What’s the Scoop? Questions and Answers About Dietary Supplements

Got Potassium? Essential Facts About This Important Nutrient


Potassium is a nutrient that everyone needs to stay healthy. It's important for almost everything your body does, including proper kidney and heart function, muscle contraction, and nerve transmission.

Most adults should get 4,700 mg of potassium a day, but many people don’t get enough. Potassium is found in many fruits (such as dried apricots, oranges, and bananas), vegetables (such as acorn squash, potatoes, and spinach), legumes (such as kidney beans and soybeans), nuts, milk, yogurt, meats, poultry, and fish. Many salt substitutes that are used to replace table salt also contain potassium. Most dietary supplements have only small amounts of potassium.

Getting too much potassium from food or beverages does not cause problems in healthy people. However, if you have chronic kidney disease or use certain medications, the potassium you get from your diet could cause your blood levels of potassium to get too high. High levels of potassium in your blood can cause muscle weakness, paralysis, and heart problems that could be fatal. For these reasons, it’s important to talk with your healthcare provider for advice about potassium.

I know bananas contain potassium. Can I get enough potassium by eating a banana every day?

Bananas do have a lot of potassium compared to many other foods but eating one banana a day won’t meet your potassium needs alone. A medium banana has about 420 mg of potassium, so you would have to eat more than 11 bananas to meet the 4,700 mg that most adults should get each day. Obviously, that’s not the best approach. Instead, eat a variety of nutritious foods that contain potassium to ensure you get enough of this important nutrient.

I can’t find a potassium supplement that provides very much potassium. Why?


Most dietary supplements contain less than 100 mg of potassium, which is only about 2% of the recommended intake. This is partly because of reports that some potassium-containing medications may damage the gastrointestinal tract. Although the U.S. Food and Drug Administration (FDA) does not limit the amount of potassium in dietary supplements, they do require warning labels on some medications that contain 100 mg of potassium or more.

Because of the small amounts of potassium in dietary supplements, you can’t rely on them to help meet your potassium needs. This underscores the importance of getting potassium by consuming a nutritious variety of foods and beverages.

Can potassium help lower my blood pressure?


Yes, it might. People with low intakes of potassium have an increased risk of high blood pressure, especially if they consume a lot of sodium (salt). Therefore, increasing your potassium intake, along with decreasing sodium intake, might help lower your blood pressure and reduce your risk of stroke. One way to do this is to follow an eating plan called DASH (Dietary Approaches to Stop Hypertension), which emphasizes potassium from fruits, vegetables, and low-fat dairy products. Also, using potassium-containing salt substitutes in place of regular salt helps lower blood pressure. But it's not clear whether this is because of the increased potassium, reduced sodium, or both.

Have more questions? See our fact sheets on potassium.

In the News

FDA: Dietary Supplements Cannot Contain Active Ingredients Found in Marijuana



Despite being available in some retail outlets and online, dietary supplements that contain the marijuana constituents tetrahydrocannabinol (THC) or cannabidiol (CBD) are prohibited, according to the FDA. The FDA has concluded that more research is needed to determine whether marijuana is a safe and effective treatment for any disease or condition, although they have approved a few drugs that contain active ingredients from marijuana for some health conditions.

National Center for Complementary and Integrative Health Launches HerbList Mobile App


The NIH National Center for Complementary and Integrative Health has launched HerbList™—an app to help consumers and healthcare providers find unbiased, evidence-based information on herbal products. Users can access information on uses for each herb, potential safety problems, side effects, and herb-drug interactions, with links to resources for more information. You can also mark favorite herbs for quick recall and offline accessibility. HerbList is available to download for iPhones, iPads, and Android devices.

Black Americans Have Lower Risk of Falls and Fractures, Despite Lower Vitamin D Status


Vitamin D plays an important role in maintaining strong bones, so it's often assumed that people with higher vitamin D status will have stronger bones. Although there is a correlation between vitamin D status and bone strength in White and Mexican Americans, the same correlation may not apply in Black Americans. On average, Black Americans have lower vitamin D status than others, but they have a lower incidence of falls, fractures, and osteopenia (weak bones that may lead to osteoporosis). This paradox was explored in a recent expert panel meeting led by the Office of Dietary Supplements and cosponsored by other parts of NIH. Findings from the meeting were recently published in the journal, BMC Proceedings. ODS’s Dr. LaVerne Brown published a blog about the topic.

Have a Question About Dietary Supplements?


The Office of Dietary Supplements (ODS) provides general information about dietary supplement ingredients in response to questions from consumers, health professionals, students, and others. While ODS cannot answer specific medical questions, make referrals, or give personal guidance on the use of dietary supplements, ODS’s registered dietitians on staff reply to each inquiry and give useful, scientific, and evidence-based information. Send your questions about dietary supplements to ODS@nih.gov.

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About ODS
The Office of Dietary Supplements (ODS) is part of the National Institutes of Health (NIH), the nation’s medical research agency—supporting scientific studies that turn discovery into health.

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Office of Dietary Supplements
National Institutes of Health
6100 Executive Blvd., Room 3B01
Bethesda, MD 20892-7517

Email: ods@nih.gov
Website: https://ods.od.nih.gov

Office of Dietary Supplements, NIH | 6100 Executive Boulevard, Room 3B01, Bethesda, MD 20892