what is vitamin d important for
Vitamin D helps regulate the immune system and the neuromuscular system. Vitamin D also plays major roles in the life cycle of human cells. Vitamin D is so important that your body makes it by itself -- but only after skin exposure to sufficient sunlight. This is a problem for people in northern climates.
Your body must have vitamin D to absorb calcium and promote bone growth. Too little vitamin D results in soft bones in children (rickets) and fragile, misshapen bones in adults (osteomalacia). You also need vitamin D for other important body functions. Vitamin D deficiency has now been linked to breast cancer, colon cancer, prostate cancer, heart disease, depression, weight gain, and other maladies.