Potassium deficiency (and how to get enough potassium)

From the desk of
Robb Wolf
SciencePotassium deficiency (and how to get enough potassium)

Over 97% of Americans are potassium deficient: they aren’t consuming enough potassium to meet the Institute of Medicine (IOM) daily target of 4.7 grams. This is due, in large part, to folks eating the majority of their total calories from processed foods, which are lacking in potassium.

The target wasn’t picked at random. It’s based on evidence that sufficient potassium intake reduces the risks of high blood pressure and kidney stones. Yet only a small fraction of people—including health-conscious people—are potassium sufficient.

Why? Simple. It’s can be difficult to get a solid 3.5–5 grams of potassium through diet alone. Even eating plenty of fruits, vegetables, and other potassium-rich foods, you may still fall short. Add to this my processed foods point above, and potassium deficiency becomes a seriously widespread issue.

I spend a lot of time talking about sodium, but potassium is the yin to sodium’s yang. And while it’s not demonized like sodium, potassium still doesn’t get enough love in most folks’ diet and supplement routines. I wrote this article to help change that.

The Need for Potassium

Every cell in your body is powered by a molecule called adenosine triphosphate (ATP). But how exactly do your cells use ATP?

Your cells use ATP with the help of a protein called the sodium-potassium pump. The pump is a complex piece of biology, but the simple story is that two potassium ions must be pumped into the cell (and three sodium ions pumped out) for an ATP molecule to be utilized.

That’s right, potassium structures the system that keeps your body humming. But that only begins to describe what potassium does for you.

Here are a few things potassium does for you:

  • Keeps blood pressure within healthy ranges by relaxing blood vessel walls and balancing the effects of sodium
  • Functions as an electrolyte to transmit messages throughout your nervous system
  • Decreases kidney stone risk by increasing calcium absorption
  • Improves glycemic control by supporting insulin secretion
  • Counteracts acidic conditions that can lead to osteoporosis
  • Supports healthy hydration and fluid balance in bodily tissues

The need for potassium is most apparent in the data on hypertension. In study after study, higher potassium intakes are linked to lower blood pressures.

Potassium supplementation is also extremely promising for hypertension. In one 2017 meta-analysis, researchers who reviewed the relevant literature concluded that taking potassium supplements could effectively ameliorate high blood pressure.

This finding, I suspect, hinged on the fact that most people are potassium deficient to begin with.

What Is Potassium Deficiency?

Potassium deficiency refers to insufficient potassium intake. It’s distinct from the medical condition of low serum potassium called hypokalemia.

Infrequently, potassium deficiency can cause hypokalemia. But it’s rare in those with healthy kidneys.

Even at low potassium intakes, your body is adept at keeping blood potassium levels within normal ranges. When you need extra, it just pulls it from bone. This explains, in part, why potassium deficiency is linked to decreased bone mineral density.

Potassium deficiency increases the risk of hypokalemia, but it’s more of a contributor than a true cause. The more obvious causes include diarrhea, vomiting, the use of laxatives or diuretics, IBD, eating clay (yes, that’s a thing), and refeeding syndrome following a period of severe calorie restriction.

I’ve said this before, but I’ll say it again: potassium deficiency won’t manifest as low serum potassium—and so a “normal” result on your electrolyte panel says little about your overall potassium status. It merely suggests your kidneys are working properly.

How do you triangulate a potassium deficiency? Use a two-pronged approach:

  1. Check for potassium deficiency symptoms
  2. Assess potassium intake

I’ll cover how to assess your potassium intake later. Let’s review the symptoms up-front.

Symptoms of Potassium Deficiency

Unless you routinely monitor your biomarkers, the signs of potassium deficiency can be hard to detect. These include:

  • Elevated blood pressure
  • Lower bone mineral density
  • Increased calcium excretion through urine (increased kidney stone and osteoporosis risk)
  • Insulin resistance

The easiest marker to monitor is blood pressure. Just buy a cuff and occasionally take your bp from the comfort of your couch, preferably at the same time each day.

