A guide to foods high in magnesium and potassium

From the desk of
Robb Wolf
ScienceA guide to foods high in magnesium and potassium

I’m a big believer in getting most of your nutrients from food. When thinking about electrolytes, this means eating plenty of foods high in magnesium and potassium. If you’re primarily supplementing these nutrients, you’re missing out on both the wonderful taste and natural synergies of food.

That’s right: Your body tends to absorb nutrients better in food form. The omega-3s EPA and DHA, for instance, are best absorbed when consumed with fat. Food also contains a spectrum of compounds — tannins, flavanols, anthocyanins, and more — that exert antioxidant, anti-cancer, anti-inflammatory, and other beneficial effects. And while you can even supplement many of these compounds, the doses found in food are typically safer.

Back to magnesium and potassium, I’m not advising against supplementation. It can definitely help, but it’s wise to prioritize dietary sources first. Let’s talk about each of these minerals a bit more, and then we’ll cover nutritional strategies.

Why Magnesium Matters

Without magnesium, your body would struggle to function. Why? Because magnesium serves as a cofactor for over 300 enzymatic reactions, which are critical for daily functioning. Producing ATP (cellular energy), breaking down body fat, synthesizing DNA, and repairing DNA are just a few examples. Many more reactions depend upon magnesium too.

Magnesium also proves useful as an electrolyte, a charged mineral that conducts electricity in various bodily fluids. Electrolytes like sodium, potassium, calcium, and magnesium all share the vitally important function of enabling cellular communication.

Magnesium is especially important for regulating the electrical activity of the heart. When magnesium status falls, cardiac arrhythmias, heart palpitations, and other electrical disturbances may follow. Other symptoms of magnesium deficiency include weakness, fatigue, muscle cramps, hypertension (high blood pressure), increased inflammation, kidney stones, osteoporosis (brittle bones), and more.

On the flipside, magnesium sufficiency brings many benefits. Some examples will help illustrate:

  • First, heart health. Magnesium suppresses needless inflammation and regulates calcification, clotting, and blood vessel relaxation. All are crucial for cardiovascular longevity.
  • Second, bone health. Higher intakes of magnesium (and potassium, by the way) are correlated with better bone mineral density.
  • Lastly, higher intakes of magnesium are also linked to better sleep and lower rates of diabetes, anxiety, and depression. From mood to sleep to blood sugar regulation, magnesium affects it all.

For a deep dive on magnesium benefits, check out this article. Time to switch gears to potassium.

Why Potassium Matters

Most people don’t get enough potassium. Only 20–40% of the population meets the National Academy of Medicine’s adequate intake of 3.4 grams for men and 2.6 grams for women. And “adequate” doesn’t exactly mean “optimal.” To my eye, the evidence for potassium intakes between 3.5–5 grams per day is strong. Getting enough potassium can reduce the risk of high blood pressure (hypertension) and kidney stones.

Like magnesium, potassium powers your nervous system as an electrolyte. Potassium is also crucial for maintaining the distribution of water in your body. This is called maintaining fluid balance, and it’s the goal of healthy hydration.

Potassium works together with sodium to regulate your blood volume, a chief determinant of blood pressure. If you’re deficient in either mineral, blood pressure goes up. Along these lines, the hallmark of potassium deficiency is elevated blood pressure. And high blood pressure is a well-established heart disease (and dementia) risk factor.

Another consequence of low potassium intake is more calcium in the urine, which raises the risk of kidney stone formation.

Potassium is also crucial for bone health. Again, lower intakes can create a higher risk of osteoporosis.

Anyways, there’s no downside to getting enough dietary potassium and magnesium — and there’s plenty of upside. Let’s see which foods unlock that upside for you.

Foods High in Magnesium and Potassium

Here’s how we’ll do this. First I’ll cover foods high in each electrolyte, then I’ll cover foods high in both electrolytes.

Magnesium-Rich Foods

The trick to getting enough magnesium is to eat dark leafy greens. Greens are green because they contain chlorophyll, and magnesium sits at the center of the chlorophyll molecule.

Nuts, seeds, and some grains are also high in magnesium, but these foods contain a compound called phytic acid that inhibits mineral absorption. The magnesium from leafy greens is more bioavailable.

