Bone Health and Osteoporosis
By Clinton L. Greenstone, M.D.
Issue: Winter 2003, Form and Structure - Issue #34
The bones are dense, highly active tissues comprised of special protein fibers called collagen that become mineralized primarily with calcium and phosphorus. Their surfaces are constantly being built up and broken down through the process of bone remodeling. Osteoclasts are bone cells that eat away old tired bone and pave the way for osteoblasts to lay down new healthy bone. Beyond that provided by simple material density, strength is added to bones through cross-bridging in their microscopic architecture.
Peak bone mass is reached in women by age 30-35 and in men between ages 40-45. After this time, breakdown exceeds bone growth and build-up. Bone loss is a normal process that takes place with aging and is not a disease.
Osteoporosis is characterized by weak, under-mineralized, and therefore frail bone that is at risk for spontaneous or fragility fracture (low impact). Even though postmenopausal women over age 60 have decreased bone density, only a small fraction of them actually experience fractures. A 50-year-old woman has a 15 percent chance of developing a hip fracture by the age of 85.1 Most of my patients are surprised to hear how low the risk is, given the media hype about osteoporosis, with accompanying bombardment of advertising for drugs that supposedly treat it. Osteoporosis is rare in men.
The most common tests for osteoporosis are DEXA or Bone Mineral Density (BMD) scans. Actually, these tests alone don’t predict fracture rates or show true bone strength in the overwhelming majority of patients. Instead, they are predictive of fractures only in people who have already had fragility fractures, and who have low bone density test scores.2 The tests are commonly conducted because administering them to large populations is relatively inexpensive. BMD is only one of many risk factors predicting fractures. Age, history of a previous fracture after age 40 and a maternal history of hip fracture are all independently more predictive than BMD.3
Furthermore, BMD measures only bone density, not bone strength. In a recent article in our premiere medical journal, The New England Journal of Medicine, experts studying osteoporosis showed that while, over time, a natural process of bone loss does take place, the strength of bone actually improves through increases in bone diameter. Changes in bone configuration and dynamics allow it to stay strong, accounting for relatively low hip fracture risks in the setting of low BMD.4
Some medications, particularly those in the bisphosphonate class, readily improve bone density within two years. Beyond two years, while bisphosphonates do not yield further BMD increases, they do poison the osteoclasts, allowing osteoblasts to lay down new bone on top of old, weak bone that would otherwise have been removed. Recent studies have suggested that even though there are slight decreases (1-5%) in fracture rates with bisphosphonates early on, after five or six years the fracture rates increase because the bone formed while on these medications is actually weaker.5
The safety of many of these medications beyond five years is relatively unknown. Furthermore, the specific dynamics of the most commonly prescribed medication for bone loss causes it to stay in the body for many years. So if it turns out not to be safe, it will be difficult to purge such a medication from your system. If a person already has a fragility fracture and low BMD, it is not unreasonable for a doctor to prescribe bisphosphonates6 –but taking them longer than two years is not wise.
There are many natural approaches to preventing bone loss, increasing bone strength, and decreasing fracture rates, falls and complications from osteoporosis. Diet plays an important role. Our bodies function best in a slightly alkaline environment, with a blood pH (a measure of acid and base balance) of 7.4. Our enzymes and internal cellular activities function best in this environment. The majority of foods we ingest, however, are acidic. Along with our kidneys, our bones provide a means of buffering the acid foods and keeping the blood in the basic pH range. To perform this buffering process, our bones lose calcium and therefore density. Furthermore, diets high in animal protein are quite acidic and cause calcium to be leeched from our bones. Our diets may also be somewhat deficient in appropriate mineralizing substances found in plants, in particular root-based and green, leafy vegetables. (See figure #1)
The process of bone remodeling goes on constantly. Weight-bearing exercises are the best way to stress the bones and stimulate the osteoblast/osteoclast activity that lays down new, healthy, strong bone. (See figure #2) Weight-bearing exercise also strengthens the supportive muscles that help us with coordination and with maintaining the strength and balance needed to prevent the frailty and falls that lead to osteoporosis-related fractures and their often debilitating complications. Weight-bearing activities have been proven to be more effective than medications at reducing fracture rates and falls.7
Other natural therapies include anthroposophical remedies, such as Calcon AM and PM, which promote healthy bone formation, calcium absorption and appropriate delivery of the calcium to bone. Appropriate calcium delivery also minimizes calcium entrance to other structures, such as our coronary arteries, where it is unwanted. The fatty sclerotic/hardening process of atherosclerosis is partly driven by inappropriate calcium deposition. Remember, heart disease is the no.1
killer of postmenopausal women.8
Hormone replacement therapy medications have been commonly recommended for treating osteoporosis. The U.S. Food and Drug Administration, however, actually pulled its recommendation and approval for the use of hormone replacement therapy in the treatment of osteoporosis in 2001. The reason: increasing evidence that the slight benefit in lowered fracture rates is significantly offset by heightened risks of developing stroke, heart attack and leg blood clots. These blood clots often migrate to the lungs with dire consequences.
It is imperative that everyone, but especially young women, become informed about these bone health issues so that they may be encouraged to take up weight-bearing exercise, and increase their consumption of whole foods and the higher plant protein-rich diets. These practices can help prevent osteoporosis, frailty and osteoporosis-related complications. We also need to support older women with their greater osteoporosis risk through similar appropriate recommendations, plus other natural approaches that support bone health and bone strength.
Finally, we must not allow ourselves to be misled by recommendations for BMD measurements before age 60 or 65. 9 They are designed to push us towards medications that show only minimal benefit, while adding significant risks and cost. It should be pointed out, also, that there are other medications and specific medical conditions that can adversely affect bone health. Ask a health care provider familiar with your health status for relevant individualized information.
Clinton L. Greenstone, M.D. received his medical degree from Yale University. He is currently a Clinical Assistant Professor of Medicine at the University of Michigan.
1.Osteoporosis Prevention, Diagnosis and Therapy. US NIH Consensus Statement March 2000.
2. Neilsen SP. The fallacy of BMD: a critical review of the diagnostic use of DXA. Clin Rheum. 2000;19(3):171-3.
3.Cummings,S.R et al. “Risk factors for hip fracture in white women.” New England Journal of Medicine. 1995;332(12)767-73.
4.Seeman, E. Periosteal bone formation-a neglected determinant of bone strength. NEJM2003;349(4):1835-7
5.Sanson, Gilliam. The myth of Osteoporosis: What every woman should know about creating bone health. MCD Century Publications, Ann Arbor, MI. 2003 Ann Intern Med. 2002;137:526-528
6.Heaney, RP. Bone mass, fragility and the decision to treat. JAMA. 1998;280(24):2119-2120.
7.Wolff, J.J ‘The effect of exercise training programsmon bone mass: a mete-analysis of published controlled trials in pre-and postmenopausal women.” Osteoporosis International 1999; 9:1-12.
8.Morbidity and Mortality weekly Report. 2003 Nov 7;52(44):1065-70.
9.USPSTF. Screening for Osteoporosis in postmenopausal women: Recommendations and rationale.