Ideally, you want to hit 120/80 or lower. Anything higher is one sign that points to potassium deficiency, though there are many other factors that could be contributing to elevated blood pressure.

If your systolic blood pressure (the top number) is over 130, or your diastolic blood pressure (the bottom number) is over 80, you meet the American Heart Association’s criteria for high blood pressure. In these situations, it generally makes sense to bump up your potassium intake. You should also check in with a medical professional.

Chronically low potassium intakes can also cause transient bouts of mild hypokalemia, leading to muscle cramps, fatigue, constipation, muscle weakness, and malaise. Keep in mind, however, that many of these symptoms also suggest a sodium or magnesium deficiency.

What Causes Potassium Deficiency?

Here are the major factors driving poor potassium status.

#1: Low dietary intakes

The best sources of potassium are fruits, vegetables, meat, and fish. I’m talking about avocados, bananas, spinach, swiss chard, sweet potatoes, potatoes, tomatoes, salmon, chicken, beef, and many others.

Needless to say, the modern diet is devoid of these foods. If most of your diet comes wrapped in plastic, I’d be willing to bet that you’re potassium deficient.

This explains the ubiquity of potassium deficiency, yet even more health-conscious folks struggle here. It’s true: eating whole foods offers few guarantees.

Take a low-carb or keto diet, for instance. When you limit carbs, you also limit potassium-rich foods like fruits and root vegetables. Sure, you can make up for it with dark leafy greens and meat. (And I recommend you try.) But it’s difficult to consume an optimal amount of potassium on keto without supplementation.

#2: Illness and medications

Contrary to popular belief, you lose negligible potassium through sweat. You lose primarily water, salt, and a bit of magnesium through sweat.

You lose potassium through vomit, feces, and urine. Those are the main potassium drains.

Any illness that causes diarrhea or vomiting (cholera, for instance) will accelerate potassium losses and increase the risk of hypokalemia. Similarly, any medication with a laxative or diuretic effect will also deplete potassium.

Diuretic medications (often prescribed to treat heart or kidney failure) largely explain why 21% of hospitalized patients develop low potassium levels. This is why clinicians often include potassium along with sodium and fluids in the IV drip.

#3: Insufficient sodium

Hypertension is commonly treated with a low sodium diet. Theory being: since sodium increases blood volume, decreasing sodium intake will lessen blood pressure.

But the theory doesn’t work in practice. Why? Because sodium restriction can trigger sodium retention hormones like aldosterone, renin, and angiotensin that actually raise blood pressure.

Part of this blood pressure bump is driven by urinary potassium losses. That’s right. When you don’t get enough sodium, your body compensates by excreting more potassium to normalize the sodium-potassium ratio.

So now you have two problems: low sodium AND low potassium. Both are bad news for hypertension risk.

If you’re skeptical, consider the fact that sodium-restricted diets (under 2.5 grams/day) have been linked to higher blood pressures in a large sample of otherwise healthy people. If low sodium diets worked, this wouldn’t happen.

How To Get Enough Potassium

To determine your potassium status, start with a full dietary assessment. This sounds like a pain, but I think it’s fun. (To be fair, my definition of fun also includes getting thrown around by sweaty youngsters in gi—but don’t let my love for jiu-jitsu ruin a good potassium audit.)

Here’s what you do. Just download an app called Cronometer, log your daily meals for about 3 days, and see where you stand with potassium.

I recommend shooting for 3.5–5 grams of potassium per day—the upper end, if possible. This may be overshooting the mark for some folks, but there’s no real downside to a little extra potassium.

In addition to prioritizing potassium-rich foods, you can also supplement potassium directly. Try to take it with food, spaced out over the day, to mimic how it’s normally absorbed.

When my former coaches assessed thousands of their clients, they found that most folks—despite eating low-carb whole food diets—were about 1 gram short on potassium. This informed our decision to include 200 mg of potassium chloride in LMNT.

As you adjust your potassium intake, monitor potassium-related signs and symptoms—especially blood pressure. This will confirm you’re moving in the right direction.

I hope this article has been helpful!

Comments are closed.