By January 2020, the FDA will require all food and supplement labels to list potassium[*]. Why? Because like vitamin D, potassium is an essential nutrient for your health.
Potassium maintains fluid levels in your body, conducts nerve impulses, stabilizes blood pressure, prevents kidney stones, promotes insulin function, and more.
Most Americans, unfortunately, aren’t getting enough potassium. Less than 3% consume the reference daily intake (RDI) of 4700 mg per day[*].
In this article you’ll learn the science of potassium, potassium benefits, and how to consume this crucial electrolyte in both food and supplements. Buckle in.
What Is Potassium?
Potassium is an electrolyte — a mineral that enables the conduction of electricity (read: nerve impulses) in your body. Listed as “K” on the periodic table, potassium is present in every single tissue in your body[*].
Yes, it’s that important. Specifically, potassium helps maintain fluid balance inside and outside your cells. Potassium also serves as a necessary ingredient for nerve signal transmission[*].
Let’s double click on potassium in your nervous system for a moment. In order for nerves to “fire”, a certain balance of sodium (Na+) and potassium (K+) ions must be available on the exterior of the nerve cell[*]. The truth is: without Na+ and K+, you couldn’t think, move, or do much of anything.
Along with potassium and sodium, the other major electrolytes are magnesium, chloride, phosphate, bicarbonate, and calcium. These minerals facilitate muscle contraction, nerve function, bone health, and much more.
You lose electrolytes through sweat, urine, and feces — and replace them by consuming food and supplements.
In particular, you absorb potassium in your small intestine, and excrete it mostly through urine[*]. Unlike sodium, only a small amount of potassium is lost in sweat.
Sodium and potassium, in fact, balance each other out. They’re BFFs.
For instance, salt sensitive people — a subset of the population for which sodium spikes blood pressure — can mitigate these effects by consuming adequate potassium[*]. Likewise, if you aren’t consuming enough salt, high potassium intakes may exacerbate sodium deficiency — but this isn’t common.
The RDI for potassium is 4700 mg per day[*]. By this metric, some 97% of Americans don’t eat enough potassium.
Because of this, it’s likely most people aren’t capitalizing on the benefits potassium brings to the human body.
Benefits of Potassium
If you don’t consume enough potassium, you may develop hypokalemia — or low blood levels of potassium. More commonly, however, hypokalemia results from excessive diarrhea, vomiting, or malnutrition[*].
Hypokalemia comes with a range of undesirable symptoms. More on that later.
Getting enough potassium through diet or supplements, on the other hand, has several documented health benefits.
#1: Healthy Blood Pressure
High blood pressure, or hypertension, is an established risk factor for both heart disease and stroke. It affects about one third of people in the United States[*].
Now the good news. A wealth of evidence, both observational and clinical, strongly supports potassium for lowering blood pressure.
In fact, the FDA has even approved this health claim[*]:
“Diets containing foods that are a good source of potassium and that are low in sodium may reduce the risk of high blood pressure and stroke.”
While the evidence for low-sodium diets improving hypertension is weak at best, consuming more dietary potassium appears to be a no-lose maneuver[*].
Potassium lowers blood pressure, it’s believed, by increasing vasodilation (widening of blood vessels) and by increasing sodium excretion in urine. To be clear, potassium lowers blood pressure most significantly in salt-sensitive people[*].
One 2017 meta analysis found that, in 1,163 people with hypertension, potassium supplementation reduced both systolic and diastolic blood pressure[*].
Another meta analysis (observational data from 247,510 adults) showed that eating about 1.6 grams more potassium per day was linked to a 21% reduction in stroke risk[*].
#2: Kidney Health
Kidney stones usually affect people between the ages of 40 to 60, and can be extremely painful when passed. Fortunately, eating more potassium may help prevent these tiny deposits of calcium that plague any part of the urinary tract[*].
How? Because potassium increases calcium absorption in the kidneys and decreases calcium excretion in the urine. Theory being: Less calcium excretion, less kidney stones.
The supporting data here is mostly observational, but it’s still worth mentioning.
For instance, when researchers followed 45,619 men with no history of kidney stones over four years — those consuming the most potassium (over 4 grams per day) had a 51% lower risk for kidney stones than the lowest potassium group[*].
#3: Blood Sugar Support
Potassium isn’t a blood sugar lowering supplement per se, but it can promote healthy blood sugar levels by supporting insulin secretion.
Insulin is your blood sugar boss — a hormone that rips glucose out of your blood and directs it inside your liver, muscle, and fat cells for safe storage. When you eat a meal, your blood sugar rises — and then your pancreas releases insulin to clean up the mess.
That insulin release depends on potassium. Low potassium levels, called hypokalemia, impairs this blood-sugar-regulation mechanism.
In the Nurses’ Health Study — which followed 84,360 women aged 34-59 over 6 years — researchers found that women consuming the most potassium had a 38% lower risk of developing type 2 diabetes than their low-potassium counterparts[*].
