Free Canadian magnesium reference. RDA for the whole demographic plus the supplement-only Tolerable Upper Intake Level — informational only, not a personal supplementation plan.
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Health Canada / IOM Recommended Daily Allowance
310mg/day
Tolerable Upper Intake Level from supplements only: 350 mg/day. There is no upper limit for magnesium that comes naturally from food — the UL applies to pharmacological sources because they can cause diarrhoea and, at very high doses, more serious effects.
Cheat sheet · approximate magnesium per serving
30 g pumpkin seeds · 156 mg
30 g almonds · 80 mg
1 cup cooked spinach · 157 mg
1 cup cooked black beans · 120 mg
1 medium avocado · 58 mg
30 g dark chocolate (70%) · 65 mg
1 cup cooked quinoa · 118 mg
1 cup edamame · 99 mg
Reference only. People with kidney disease should not exceed the supplemental UL without physician supervision — impaired kidney function reduces magnesium excretion.
Food first
Magnesium is dense in plant foods that are easy to over-look in a typical North American eating pattern: pumpkin seeds, almonds, cooked leafy greens, beans, lentils, dark chocolate, whole grains. Two servings per day from this list generally covers the RDA without supplementation.
Why the UL is supplement-only
The Tolerable Upper Intake Level (350 mg/day for adults from supplements) reflects the dose at which gastrointestinal side effects start to appear. Magnesium that comes naturally from food has no UL because the matrix slows absorption — you would have to eat unfeasible quantities of food to hit those doses.
When to talk to your doctor
People with chronic kidney disease excrete magnesium less efficiently and are at higher risk of toxicity. Anyone on potassium-sparing diuretics, certain antibiotics (e.g. tetracyclines), or proton pump inhibitors may also need individualised guidance — bring all your supplements to your next appointment.
This tool is for educational purposes only and does not provide medical advice, diagnosis, or treatment. Always consult a licensed Canadian healthcare professional. Read our full disclaimer.