Q.  As a reader of your website and enjoying every page of it, I must say though, that you could recommend a better form of magnesium instead of oxide. Magnesium oxide has a lower rate of absorption and in higher doses will mess up the colon. I understand that it's the cheapest form but far the better. The recommendation should be with a form of citrate, glycinate or taurinate.

A.
  I would appreciate if you can provide us with references to long term human studies, at least 5 years, that show taking one form of magnesium provides better health benefits than another form. This would be quite interesting to our readers. I am currently agnostic on the form of magnesium to use. Many people think that absorption, alone, determines the value of one form over another. But there are many factors that determine the benefits or risks of supplements besides absorption. Assuming one form is better absorbed, it is also possible that it could have more side effects or toxicity over long term use or interactions with other supplements or medications. Hence, if a study was done giving 400  mg of mag oxide and compared to 400 mg of, let's say, citrate, for several years on a daily basis, assuming the citrate is better absorbed, it is possible that we may find some unknown harm has occurred in someone who took the citrate versus the oxide. In the September issue of the newsletter I reviewed studies that showed that excess calcium intake through supplementation actually increases the risk for heart attacks and stroke. Isn't it possible that if some people had used a form of calcium that had was not absorbed as well that their rate of heart attacks would have been less? My point is that a whole range of factors have to be considered in determining the benefits of a supplement rather than one factor, such as absorption. Nutritional medicine is much more complicated than most people realize. See http://www.raysahelian.com/complementarymedicine.html for prior issues of the newsletter.