Some plant foods contain substances that can reduce the absorption of calcium, such as oxalates and phytates. To increase the absorption of calcium from plant foods, you can do the following:
Cook or soak the plant foods to reduce the amount of oxalates and phytates. Eat plant foods with vitamin C-rich foods, such as citrus fruits, tomatoes, peppers, or broccoli. Vitamin C can enhance the absorption of calcium. Eat plant foods with vitamin D-rich foods, such as fatty fish, eggs, mushrooms, or fortified foods. Vitamin D can also enhance the absorption of calcium.