With that in mind, here’s a list of magnesium-rich foods:

  • Spinach (157 mg per cup)
  • Swiss chard (151 mg per cup)
  • Beet greens (98 mg per cup)
  • Sunflower seeds (114 mg per cup)
  • Pumpkin seeds (190 mg per ¼ cup)
  • Summer squash (43 mg per cup)
  • Black beans (120 mg per cup)
  • Edamame (100 mg per cup)
  • Brown rice (84 mg per cup)
  • Soymilk (61 mg per cup)
  • Baked potato (43 mg per 3 ounces)
  • Avocado, cubed (44 mg per cup)
  • Broccoli (24 mg per cup)

Potassium-Rich Foods

Fruits, vegetables, and meat are all high in potassium. Here’s a list of potassium-rich foods:

  • Dried apricots (2,202 mg per cup)
  • Avocado (690 mg per avocado)
  • Banana (422 mg per banana)
  • Cantaloupe (428 mg per cup)
  • Spinach (271 mg per cup)
  • Asparagus (271 mg per cup)
  • Tomato (292 mg per tomato)
  • Potato (610 mg per medium potato)
  • Lentils (731 mg per cup)
  • Salmon (624 mg per 6 ounce filet)
  • Chicken breast (332 mg per 3 ounces)
  • Beef (315 mg per 3 ounces)
  • 1% milk (366 mg per cup)

Foods High In Both Magnesium and Potassium

If you want a double dose of these electrolytes, eat dark leafy greens. Spinach in particular is an excellent source of both magnesium and potassium.

But don’t forget fruits (avocado, banana, apple), starchy vegetables (potatoes, yams, carrots), legumes, and meat and fish like chicken, beef, and salmon. Depending on your carb tolerance, budget, and digestive health, consider dabbling in each of these categories to reach your daily magnesium and potassium targets.

How To Assess Magnesium and Potassium Status

It’s good to know which electrolyte-rich foods to target. But how do you know you’re getting enough electrolytes overall? The first step is to conduct a dietary analysis. Use an app like Cronometer to log your meals, review the results (it automatically calculates micronutrient status), and adjust accordingly.

Ideally, you’re shooting for 3.5–5 grams of potassium and 400–600 mg of magnesium daily. If you’re a little short, that’s okay — supplements can fill the gap. But if you’re very short, review the food list and make adjustments.

The other data point is how you feel. This can be tricky to unpack because magnesium and potassium deficiencies often present asymptomatically. Are you experiencing symptoms? And if so, are they characteristic of magnesium or potassium deficiency?

If your blood pressure is mildly elevated, that could be a potassium issue. If you’re weak, fatigued, or crampy, magnesium could be the culprit. But if you feel okay, it doesn’t necessarily mean you’re in the clear. That’s why I favor the food log in this analysis.

What about blood electrolyte levels? It’s a common misconception that they reflect nutritional status. Let me clear that up. They don’t. Serum levels are too important to let fall. Life-critical functions depend on them. So when blood electrolytes are low — or if you simply don’t consume enough electrolytes — your body pulls them from bone to normalize serum levels. As you can imagine, that’s bad news for bone health. The important takeaway is that you won’t learn whether or not you are electrolyte deficient from a blood test. But your body will notice it months or years down the road.

Getting Enough Magnesium and Potassium

Getting enough magnesium and potassium involves two steps:

  1. Consume plenty of foods high in magnesium and potassium
  2. Supplement to make up for any shortfalls

For step 1, green vegetables are your best friend. Fill your plate with spinach, chard, and kale and you’ll be in the top 1%. Yet you still might fall short of your targets.

We did – which is why we chose to include 200 mg potassium and 60 mg magnesium (along with a 1000 mg hit of sodium) in each stick of LMNT, our zero-sugar electrolyte drink mix. We carefully formulated LMNT to get folks closer to their electrolyte needs. The ultimate goal was to help folks stay hydrated for better performance and overall energy.

You don’t need to use LMNT, of course. You can supplement ad hoc or make electrolyte home brews. The important thing is to get enough electrolytes. Do that and you’ll be well-positioned to feel and function your best.

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