Magnesium is involved in over 300 enzyme reactions, including insulin signaling. Low magnesium is strongly associated with type 2 diabetes risk and poor glucose control.
The evidence
- People with type 2 diabetes are 25–38% more likely to be magnesium deficient
- Higher magnesium intake correlates with lower diabetes risk
- Supplementation has lowered HbA1c by ~0.4% in some meta-analyses
How much you need
- RDA: 310–420mg/day depending on sex and age
- Diabetic adults often benefit from 350–500mg/day
Best food sources
- Pumpkin seeds (1 oz: 150mg)
- Spinach (1 cup cooked: 157mg)
- Almonds (1 oz: 80mg)
- Avocado (1 medium: 58mg)
- Dark chocolate 85%+ (1 oz: 65mg)
- Black beans (½ cup: 60mg)
- Salmon (3 oz: 26mg)
Supplement forms
- **Magnesium glycinate**: best absorbed, calming, no GI upset
- **Magnesium citrate**: good absorption, mild laxative effect
- **Magnesium malate**: good for energy/muscle pain
- **Magnesium oxide**: poorly absorbed, mainly a laxative — avoid for diabetes
- **Magnesium threonate**: crosses blood-brain barrier, used for cognition
Practical dosing
- Start with 200mg glycinate at bedtime
- Increase to 300–400mg if no GI side effects
- Splitting into 2 doses improves absorption
Bonus: sleep
Magnesium glycinate is one of the best-tolerated natural sleep aids. Since poor sleep raises glucose, better sleep is itself a glucose intervention.
Cautions
- Talk to your doctor if you have kidney disease (impaired clearance)
- Magnesium can interact with certain antibiotics and diuretics
- Don't exceed 500mg/day from supplements without medical advice