KN

KIN 343 - 5.3 Magnesium Bioavailability

5.3 Magnesium Bioavailability

Overview of Bioavailability

  • Magnesium bioavailability is influenced by several factors, paralleling calcium bioavailability factors.

Influence of Phytate

  • Phytate's Role: Phytate decreases magnesium absorption by binding to magnesium.

    • Phytate can form insoluble complexes that are not absorbed, necessitating free ionic magnesium for absorption.

    • Digestion Limitation: Humans lack phytase and cannot digest phytate efficiently; thus, magnesium remains bound and is excreted in feces.

  • Improving Absorption with Phytase:

    • Adding phytase from yeast or bacteria can enhance magnesium release during digestion.

    • Pretreatment of foods, like allowing yeast to act on bread, can make magnesium more bioavailable (up to 70% more compared to untreated bread).

Effects of Long Chain Fatty Acids

  • Binding with Magnesium: High levels of unabsorbed long chain saturated fatty acids can sequester magnesium by forming insoluble soaps, leading to decreased bioavailability.

    • Fatty Soaps Formation:

      • Interaction of magnesium with long chain fatty acids reduces magnesium absorption, similarly to soap scum formation in hard water.