Nutrition Nuts and Bolts

By Shelly Najjar

Can you list at least 3 foods that have more than 500 mg of potassium? (Hint: one is in the title of this post.) If you can’t, that’s okay. A few days ago, I couldn’t either.

A family friend asked me to find some information about potassium, including how much she should get every day and what foods she should be eating to reach that goal. I couldn’t tell her off the top of my head (even though we’ve had assignments on this topic in the past) so I told her I’d get some resources for her.

What is potassium? What does it do?

Potassium is an element/mineral that helps maintain electrolyte and pH balance, affects muscle contraction (including the heart muscle), and allows nerves to transfer signals more efficiently.

How does it work?

Many cells in our body use potassium to transfer other ions (electrically charged particles) across membranes. Sodium (another electrolyte and a part of table salt) has a negative charge. Potassium has a positive charge. These signals are important because they affect how well a signal can travel through the cell (like what nerve cells do).

Potassium and sodium are also transferred in and out of the cells to maintain fluid balance, because water likes to collect in areas where there is a lot of sodium. If the inside of a cell has too much sodium, water will be drawn in to dilute it, through the process of osmosis (water moving from an area of low concentration to an area of high concentration). If too much water collects in the cell, it will burst.

One of the things cells do to prevent this from happening is to exchange sodium for potassium (potassium molecules are pulled into the cell and sodium molecules are pushed out).

Where is it found?

Obviously, potassium is important. It is in many foods, including

• baked potatoes with skin (925 mg/medium potato)
• canned white beans (595 mg/cup), and
• canned clams (535 mg/3 oz).

(Note: You should now be able to answer the potassium question at the beginning of this post.)

There are a couple of lists of potassium-containing foods that I want to share with you.

1. The first is a list sorted by the amount of potassium per serving: Food Sources of Potassium.
2. The second is a more comprehensive list, organized by food groups separated into three categories (High Potassium, Moderate Potassium, and Lower Potassium foods), and then alphabetized by food name, rather than by amount: Potassium Values of Food.

How much do we need?

The recommendation for adults without kidney disease ages 19 and over is 4,700 mg (milligrams) of potassium daily. (See the Dietary Reference Intakes. They list it in grams, so you may need to know that 1 g = 1,000 mg.) Dietary Reference Intakes are listed by age and sex for each nutrient.

Important: Your health care professional may recommend a different daily amount if you have certain medical conditions, including but not limited to kidney disease or hypertension (high blood pressure). Please consult a doctor or Registered Dietitian. Also, see my disclosure.

Summary

• Potassium is a mineral that our bodies need to work properly.
• Many foods contain potassium. Besides potatoes and bananas, some foods with high potassium (more than 200 mg per serving) are avocados, fish, chocolate milk, and turkey. The two lists mentioned above contain many more options.
• The recommendation for most adults is 4,700 mg of potassium daily.

Also read…

• Is fiber in anything that tastes good?
• What Is Potassium?
• What are whole foods?

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Shelly Najjar, MPH, RDN is a Registered Dietitian Nutritionist and wellness coach at Confident Nutrition. You can find her on Facebook, Twitter (@ShellyNajjar), and LinkedIn.