Perspective: Call for Re-evaluation of the Tolerable Upper Intake Level for Magnesium Supplementation in Adults.
Level 5 - mechanism / opinion, no new human data
Perspective / narrative review with non-systematic literature and database search
PubMed 37487817 · doi:10.1016/j.advnut.2023.06.008
What was done
The authors conducted a perspective review to reassess the 1997 US Institute of Medicine tolerable upper intake level (UL) of 350 mg/day for supplemental magnesium in adults. They searched PubMed for single-ingredient magnesium intervention studies published between 1997 and 2022 that reported a priori diarrhea adverse events in adults, and searched the FDA Center for Food Safety and Adverse Event Reporting System (CAERS) for adverse events attributed to single-ingredient magnesium products.
What was found
The search identified 10 studies (5 meta-analyses and 5 randomized controlled trials). Seven studies evaluating magnesium intakes between 128 and 1200 mg/day found no significant difference in diarrhea occurrence between intervention and control groups. One meta-analysis found only minor differences in gastrointestinal disturbances between placebo and 520 mg/day magnesium, with no significant difference in withdrawals. Another meta-analysis found 3 of 13 studies (120–973 mg/day) reported diarrhea leading to withdrawal, though the treatment arm was unspecified in 2 studies. The CAERS database yielded 40 attributable gastrointestinal adverse event reports, of which only one-third noted diarrhea.
Why it matters
The authors argue that the current 350 mg/day UL is overly restrictive given modern trial safety data. Raising the UL could facilitate higher supplemental magnesium dosing to treat population-level inadequacy and address associated chronic disease risks.
Limits
This is a narrative perspective rather than a formal PRISMA-compliant systematic review. The search was limited to PubMed and single-ingredient formulations, and specific magnesium salts/formulations or total sample sizes across studies were not detailed in the abstract. CAERS data rely on passive, voluntary reporting that is subject to substantial underreporting and confounding.
Cited by
- supports The Institute of Medicine set the upper tolerable limit for daily supplemental magnesium at 350 mg per day.