Other observational data suggests potassium intake to be inversely correlated with blood sugar levels, but (surprisingly enough) not linked to diabetes risk[*].
The punchline? Potassium supports insulin release, but more rigorous data is needed before recommending it for diabetes support or prevention.
#4: Bone Health
Potassium may, researchers believe, boost bone mineral density by promoting a healthy PH in the human body. Specifically, certain alkaline components of potassium may counteract the potentially bone-damaging effects of a high-acid diet[*].
One piece of support? Diets high in fruits and vegetables (the best sources of potassium) are associated with higher bone density[*].
There are clinical trials too. For instance, one study on 201 people over 65 found that potassium supplementation increased lumbar spine bone density compared to placebo[*]. A similar study found that taking potassium reduced markers of bone loss in older adults[*].
Another study, however, found no effect on pottasium supplemention on either bone loss or bone density in postmenopausal women[*].
And so, the jury is still out on potassium for bone health.
Potassium-Rich Foods
You should strive to get your potassium (and most other nutrients) through diet. Specifically, you’ll want to eat lots of fruits and vegetables to meet your potassium needs.
Don’t worry about consuming too much potassium through foods. Foods raise blood levels of potassium more slowly than supplements, and you won’t develop hyperkalemia (dangerously high potassium levels) by eating potassium-rich foods[*].
With that in mind, here’s a short list of foods with a high potassium content:
- Salmon (624 milligrams per 6 ounce filet)
- Banana (422 milligrams per banana)
- Spinach (271 milligrams per cup)
- Cooked lentils (731 milligrams per cup)
- Avocado (690 milligrams per avocado)
- Asparagus (271 milligrams per cup)
- Tomato (292 milligrams per tomato)
- Dried apricots (2,202 milligrams per cup)
- Cantaloupe (428 milligrams per cup)
If you’re following a ketogenic diet, be sure to consume plenty of vegetables (leafy greens in particular) to avoid potassium deficiency. For twelve keto-friendly potassium foods, see this comprehensive post.
What Form of Potassium Should I Supplement With?
Again, if possible, try to get your 4.7 grams of daily potassium through diet. This means eating plenty of fruits and vegetables — the kings and queens of potassium-rich foods.
But for various reasons, you may want to supplement. Perhaps you have dietary restrictions that don’t allow you consume certain fruits and vegetables.
Or perhaps your low-carb diet makes it difficult to hit the RDI for potassium. Arugula, watercress, spinach, mustard greens, red leaf lettuce, and cabbage are your best vegetable sources — but it’s not always easy, depending on your schedule, to eat multiple servings of veggies per day.
When it comes to supplemental potassium, you have many options. Here are some of the most common forms:
- Potassium chloride
- Potassium gluconate
- Potassium citrate
- Potassium aspartate
- Potassium bicarbonate
- Potassium phosphate
Some data suggest potassium chloride and potassium gluconate raise blood levels of potassium. There’s scant evidence, however, on which form of potassium is best absorbed[*].
If you’re going to supplement, take potassium pills or powder in divided doses, spread out over the day with food. This will mimic how potassium gets absorbed through diet, and minimize unnatural spikes in blood potassium levels.
Most potassium supplements come in 99 milligram increments to limit the small risk of hyperkalemia in those susceptible. More on this soon.
Folks with healthy kidney function, however, should be fine taking more. Supplemental doses of up to 15.6 grams per day have been used without causing excess potassium levels in the blood[*].
That said, shoot for 4.7 grams of daily potassium in food and supplements. That’s the dosage with the best evidence behind it.
Next up: any concerns with taking potassium supplements?
Side Effects of Potassium Supplements
The most common side effect of taking potassium is GI distress. This will vary from person to person, and can be mitigated by taking potassium with food.
Eating potassium-rich foods, you’ll recall, does not pose a risk for hyperkalemia. Potassium supplements, however, are another story.
People with the following conditions should exercise extreme caution with potassium supplements[*]:
- Chronic kidney disease
- Type 1 diabetes
- Congestive heart failure
- Liver disease
These conditions can prevent the excretion of potassium through urine, causing it to rise to dangerous levels in the blood. Symptoms of hyperkalemia include heart palpitations, muscle weakness, and even paralysis[*].
Also, potassium may interact with certain medications and should be avoided in those taking ACE inhibitors, diuretics, beta blockers, or NSAIDs[*]. When in doubt, consult your medical professional for medical advice on this matter.
The Takeaway On Potassium
Potassium helps regulate your blood pressure, balance bodily fluids, and power your nervous system. Unfortunately, most people are below the adequate intake for this key electrolyte.
Research suggests that higher potassium intakes help with blood pressure, bone health, glycemic control, and kidney stone prevention.
If possible, get your 4700 milligrams of daily potassium through food, with fruits and veggies as your best sources. Because fruits tend to be high in carbohydrates, keto dieters must work extra hard to eat enough potassium-rich foods to meet their needs.
If diet isn’t getting you there, consider supplementing potassium. Just be sure to clear it with your doctor first, especially if you have kidney issues.