What is the health risk of too much magnesium?
Dietary magnesium does not pose a health risk, however very high doses of magnesium supplements, which may be added to laxatives, can promote adverse effects such as diarrhea. Magnesium toxicity is more often associated with kidney failure, when the kidney loses the ability to remove excess magnesium. Very large doses of laxatives also have been associated with magnesium toxicity, even with normal kidney function. The elderly are at risk of magnesium toxicity because kidney function declines with age and they are more likely to take magnesium-containing laxatives and antacids. Signs of excess magnesium can be similar to magnesium deficiency and include mental status changes, nausea, diarrhea, appetite loss, muscle weakness, difficulty breathing, extremely low blood pressure, and irregular heartbeat. The Institute of Medicine of the National Academy of Sciences has established a tolerable upper intake level (UL) for supplementary magnesium for adolescents and adults at 350 mg daily. As
