Aquamin: A Source of Bioavailable Calcium, Magnesium, and Additional Cationic Trace Elements in Colon Health and Beyond

Introduction: Aquamin is a calcium- and magnesium-rich natural product derived from marine red algae that contains multiple trace elements. Human and mouse studies have demonstrated potential health benefits. Methods: Aquamin and calcium carbonate were compared using a two-stage simulated gastric and intestinal digestion protocol. ICP-OES/ICP-MS was used to quantify cationic elements in soluble and insoluble fractions. Binding of dispersed mineral powders to human colon epithelial cells was assessed by light and scanning electron microscopy, and uptake was assessed by transmission electron microscopy. TMT-based proteomics identified protein changes in colon epithelial organoids following mineral exposure. Serum samples from 90- and 180-day Aquamin intervention trials were analyzed for changes in circulating cationic elements. Results: Both Aquamin and calcium carbonate were solubilized under simulated gastric conditions, although Aquamin was more acid-resistant. After transfer to neutral-pH intestinal conditions, limited precipitation occurred, and most calcium remained soluble. With Aquamin, magnesium and strontium also remained soluble, whereas several trace elements became partially or completely insoluble. Aquamin rapidly bound to colon epithelial cells, with ultrafine Aquamin particles detected between adjacent cells. Calcium carbonate bound more slowly and to fewer cells. Aquamin increased proteins involved in enterocyte cation uptake, intracellular trafficking, and basolateral secretion. Serum strontium levels increased in study participants after 90 or 180 days of Aquamin consumption; most other elements changed minimally, although serum iron increased modestly. Conclusions: Aquamin provides a bioavailable source of several cationic elements. Soluble calcium, magnesium, and strontium may be absorbed primarily through transcellular pathways, while less-soluble elements may also cross the colonic epithelium through paracellular mechanisms.