Osteoporosis is a common bone condition affecting one quarter of women over the age of 50, in which there is a reduction of bone mass. There is normally a balance between the amount of bone being made and the amount being resorbed. In osteoporosis this balance is lost and less bone is manufactured than required, and bone resorbing cells become overactive.
The basic constituent of bone, calcium, drops to a dangerously low level, and the bones soften and may bend, break or collapse. Calcium is found in all dairy food (particularly cheese), sardines, shellfish, beans, nuts and tripe. Adults require up to 800 mg. of calcium, and children and pregnant women up to 1400 mg. a day. The structure of bones is being constantly renewed, and a lack of calcium over many years leads to a gradual deterioration in bone strength. Once women reach the menopause, the drop in hormone levels accelerates the loss of calcium from bones. It may be hereditary and is more common in petite, small-boned women.
Over the age of 50, half of all women will have a fracture due to osteoporosis, and one third of men over 70 will develop the same problem. Many of these fractures, particularly those in the vertebrae of the back, may have no symptoms.