Osteoporosis means 'porous bones' and is a disease where bone density and structural quality deteriorate, leading to weakness and bone fragility of the skeleton and increased risk of fracture. Bone loss is often gradual and without warning signs, until the disease is advanced. From the mid-30's onwards there is a mismatch between bone production and bone breakdown, resulting in a gradual decrease in bone strength with increasing age in both men and women. The hormonal changes that occur at menopause can accelerate the loss of bone tissue as oestrogen levels fall rapidly which significantly increases the loss of calcium from bone. Osteopenia is a medical term to describe thinning of the bones. (Osteoporosis Australia)
Bones hold 99% of the body's calcium and act as a calcium storage facility, allowing it to move from bone to blood and vice versa. Calcium is a mineral that constitutes up to two per cent of our body weight. If there is insufficient calcium in our diet, the body will take it from our bones to maintain important things such as cell structure etc. It also helps to neutralise excess lactic acid built up from exercise or stress and is often recommended alongside magnesium to help muscle cramps. The recommended daily dose of calcium is 800mg for men and 800-1300mg for women (even more for post-menopausal).
Good sources of calcium include milk and dairy products, nuts, seeds, whole grains, figs, tofu, Asian green vegetables and fish with edible bones (sardines, canned salmon).
Foods that negatively impact on calcium (i.e. affect absorption) include tea, salt, sugar, coffee, animal protein (meat) and phosphates mainly found in fizzy drinks.
Supplements are often recommended, particularly the ones that contain calcium citrate, calcium lactate, calcium gluconate or calcium hydroxyapatite, which are the best absorbed – it is best taken at night.
For more information, take a look through "Help Yourself: an A-Z of natural cures for common complaints" by Mim Beim and Jan Castorina. It's published by Doubleday and is available through all good bookstores.