Bone mass is built until age 29 years or so. After that, you cannot build more bone by increasing your calcium intake, but you can help prevent bone loss by maintaining a good intake of calcium and Vitamin D and exercising regularly. Chronically low calcium intake decreases bone mass and osteoporosis, leading to increased risks of bone fracture.
Osteoporosis is usually silent until people reach their later years.
Children, adolescents, and adult women may find it challenging to include enough calcium in their diets. Calcium deficiency is usually diagnosed in later years through bone density studies. Vitamin D is critical to aid in absorption of calcium from the gastrointestinal tract and in bone formation. Healthy adults over 50 years should have 400 IU per day. Elderly persons who are frail, housebound and have little sun exposure should have 600 IU of vitamin D daily.