This post was on another forum in reply to Hv,
>>"Thus, magnesium citrate was more soluble and bioavailable than magnesium oxide."<<
1 for 1, this is true, however many things affect the absorption rate including the digestive health of the individual and when and with what the supplement is taken.
And I pointed out the digestive issues on the other forum. As I pointed out there is a big difference between the 8 to 14 year old girls that will have sufficient stomach acid and the ability to produce stomach acid and an older adult with declining stomach acid. The other thing to keep in mind is what is the likelihood that an 8 to 14 year old girl will be supplementing with magnesium oxide anyway? Older people are more likely to supplement since acid levels DECLINE with age making nutritional deficiencies more likely.
In addition, magnesium content in an oxide is about 60%, and in a citrate or chelate, 12 - 16%.
Actually I can get acidified magnesiums in higher concentrations than that. Although this still does not change the fact that magnesium oxide is the least absorbed of magnesiums and magnesium oxide/hydroxide is caustic. That is like telling some one to drink Drano for the alkalinizing potassium hydroxide. All forms of minerals ARE NOT safe!!!!
So while gram for gram the magnesium in a citrate or chelate form may be absorbed at a higher rate, the oxide form has more magnesium to absorb and in certain individuals, can offer more magnesium. 2 out of 6 individuals showed this in one small study.
I would like to see the study. Which study are you referring to? Is it a human study? What was the age group tested? Should I go back over how easy it is to manipulate studies to prove whatever it is that the researcher wants to prove?
Again this depends upon digestive health, with what, and when taken.
Which again provides ways to manipulate studies.
Another interesting aside here is that magnesium levels in blood are tightly regulated, and increased magnesium levels in urine happen with all magnesium supplements, including Epsom Salt baths or magnesium oil use...
That one has greater amounts in their urine is an indication that they are taking more than they can use at any one time...
Actually this is incorrect. First of all in order for magnesium to be excreted through the urine it must first be absorbed in to the bloodstream. Because less magnesium oxide is absorbed in to the bloodstream less of this magnesium is excreted through the urine. As more evidence to this acidified magnesiums such as malate and citrate are very effective in controlling calcium induced hypertension. Magnesium oxide/hydroxide is not, but it works as a laxative. Why? Because most of the magnesium oxide/hydroxide stays in the intestines where by its caustic nature it chemically burns the intestinal wall leading to a release of water in to the intestines and increased peristalsis. The same process by which bile dumping after gallbladder removal causes diarrhea. The chronic burning also increases the risk of intestinal cancer.
In addition magnesium can also be displaced, for example by alcohol consumption. The displaced magnesium can be eliminated through the urine. This does not mean the person has more magnesium than they can use. The same applies to calcium. For example a person can have hyperparathyroidism and can dump a lot of calcium in the urine. This does not mean they have more calcium can they can utilize. In fact this condition can quickly lead to osteoporosis.