The periodic symbol for potassium is “K.” Why would that be? Were the table’s inventors too preoccupied with their fascinating discoveries to perform a simple spell-check?
It turns out that, starting centuries ago, the English had a habit of sprinkling wood ashes on their garden beds, and seeing the plants grow faster and healthier as a result.
Over time, they learned that when they soaked wood ash in iron pots, they could create what came to be called “potash.”
Then, in 1807, a British chemist by the name of Sir Humphry Davy isolated potassium from potash. He called the result “kalium,” which is the Latin word for potassium — and the periodic table had its “K.”
Even though the English later named potassium after the potash that led to its discovery, the “K” stuck, which turned out to be a very good thing for phosphorus fans, who to this day claim the sole periodic-table rights to the letter “P.”
In this article, we’ll explore potassium’s role in the body, how much you need, and its benefits for human health. And we’ll look at the best sources of potassium, so you can make sure to include them in your diet.
What Is Potassium?
Plants require significant amounts of potassium to run critical biological functions. That’s why we often find plenty of this important, healthful mineral in fresh, plant-based foods.
In addition to being critical to the growth of healthy plants, potassium also plays a profoundly important role in the human body. It is one of several vital nutrients that make up the electrolyte family, which includes sodium, magnesium, calcium, and others. Potassium, like all electrolytes, plays an essential role in maintaining your body’s fluid balance and facilitating nerve signaling due to its exceptional capacity for ionic charge.
Potassium plays a vital role in many critical functions throughout the body, especially in the heart and kidneys.
The roles of potassium include:
- regulating fluid levels in cells
- sending nerve signals
- contracting and relaxing muscles
- limiting calcium loss through urine
- balancing the body’s sodium levels
Given the number of essential functions of potassium, it’s no wonder it’s considered an important nutrient. But what are the specific health benefits of potassium? Here are a few reasons why it’s worthwhile to optimize your intake.
Potassium and Blood Pressure
When you eat too much sodium — usually from table salt or salty foods — your body releases more water to dilute the excess sodium in your blood. The increased fluid presses on your blood vessels, increasing the pressure, like too much water moving through a garden hose. High blood pressure is also called hypertension, and is a significant factor in the development of cardiovascular disease, stroke, and kidney disease.
But it turns out that potassium can help to mitigate some of this impact — which is good news for your heart. In fact, a 2016 study in the journal Nutrients found that higher levels of potassium lower the overall risk of hypertension. And in the Framingham Offspring Study, published in 2021, researchers concluded that higher intakes of potassium are strongly associated with a lower risk of cardiovascular disease.
Potassium and Strokes
Potassium is increasingly understood to be significant in the management and prevention of cardiovascular disease and related incidents. A 2014 meta-analysis of more than 333,250 people and 10,659 stroke events saw a “significant association between K intake and stroke.” The more potassium people consumed, the less likely they were to suffer a stroke.
Potassium and Diabetes
According to the CDC, there were more than 1.4 million new cases of diabetes in the US in 2019. Preventing diabetes is far easier than reversing the condition, and on that front, there is hope. While low levels of potassium in the blood are correlated with an increased risk of type 2 diabetes, a 2016 article in Nutrients explains that increased dietary potassium may help maintain healthy blood glucose control and limit the risk of developing diabetes. And even if you’re already diagnosed with prediabetes, research shows that increased potassium can stabilize fasting glucose levels.
Potassium and Kidney Health
Potassium is also healthful for your kidneys. Not only can adequate potassium help prevent kidney stones, but it’s a powerhouse for the prevention and management of chronic kidney disease (CKD). Many patients with CKD are advised to limit their potassium in order to lower the risk of developing hyperkalemia (excessive potassium in the body). However, a 2020 meta-analysis found that a higher intake of potassium in the early stages of the disease was actually protective and slowed progression. Results are more mixed for higher potassium diets during the later stages of CKD. (Make sure to check with your health care provider before loading up with potassium if you have kidney disease.) If you’re struggling with CKD, you can learn more about the ideal foods for kidney health in our comprehensive article.
Is Potassium Good for Your Bones?
When we think of bone health, most of us don’t think first about potassium. But maybe we should! Research shows that potassium is strongly linked to higher bone mass density. And many studies tell us that positive effects on bone health are seen even with a minimum of just 2,300 mg of potassium per day, although some studies recommend aiming for a daily intake of around 4,700 mg.
How Much Potassium Do You Need?
The National Institute of Health’s recommendations for daily potassium intake are:
- Children up to 13 years have varying needs over time
- Teens 14–18: 2,300 mg for girls and 3,000 mg for boys
- Women 19+: 2,600 mg (Pregnant or lactating women: 2,600 mg – 2,800 mg)
- Men 19+: 3,400 mg
Importantly, these recommendations may not actually be enough for many people. The Food and Nutrition Board encourages adults to get 4,700 mg per day — more than twice the NIH recommendation for adult women.
Perhaps even more critically, a 2013 research review on potassium and health explains that the ratio of potassium to sodium in the diet significantly influences many health markers, even more than potassium alone. In other words, the more sodium you eat, the more potassium you need.
