FAMILY MEDICINE® COLUMN
By John C. Wolf, D.O.
Associate Professor of Family Medicine®
Ohio University College of Osteopathic Medicine

IN-HOME PILL TEST CAN REVEAL "BIO-AVAILABILITY" OF CALCIUM

Question: I am in my 40s and am concerned about bone loss. I know that calcium is suppose to help, but I don't know which type to take. And, can't it cause kidney stones? Is there anything I can do to guard against this? Also, I know that estrogen is good for osteoporosis, but is it safe and should it be taken with progesterone?

Answer: Bones are made of stored minerals -- mostly calcium -- and several types of living bone cells. Some of these cells constantly dissolve existing bone, and at the same time, others lay down new bone. All bones, whether in an adult or a child, are continually undergoing this type of change. Until early adulthood the rate of "bone making" is greater than that of "bone destruction." Therefore, there is an increase in the total amount of bone -- in other words, growth. Normally during adult years, the amount of bone formed is equal to that lost. This produces no net change in the strength of bones because the quantity of stored minerals and living bone cells remains constant.

Osteoporosis is a disease characterized by a loss of bone mineral content. This loss of minerals can be the result of diabetes, kidney disease, the use of certain medications, or because of other poorly understood causes. Nutrition also plays an important role. Consumption of large quantities of sodium, phosphates, proteins, caffeine or alcohol can all decrease the amount of calcium and, thereby, increase the risk of osteoporosis. Excessive phosphate intake usually comes from drinking too many soft drinks and excessive caffeine ingestion from too many soft drinks or cups of coffee.

The loss of bone strength from decreased mineral content often results in fractures in the vertebra in the region of the shoulders and low back, in the lower arm and also in the hip. Most of these bones are broken suddenly with only minor exertion. Sometimes all that's needed to break a weakened bone is lifting a light object, getting out of a car, stumbling over a curb, suffering a minor fall or even just riding in a car traveling on a bumpy road. At the moment the bone is fractured, the person experiences acute pain in the area of injury, which is accompanied by many spasms in the surrounding muscles.

As you obviously know, the body needs calcium in order to build strong bones. The most common dietary source is dairy products. However, most adults don't consume sufficient milk and milk products to meet their calcium needs. The average cup of milk contains only 300 milligrams, and the typical diet provides about 700 milligrams per day. Since the average post-menopausal woman should have 1500 milligrams of calcium each day, it is apparent that most need to take supplemental calcium.

Not all calcium is the same. In order to derive any benefit from it, it must be in a form that the body can readily absorb. Calcium citrate, calcium carbonate and calcium phosphate are usually good choices. Even within these types of calcium, however, there is considerable variation between brands. There is a simple in-home test you can do determine if your body will absorb enough of the product for it to be "bio-available." Place a tablet in a glass of room-temperature vinegar. If it dissolves within 30 minutes it's OK, if not, find another brand.

While the most common kidney stones are formed from calcium oxalate, taking extra calcium in the quantities I've mentioned doesn't increase this risk. It is the level of oxalate that enhances the risk of stone formation, not the level of calcium.

Your question about the roles of estrogen and progesterone in the prevention of osteoporosis is important, but sufficiently complex that its discussion fills volumes. I suggest that you take your calcium and also talk to your doctor about any benefits hormone replacement therapy could have for you.

Family Medicine® is a weekly column. To submit questions, write to John C. Wolf, D.O., Ohio University College of Osteopathic Medicine, Grosvenor Hall, Athens, Ohio 45701. Past columns are available online at http://www.FamilyMedicineNews.org.