Can reduced digestive enzyme activity limit magnesium absorption and tissue repletion?

Reduced digestive enzyme activity is most relevant to magnesium status in pancreatic exocrine insufficiency (EPI), particularly chronic-pancreatitis–associated EPI. The overall claim is biologically credible and clinically consistent, although direct proof that enzyme deficiency itself reduces fractional magnesium absorption remains limited.

Clinical evidence

• EPI causes maldigestion and steatorrhea and commonly coexists with broader nutritional compromise, including magnesium, calcium, zinc, and fat-soluble vitamins.
• In a prospective 112-person cohort, magnesium deficiency occurred in 12.2% of patients with EPI and was significantly more frequent than among those without EPI.
• In a smaller chronic-pancreatitis study, intravenous magnesium-loading testing identified total-body magnesium deficiency in 10 of 13 participants. Low serum magnesium (<2.05 mg/dL) was also associated with EPI, though serum magnesium is neither a sensitive measure of total-body stores nor a specific marker of intestinal malabsorption.

Mechanistic and practical considerations

• Pancreatic enzyme deficiency impairs fat and protein digestion; persistent fat malabsorption may create conditions in which calcium and magnesium form poorly absorbed soaps with fatty acids.
• Magnesium absorption is inherently incomplete and dose-dependent: fractional absorption is roughly 65% at 36 mg/day but about 11% at 973 mg/day. At ~370 mg/day, reported absorption is generally 30–50%.
• Formulation also matters: magnesium oxide, hydroxide, and sulfate generally have lower fractional absorption than citrate, lactate, or chloride. Escalating dose can be counterproductive because unabsorbed magnesium causes osmotic diarrhea; diarrhea occurred in 18/50 people receiving 476 mg/day magnesium oxide.

Bottom line

• Reduced digestive enzyme activity can plausibly contribute to inefficient mineral absorption and make a given magnesium intake less likely to meet tissue demand, especially in EPI. Magnesium status should be assessed individually while addressing EPI, diarrhea, diet, alcohol exposure, medications, renal losses, and other contributors.