Potassium and Sodium Balance
Potassium and sodium are two important electrolytes that work together to achieve some fantastic things. They both help to regulate nerve function — supporting muscle contraction and heart function. And they work in tandem to maintain fluid equilibrium across cell walls. Having a healthy balance of these minerals is vital to their proper function.
Harvard Health explains that early Paleolithic people probably got about 16 times more potassium than sodium, and that the typical modern industrial diet supplies a potassium-sodium ratio of just 0.74 to 1. Meanwhile, the ideal potassium-to-sodium proportion, according to the NIH, seems to be about 2:1. So most of us are getting less than half the potassium we need, at least in relation to the sodium in our diets. And when the balance is off, problems ensue.
What Happens if Your Potassium Level Is Too Low or Too High?
Sometimes, potassium levels in the body can fall outside the ideal range, being either too high or too low. Having potassium levels that are too low is more common than levels that are too high.
Not having enough potassium in your body is called hypokalemia. Though many people who develop potassium deficiency may not have any symptoms, the effects of low potassium can be debilitating and even deadly. It’s a serious concern that can lead to muscle weakness or paralysis and abnormal heart rhythms (arrhythmias). Hypokalemia is also associated with increased blood pressure, kidney stones, and osteoporosis.
Despite being more common than excessive potassium levels, cases of low potassium are usually mild and are often the result of another condition or a side effect of medication.
In contrast, potassium toxicity and the risks from too much potassium, hyperkalemia, are rare in healthy people because kidneys efficiently excrete excess potassium in the urine. However, people with certain conditions should be aware of the risks of consuming too much potassium. Mild hyperkalemia is usually asymptomatic, but high levels of potassium can cause life-threatening cardiac arrhythmias, muscle weakness, or paralysis. Most cases of hospitalization for excessive potassium are due to medications and renal insufficiency.
Risk factors for potassium toxicity include:
- Kidney issues, advanced kidney disease, or kidney failure
- Prolonged NSAID-use
- Insulin deficiency
- Tissue or cellular damage
Dietary causes of hyperkalemia are very rare, particularly in people not at risk. If you’re in a high-risk group, consult with your healthcare provider to ensure you’re consuming safe potassium levels.
Where Should You Get Your Potassium?
Plants are incredibly effective at drawing minerals from the soil, including potassium which is promptly taken up by plant roots. In most conventional land practices, potassium is added to the soil as a fertilizer to help plants grow. In more traditional practices, potassium is returned to the soil when plants die or through composting or animal manure during grazing.
Potassium is found in many whole plant foods — including many of our favorite comfort foods, like potatoes! Beans and other legumes, nuts, vegetables, and fruit (including dried fruit) are also good food sources of potassium. However, dried fruits will have even higher amounts of potassium because the water has been removed and all the nutrients are concentrated (although they also have an increased sugar content for the same reason).
Here are some examples of the most potassium-rich foods. (Remember, the NIH’s recommended minimum is at least 2,600 mg per day for women, and at least 3,400 mg per day for men — and you don’t have to get it all in one place.)
- Cooked beet greens, 1 cup — 1,309 mg (more than a quarter of the optimal recommended potassium intake for a whole day!)
- Medium baked potato with skin — 926 mg
- Cooked acorn squash, 1 cup — 896 mg
- Cooked spinach, 1 cup — 839 mg
- Cooked pinto beans, 1 cup — 746 mg
- Jackfruit, 1 cup — 739 mg
- 100% prune juice, 1 cup — 707 mg
- Kiwi, 1 cup — 562 mg
- Cooked broccoli raab, 1 cup — 550 mg
- 100% orange juice, 1 cup — 496 mg
- Medium avocado — 487 mg
- Medium banana — 451 mg
- Unsweetened coconut water, 1 cup — 396 mg
- Pumpkin seeds, 1 oz — 261 mg
- Cooked lentils, 1 cup — 230 mg
This list could be pages long, in fact. Many different fruits and vegetables include potassium — even more so when they come from healthy, potassium-rich soil. These kinds of foods are also:
- Naturally abundant in some important micronutrients, like folate, vitamin C, and magnesium
- Rich in colorful phytonutrients that work as powerful antioxidants to help prevent cancer and lower the risk of heart disease, stroke, and Alzheimer’s
- Great sources of prebiotic fiber to keep your gut healthy
Potassium is also found in abundance in dairy products and in some fish, although these come with other health and ethical considerations. (For more on dairy, see our article here, and for more on fish, see our article here.)
Don’t Pass on Potassium!
Potassium is an essential mineral necessary for the vital functioning of your entire body. The research overwhelmingly shows that diets rich in whole foods, especially fruits and vegetables, significantly impact potassium levels and help lower the risk of cardiovascular disease, type 2 diabetes, kidney stones, and osteoporosis. Plus, potassium helps counteract the negative consequences of excess sodium, which is one of the main dietary risk factors for high blood pressure.
Some of the best sources of potassium include leafy greens, beans, nuts, dried fruits, bananas, avocados, and starchy vegetables like potatoes and winter squash.
Tell us in the comments:
- Do you try to get more potassium in your diet? Why or why not?
- What are some naturally potassium-rich foods you enjoy?
- What are a few new high-potassium foods you could try?
Featured Image: iStock.com/yulka3ice