Potassium: Benefits and best sources

From the desk of
Robb Wolf
SciencePotassium: Benefits and best sources

Are you getting enough potassium? If you are, you’re in the minority. Only 20–40% of Americans meet the National Academy of Medicine’s adequate intake of 3.4 grams/day for men and 2.6 grams/day for women. And the evidence for higher intakes (between 3.5–5 grams per day) seems promising to reap greater benefits than adequacy alone will get you.

The good news is that getting enough potassium is a relatively easy fix, with a lot of benefits to show for it. You’ve probably heard that potassium lowers blood pressure. But did you know this electrolyte also helps with osteoporosis, kidney stones, and blood sugar regulation?

Potassium is super important, and that’s why I wrote this article. I’ll make a case for the benefits of potassium, then I’ll explain how to optimize potassium status through food and supplements.

It’s also why I formulated LMNT, our electrolyte drink mix, with 200 mg of potassium. Even whole food diets (especially low-carb diets) can be low in potassium, so this 200 mg gives folks a much-needed boost. We’ll cover potassium benefits in a sec. First, I want to explain the basics of this mineral.

Potassium 101

Potassium is an element with the chemical symbol K and its importance to life can’t be overstated. This mineral is the star of cellular communication pathways (called potassium channels) in all living things.

In the human body, potassium atoms (or ions) generally appear as K+. This means these ions carry a positive charge.

Minerals that carry charges in a solvent (like water) are called electrolytes. The electrolytes potassium, sodium, and chloride carry charges that allow nerve impulses to fire, along with helping balance fluid levels in bodily tissues. This second function is the key to healthy hydration.

The minerals magnesium, calcium, phosphate, and bicarbonate are also electrolytes, but their primary functions fall outside the sphere of electricity conduction. Calcium, for instance, mainly serves to structure hard tissue and enable muscle contractions.

Back to potassium. Let’s review how it enters and leaves the body.

Potassium enters through diet and supplements. Easy enough to remember. We’ll talk more soon about the best sources of potassium.

Potassium leaves through urine, feces, vomit, diarrhea, and, to a lesser extent, sweat. In cases of diarrhea or vomiting, potassium losses can be severe. These losses can provoke a state of low serum potassium called hypokalemia.

The symptoms of low potassium depend on the severity of the deficiency. For minor deficiencies, the symptoms may include muscle cramps, tiredness, weakness, and constipation. More serious hypokalemia can result in cardiac arrhythmias, brain damage, paralysis, and life-threatening heart complications.

The consequences of low potassium can also be more subtle, like problems with blood pressure, kidney stone formation, and bone density. This dovetails nicely into the next section.

Benefits of Potassium

Preventing the symptoms of potassium deficiency (i.e., preventing muscle cramps) is an obvious benefit of getting enough potassium. This section, however, will focus more on the positive health effects of optimizing potassium status.

#1: Lower blood pressure

Blood pressure is defined as the pressure of blood against your blood vessel walls. When this pressure gets too high, the risks of heart disease, stroke, and neurodegenerative disease go up dramatically.

High blood pressure (called hypertension) is a complex phenomenon. It affects about a third of Americans and is correlated with poor sleep, lack of exercise, obesity, and a variety of other genetic and lifestyle factors—but in particular, insulin resistance.

One of those lifestyle factors is inadequate potassium intake. In multiple observational studies, as potassium intake goes up, the risk of hypertension goes down. And in a study of nearly 250,000 men and women, the risk of stroke went down by 21% for every 1.6 grams of daily potassium consumed.

You’re probably thinking, this is just observational data, Robb. It doesn’t prove that potassium is lowering blood pressure. What if fruits and vegetables, which tend to be high in potassium, are lowering bp by some other mechanism?

Good point. That’s why I pay more attention to clinical data, like this meta-analysis of human trials that found potassium supplementation effectively treats hypertension. Pretty convincing stuff.

#2: Bone density

Potassium is an alkaline mineral, meaning it has a pH greater than 7. Because of this, researchers believe that potassium can protect bone from the acidification borne of a high-acid diet.

Supporting data? Well, as dietary potassium goes up, bone density goes up along with it.

