Electrolytes: Clearing up confusion on sodium and potassium
Sodium and potassium are both vital electrolytes. Most sources agree Americans do not consume enough potassium; but the jury is still out on sodium. Is there a real connection between salt intake and various diseases and medical problems?
Many people, some health professionals included, believe US salt intake levels are dangerously high. However, several recent studies have painted a much different picture. Here’s the low-down.
Your body needs potassium…it is an essential mineral/electrolyte that isn’t produced by your body; so you need to absorb it through food (or supplements).
Potassium is important for maintaining the electrochemical gradient across cell membranes (a fancy way of saying it’s important for nerve impulse control, cardiac function and muscle contraction). It’s also critical for assisting in enzyme activity.
Still, nearly 98% of US adults are not consuming enough potassium.
There is no specific recommended daily allowance (RDI) for potassium, but organizations around the world, including the World Health Organizations of the UK, Spain, Mexico and Belgium, have recommended consuming at least 3,500 mg per day.
The Food and Nutrition Board of the Institute of Medicine established 4,700 mg per day as the adequate intake, a higher recommendation than that of the World Health Organization.
It’s unclear whether the higher intake level provides any added value for most people, as opposed to the 3,500 mg recommendation. However, experts agree a higher intake could be beneficial to several select groups, including athletes (who are prone to losing excess potassium through sweat).
Sodium is also an essential mineral that is not produced by your body. Like potassium, you need to obtain it through food.
Many people use the terms “salt” and “sodium” interchangeably, which isn’t actually accurate. Sodium is a component of salt (only composing 40% of salt’s full makeup). The other 60% of salt is made up of chloride. Therefore a teaspoon of salt, or 5,000 mg, only provides about 2,300 mg of sodium.
Like potassium, sodium is essential for maintaining the electrochemical gradient across cell membranes. Sodium has many other functions in the body as well, including assisting in the absorption of chloride, amino acids, glucose and water and regulating blood volume and blood pressure.
The average North American consumes about 3,400 mg of sodium per day even though the recommended amount is about 2,300 mg per day. And interestingly, just 500 mg is needed for survival.
It’s almost impossible to consume more than 1,200 mg of sodium per day from a completely unprocessed diet, so it’s clear most sodium comes from processed foods.
A quick way to think about sodium and potassium is that they both assist in retaining fluids in the body. Potassium holds water INSIDE cells while sodium holds water OUTSIDE cells.
The reason many people think they "can't" eat salt
Lets say you eat a very low sodium diet. You never eat processed foods and don't add salt to any of your meals. As a result of this your body will adapt to this intake and your kidneys will regulate your sodium loss in urine down, to preserve the little you ingest.
Now, on the rare occasion you go out to sushi: you eat a bunch or carbohydrates from rice and dip a bunch of your food in soy sauce. The next day you experience a 4lb increase in weight, your ankles are swollen and it seems like you're softer all around, especially in the middle. What's the typical reaction? "Sodium is SO bad for you!! See, I ate soy sauce and gained all this water weight, edema and feel awful!".
But what you don't realize is that your body had adapted to a low sodium intake so on the rare occasion you eat a lot of it (paired with a bunch of carbohydrates) you will temporarily hold a lot of water until your kidneys regulate the new sodium and water balance which will result in the loss of that exta water weight and edema.
However, the person who regularly salts their food and eats a consistent carbohydrate and sodium intake can go out to sushi and see literally NO change in weight or edema from that food.
So.....what gives? This is merely an example of adaptation. Many people who see big swings in water weight from consuming sodium would see those swings level out if they simply consumed an adequate amount of sodium on a regular basis. It's sort of the equivalent of gtting sore from working out. If you never lift weights, the first session in the gym might leave you feeling crippled. But.....regularly going will lessen that feeling and make you better adapted to the activity, resulting in less soreness over time. Just because you got really sore once is not a reason to write off exercise, just like some water retention from one meal high in sodium doesn't mean you should never consume it.
To sum it up, if you are adding salt to your diet because you suspect your intake is low; simply give yourself a week or two to adapt, then those wild fluctuations should go away.
What mainstream media has been lying to you about
As I’m sure you’ve heard, sodium is bad for you, right? Maybe not…In fact, for every study linking salt to medical problems, there is another that denies any link at all.
For instance, a recent meta-analysis of seven studies (involving a total of 6,250 subjects) found “no strong evidence that cutting salt intake reduces the risk for heart attacks, strokes or death in people with normal or high blood pressure”.
Another study, published in 2007, after following 1,500 older people for five years, found no association between urinary sodium levels and the risk of coronary vascular disease or death.
A large 1988 study compared sodium intake with blood pressure in subjects from 52 international research centers and found no relationship between sodium intake and the prevalence of hypertension. In fact, the population that ate the most salt (about 14 grams a day) had a lower median blood pressure than the population that ate the least (about 7.2 grams a day).
There are even studies that not only refute the correlation between salt intake and disease, but contend the exact opposite.
A 2006 American Journal of Medicine study compared the reported daily sodium intakes of 78 million Americans to their risk of dying from heart disease over the course of 14 years. It found that the more sodium people ate, the less likely they were to die from heart disease.
Furthermore, in 2011 European researchers reported that across all test subjects, as sodium levels found in the urine decreased, the risk of dying from heart disease increased.
All in all, there are many studies claiming there is little evidence of any long-term benefit resulting from reduced salt intake.
So next time you’re stressing about salt intake just remember, sodium is an essential electrolyte. Like potassium, you need it to survive and it’s paramount in ensuring your body functions properly. As long as you’re living an active lifestyle and avoiding an all-processed food diet, sodium is your friend, not your enemy.
Note from Luke: Back at UCONN, I had the pleasure of being taught by Dr. Armstrong, a leading researcher in hydration. He found from years of studying, researching and compiling data that many of us simply vary from person to person in our sodium needs specifically. In addition, we can also adapt to higher and lower intake, leading to a huge variability in what people consume. In some studies he remarked that upwards of 18g of sodium per day showed no adverse health risks in some people!
Dr. Ben House even says people "who train and sweat" can throw the RDA salt requirement out the window! More salt info from him HERE.
In practicality, it seems that avoding packaged and prepared foods high in sodium and simply salting your food to taste as you cook it suits many people well. When paired with adequate hydration based off around 1/2 ounce per pound of bodyweight, that is a great starting point. Then simply using urine color as a guideline (per Dr. Armstrong) for confirming your hydration status.
Not that hard, nothing to be afraid of.
“All about Sodium.” Precision Nutrition, 30 May 2017, www.precisionnutrition.com/all-about-sodium.
Coila, Bridget. “What Is the Recommended Daily Amount of Potassium?”LIVESTRONG.COM, Leaf Group, 3 Oct. 2017, www.livestrong.com/article/360569-what-is-the-recommended-daily-amount-of-potassium/.
“How Much Potassium Do You Need Per Day?” Healthline, Healthline Media, www.healthline.com/nutrition/how-much-potassium-per-day#section1.
Moyer, Melinda Wenner. “It's Time to End the War on Salt.” Scientific American, 8 July 2011, www.scientificamerican.com/article/its-time-to-end-the-war-on-salt/.
“Potassium Recipe & Nutrition | Precision Nutrition's Encyclopedia of Food.” Precision Nutrition, www.precisionnutrition.com/encyclopedia/food/potassium.
“Sodium Recipe & Nutrition | Precision Nutrition's Encyclopedia of Food.” Precision Nutrition, www.precisionnutrition.com/encyclopedia/food/sodium.