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Based on how we evolved, the Optimum Dietary Potassium Intake likely greatly exceeds current and even recommended intakes. The problem is, we replaced many of the potassium-rich plant foods we used to stuff our faces with, like fruits, leafy greens, and other vegetables, including roots and tubers, with calorie-dense junk stripped not only of fiber but also potassium––such as added fats and sugars. So, in a traditional, largely plant-based diet, potassium content is high and sodium content is low.
But now, high blood pressure is the second leading cause of death in the world, killing more than 10 million people a year––second only to unhealthy diets, the #1 killer of humanity. We can improve both by eating more whole healthy plant foods like greens and beans, which are packed with potassium, which lowers blood pressure. But since most of us are getting too much sodium along with too little potassium, what about using salt substitutes? After all, the most commonly-used salt substitute is potassium chloride; so, you’d be swapping out sodium for potassium.
And it works. Based on a meta-analysis of more than a dozen randomized controlled trials, replacing sodium chloride with potassium chloride lowers blood pressure, and most of the trials involved just swapping out regular salt for less than 30 percent potassium chloride, and they still got results. And at less than 30 percent, most people can’t even tell the difference between regular salt and the potassium salt. So, it can taste exactly the same yet still drop your blood pressures? What’s the catch?
Potassium chloride is “generally considered as safe” by FDA, with the only major concern for healthy people being that if you go completely 100 percent sodium-free and use straight potassium chloride, like all of these, it can taste kind of funny, adding a bitter or metallic taste. I’ve found that it depends on what I’m seasoning with it. It works perfectly well on some things, but makes other things completely inedible. When I learned about the sodium science and threw out my salt shaker for good, within a few weeks my palate totally changed, and everything tasted fine without salt—except pesto. For some reason, pesto without salt just never tasted like it used to to me. So, I tried the potassium chloride salt substitute, and it worked perfectly—I couldn’t tell the difference at all. So, I had the best of both worlds. Then, I remembered how as a kid I used to put a tiny sprinkle of salt on watermelon like they do in the South to make it even sweeter. So, I tried it with the potassium salt and almost gagged. So, it’s definitely not for everything.
The reason healthy people don’t have to worry about getting too much potassium is that our kidneys just pee out the excess. Okay, but that’s with potassium in food. What about supplements? No adverse effects have been shown for long-term intakes of potassium supplements as high as 3,000 mg a day. And in fact, blood levels of potassium are maintained in the normal range by healthy kidneys, even when potassium intake is increased to approximately 15,000 mg a day––which is no surprise, since we evolved eating so many healthy plant foods, so many fruits and vegetables, that the normal, natural potassium intake for the human species may be on the order of 15,000 mg a day.
Basically, the normal range for potassium levels in the blood is between 3.5 and 5.0, and you start to worry when it starts creeping up towards 6. But give people potassium supplements, like all the salt substitution trials that have been giving study subjects an average of about 2,000 mg a day, and blood levels only go up 0.14. So, they might go from 4 to 4.14––not something that would push you into trouble.
Now, there is a limit. If you have a “massive banana eating habit,” you could bump your potassium from normal to above 6, but that was evidently from years of not eating much of anything except up to 20 bananas a day. Eating ten pounds of carrots every day is also probably not a good idea. That’s like 75 carrots in one day, which you could only do with a juicer, which is what this person attempted to do as part of a quack cancer cure. What about overdoing salt substitutes?
This report from the ‘40s was on lithium poisoning from the use of salt substitutes. Why? Because lithium chloride was used as a salt substitute—Jesus! But what about potassium chloride, which is what’s used today? There is one fatal case of someone who committed suicide by downing a little more than a tablespoon of a potassium chloride salt substitute. That doesn’t seem like a lot, just a tablespoon? I mean, how can we keep that on the shelves if only a tablespoon will kill you? Well, even less than that of regular salt taken at once can kill you, too. In fact, salt water ingestion was evidently a traditional method of suicide in ancient China, though these days, one may be more likely to die that way from abusive religious practices.
Having said all that, there are a small number of the population who may run into problems, primarily those with severely impaired kidney function. That’s why there’s been such a reluctance to push potassium‐based salt substitutes on a population level. If your kidneys can’t regulate your potassium, then you can definitely run into a serious issue. We’re talking about folks with known kidney disease; diabetes, since diabetes can lead to kidney damage; severe heart failure; those on medications that impair potassium excretion; older adults; and individuals with adrenal insufficiency. If you aren’t sure if you’re at risk, ask your doctor about getting your kidney function tested.
Ironically, potassium is so good at reducing deaths from high blood pressure, even among even among those with kidney disease, using potassium chloride salt substitutes would probably still save more lives despite the risk. Traditional dietary recommendations to kidney patients limited the intake of fruits and vegetables because of their high potassium content. However, this paradigm is rapidly changing due to the multiple beneﬁts derived from a fundamentally plant-based diet. A whole food plant-based diet may even ameliorate chronic kidney disease. There is increasing evidence that a whole food plant-based diet may oﬀer beneﬁts like slowing the progression of chronic kidney disease, and delaying kidney failure. So, the practice of restricting dietary potassium in kidney patients should really be reserved for patients with documented hyperkalemia––a potassium level of 6 or higher––because the key to halting progression of chronic kidney disease might in fact lie in the produce aisle.
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