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[RC] magnesium? - Duncan McLaughlinHeidi wrote: ?On the other hand, the reason that it works as a laxative is because it isn't absorbed and therefore pulls fluids back into the bowel--so it isn't doing you any good as a magnesium supplement, either. And even though you might have to give more than you're apt to put into an e-lyte mix to have an appreciable laxative effect on a constipated horse, it is still not a very smart thing to put into a horse's gut when you're trying so hard to get fluids from the gut into the circulation and cells.? ---------------------------------------- It is too simple to say: the reason magnesium salts work as a laxative is because they are not absorbed and that they pull fluids back into the bowel. Magnesium absorption is primarily controlled by its level in the blood and there are two factors, the form of delivery and the dose rate, that affect uptake: 1. Generally, uptake (bioavailability) of salts, including magnesium runs from lesser to greater as follows: carbonate, sulfate, acetate, citrate. That is, citrates are more available than carbonates. 2. The rate of uptake is inversely proportional to the dose. If you give a small dose of magnesium, most of it (around 70%) is absorbed. If you give a large dose of magnesium, little of it (down to 20%) is absorbed. There are a whole bunch of factors (including presence of other minerals, plant phytates, stomach pH and so on) that also affect magnesium uptake. But generally, if serum magnesium level is low and/or falling, magnesium will be absorbed (actively transported), irrespective of hydration. If a small amount of bioavailable magnesium is used (as per commercial electrolyte mixes) this will be taken up and there is no risk of drawing fluid from circulation back to the gut. The risk occurs only if the magnesium dose is too large and/or not available. If this is the case you are going to have far more serious issues arising from the other electrolyte salts that are present in, absolutely and proportionally, much larger amounts. And although excessive magnesium salts can lead to diarrhoea, diarrhoeacan also be a symptom of magnesium deficiency. The key is to use the correct amount. Cheers Dunc Send instant messages to your online friends http://au.messenger.yahoo.com =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-= Ridecamp is a service of Endurance Net, http://www.endurance.net. Information, Policy, Disclaimer: http://www.endurance.net/Ridecamp Subscribe/Unsubscribe http://www.endurance.net/ridecamp/logon.asp Ride Long and Ride Safe!! =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
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