Your bones are alive

Many people are not aware that their bones are dynamic, meaning that they grow and change throughout your life. Because of this new growth and replacement of old bone cells, your skeleton completely changes over once every 7 to 10 years. Just like everything else in your body, you can ensure that the new cells are better than the old ones by eating well, living clean and exercising.

For those people whose bones are thinning due to osteoporosis, the breakdown of the old cells outpaces the renewal of new healthy bone cells, leaving the bones brittle, porous and thin, leading to breakage.

Osteoporosis is sometimes found after a bone has been broken or an illness has required an X-ray. Sometimes it is diagnosed when a health care provider has taken height measurements and noted that an older adult is shrinking in height. The vertebrae in the back are often the first bones to be affected by osteoporosis. It is notable that as many as 10 million Americans have osteoporosis and another 34 million have osteopenia, which is low bone mass — the precursor to osteoporosis.

Bone mass is at its greatest when people are in their 20s, and thereafter we need to fight to keep our bones strong and thick. Most everyone knows that we need sufficient calcium in our diets to keep bones strong, but there are many other factors as well that lead to osteopenia and then osteoporosis.

Low estrogen in women is actually the most prevalent cause of osteoporosis. This is an obvious problem for post-menopausal women but also shows up in very thin, athletic young women or those who starve themselves and are too thin to menstruate.

Another way women can become estrogen deficient is to have surgery to remove both ovaries. One study noted a 54 percent increase in hip, spine and wrist fractures in post-menopausal women.

Men need both testosterone and estrogen for bone health. Men convert testosterone into estrogen which helps preserve the integrity of their bones. When men have osteoporosis, testosterone levels must be checked. Other hormones that help regulate bone density are parathyroid hormone and growth hormone, because they help with calcium deposition and excretion. As we age we produce less growth hormone, which is vital for preserving strong bones.

Our bones are depositories for two minerals — calcium and phosphorus. We require a constant source of calcium in our blood because our heart, muscles and nerves need calcium. These essential body elements will take calcium from the bones in order so that they might function properly and if there is not sufficient calcium coming in, in the diet, the mineral reservoir in the bones depletes. Insufficient Vitamin D will lead to weakened bones and bone loss because it helps your body to absorb calcium.

Other causes of bone loss are: high levels of thyroid hormones; smoking, because it blocks the body’s ability to use estrogen, calcium and vitamins effectively; medications such as cortisone, hydrocortisone, glucocortisoids and prednisone; and some anti-seizure drugs; as well as too much alcohol (which can also increase your risk of falling).

Medical conditions that can lead to bone loss are: cystic fibrosis, digestive diseases, multiple myeloma and conditions that cause people to excrete too much calcium rather than capturing it, and laying it down in the bones.

However, for most of us, bone health is mostly a matter of lifestyle. Eating calcium-rich foods and getting enough Vitamin D, as well as doing weight-bearing exercises, are all strategies that help build and retain strong bones.

Next week, I’ll go into more detail about the food choices that you can make to build strong bones, and you are likely going to be in for a surprise! Until then, live well!

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Jane Riley, M.S., B.A., C.P.T., Certified Nutritional Adviser, can be reached at janerileyfitness@gmail.com, 212-1451 or www.janerileyfitness.com.