12 replies to this topic

[SeekingSerenity]

Very few multivitamins contain magnesium, although most Americans don't get enough of it and it's an essential element in the body.


Why is that? And how do you ensure that you're getting enough magnesium?

[nameless]

Some include magnesium oxide. The problem is that magnesium is fat... it'll take up too much space to put in a one-a-day.
The RDA for magnesium would take up several capsules by itself.

As to figuring out how you are getting enough magnesium, you can try cronometer and measure your daily intake from food. A mag RBC blood test may give you a rough estimate.

[ta5]

It's bulky. Heaven forbid someone would have to swallow more than a single pill. Pills are dangerous, you know. (That's how a lot of people seem to think.)

One would probably want calcium with it. So, now you're talking even more bulk and another pill or two. If you take calcium, you probably want vitamin D. It makes sense to put those in separate supplements. Then, if you want more or less, you can adjust it separately from your other sups.

[niner]

Magnesium oxide is not very bulky, which is why most multis use it. Centrum, one of the most popular mainstream multis, contains 50 mg of elemental Mg in the oxide form. It is a single tablet. For my own use, I would prefer to see more than 50 mg, but it's better than nothing. Most of the organic counterions (citrate, malate, aspartate, orotate, etc) are quite large, so a given quantity of them would have only a small percentage of Mg. The oxide, on the other hand, is around 60% magnesium by weight.

[SeekingSerenity]

Magnesium oxide is not very bulky, which is why most multis use it. Centrum, one of the most popular mainstream multis, contains 50 mg of elemental Mg in the oxide form. It is a single tablet. For my own use, I would prefer to see more than 50 mg, but it's better than nothing. Most of the organic counterions (citrate, malate, aspartate, orotate, etc) are quite large, so a given quantity of them would have only a small percentage of Mg. The oxide, on the other hand, is around 60% magnesium by weight.

Doesn't magnesium oxide have a very low absorption rate?

[niner]

Doesn't magnesium oxide have a very low absorption rate?

It's not as bad as a lot of people think. There's a widespread belief that it's close to zero, but this paper shows it to be almost as good as the organic counterions, and better than other inorganic (Cl, SO4, CO3) ions. The bulky organic counterions do provide somewhat better bioavailability, but some of them have other problems, like potentiating the absorption of aluminum. Their main problem is bulk. If you are stuck with a single-tablet dosage form, you'd be better off with 100 mg of Mg as the oxide than with 5 mg of Mg as orotate, even if the bioavailability of the oxide was a little worse.

Edited by niner, 15 September 2012 - 12:54 PM.

[SeekingSerenity]

niner,

What do you think of magnesium citrate and magnesium asparate?


I saw two Calcium/Magnesium supplements that contain them:

http://www.iherb.com...oz-473-ml/36213

http://www.iherb.com...0-Caplets/15101

[niner]

What do you think of magnesium citrate and magnesium asparate?

They both have decent bioavailability. Citrate is less expensive, but it has two negatives that I'm aware of. One is that it causes GI problems in some people, and the second, which caused me to stop using it, is that it potentiates aluminum absorption. I don't know if the other organic ions have the aluminum problem, or if that's strictly a citrate problem.

[SeekingSerenity]

niner,

How would it potentiate aluminium absorption? Wouldn't you have to eat aluminum-containing foods in order for this to happen?

I didn't know that foods can contain aluminum.

[niner]

How would it potentiate aluminium absorption? Wouldn't you have to eat aluminum-containing foods in order for this to happen?

I didn't know that foods can contain aluminum.

I'm not sure what the mechanism is, but some combinations of metal ions and organic counterions appear more hydrophobic to the body than the bare metal would be. It's probably something like that. At any rate, aluminum is found in a lot of water supplies. Mine is a little higher than I'd like.

[SeekingSerenity]

niner,

How did you find out how much aluminum is in your water supply?

Btw, you are incredibly informative.

[nameless]

I recall going over the mag citrate/aluminum stuff with FunkOdyssey, way back when he was around, and although rodent studies show a possibility of increased aluminum absorption, there are pubmed studies showing that it doesn't happen in people, unless they are consuming high aluminum foods/antacids at the same time or have renal problems.

---

Calcium citrate markedly enhances aluminum absorption from aluminum hydroxide.

http://www.ncbi.nlm..../pubmed/2042654

Calcium citrate without aluminum antacids does not cause aluminum retention in patients with functioning kidneys.

http://www.ncbi.nlm..../pubmed/8453325

The lack of influence of long-term potassium citrate and calcium citrate treatment in total body aluminum burden in patients with functioning kidneys.

http://www.ncbi.nlm..../pubmed/8632109


One thing I never quite understood... in the studies that show increased urinary aluminum being excreted due to citrate + aluminum, couldn't this just mean less aluminum is being absorbed by the body, and is instead being excreted, due to citrate? Why is it assumed that body absorption is higher? Couldn't it be the opposite?

I'm also pretty sure I read that it may not just be citrate that could increase aluminum (or increase urinary excretion), but same for malic acid (and possibly others). Although in malic acid's case, the increased urinary excretion is typically mentioned as a positive, as a way to decrease absorption of aluminum, due to excretion. So basically it has the same effect as citrate, but spun as a positive.

[niner]

How did you find out how much aluminum is in your water supply?

Btw, you are incredibly informative.

I just called up my water company and asked them. I was interested in several other things as well, like copper, silicon, lithium, and toxic heavy metals. Once I got past the phone answerer who just wanted to reassure me that "everything is fine", they were very cool about it and sent me a very complete report. Thanks for the kind words!

I recall going over the mag citrate/aluminum stuff with FunkOdyssey, way back when he was around, and although rodent studies show a possibility of increased aluminum absorption, there are pubmed studies showing that it doesn't happen in people, unless they are consuming high aluminum foods/antacids at the same time or have renal problems.
[...]
One thing I never quite understood... in the studies that show increased urinary aluminum being excreted due to citrate + aluminum, couldn't this just mean less aluminum is being absorbed by the body, and is instead being excreted, due to citrate? Why is it assumed that body absorption is higher? Couldn't it be the opposite?

I'm also pretty sure I read that it may not just be citrate that could increase aluminum (or increase urinary excretion), but same for malic acid (and possibly others). Although in malic acid's case, the increased urinary excretion is typically mentioned as a positive, as a way to decrease absorption of aluminum, due to excretion. So basically it has the same effect as citrate, but spun as a positive.

Thanks for the refs. It's encouraging to know that there are not obvious effects with healthy kidneys and not-high Al intake. After seeing the epidemiology of Alzheimer's as a function of levels of Al in tap water, and knowing that my water is right on the edge, I was worried about chronic effects from very long term use. Call it an abundance of caution/paranoia... I wouldn't be surprised if other organic anions would have similar effects, although citrate might be special because its charge is -3 and the Al ion is +3, so it might form a neutral coordination complex. You raise a good point about the spin on the urinary excretion data. For a lot of metals, it's really hard to get accurate levels or speciation data, because the levels are biologically controlled and differ according to the biological compartment you look at. I don't know if Al is one of those metals, but I'd be happier with data that came from tissue samples, even if the tissue is blood, which also may be misleading if, for example, the main repository were bone.

Edited by niner, 17 September 2012 - 06:40 PM.