Pumpkin seeds are the standout: USDA lists 592 mg of magnesium per 100 g, far more than almonds (270 mg), dark chocolate (228 mg) or raw spinach (79 mg) per 100 g. Since adults need roughly 310–420 mg of magnesium a day, a single ounce of pumpkin seeds covers close to half of that.
How the top sources compare
All figures below are from USDA data, shown both per 100 g and per typical serving.
| Food | Magnesium per 100 g | Per serving |
|---|---|---|
| Pumpkin seed kernels, dried | 592 mg | ~166 mg per 1 oz (28 g) |
| Almonds | 270 mg | ~76 mg per 1 oz (28 g, about 23 kernels) |
| Dark chocolate, 70–85% cacao | 228 mg | ~64 mg per 1 oz (28 g) |
| Spinach, raw | 79 mg | ~269 mg per 340 g bunch |
Spinach looks modest per 100 g, but raw leaves are mostly water and cook down dramatically — a big pile of raw spinach shrinks to a few forkfuls, so cooked spinach delivers considerably more magnesium per bite than the raw figure suggests.
What else these foods bring
Magnesium-rich foods tend to be nutrient-dense in general:
- Pumpkin seeds (per 100 g, USDA): 30 g protein, 8.8 mg iron, 7.8 mg zinc, 1,233 mg phosphorus. They're also calorie-dense at 559 kcal per 100 g, so an ounce or two is a sensible portion.
- Almonds (per 100 g): 26 mg vitamin E — one of the richest everyday sources — plus 13 g fiber and 269 mg calcium.
- Dark chocolate (per 100 g): 12 mg iron and 1.8 mg copper, but also 24 g sugar, 24 g saturated fat and 80 mg caffeine, which is roughly a weak cup of coffee's worth per 100 g.
- Spinach (per 100 g): 483 µg vitamin K, 194 µg folate, 469 µg vitamin A and 28 mg vitamin C for just 23 calories.
Absorption and practical notes
A few things worth knowing, with the caveat that absorption research is less precise than the food composition numbers:
- Typical absorption is partial. Studies generally find people absorb somewhere in the range of 30–50% of dietary magnesium, and the proportion rises when intake is low — the body adapts.
- Phytate and oxalate reduce uptake somewhat. Seeds, nuts and whole grains contain phytic acid, and spinach is high in oxalate. These bind minerals and lower absorption, but the effect is moderate, not disqualifying; these foods still count as good sources. Soaking, sprouting or roasting seeds modestly reduces phytate.
- Variety beats any single food. Legumes, whole grains, tofu, avocado and even some mineral waters contribute meaningfully. Refining grains strips most of the magnesium, so whole-grain versions matter.
- True deficiency is uncommon in healthy people, but risk rises with poorly controlled diabetes, chronic alcohol use, gut disorders like Crohn's disease, and long-term use of proton pump inhibitors (acid-reflux drugs) or some diuretics.
If you're considering a magnesium supplement, it's worth asking a doctor or pharmacist first — high doses of certain forms cause diarrhea, and magnesium can interfere with the absorption of some antibiotics and thyroid medication. People with reduced kidney function should be especially cautious, since the kidneys clear excess magnesium.
