Bone Density Mistakes

April 27, 2010

Break Your Bones 2: Bone Density Mistakes 

 Competency: #5 The Way to Eat Reference:  Building Bone Vitality by Michael Castleman and Amy Joy Lanou, McGraw Hill 2009 Bone Mineral Density.  

It’s how we measure your risk for a broken bone.  We put you under a big machine that takes a snap shot of how many calcium atoms you have in your bone and we call that your bone mineral density (BMD).  The premise of all that is the more calcium you have in your bones, the stronger your bones should be.  It’s an interesting hypothesis.  We even have guidelines to suggest that you should have scans done of your bone mineral density starting at certain ages.  We’ve done millions of them.  DEXA stands for Dual-Energy X-ray Absorptiometry.  They are expensive.  They tell you how dense your bones are.  There is clear evidence that very low-density bones have a higher risk of fractures. 

 As a consequence, most research on osteoporosis in the last 30 years has switched from fractures to BMD studies.  These studies are faster and cheaper to do than fracture studies that require waiting around for folks to break bones.  Unfortunately, they do not study the problem of fractures directly.  They study bone density which is one step removed from what matters to you and me, fractures.   Does doing any intervention change your BMD or does it change your fracture risk?  We have presumed they are the same.  They aren’t. 

 Here’s the rub.  Castlemann and Lanou review all 141 fracture studies published in the medical literature and elegantly show that the fracture studies don’t support the calcium hypothesis.  What they point out is that of the 141 studies, only 47 studies, or 33%, produce significant statistical results that support extra calcium reducing fractures.   But 75 of the 141 show no beneficial effect on fractures from extra calcium or milk.  That’s a problem.  Research is messy.   But this is a two to one ratio against benefit, over decades of research.  I’ve personally been on the camp of the calcium side, because there has just been so much momentum with guidelines and tests and everyone just doing it.  It seems like the right thing to do.  Besides, the milk industry does very effective advertising. 

 But is it true?  Maybe we should rethink this again.  We need an alternative hypothesis to consider in a thoughtful way.  Particularly when we realize that there are cultures and societies that have less than 1% of the hip fractures than we do in America.  When the best research we can come up with consistently shows in a ratio of two studies to one that adding more calcium doesn’t do it, it’s time to throw in that towel and figure out just what it is that does do it. What is the alternative hypothesis?  The alternative is acid and the need for your kidneys to keep your body in acid-base balance when you eat acid.  Where do you get acid from?  Animal protein (meat, milk, cheese, yogurt, fish, eggs).  Next week, we’ll explain how. 

 WWW.  What will work for me. The evidence is piling up.  We know that societies that eat more plants have less fractures.  Now we understand the reason.  Acid comes from animal protein.  I need to learn this stuff.   We all do.  Next week, more details.

Column written by Dr. John E Whitcomb, MD, Brookfield Longevity, Brookfield, WI (262-784-5300)