Absorption

To be well absorbed, magnesium needs to be in a soluble state.
All the compounds forming insoluble complexes (oxalates and phytates) reduce its absorption.

We used to think that dietary fibres reduce its absorption but on the contrary, they might even enhance it.

Approximately 30% of magnesium is absorbed in our intestines.
It means that when you consume 300 mg of magnesium only, 90 mg are absorbed.