I always used to think that k2 and d3 were the critical factors for BMD, but then I read this study: http://www.ncbi.nlm.nih.gov/pubmed/21162947 which says "Type IIB human skeletal muscle fibers positively correlate with bone mineral density irrespective to age" and it got me thinking that activities that Increase Super Fast Twitch IIB muscles might likely be more important than even supplementing with k2/d3. What's your take on this?
I theorize it might be because IIB muscles have higher ca2+ signaling than slow and regular fast twitch fibers so, in the same way that k2 puts calcium where it should go, Super Fast Twitch muscles also keep calcium where it is supposed to be. So which do you think is more important for BMD, exercise or diet; or do you think they're equal?
asked byStephen_4 (10989)
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on February 18, 2013
at 12:51 PM
Wasting is common in the geriatric, as is protein deficiency. Protein intake correlates with BMD as well. So I'd wager a lot of it is diet. D/K2/Calcium are all important, but bone has a significant protein component.
Of course, I think there's quite a bit of activity components as well. As surfin' points out, activity will necessarily cause all sorts of hormonal changes, release of growth factors, chemocine secretion, etc...
on February 17, 2013
at 01:47 AM
If one were to use the analogy of a building site:
Diet is like the building materials. Provided the rate of supply is relative to their rate of use then there is no delay in construction (or suboptimal physiological response). But increasing the rate of building materials will not increase rate of construction above what the workmen, their equipment and site access can provide.
Activity is like the workmen and equipment. Exercise activates genes that encode growth factors and enzymes that direct and facilitate growth and repair.
Site access is like genetic limitations and age. These are constraints that are very difficult or sometimes not possible to get around.
In other words both exercise and diet are important but overall there are genetic and age related limitations.