Magnesium: causes of deficiency
Magnesium deficiency usually stems from an imbalance between intake, absorption, and losses. It can be transient (acute diarrhea) or chronic (poor intake over time, medications, diseases). Understanding the cause guides durable correction—food first, then targeted supplementation if needed.
Why we fall short: low intake or increased losses
Two mechanisms dominate:
- Insufficient intake, typically from diets low in plant foods, seeds, and legumes
- Increased losses from the gut (diarrhea, malabsorption) or kidneys (diuretics, tubulopathies)
Some situations combine both (alcohol use, GI diseases).
Digestive causes: malabsorption, diarrhea, surgery, and chronic alcohol use
Intestinal diseases (IBD, celiac), chronic diarrhea, and resections/bypass surgery reduce absorption and increase losses. Chronic alcohol use lowers intake, impairs absorption, and raises renal losses, combining mechanisms (see hypomagnesemia).
Renal losses: drugs, diabetes, tubular disorders, and diuretics
Diuretics (thiazide, loop) increase urinary magnesium excretion. Some tubulopathies, glycosuria (poorly controlled diabetes), and drugs (aminoglycosides, amphotericin B, cisplatin) raise renal losses.
Proton‑pump inhibitors are associated with sometimes severe hypomagnesemia, especially long‑term or combined with diuretics. Reassess indication and monitor if symptoms appear.
Low dietary intake and increased needs in common scenarios
Low intake of nuts, seeds, legumes, whole grains, greens exposes to low dietary magnesium; needs increase during pregnancy, breastfeeding, heavy training blocks, or some chronic conditions — see the reference factsheet.
Role of PPIs and other treatments
Beyond PPIs, several medicines contribute: diuretics, aminoglycosides, amphotericin B, cisplatin, cyclosporine, tacrolimus. Long‑term laxatives and alcohol also increase losses. A detailed medication review is essential before concluding/adjusting (see hypomagnesemia and clinical summary).
Increase dietary intake first. Where feasible, adjusting causal meds reduces supplement needs and improves stability.
Main causes by mechanism and practical clinical clues
- GI losses: chronic diarrhea, IBD, surgery; lower absorption + higher losses
- Renal losses: diuretics, tubulopathies, diabetes; higher urinary excretion
- Drug‑related: PPIs, aminoglycosides, cisplatin; lower absorption or higher losses
- Low intake: refined diets low in plant foods
- Increased needs: pregnancy, heavy training; higher tissue use
- Alcohol: chronic use; lower absorption + higher losses
