i want to start off with saying that this is not a scientific paper but rather just some thoughts after a discussion with my mom. she is 64 years old and has significant osteoarthritis and fibromyalgia. due to the fibromyalgia she has not been very active for over 30 years. she has recently been undergoing a bunch of doctor exams for spine problems and pain in her hands and hips.
i was speaking with her this morning and she was reading me the radiologist reports on her numerous x rays. it stated several times that she had significant osteopenia. i told her that that was bone loss and was the reason for taking calcium to prevent it. she told me that she had been taking caltrate for years based on the recommendation of my aunt who is an internal medicine specialist. she then wondered why if she was taking calcium supplementation would her bones be losing calcium.
i am a common sense sort of person. i am a big believer in research but it has to have some practical purpose to it for me to remain interested in it. in my profession it is important to be able to relate things in a practical way that people understand.
calcium is very very important for bodily function. one, it obviously is needed for boney growth, remodeling and support but it is also very important for muscle contraction. when one doesnt have enough calcium they will go into a tetnic state and have severe muscle tremors. muscle can not contract without calcium.
Summary of Events in Muscle Contraction and Relaxation
Arrival of motoneuron action potential
Synaptic transmission at neuromuscular junction
Action potential propagates along sarcolemma
Hypopolarization of T tubules
Ca++ released into sarcoplasm from sarcoplasmic reticulum
Ca++ bound by troponin
Cooperative configurational change in troponin and tropomyosin
Release of inhibition of myosin-ATPase
Link between thick and thin filaments, swivel of myosin head
Shortening by sliding filament
Ca++ removed from sarcoplasm
Mg++ATP bound by actinomyosin
Active tension disappears
Series elastic elements restore resting length
Chapter 14 - Muscle Contraction
another important thing in calcium regulation is vitamin D.
Vitamin D promotes calcium absorption in the gut and maintains adequate serum calcium and phosphate concentrations to enable normal mineralization of bone and to prevent hypocalcemic tetany. It is also needed for bone growth and bone remodeling by osteoblasts and osteoclasts [1,2]. Without sufficient vitamin D, bones can become thin, brittle, or misshapen. Vitamin D sufficiency prevents rickets in children and osteomalacia in adults . Together with calcium, vitamin D also helps protect older adults from osteoporosis.
Dietary Supplement Fact Sheet: Vitamin D
so we have to have adequate calcium and vitamin D for bones to function properly and be healthy. so why is it that my mother has low bone density even though she has been taking caltrate which has both calcium and vit D?
my theory- in race horses there is a condition that very commonly affects young horses in training called bucked shins. it is fracture of the cannon bone, the cannon bone is the long bone between the horses foot and its knee. this occurs because as the horses are being conditioned they are often galloped around the track to get their lungs and muscles in shape. this puts many loading cycles on the bone. the more the horse gallops the more stress on the bone and the bone starts remodeling to hold up to the applied forces. the problem is that as soon as the horse has its first work or first race where they are asked to run, the bone then develops microfractures. it is very painful and often interrupts training. this happens because bone remodels to the forces put on it. these horses bones have remodeled for the load of a gallop but not the load of a run which is significantly more forceful. so how does this relate to my mom? haha well, because of the fibromyalgia, my mom has been pretty seditary for over 30 years. she sits at the computer most of the day and any work she does is not heavy or forceful in any way. she might have brief moments of lifting something but overall, she doesnt do much of anything like that. her bones have no expectation of any kind of force. because of this, the body is not taking any calcium to remodel her bones and make them stronger, why should it, there is no stimulus for it to do so. so even though she is taking the calcium her body isnt using it to make her bones stronger, it is using if for muscle contraction and then probably dumping the rest of it. i imagine it is also still drawing calcium from her bones to utilize as well, thereby causing further osteopenia. the vertebra in her back are deteriorating as well as her discs. but never has she done any lifting to signal her back and the bones that make it up to remodel and get stronger.
now this is just my common sense way of tying it all together. im not saying it is right but it makes sense to me. so why am i even writing this? well, to me it just confirms that every woman out there should be doing some sort of physical exercise and lifting weights should be part of it. not that they have to be out there building muscle and trying to get huge but rather they should be doing it to apply stress to their bones so that their bones stay active and continue to keep up on its calcium absorption.