Development of a Model for In‐Vitro Comparative Absorption of Magnesium from Five Magnesium Sources Commonly Used as Dietary Supplements

Abstract

The purpose of this study was to develop a model system to mimic the intestinal absorption of magnesium when administered as a dietary supplement and then test various magnesium sources in the system. Caco‐2 cells (ATCC HTB‐37) were seeded in welled culture plates and allowed to mature for 21 days. Maturity was determined by stable trans‐epithelial conductivity measurements. The model was developed by evaluating applicable concentration ranges and incubation times. The optimum conditions for application of magnesium to the cells were determined to be 50 mM concentrations for four hours to 6 well culture plates. Absorption of the cation was determined enzymatically from the fluid in the basal chamber. After determining the model, magnesium bisglycinate (MgBG), magnesium bisglycinate with magnesium oxide (MgBuf), dimagnesium malate (DMM), magnesium oxide (MgO), magnesium citrate (MgCit) and a negative control were tested for absorption. It was found that all magnesium treatments had significantly elevated Mg content in the basal side (p<0.05). Within the magnesium treatments MgBG had the highest absorption of Mg (p<0.05). MgBuf had a numerically lower absorption result than MgBG but was statistically similar. DMM was greater than MgCit and MgO (p<0.05) but was not statistically different from MgBG although it was numerically less. MgCit and MgO were numerically similar and statistically equivalent. MgCit and MgO also exhibited lower absorption than MgBG, MgBuf and DMM. It was concluded that this model is an effective method for determining intestinal absorption of magnesium compounds as would be found in dietary supplements. It was also concluded that magnesium bisglycinate had the greatest absorption and transport across the intestinal epithelial layer and may be the most bioavailable of the compounds tested.Support or Funding InformationAlbion