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—and I’ll cover those in a bit—but that’s just a starting point.

When we are thinking about the whole enchilada of nutrients and nutrient density, you also want to eat foods high in vitamins like A, C, and K, omega-3 fatty acids like EPA and DHA, zinc, copper, and manganese, protein, and antioxidants. In other words, you want to eat nutrient-dense foods to keep your body humming along like the beautiful machine that it is.

Of course, you can supplement all of the above nutrients. And targeted supplementation can be beneficial. But if you’re only supplementing these nutrients, you’re missing out. You’re missing out—not just on the pleasures of taste—but also on the natural synergies of food.

The thing is, nutrients tend to be better absorbed 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, etc.—that exert antioxidant, anti-cancer, anti-inflammatory, and other beneficial effects. You can supplement many of these compounds, but I prefer the safer, human-style doses found in food.

What about magnesium and potassium? Supplementation can definitely help, but it’s still wise to prioritize dietary sources. Let’s double-click on these minerals now, 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 critical for daily functioning.

Do you care about producing ATP, aka cellular energy? How about breaking down body fat? Synthesizing and repairing DNA? All of these reactions depend upon magnesium.

Magnesium also serves as an electrolyte, a charged mineral that conducts electricity in various bodily fluids. Electrolytes like sodium, potassium, calcium, and magnesium have a critical job: 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)

The converse is also true: being magnesium sufficient brings many benefits. Some examples will help illustrate.

First, heart health. Magnesium not only suppresses needless inflammation, but also regulates calcification, clotting, and blood vessel relaxation—all crucial for cardiovascular longevity.

Second, bone health. Higher intakes of magnesium (and potassium, by the way) are correlated with better bone mineral density.

Higher intakes of magnesium are also linked to 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 blog. Time to switch gears to potassium.

Why Potassium Matters

Most people don’t get enough potassium. Only 3% of the population meets the Institute of Medicine’s recommended daily target of 4.7 grams.

Experts calibrated this target based on evidence that higher potassium intakes reduced the risk of high blood pressure (hypertension) and kidney stones. The US government has since lowered the target to about 3.2 grams, a move that isn’t helping the US population become less hypertensive.

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? More calcium in the urine, which raises the risk of kidney stone formation.

Potassium is also crucial for bone health. Again, lower intakes can mean 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 you’re 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. When we surveyed hundreds of clients eating real food diets, they were (on average) about a gram low on potassium and 300 mg light on magnesium.

These results guided our decision to include 200 mg potassium and 60 mg magnesium in each stick of LMNT, our zero-sugar electrolyte drink mix. We calibrated these doses (along with a 1000 mg hit of sodium) to get folks closer to their electrolyte needs. The ultimate goal was to help folks stay hydrated for performance, energy, and symptom prevention.

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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