncollagen protein within the bones known as osteocalcin. The plants also provide vitamin B6 and folic acid, which are both nutrients that can decrease the accumulation of a metabolic byproduct known as homocysteine, which is dangerous and can block cross-linking of collagen, which could lead to osteoporosis.