The daily requirements for calcium and vitamin D have been changed to avoid certain problems, but controversy remains. More >
Taking Osteoporosis Out of Your Future — A Major Challenge for WomenOsteoporosis is the thinning of the solid structure of bone, the protein matrix with its deposited calcium, resulting in bone that is weak and at risk for fracture or collapse. To understand how osteoporosis occurs, you have to understand bone metabolism. Bone is not just sitting there in your body like an inert piece of rock. Bone is living tissue, in which there is a dynamic process of build up and breakdown (resorption) constantly going on. Build-up requires the building blocks, calcium and protein. The female hormone estrogen stimulates build up and discourages breakdown thereby maintaining bone strength. When estrogen drops for any reason — extreme weight loss, removal of the ovaries, or menopause — bone loss will occur.
Women of any age, but especially young women, mothers and women around the time of menopause, "perimenopause," need to take steps to prevent osteoporosis.
How to Prevent OsteoporosisGiven what we know today about osteoporosis, there is really no reason why contemporary young women should suffer the deformities and fractures of osteoporosis when they reach old age. Spine, hip and wrist fractures are not the inevitable consequences of aging. Proper diet, exercise and a number of new medications can be used for both prevention and treatment of primary osteoporosis. "Primary" osteoporosis refers to those cases where there are no other detectable causes, i.e., medications (steroids, anticonvulsants), endocrine conditions (hyperthyroidism or hyperparathyroidism) or bone disease, causing the bone loss.
In every woman, active bone formation occurs up to the age of 30, when she achieves peak bone mass. Thereafter, a gradual loss of bone begins until menopause, with an acceleration of bone loss for a period of about five years. Following that, there is again a gradual steady decrease. A woman who achieves a high peak bone density is much less likely to fall below the bone density level at which fracture risk becomes high.
Young women must adopt eating and exercise habits that contribute to bone formation. One half to one hour of weight bearing exercise three to six days per week, combined with adequate calcium intake, 1000-1500 mg/day, and vitamin D, 400-800 IU/day, are the most important building blocks of bone.
Diet Sodas and Couch PotatoesTwo trends in modern life are great hazards to bone formation: phosphoric acid-containing diet soda drinks and the sedentary lifestyle. Diet sodas have a high acid content that the body must neutralize with alkaline substances, notably calcium carbonate, which is leached from the bones. Frequently, girls and young women have made matters worse by trading in their milk for diet sodas and have thus deprived themselves of the single most important source of calcium. All women need milk products in their diets but it is especially critical for women who drink diet sodas. An 8 oz. glass of milk, 8 oz. of yogurt, a 1.5 oz. serving of cheese all provide 300 or more milligrams of calcium, providing a big boost to the daily requirement.
Whether the sedentary lifestyle happens in front of a TV screen or a computer terminal, it is still sedentary. But it is also true that too much exercise can backfire and interrupt bone mass build-up. Exercises that are associated with extreme thinness — distance running, gymnastics and ballet dancing — can lead to abnormally low estrogen levels with cessation of menstrual periods. This pseudo "post-menopausal state" can, by itself, produce further bone loss. The eating disorder, anorexia nervosa, contributes to bone loss by the same mechanism.
Tests to Detect Osteoporosis
Regular X-rays and DEXA (DXA)If you have an X-ray that reveals osteoporosis, you've already had a 30-50% decrease in bone mass from the normal level. Plain X-rays are certainly not appropriate for screening for osteoporosis, since they reveal late-stage disease. The current best test is the "DEXA," Dual Energy X-ray Absorptiometry. This technique is becoming widely available. The standard test provides a density measurement of the lower spine and the thigh bone (femur).
These measurements are compared with a standardized measurement of a healthy 35-year-old woman, the T-score, and with the average for your age group, the Z-score. Your score may be expressed as a percentage of those numbers. Your scores can also be plotted on a graph (below) of bone mass densities (BMD) at various ages. The reports are impossible to read (even for doctors) but with a little detective work you can sort them out. On your own report, there will be a little star on the graph, indicating your density. You will be given one report for the hip and one for the spine.
The dotted line in the graph is the fracture threshold. Note how more and more women fall below that line as they age. The light green area is two standard deviations (a measure of variation) above average and the dark green area, which is the one that concerns us, is two standard deviations below the average. As you can see, as women age, even average and above average BMDs can fall below the fracture line.
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