by Pamela M. Nisevich, M.S., R.D., L.D.
Think fast. If I say, “potassium,” what’s the first thing that comes to mind?
Was it bananas or something about being good for muscles? While both these things are on track, potassium is truly so much more. This little mineral may just help save lives by helping lower blood pressure, with little to no risk for most people.
HOW POTASSIUM LOWERS BLOOD PRESSURE
Studies have shown that diets high in potassium can reduce blood pressure. There’s still some debate about exactly how it works, but much of the data points to potassium’s ability to help the body excrete sodium, the mineral most connected to high blood pressure. Potassium and sodium are antagonists; when potassium increases, sodium decreases.
WHAT FOODS HAVE POTASSIUM?
Potassium abounds in many healthy foods, such as certain fruits, vegetables, whole grains and milk products. But you can also get it from less common sources. Some people have found that potassium chloride, a salt substitute (such as the brand No Salt), is an acceptable alternative to its sodium-touting cousin.
Unfortunately, raw potassium chloride may not be the tastiest spice in the aisle to the uninitiated. (Though some people get used to it and love it!) However, when used in cooking, the bitter, tangy taste often subsides. And most people find that after a week or two with less salt in the diet, the penchant for all things salty is gone.
CAN YOU OVERDOSE ON POTASSIUM?
America’s common highly processed, high-salt diet makes potassium overdose unusual. In fact, the body must continually take in potassium since it doesn’t store it. It absorbs more than it needs and adjusts by excreting just the right amount from the kidneys and intestines. But because of this, people who have compromised kidney function do need to monitor how much potassium they eat. Also, if you have a chronic disease or take any medicines, check with your health-care provider. This is important. It could be lethal.
ARE SALT SUBSTITUTES NATURAL?
The salt substitute potassium chloride is manufactured (as is table salt, sodium chloride). Both this and naturally occurring potassium positively affect blood pressure. In fact, a lot of trials demonstrating potassium’s benefits used the chloride version. (It’s easy to control the dosage.)
Nonetheless, health professionals strongly advise getting your potassium from natural sources. This recommendation is likely due to other ingredients you ingest at the same time. Nutritionists generally recommend a balanced diet over supplements. You never know how other ingredients might be working with the main one you want to get.
BEST FOODS TO EAT FOR POTASSIUM
One medium banana has a little less than 10 percent of the recommended daily intake of potassium. So, believe it or not, it doesn’t qualify as a “good source of” the mineral, as the Food and Drug Administration defines it.
Eh, it comes pretty close.
Here are some foods that are particularly high in potassium. The 2005 Dietary Guidelines for Americans recommends 4,700 milligrams a day for healthy adults.
- Potato, baked, with skin, medium: 926 mg
- Salt substitute (potassium chloride), ¼ tsp.: 650 mg
- Yogurt, plain, nonfat, 1 cup: 625 mg
- Sweet potato, baked with skin, medium: 542 mg
- Halibut, 3 oz.: 490 mg
- Lima beans, ½ cup: 478 mg
- Banana, medium: 422 mg
- Spinach, cooked, ½ cup: 419 mg
Source for potassium amounts: USDA National Nutrient Database for Standard Reference
PAMELA M. NISEVICH, M.S., R.D., L.D., is a consultant for Nutrition for the Long Run in Dayton, Ohio, and an author, speaker and counselor in sports nutrition, weight management and wellness.
Last updated and/or approved: November 2008
Article originally appeard in July/August 2008 print issue.