Magnesium: Daily Needs and Best Food Sources

Key takeaways

1. Adults need roughly 300–400 mg of magnesium a day; men need a little more than women.
2. 30 g of pumpkin seeds gives about 178 mg and a cup of boiled spinach about 157 mg (USDA data).
3. Refined grains lose much of their magnesium, so whole grains are the better everyday choice.
4. The NHS says up to 400 mg a day from supplements is unlikely to cause harm; more can cause diarrhoea.
5. People with kidney disease or on regular medication should ask a doctor before taking magnesium.

What does magnesium do in the body?

Magnesium is a mineral involved in hundreds of chemical reactions in the body, from turning food into energy to muscle and nerve function, heart rhythm and bone structure. Most of the body's magnesium is stored in bone, with the rest in muscles and soft tissues and only a small fraction in the blood. That is one reason a normal blood test does not always tell the full story.

The good news is that magnesium is spread across many everyday foods. Green leafy vegetables, nuts, seeds, beans and whole grains are the richest sources, while legumes, fruit, fish and meat sit in the middle and most dairy foods are lower. Refining grains removes a large share of it, so white flour and white rice contain far less than their whole-grain versions.

How much magnesium do you need per day?

Recommendations differ slightly between countries because experts set them in different ways:

For a practical target, think of roughly 300–400 mg a day for most adults, with men at the higher end. Teenagers, pregnant and breastfeeding women have their own values, so check with a doctor or midwife if that applies to you.

Which foods are richest in magnesium?

The table below shows realistic portions, calculated from USDA FoodData Central values per 100 g. Real amounts vary with variety, soil and processing, so treat them as approximate.

Seeds and nuts are the most concentrated sources, but they are also energy-dense: 30 g of pumpkin seeds has about 170 kcal. Leafy greens and beans give a lot of magnesium for few calories, which makes them especially useful in a calorie deficit. The guide to nuts and seeds portions shows how to keep the handfuls sensible.

What does a magnesium-rich day look like?

You do not need special foods to reach the target. Here is one example built from ordinary meals:

• Breakfast: oats with plain yogurt, a banana and a tablespoon of chia seeds (about 110 mg from the yogurt, banana and chia, plus more from the oats).
• Lunch: a bowl of black bean chilli or a lentil and bean salad with brown rice (about 180 mg).
• Snack: 30 g of almonds (about 81 mg).
• Dinner: salmon or tofu with a generous portion of cooked spinach (about 160–210 mg).

That day lands comfortably above 400 mg without any supplement. A spinach omelette, a bean stew or a handful of seeds on a salad are easy ways to add more. If you build meals around whole grains, the comparison of whole and refined grains explains why the whole-grain version matters for minerals as well as fibre.

Many cuisines already do this well: black beans in Mexican cooking, edamame and tofu in Japanese meals, dal in Indian food, chickpeas and hummus around the Mediterranean, and Turkish dishes such as white bean stew, lentil soup and bulgur pilaf. Spreading these foods across the week works better than relying on one "superfood".

Who is more likely to run low?

Most healthy people who eat a varied diet with plants, legumes and whole grains get enough. Low magnesium is more likely in some situations, according to a 2015 review in the journal Nutrients:

• long-term use of certain medicines, such as loop or thiazide diuretics and proton pump inhibitors (acid-reducing tablets);
• heavy alcohol use;
• poorly controlled diabetes;
• digestive conditions that reduce absorption, such as coeliac disease or Crohn's disease;
• diets built mostly on refined, low-fibre foods.

Early signs of low magnesium are vague: tiredness, weakness, loss of appetite or nausea. More severe deficiency can cause muscle cramps, tremor and heart rhythm problems. Because these symptoms overlap with many other conditions, it is better to see a doctor than to guess and self-treat.

Do you need a magnesium supplement?

For most people, food is enough, and the NHS advises getting magnesium from a varied, balanced diet. If you do take a supplement, the NHS says that 400 mg or less a day from supplements is unlikely to cause harm. Higher short-term doses can cause diarrhoea, which is the most common side effect.

Supplements are not for everyone. People with kidney disease clear magnesium less efficiently, so extra magnesium can build up; the review advises particular caution when kidney function is reduced. Magnesium can also reduce the absorption of some medicines, including certain antibiotics and osteoporosis drugs, when taken at the same time. If you have a kidney condition, take regular medication, are pregnant or are under 18, talk to a doctor, pharmacist or registered dietitian before starting one.

Does magnesium help with weight loss?

There is no good evidence that magnesium on its own makes you lose weight. What it does is remind you that eating less should not mean eating worse. When calories go down, the foods that stay in your day matter more. Beans, leafy greens, seeds and whole grains supply magnesium alongside fibre and protein, and many of them are filling for their calories.

If you track your meals, Sporty shows calories and macros for each entry, which makes it easier to see whether these foods are regularly on your plate. For a broader look at nutrients while eating less, see the guide to vitamins and minerals in a calorie deficit.

This article is general information, not medical advice. If you have a medical condition or symptoms you are worried about, speak to a doctor or registered dietitian.

Frequently asked questions

Which food has the most magnesium?

Per portion, pumpkin seeds are among the richest, with about 178 mg in 30 g. Boiled spinach, black beans, edamame, cashews and almonds are also excellent sources.

Can you get enough magnesium from food alone?

Yes, for most healthy people. A day that includes leafy greens, beans or lentils, a handful of nuts or seeds and whole grains easily reaches 300–400 mg.

What happens if you take too much magnesium?

From food, excess is rarely a problem in healthy people. From supplements, doses above about 400 mg a day can cause diarrhoea, and people with kidney disease can build up magnesium, so they need medical advice first.

Does magnesium help you lose weight?

There is no good evidence that magnesium alone causes weight loss. Magnesium-rich foods such as beans, greens and whole grains are, however, filling and nutrient-dense choices in a calorie deficit.

Sources

• NHS, Vitamins and minerals: others (magnesium)
• Gröber et al. 2015, Magnesium in Prevention and Therapy (Nutrients, review)
• USDA FoodData Central

This article is general information, not medical advice. If you have a health condition, are pregnant or under 18, talk to a doctor or registered dietitian before changing your diet.