Potassium--the Other Half of the Salt Equation

It’s not enough to eat less salt. You probably need more potassium too. It helps your body get rid of extra salt. If you get the ratio right, you may lower your risk of high blood pressure, heart disease, stroke, osteoporosis and kidney stones.

How? Eat plenty of whole plant foods, especially bananas, raisins, prunes, oranges, avocado, yams, spinach, tomatoes and almonds. Orange juice and a bowl of raisin bran cereal with banana slices is a good head start towards your daily quota.

We’re badly out of whack. Ancient humans ate mostly plant foods. And salt (sodium) was scarce. They got about 7 times more potassium than sodium. Our bodies adapted to hold on to sodium and release potassium. But now we eat more salt than potassium. It’s in nearly all fast and processed food.

The extra salt makes us retain fluids, so we have more blood volume. At the same time it tends to narrow our blood vessels. More blood through smaller vessels can lead to high blood pressure and heart disease over time.

What is potassium? What does it do for us?

It's an electrolyte, a mineral that helps conduct electricity within our bodies. It helps our muscles contract, our nerves send impulses and our blood vessels stay healthy. Our cells are constantly working to pump sodium out of cells in exchange for potassium. It also helps us burn carbohydrate foods.

Over the long term, being low on potassium increases the risk of many diseases and conditions.

Are some people more likely to be low on potassium? What happens if you are?

If you eat few fruits, vegetables or nuts you may be a little low all the time. That raises your risk of:

• High blood pressure
• Heart attack and heart disease
• Stroke
• Osteoporosis (weak bones that are apt to break)
• Kidney stones

Even lower blood levels of potassium causes hypokalemia. Symptoms include fatigue, muscle weakness and cramps, constipation and irritability. A very severe lack can paralyze your muscles, including your intestines and your heart. That can be fatal.

Your risk of hypokalemia is higher if you:

• Take thiazide diuretics or furosemide (used for high blood pressure or heart failure)
• Are an alcoholic
• Get dehydrated from severe vomiting or diarrhea
• Use laxatives too much
• Have an eating disorder like anorexia or bulimia
• Have heart failure
• Sweat a lot from extreme exercise or heat
• Take certain other medicines including bronchodilators, decongestants and high-dose antibiotics

Eating lots of black licorice can do it, too. It contains a chemical that can cause hypokalemia. According to the Food and Drug Administration, if you’re 40 or older, eating 2 ounces of black licorice a day for at least 2 weeks could land you in the hospital with an irregular heart rhythm.

How much potassium do I need?

The U.S. Institute of Medicine recommends these amounts of daily potassium to lower blood pressure, reduce salt sensitivity, and minimize the risk of kidney stones.

Infants

• 0-6 months: 400 mg/day
• 7-12 months: 700 mg/day

Children and Teens

• 1-3 years: 3,000 mg/day
• 4-8 years: 3,800 mg/day
• 9-13 years: 4,500 mg/day
• 14-18 years: 4,700 mg/day

Adults

• 19 years and older: 4,700 mg/day
• Breastfeeding women: 5,100 mg/day

Should I take a multivitamin or potassium supplement? Can you get too much potassium?

A multivitamin won’t hurt, but it also won’t help much. Most have only about 100 mg of potassium. High-dose supplements can be dangerous, unless your health care provider is checking your blood levels.

A bit too much potassium can cause nausea, vomiting, belly pain and diarrhea. Much too much (hyperkalemia) can cause serious problems like kidney failure and abnormal heart rhythm that can lead to cardiac arrest. People with kidney disease, type 1 diabetes, or who take certain drugs for high blood pressure or heart failure are at higher risk of hyperkalemia.

Except for black licorice, you won’t get too much from food. Eat more foods that are rich in the mineral instead of taking pills.

What foods have the most potassium?

Most fruits and vegetables have some--and little to no salt. But these are rich sources:

930 mg-- Potato, baked with skin  
620 mg—Raisins (1/2 cup)   
490 mg-- Avocado (1/2)   
460 mg-- Yam (1/2 cup)   
420 mg-- Banana     
420 mg-- Spinach, cooked (1/2 cup) 
420 mg-- Tomato juice (6 ounces) 
400 mg-- Prunes (1/2 cup)   
370 mg-- Raisin bran cereal (1 cup)  
360 mg-- Orange juice (6 ounces) 
330 mg-- Broccoli (3 spears)   
320 mg-- Acorn squash (1/2 cup) 
290 mg-- Tomato    
260 mg-- Almonds (1/4 cup)   
250 mg-- Sunflower seeds (1/4 cup)  
240 mg-- Apricot, dried (3)   
230 mg-- Orange   

So start your day with the breakfast we mentioned: a small glass of orange juice and a bowl of raisin bran cereal with a sliced banana. Take an orange and a handful of almonds, sunflower seeds or raisins to work. Have spinach, broccoli, yam or acorn squash with dinner. You’ll get plenty of potassium, and a better shot at a healthier life.

Updated on 1/2/2012 by Jennifer Johnson, BA English composition, Northwestern University. Reviewed by Steve Silverstein, MD. Published on 1/30/2012.

References:
1. Potassium. Micronutrient Information Center at http://lpi.oregonstate.edu.
2. Yang Q, et al. Sodium and potassium intake and mortality among US adults: Prospective data from the third national health and nutrition examination survey. Arch Intern Med 2011; 171(13): 1183-1191.
3. Silver LD, Farley TA. Sodium and potassium intake: mortality effects and policy implications. Arch Intern Med 2011; 171(13): 1191-1192.
4. Institute of Medicine. A population-based policy and systems change approach to prevent and control hypertension. 2010; Washington, DC: The National Academies Press.
5. Black Licorice: Trick or Treat? at www.fda.gov/ForConsumers .
6. Cook NR, et al. Joint effects of sodium and potassium intake on subsequent cardiovascular disease. Arch Intern Med 2009; 169: 32-40.

Copyright © 2012 McKesson Health Solutions. All Rights Reserved. 

Page last updated: January 27, 2012