Wednesday, December 13, 2006

Bone Mineral Density

Bone Mineral Density (BMD) is basically how much calcium is in your bones. We all deposit calcium as we are growing up into adulthood and then we start losing a little bit every year as we get older. Women begin to lose BMD at a younger age, start with less, and lose it even faster after menopause. Calcium is used by the body to maintain its pH or homeostasis. Our blood system is like a thermostat: it needs to maintain a steady balance between acidity and alkalinity. The balance it is set at is a pH of 7.4 or basically neutral. Any slight imbalance can cause chaos in the body and can lead to organ failure and death. In order to maintain the balance, calcium is used as a stabilizer.

Our blood pH is influenced by the acidity and alkalinity of the foods that we eat. Proteins acidify the blood while fruits, vegetables, and grains maintain the neutrality. A diet that is rich in protein requires that the blood “borrow” from the calcium bank in the bones. When it is through with the calcium, it escorts it out of the body via the urine. The end result is that the bone is a little bit poorer in calcium.

Katherine L. Tucker, MD, from Tufts University in Boston, Massachusetts, stated that “Soft drink consumption may have adverse effects on bone mineral density (BMD), but studies have shown mixed results." "In addition to displacing healthier beverages, colas contain caffeine and phosphoric acid (H 3PO 4), which may adversely affect bone." (Am J Clin Nutr. 2006;84:936-942). Other studies have pointed out that heavy users of caffeinated beverages such as coffee, tea, and colas, should be aware that some evidence suggests a link between caffeine use and osteoporosis, although other findings do not point to caffeine use as a risk factor. Caffeine may exert an effect only when calcium intakes are low.

As we can see, there are some studies that show evidence that links caffeine with osteoporosis and that colas also may increase the risk of low BMD or osteopenia. Osteopenia - reduced BMD – is a result of calcium leaching. What one sees on X-ray is an increased radiolucency of the bone, meaning that it is more transparent than expected.

Think of our bones as the structure of a high rise building; for it to be able to stay upright and withstand wind and other stresses, it needs to not only have a framework but also have something inside of the framework to strengthen it. With osteopenia and, consequently osteoporosis, the material inside of the framework disappears over time, making the framework less able to withstand the stresses of normal use (wear and tear). When this happens you end up with bones breaking unexpectedly because there is nothing in the framework to keep them from buckling or collapsing. We are all familiar with what collapse of the spine looks like; it is called the “dowager’s hump”.

How to prevent calcium leaching? This is done through good nutrition. A diet that is non-acidic, rich in raw fruits, vegetables, and grains, and low in acidic foods and carbonated drinks, will protect the bone because less calcium will be lost, maintaining the stability of the blood’s “thermostat”. In other words, it makes more sense to mend the leak in a bucket than to keep pouring more water into it.

For more information on how to protect your bones from calcium leaching and how to start eating an alkaline diet, go to http://www.betterbones.com/bbbb_program/step_four.htm.

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