Spinach is one of the richest vegetable sources of magnesium, providing about 75 to 82 milligrams per 100 grams whether raw, cooked, or frozen. A half cup of cooked spinach delivers roughly 78 mg, which covers about 20% of the daily recommended intake for most adults. That puts it in the same league as almonds and ahead of most other vegetables.
How Much Magnesium Spinach Actually Provides
The numbers are consistent regardless of how you buy it. According to the USDA Nutrient Database, raw spinach, frozen spinach, and boiled-then-drained spinach all land in the 75 to 82 mg per 100 grams range. The key difference is volume: raw spinach is bulky, so you’d need to eat several large handfuls to hit 100 grams. Cooking wilts spinach down dramatically, making it much easier to consume a meaningful amount in one sitting. A half cup of cooked spinach weighs roughly 90 grams and contains about 78 mg of magnesium.
For context, the recommended daily intake of magnesium is 400 to 420 mg for adult men and 310 to 320 mg for adult women. So that half cup of cooked spinach gets you roughly a fifth of the way there in a single side dish. Add it to a smoothie, an omelet, or a pasta dish and you can easily double that without much effort.
Spinach vs. Other Magnesium-Rich Foods
Spinach holds its own against nuts and seeds, which are often considered the top magnesium sources. Here’s how a typical serving of each compares:
- Pumpkin seeds (hulled, roasted): 150 mg per ounce
- Chia seeds: 111 mg per ounce
- Almonds (roasted): 80 mg per ounce
- Spinach (cooked): 78 mg per half cup
- Cashews (roasted): 72 mg per ounce
- Peanuts (dry roasted): 49 mg per ounce
Pumpkin seeds and chia seeds are the clear winners per serving, but spinach is the most magnesium-dense cooked vegetable you’ll find at a typical grocery store. It also comes with far fewer calories than nuts and seeds, which makes it useful if you’re trying to increase your magnesium intake without adding a lot of energy-dense food to your diet.
The Oxalate Problem
There’s a catch with spinach that rarely gets mentioned in nutrition lists. Spinach is high in oxalic acid, a compound that binds to minerals like magnesium and calcium in your digestive tract, forming complexes your body can’t absorb. A study published in The British Journal of Nutrition measured this directly: people absorbed only about 27% of the magnesium from a meal containing spinach, compared to about 37% from the same meal made with kale, a low-oxalate green. That’s roughly a quarter less magnesium reaching your bloodstream.
This doesn’t make spinach a bad source of magnesium. The researchers noted that spinach contains so much more magnesium than kale in the first place that the higher oxalate content is at least partly offset by the larger amount of mineral present. You still absorb a meaningful dose. But if you’re relying on spinach as your primary magnesium source, it’s worth knowing that the number on the nutrition label overstates what your body actually takes in. Pairing spinach with other magnesium-rich foods, or rotating between spinach and lower-oxalate greens like kale or Swiss chard, gives you better overall absorption.
Cooking Methods and Mineral Retention
Unlike vitamin C, which breaks down with heat, magnesium is a mineral and isn’t destroyed by cooking. You’ll get similar magnesium levels from steamed, sautéed, or boiled spinach. The one thing to watch for is boiling spinach in a large amount of water and then discarding the liquid, since some minerals can leach into the cooking water. If you’re making soup or a sauce where the liquid stays in the dish, that’s not a concern. For other preparations, steaming or quick sautéing keeps everything in the pan.
Cooking also has a practical advantage: it concentrates spinach. A 100-gram bag of raw spinach looks like a big salad. Cook that same amount and it shrinks to a few tablespoons. Most people find it far easier to eat 200 or 300 grams of spinach when it’s cooked down, which is how you get meaningful magnesium numbers from a single meal.
Why Magnesium Matters
Magnesium is involved in over 300 enzyme reactions in your body. It plays a direct role in muscle contraction and relaxation, nerve signaling, bone structure, and energy production. Your body uses it to maintain a steady heart rhythm and to regulate blood sugar levels.
Mild magnesium deficiency shows up as muscle cramps, twitching, fatigue, and weakness. Some people notice numbness or tingling in their hands and feet. Severe deficiency, which is less common, can cause abnormal heart rhythms, seizures, and confusion. Because magnesium is distributed across so many bodily systems, running low tends to create vague symptoms that are easy to dismiss or attribute to something else, like poor sleep or stress.
Many adults fall short of the recommended 310 to 420 mg per day. Adding a half cup of cooked spinach to one meal each day closes that gap noticeably, especially when combined with a handful of nuts, seeds, or other whole foods that contribute smaller amounts throughout the day.