You get potassium primarily from plant foods: beans, potatoes, leafy greens, fruits, and tomato products. Most adults need between 2,600 and 3,400 milligrams per day, and the best strategy is eating a variety of whole foods rather than relying on supplements, which are capped at just 99 mg per dose by the FDA.
The Best Food Sources of Potassium
Bananas get all the credit, but they’re actually a middling source. A medium banana delivers about 451 mg of potassium. A medium baked potato with the skin on contains over 900 mg, roughly double. Sweet potatoes land around 500 mg. If you’re trying to boost your intake, potatoes are one of the easiest single-food wins available.
Beans are the real powerhouses. A cup of dried pink beans contains over 3,000 mg, and black beans come in around 2,800 mg per cup (these are dry measurements before cooking, so the per-serving amount after preparation is lower, but still substantial). Soybeans, lentils, and adzuki beans are all in the same league. Even a half-cup cooked serving of most beans delivers 400 to 600 mg.
Beyond beans and potatoes, here are other potassium-rich foods worth knowing about:
- Tomato products: A cup of canned tomato puree has about 1,098 mg. Tomato sauce and paste are similarly concentrated.
- Dried fruits: Dehydrated apricots pack over 2,200 mg per cup. Dried currants come in around 1,119 mg per cup. Even smaller portions add up quickly.
- Plantains: One raw plantain contains about 1,315 mg.
- Orange juice: A cup of frozen concentrate (reconstituted) provides roughly 1,648 mg, though fresh-squeezed has less.
- Leafy greens: Spinach, Swiss chard, and beet greens are all reliable sources in the 800 to 1,000 mg per cooked cup range.
The common thread is that minimally processed plant foods tend to be the richest sources. Meat, dairy, and fish contain potassium too, but generally in smaller amounts per serving. A diet built around vegetables, fruits, and legumes will naturally get you close to your daily target.
How Much You Actually Need
Adult men need 3,400 mg per day. Adult women need 2,600 mg. During pregnancy, the target rises to 2,900 mg, and during breastfeeding it’s 2,800 mg. For context, most Americans fall well short of these numbers. The DASH diet, designed specifically to lower blood pressure, was built around hitting these potassium targets through food.
Children’s needs scale with age: 2,000 mg for toddlers, 2,300 mg for kids ages 4 to 8, and 2,500 to 3,000 mg for teenage boys (2,300 mg for teenage girls). These numbers come from the National Institutes of Health’s adequate intake recommendations.
Why Your Body Needs Potassium
Potassium is one half of a cellular balancing act. Every cell in your body runs a tiny pump that pushes sodium out and pulls potassium in. This pump maintains the electrical charge across cell membranes, which is what allows nerves to fire and muscles to contract. Without enough potassium, that electrical gradient weakens.
This matters most for your heart, which is a muscle that depends on precise electrical signaling to beat in rhythm. It also matters for your kidneys, which use potassium gradients to filter waste from your blood. Even basic functions like digestion rely on potassium to keep the smooth muscles in your gut contracting properly.
Your Body Absorbs Food Potassium Better Than Supplements
About 90% of dietary potassium is absorbed through the small intestine by passive diffusion, making it one of the more efficiently absorbed minerals. Research comparing potassium from potatoes versus potassium supplements found that urinary potassium levels (a marker of how much your body actually took in) were higher from potatoes than from supplements at the same dose. In other words, your body appears to use potassium from food more effectively.
This matters practically because over-the-counter potassium supplements are limited to just 99 mg per dose. That’s roughly 3% of what an adult man needs daily. The FDA imposed this cap because concentrated potassium in pill form can damage the lining of the digestive tract and, in excess, cause dangerous heart rhythm changes. Getting your potassium from food avoids both problems: the potassium is diluted across a larger volume, absorbed more gradually, and paired with other beneficial nutrients.
What Happens When Potassium Is Too Low
Low potassium, called hypokalemia, often produces no symptoms until levels drop significantly. Most people won’t feel anything until their blood potassium falls below 3.0 mmol/L (the normal lower limit is 3.5 mmol/L). At that point, symptoms typically start with fatigue, muscle weakness, and cramping. Constipation is another early sign, since the gut muscles slow down.
Mild deficiency (3.0 to 3.5 mmol/L) is common and usually caused by not eating enough potassium-rich foods, excessive sweating, or prolonged vomiting or diarrhea. Moderate deficiency (2.5 to 3.0 mmol/L) brings more noticeable muscle problems. Severe deficiency (below 2.5 mmol/L) is a medical emergency. It can cause ascending paralysis, starting in the legs and moving upward, and potentially affect the muscles you use to breathe. It can also trigger dangerous heart rhythm abnormalities.
Certain medications, particularly diuretics (water pills), are a leading cause of potassium depletion. People with chronic digestive conditions that cause ongoing diarrhea are also at elevated risk.
When Potassium Gets Too High
Healthy kidneys are efficient at flushing excess potassium through urine, so getting too much from food alone is rare if your kidneys work normally. The colon handles about 10% of potassium excretion as a backup route.
The risk rises sharply for people with chronic kidney disease. As kidney filtration declines, the body loses its ability to dump excess potassium, and levels in the blood can climb to dangerous territory. This becomes especially problematic when kidney filtration drops below about 20 mL per minute, a level seen in advanced kidney disease. Diabetes, heart failure, and certain blood pressure medications that affect kidney hormones also increase the risk.
High potassium is dangerous for the same reason low potassium is: it disrupts the electrical balance your heart depends on. Both extremes can cause fatal heart rhythm problems, which is why people with kidney disease are often told to limit high-potassium foods, the exact opposite advice given to the general population.
Practical Ways to Hit Your Target
A baked potato with skin (900+ mg), a banana (451 mg), a cup of cooked beans (600 mg), and a cup of cooked spinach (roughly 800 mg) would put you well over 2,600 mg before accounting for anything else you eat that day. The key is consistency rather than heroic single meals.
Cooking method matters. Boiling vegetables in water leaches potassium into the liquid, which you then pour down the drain. Baking, roasting, steaming, or microwaving preserves more potassium. If you do boil, using the cooking liquid in soups or sauces recaptures what would otherwise be lost.
Canned and processed foods tend to be lower in potassium and higher in sodium, which works against you on both sides of the equation. Potassium and sodium have opposing effects on blood pressure: potassium helps lower it, sodium raises it. A diet heavy in processed food creates a double deficit. Shifting even a few servings per day from packaged foods to whole vegetables, fruits, and beans can meaningfully change the ratio.