They do not contain all eight essential proteins like meat, so plant foods must be combined with other foods to make a complete source of protein. Eating red beans and rice for instance, turns two incomplete proteins into a complete source. Calcium is need for strong teeth and bones. It is hard to fulfill the requirements for calcium from plant foods alone. Further, the calcium in plant foods may not be absorbed as readily as the calcium in animal sources.
Almonds also contain a fair amount of calcium.
Iron, an important component in the oxygen-carrying hemoglobin is fortunately abundant in plant sources such as, dried beans, peas and lentils. However, like calcium, the plant sources are not well absorbed by the body. One trick is to consume a food high in vitamin C at the same time you are eating these foods because vitamin C aids in the absorption of iron. Vitamin B 12 is another structural component of the red blood cells is not abundant in many plant foods. One way to ensure sufficient B-12 is to consume fortified dry cereals daily.