Posted by Larry Hoover on April 28, 2003, at 22:49:21
In reply to Magnesium and Calcium Questions, posted by noa on April 28, 2003, at 18:53:50
> Help!
>
> I had a kidney stone (or may still have it but it is quiet at the moment, perhaps hiding in my bladder for now).
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> My first, and hopefully last! Pain as I have never known it visited me (and overstayed its welcome by about 6 hours!) when the stone was passing through my ureter.They say it's some of the worst pain there is. I'm sorry.
> OK, so this is not exactly psychopharm material, but there are some experts on magnesium supplements here, so I figured I'd ask...
>
> I am reading up on kidney stones and quite unsure about what to do about calcium. It *seems* the latest info is that reducing calcium intake is NOT likely to reduce kidney stone formation, but there is something about whether calcium is absorbed in the bones or eliminated through the kidneys, etc. that I don't quite get yet. However, several sites do say that calcium supplements could increase risk of stones (but I need my calcium supplements to prevent osteoporosis which runs in the family).There is a complex interplay of events to consider, so simple statements like "avoid calcium supplements" or "you need calcium supplements to deal with osteoporosis" are really not very useful. Each statment depends on a lot of other things, but you don't often hear about those conditions.
> Anyway, a couple of web sites talk about magnesium being helpful to prevent calcium-based stones, particulary magnesium citrate (both the magnesium and citrate having different preventive actions). They also talk about potassium citrate as helpful (again, both the potassium and citrate being helpful).
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> Can someone explain in basic terms how magnesium and calcium relate to each other?I'll talk about the part I do know. Bone is composed of calcium phosphate in a crystal structure known as hydroxyapatite. Magnesium replaces a bit of the calcium in the crystal structure such that the ratio of these two in bone is something like 40:1. Just as the dominant storage site for calcium is bone, the same is true for magnesium. If your body needs either mineral, bone is resorbed. It can be said that you won't long survive low calcium or magnesium in the blood, but you'll probably survive weakened bones.
Your bones are constantly being renewed, in a balancing act between deposition of new bone by osteoblasts, and destruction of bone by osteoclasts. There are three major hormones which interact to affect the balance, parathyroid hormone, calcitonin (from the thyroid, and dependent on zinc), and vitamin D (actually a steroid hormone). There are different sensors in the gut, bone, parathyroid gland and kidney which determine circulating levels of calcium and magnesium, and regulate uptake and secretion. The take-home message is that there's a lot going on. Some things increase bone strength, while simultaneously, others are weakening it. Your kidneys try to keep blood calcium and magnesium from leaking into the urine, but stress hormones can override that.
Back to simple statements. Magnesium citrate can help with certain stone-forming processes, because one major cause of high blood calcium (and thus calcium load in the kidney) is magnesium deficiency. Get the magnesium back up, and blood calcium levels will fall. I'm not sure, but I think the citrate helps to keep any calcium that does get into the urine dissolved.
I'm not sure that simple statements are a good idea. I think you need to find out what is causing your stones (there are a number of causes, and types of stones), and you probably need to know something about your current bone density and circulating levels of calcium and magnesium. In other words, I think a good workup is in order.
> Also, I am at risk of osteoporosis, and I read one abstract that suggests that there could be common genetic marker between kidney stones and low bone density. I figure this must have something to do with how calcium is absorbed by the bones or not.
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> Any help understanding this stuff is much appreciated.Here's probably more than you wanted to know about calcium and bone:
http://www.endotext.org/parathyroid/parathyroid2/parathyroid2.htm
Good luck with this. It is a manageable condition, once you know what it is you're trying to manage.
Lar
poster:Larry Hoover
thread:222998
URL: http://www.dr-bob.org/babble/20030423/msgs/223054.html