The effects of micronutrient beverages influencing the bioavailability of calcium and magnesium via antacid supplementation were investigated in vitro. The beverages containing aqueous (free) calcium and magnesium were examined for additional binding capability upon antacid utilization. Samples were analyzed for calcium and magnesium content by inductively-coupled plasma (ICP-AES). The calcium and magnesium concentrations were measured with both regular and extra strength antacids tablets both neat and also mixed with ~30 mL of the each beverages. Temperature and pH were controlled to mimic stomach conditions (pHs = 1.3-2.3, T = 37°C) as close as possible. The neat antacid samples were measured in the range listed for calcium and magnesium on the USRDA labels for each beverage tested. Upon supplementation using the beverages, the calcium and magnesium levels spiked up to 3500 mg/L Ca and 140 mg/L Mg, well above USRDA values. A kinetic study was also conducted and found that significant reductions in aqueous calcium and magnesium were found in the neat samples as pH was increased from 1.3 to 2.3 over 90 minutes. However, when the beverages were added, a substantial leveling effect occurred and reductions of aqueous calcium and magnesium were miniscule.