Not banans ftw
By the way… bananas are a pretty mediocre source of potassium. Avocados, tomatoes or potatoes all day.
The reason many doctors and nutritionists advise against adding potassium to the diet is because they have concerns of cardiovascular complications secondary to excessive potassium intake. The most likely result from excess is heart palpitations, muscle weakness and in theory, the worst case of cardiac arrest.
This is a possibility in more folks than you might think. Your body very tightly regulates your serum potassium levels, but there are disease states that derail this balancing act.
The most common issues are chronic kidney disease and diabetes.
Insulin resistance and deficiency are a features of diabetes. Insulin drives potassium into your cells and out of the blood stream. Problems with insulin signaling impair this process, and you put more pressure on the kidney-adrenal axis in excreting potassium.
The kidneys excrete potassium in an aldosterone dependent process. If you have chronic kidney disease, you don’t excrete potassium very well.
You might be aware that diabetes and chronic kidney disease tend be strongly associated with one another. Often folks with diabetes have chronic kidney disease, so you have this two-hit effect whereby you don’t move potassium into your cells very well nor do you excrete it as well. And so you’re more likely to suffer cardiovascular issues.
Knowing this, it sensible for health professionals to have reservations about extra potassium intake, because a large fraction of the population suffers some degree of insulin resistance and renal failure.
What about healthy individuals?
Studies have been done demonstrating the safety of potassium intake at levels of 15 grams per day. If you’re healthy, you’ll likely regulate it well.
That’s a lot of potassium!
Your potassium needs
The Institute of Medicine Recommends 4.7 grams per day. Just about every adult population studied in the U.S. has been under IOM recommendation. That being said, just about every patient I’ve interacted with who I have track their nutrition aren’t even getting 3 grams per day.
Some nutrition experts argue that pre-agriculural diets contained more than 10 grams per day.
A brief experiment
Being exposed to the latter information, I decided to kick my potassium intake up to 9–11 grams a day for a few months. My primary source was coconut water, so I was consuming around 8 17-ounce cans daily. I ordered lab work a few months in, and my potassium levels were smack in the middle of the reference range at 4.4mmol/L. My fasting glucose was 67 and my HgbA1c was 5.0. I mention the glucose markers, because that’s a ton of sugar, right?
It seemed to be that I just felt better overall doing this. Obviously I can’t only attribute that solely to an increased potassium intake.
I have reservations about having most folks consume the amount of coconut water I did. My decision to select coconut water as my source was based on convenience and the fact that I’m very active.
I definitely strive to have my patients aim for that 4.7 grams per day. Potassium is critical for blood pressure regulation (hypertension is a problem that is just rampant) and glucose regulation.
I am more sensitive about potassium related issues even at these lower levels of sufficiency in patients with diabetes and/or kidney disease.
I explain that there may be additional benefit to increasing their intakes above and beyond what the IOM recommends, but we always frame this in the context of good kidney function and insulin sensitivity. I’m always pretty conservative with additional dietary potassium and won’t advise most healthy patients above 7 grams per day.
If there is no evidence of diabetes or kidney impairment and you have evidence that you’re not getting that 4.7 grams a day, you should discuss these points I raised with your health and nutrition providers. Especially if you have hypertension.
Further Reading
National Insitutes of Health Potassium Data Sheet