3 replies to this topic

[DeepB]

Hello,

I use cronometer to track my nutrients, and use a new multi now.
It says Magnesiumoxide 100mg. I guess this does not factor in bioavailability, so if I factor that in I just put 20mg in cronometer (if we assume bioavailability of 20%)?

Is that correct?

best regards
Daniel

[Heh]

100mg is probably the amount of Magnesium (Mg) in the total molecule (MgO). Then after that you take into account bio-availability. Magnesium Oxide's bio-availability is around 4%.

Edited by Joel, 13 May 2013 - 08:58 PM.

[niner]

100mg is probably the amount of Magnesium (Mg) in the total molecule (MgO). Then after that you take into account bio-availability. Magnesium Oxide's bio-availability is around 4%.

Yes, 100mg is the elemental amount of magnesium in the pill, which excludes whatever counterion it's bound to. The 4% bioavailability of MgO is a myth. The correct number is more like 20%. I'd check the documentation for Cron-O-Meter to see how supplements are supposed to be treated. RDAs are based on the amount of substance that you are supposed to consume, not the amount that is absorbed, so it implicitly factors bioavailability in already, although the bioavailability of food source minerals and supplemental minerals may be different, perhaps by a lot.

[DeepB]

But how is biovailability factored into RDA? or is RDA without bioavailability?

If it is without I just use 20%, if it is with bioavailability I have to adjust accordingly.
So it does not really have anything to do with the used software I think.