Most human cells can only replicate a limited number of times in cultures before they lose the ability to divide, a phenomenon known as replicative senescence, which seems to play a role in aging at the organismal level. Recent studies have shown that culture in low magnesium (Mg) accelerates the senescence of human endothelial cells and fibroblasts. Given the numerous critical roles of Mg, it seems likely that Mg inadequacy would interfere with cellular metabolism, which could affect the senescence process. Since i) several pieces of evidence link low Mg to aging and age-related diseases and ii) the Occidental diet is relatively deficient in Mg, we propose that broadly correcting nutritional intakes of Mg might contribute to healthier aging and the prevention of age-related diseases.