Osteoporosis, Balance and Yoga

by Brad

A couple weeks ago, I attended a very interesting seminar on “Bone Marrow Adiposity:  An Age-Associated Phenotype; What's between bone and fat?  New insights into age-related osteoporosis” by Dr. Clifford Rosen, MD.  Dr. Rosen is the Director of the Center for Clinical and Translational Research at the Maine Medical Center Research Institute in Scarborough.  His talk was fairly technical and had to do with the regulation of fat in bone and how it increases slowly with age, as well as being affected by other environmental and genetic factors. His data showed that as fat accumulates in bone with age, it appeared to be related to a decrease in bone density, and therefore could be a driver of osteoporosis in both men and woman. He also stated that the clinical manifestation of osteoporosis is bone breakage, and therefore as your bone density decreases, it is the fall and inevitable bone fracture that typically turns people into patients. Avoiding a fall in the first place is possibly the best and for some the only way to avoid the adverse effects of this age-related decline in bone density.

After his seminar, I had a chance to talk with him after his research and asked him whether yoga might help by decreasing the risk of falling. He immediately said yes, and added that the yoga and tai chi were the two things that he knew that had been shown to have the greatest benefits in reducing this falling and bone fractures (see, for example, the Mayo Clinic web site's Exercising with osteoporosis: Stay active the safe way by choosing the right form of exercise and the New York Times article Ancient Moves for Orthopedic Problems). He implied that this was primarily through an increase in balance as opposed to strength. Indeed, while there is plenty of evidence that strength training is important, an increase in balance and flexibility can make all the difference between a stumble or misstep and a full-fledged fall.

As I sit on my flight to Seattle, I am reminded of how much variation exists in flexibility and balance among adults. Squeezing out of an aisle seat to make your way to the restroom or retrieving a suitcase from the overhead bin can easily become an awkward and precarious—and at times dangerous—act. And it is often not the oldest passengers, but the middle-aged and muscle-bound adults who induce serious cringing from neighboring passengers. Imagine how much more agile they would be if they all practiced yoga!

And for those of us who already do yoga, this is yet another compelling argument that working on balance is critical as we age. So if you haven't done so already, check out Shari's post last week about how to create a yoga practice to improve your balance (see Planning a Practice for Improving Balance).

Caloric Restriction: Comment and Response

by Nina and Brad

Brad’s post on caloric restriction (see Caloric Restriction and Longevity) prompted an interesting comment from Kathleen Summers MD PhD that I thought it worthwhile to share with you. Rather than having Brad respond in the comments section (I'm not sure how many of you actually read the comments), I asked him to reply to her comment at the end of this post. So have a look! This debate is a very good example of how little scientists currently understand about the aging process (a theme we return to periodically) and provides a hint of some of the many issues surrounding the controversy regarding the best diet for healthy aging.

Posted by Kathleen Summers MD PhD to YOGA FOR HEALTHY AGING

The biggest lesson here is that an excess of energy intake brings disease, disability, and early death. Restricting intake protects against cancer - and also diabetes, arthritis, and heart disease to some degree, although the numbers in the latest study didn't reach significance for the latter (potentially due to limited sample size). Teasing out just what the optimal amount of intake is takes time and research. And it's complicated - there's nutritional, environmental, mental/emotional health, and genetics among other factors playing a role.

The monkeys in both groups of the Wisconsin study ate more and weighed more than the NIH monkeys. The researchers used different sources for their proteins, fats, and carbs as well as a different approach to vitamin and mineral supplementation.

We have one primate study showing extended life span with calorie restriction and one not showing the same but yet other positive results. Let's not jump to absolute conclusions about what the latter study means.

Response from Brad Gibson PhD

Kathleen,

You make some good points, and I agree that this most recent NIA caloric restriction study needs to be considered within the context of other published work. There are undoubtedly many nuances in experimental design and interpretation that future experiments will need to address. That said, my major point is that the data for CR in primates is weak at best.  Many of my colleagues were very critical of the earlier Wisconsin study on two counts: the fact that they fed the control group a fairly high caloric diet and that they removed animals from their final analysis on the basis that they died from non age-related reasons. The removal of animals in the final statistical analysis was a very dubious call. And, as it was pointed out in the NYT article—and by many critics of the Wisconsin study—if those animals were included there was no difference in longevity between the two primate groups. Combined with other studies on more diverse genetic backgrounds in mice that show very mixed effects of CR, one really has to wonder how much traction the CR models has left in it, at least in mammals. Oddly, the data on other model organisms (flies, worms etc.) remain strong.  But one can only push these conserved evolutionary arguments so far.

While there may be benefits in a CR diet as you indicate (e.g., cancer and heart disease), one needs to make a distinction between a low calorie diet and caloric restriction. Many years ago a very prominent scientist in the field of aging who practiced the CR diet stated at the end of his seminar that "we scientists" needed to make a case to the public about the benefits of CR. I challenged him on this assertion, saying that American's relationship to food is so screwed up as it is, that to send a message that food is your enemy is not good advice. There is no evidence that CR in humans is beneficial. In contrast, there's plenty of evidence that a sound, balanced, healthy, low-to-moderate caloric diet (especially one that limits or avoid meat and dairy) is good for you. I suspect we are in agreement on that point.

I also agree that we are still far from drawing a final conclusion on the benefits of CR on human longevity. I was a bit flippant on this point in my last blog post. Guilty as charged. And there is little doubt that there will be more NIH studies examining CR and longevity in various mammalian and primate models as there is still compelling and interesting evidence that needs to be sorted when all animal models of CR and longevity are considered. However, I for one, will be placing my bets elsewhere.