More convincing is clinical evidence like this randomized controlled trial that found 24 months of potassium supplementation increased bone density in healthy older adults without osteoporosis. Another RCT found something similar: That taking potassium reduced biomarkers of bone loss.

Not all studies, however, have found positive results. In one, two years of potassium supplements did not improve bone health in postmenopausal women.

#3: Kidney health

Kidney stones are deposits made of minerals (like calcium) that collect in the urine. They can be excruciating when passed.

Since potassium lowers calcium excretion through urine, it may decrease the risk of kidney stones forming.

There’s supporting data, albeit observational data. In one study following 45,619 men over 4 years, those consuming over 4 grams of potassium per day had a 51% lower risk of kidney stones than those consuming less than 2.8 grams per day.

#4: Blood sugar regulation

When you eat a meal—especially a meal containing carbohydrates—your pancreas secretes insulin to handle your rising blood sugar. High blood sugar is toxic, so insulin helps move it into cells.

Potassium may support the insulin response. To be clear, however, the support for this claim is mostly observational. For instance:

  • Serum potassium levels are inversely correlated with blood sugar levels, though (oddly) not with type 2 diabetes risk.
  • In 84,360 women from The Nurses’ Health Study, the women who consumed the most potassium had a 38% lower diabetes risk over six years than women in the lowest potassium quintile. But it’s worth noting that the foods highest in potassium also tend to be minimally processed. So folks who eat a “whole food, minimally processed” diet tend to have very low rates of type 2 diabetes. Potassium likely plays a part in all that, but we’d be foolish to assume that is the ONLY mechanism at play here.

Okay, enough stats and figures. Let’s get practical with potassium now.

Assessing Potassium Status

To assess your potassium status, start by calculating your daily intake from diet and supplements. (Use an app like Cronometer to make this easy). If your intake is south of 4 grams, you probably need more potassium.

Combine this data with any relevant symptoms and health issues. For instance, if your blood pressure is slightly elevated and your potassium intake is low, you probably have a potassium deficiency.

Even if you don’t have any low potassium symptoms, you may stand to benefit from a potassium intake greater than 3.5 grams per day. For those with healthy kidneys, it’s all upside.

A quick note on blood testing. If your serum potassium is in range, it merely indicates that your kidneys are functioning properly. It doesn’t mean you’re consuming enough potassium for optimal health.

Best Dietary Sources of Potassium

In general, fruits and vegetables should be your go-to potassium-rich foods. If you’re eating a lot of plants, you’re probably doing okay.

Meat and fish are also good sources of potassium. But even so, those on a Carnivore (or Carnivore-ish) diet will struggle to clear 4 grams per day on steak alone.

Here’s a partial list of foods that are high in potassium:

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

If you’re unable to get enough dietary potassium (and most people don’t), the next step is to supplement.

Potassium Supplements

Potassium supplements come in a variety of forms including:

  • Potassium citrate
  • Potassium gluconate
  • Potassium chloride
  • Potassium bicarbonate
  • Potassium aspartate
  • Potassium phosphate

It’s not clear which form is best absorbed. It’s been shown, however, that enteric-coated potassium tablets are less rapidly absorbed than liquid forms.

As an aside, I use potassium chloride in LMNT for its health benefits.

Potassium supplements often come in 99 mg doses to limit the risk of hyperkalemia (high serum potassium) in those with chronic kidney disease, type 1 diabetes, congestive heart failure, and liver disease. People with these conditions can’t effectively excrete potassium through urine.

Healthy people, however, can handle much higher doses of potassium. For instance, up to 15.6 grams per day of potassium (for 5 days) didn’t elevate serum potassium beyond the normal range.

I don’t recommend going that high. A gram per day of supplemental potassium seems to be about right for most folks.

How to Get Enough Potassium

To get enough potassium, just eat potassium-rich foods and supplement to make up the shortfall. It’s as simple as that.

Rather than taking one big bolus, I recommend spreading out your supplemental potassium throughout the day. This will mimic getting potassium through foods and reduce the risk of GI distress.

One last thing. While you’re motivated, spend a couple of minutes assessing your potassium intake. Do you need more potassium?

Comments are closed.