Some minerals, like iron, your body only needs in small amounts, but potassium is one of the “big guns.” You need a substantial quantity of potassium circulating in your bloodstream and inside cells on a minute-by-minute basis to control a variety of critical bodily functions. For one, potassium and sodium help to regulate fluid balance both inside cells and in the body as a whole.
Potassium is also vital for healthy heart and blood vessel function, as potassium plays a vital role in initiating each heartbeat and for controlling the flexibility of blood vessels. Low levels can cause a rise in blood pressure. Even more importantly, if potassium falls too low, it can lead to heart irregularities or even a fatal, abnormal heart rhythm. Plus, you need potassium for muscle contractions and normal nerve function.
Since potassium plays such a critical role in health, it’s carefully regulated, mainly by the kidneys. With it having such an important role in health, you might think your body would produce it, but it doesn’t. You must get potassium through diet. If you should become severely deficient, the results can be catastrophic. A substantial drop in potassium can cause life-threatening symptoms, including irregular heart rhythm, muscle spasms, muscle weakness, or muscle cramps. If it’s modestly low, you might experience vaguer symptoms such as fatigue, constipation, or nausea.
Certain situations increase the likelihood of a potassium shortfall. If you exercise for a prolonged period of time, you can temporarily lower your potassium level, as you lose potassium when you sweat. That’s why it’s important to drink an electrolyte-rich drink if you exercise for more than an hour, especially in a warm environment. That’s why sports drinks are so popular among athletes.
How Much Potassium Are You Getting?
The recommended daily intake of potassium is 4,700 milligrams daily. Are most people getting that amount? Not even close. According to the USDA, the average American adult takes in only 2640 milligrams, on average, daily. That’s a substantial shortfall! In addition, a study found that only 10% of men and less than 1% of women get the recommended daily amount of potassium in their diet. Shocking, right? Older adults, aged 40 and over, tend to consume more potassium than younger adults, ages 20 to 39 and men, in general, consume more than women.
Why is potassium insufficiency so common? It’s partially due to the penchant of Americans for fast food and convenience items. According to the Harvard T.H. Chan School of Public Health, most Americans overconsume sodium and don’t get enough potassium in their diet. Most packaged and processed foods are heavy on sodium and fall short in potassium, creating an imbalance between these two electrolytes.
Potassium Intake and Blood pressure
As mentioned, potassium plays a key role in blood pressure regulation. When potassium levels are suboptimal, the arteries can’t relax as easily, and blood pressure rises. Plus, a diet low in potassium and high in sodium can lead to fluid retention, another factor that can raise blood pressure. With high blood pressure being so common in older adults, one wonders whether shortfalls in potassium are partially fueling the epidemic.
Low dietary intake of potassium is linked in several studies with higher blood pressure and an increased risk of stroke. In fact, an analysis of 11 studies found that consuming more dietary potassium was associated with a 21% lower risk of stroke. Also, studies show that consuming a diet higher in potassium can lower systolic and diastolic blood pressure by as much as 5 mmHg. That’s significant!
Because of the impact potassium has on blood pressure, people with hypertension and pre-hypertension should focus on meeting the daily recommended intake of 4700 milligrams of potassium. One precaution though. Some people with high blood pressure also have mild kidney dysfunction. If you have kidneys that aren’t functioning properly, consuming excess potassium is harmful. Also, certain medications, including some blood pressure prescriptions and non-steroidal anti-inflammatory medications, can cause your body to retain potassium. Keep in mind, too much can be as harmful as too little. So, talk to your physician before bumping up your potassium intake if you take medications or don’t know whether your kidneys are healthy.
Dietary Sources of Potassium
As mentioned, processed foods are high in sodium and low in potassium. In contrast, fruits and vegetables are naturally potassium-rich. Eating a variety of colorful produce daily will help you meet your body’s potassium requirements and supply other beneficial vitamins, minerals, and phytochemicals as well. One of the best sources of potassium, avocados, is also rich in healthy, monounsaturated fats. In fact, a single cup of avocado has 708 milligrams of potassium. Plus, adding avocado to a salad helps your body better absorb fat-soluble nutrients, like beta-carotene, from a salad.
Other than fruits and vegetables, fish and dairy, like yogurt, are other foods that contain substantial quantities of potassium. But, fruits and veggies have other benefits. A higher intake of fruits and vegetables is linked, in studies, with a lower risk of heart disease, stroke, high blood pressure, and metabolic syndrome.
The Bottom Line
Most of us are falling short on meeting the daily recommendations for potassium, as confirmed by the United States Department of Agriculture. Most people aren’t critically deficient to the point that they heart irregularities, muscle weakness, or abnormal nerve function, but even a mild potassium shortfall can make it harder to maintain healthy blood pressure. So, make sure your diet isn’t heavy on the processed foods and that you’re getting a variety of fruits and vegetables in your diet. If you eat dairy foods, yogurt and fish are good sources that also have a variety of health benefits, including probiotics in yogurt and omega-3’s in fish. So, enjoy a variety of potassium-rich foods!
Harvard T.H. Chan School of Public Health. “Shifting the Balance of Sodium and Potassium in Your Diet”
U.S. Department of Agriculture. “Potassium Intake of the U.S. Population”
Arch Intern Med. 2011;171:1183–91.
J Am Soc Hypertens. 2014 Apr;8(4):232-8. doi: 10.1016/j.jash.2014.01.001.
J Am Coll Cardiol. 2011 Mar;57(10):1210-9.
Up-to-Date. “Potassium and Hypertension”
American Heart Association. “How Potassium Can Help Control High Blood Pressure”
Lifestyle Medicine. Second edition. CRC Press. 2013.