In the summertime when it’s hot outside I tend to have problems with cramps, mostly in my feet and hands. I have been told that sometimes this is caused by a potassium deficiency.
Coincidentally, late last summer I was diagnosed with hypertension. As part of my treatment plan my doctor told me to reduce my sodium intake.
So I went to the grocery and purchased Morton’s Salt Substitute for when I’m eating something that really needs some (pseudo-)salty goodness. I also purchased potassium supplement tablets.
I didn’t read the fine print until I got home. Yeah, I know, serves me right that I wasted my money. The potassium supplements have a recommended dose of one tablet per day which provides a whopping big 3% of the recommended daily amount. I mean, why bother?
The salt substitute on the other hand is made of potassium chloride. A quarter teaspoon of the stuff provides 17% of the RDA for potassium.
So how come they don’t make the potassium supplements out of salt substitute?
I was going to ask the same question. I’m certain it’s because an OD of potassium is fatal. The problem is that potassium seems to be very difficult to come by diet. I’ve never seen anything that really had much potassium and when I track my potassium I’m always very low. So the real question for me is, what’s the deal with potassium supplements or dietary. It seems impossible to get the recommended amount and much over that is fatal. So why is the recommended intake so high.
I wonder if it is intentionally small in order that you won’t overdose on potassium, which is potentially fatal. Which is also possible with potassium chloride, but it would taste really awful! Whereas it would be more feasible to get an overly high dose of potassium by simply swallowing lots of more palatable pills.
Also, in order to make it into a pill form they have to bind it somehow, which will decrease the potassium per volume vis a vis potassium chloride. How big are the pills? If they are really tiny, it might not be possible to pack more potassium into them.
There are potassium supplements with much more potassium but they are usually by prescription only. The reason they don’t sell them over the counter is that it is easy to overdose on potassium when it is in supplement form and that can be very bad news. Hyperkalemia (high blood potassium concentration) can cause cardiac arrest and sudden death.
Potassium obtained through the normal diet doesn’t pose such a risk. People also don’t generally eat enough high-potassium salt substitute to cause the same issue because it is simply too salty.
I agree that OTC potassium supplements are a borderline scam because they contain so little potassium. It is better just to eat extra bananas or other high potassium foods to boost calcium blood levels. Multiviatamins usually have about the same potassium as dedicated supplements.
All foods (apart from refined sugar, and the like) contain potassium, and most people, unless they are taking diuretics or some such, ought not to need potassium supplements or even particularly potassium rich foods. If you are chronically low in potassium, and are not taking a diuretic (or way too much sodium) you probably have a kidney problem.
I think we’ve had this discussion before. The OD level for potassium is perilously close to the RDA for it, if I recall. A very tight balance. I think people have OD’d from salt substitutes, even.
I’m not concerned about my potassium level, but I find it curious that when I track my diet with on of those diet tracker apps, the potassium never approaches the RDA. It seems that the RDA must be too high if it is so close to dangerous and I’m fine without getting the RDA every day I’ve tracked it.
My potassium is dangerously low because I go through periods (days, even) when I just don’t eat. My magnesium is also low for this reason, as is my Vitamin D. I supplement with orange juice and V-8 (the original veggie drink). Both are loaded with potassium.
Ensure is also a good substitute but it’s a bit heavy for me.
The LD50 for potassium chloride is 2.5 grams per kilogram, which is to say, so much higher than the RDA that you don’t even have to come close to worrying about overdose, which is (hyperkalemia) mostly associated with causes other than diet (the LD50 for injection is much lower at only 30 mg/kg, less than your recommended daily intake, because your body can’t handle the sudden influx directly into the bloodstream). In fact, there isn’t even a tolerable upper intake for potassium. For comparison, for sodium it is 2,300 mg (5.8 grams of NaCl) - less than what most people consume, with the recommended intake for potassium at 4,700 mg per day (equivalent to 9 grams of KCl), but the average intake is only about half that.
The DRI ( Dietary Reference Intake) is set such that it will cover 98% of healthy individuals. Your individual need for any specific nutrient may be (and probably is) much lower. There is no Upper Limit for potassium because there is no evidence that chronic excess intake of potassium in apparently health individuals has any ill effects. If you are eating at 60% of the DRI, you are probably getting plenty of potassium for your individual needs.
A fatal dose is in fact no where near close to the DRI level of 4700mg per day. It’s 2600mg PER KILOGRAM of a person’s weight or for a 75kg person, 195,000mg. NO. WHERE. CLOSE. You could have to be eating 4000% of the DRI to approach a lethal dose. Or 487 bananas. If you could eat 487 bananas in one sitting, you’d probably die of a gastrointestinal rupture before a potassium overdose.
That brings us back to the original question however. Why aren’t potassium supplements with significant amounts of potassium available over the counter?
I had to take the prescription potassium supplemnets a few years ago during a very serious health problem and I got monitored closely while I was on them (frequent blood tests). My General Practitioner cut them off as soon as went into low normal range for potassium levels because he said the risk of cardiac arrest wasn’t worth it unless it was absolutely necessary to take them.
Ok, that was for a quick correction of a clinical issue but getting up to the RDA of potassium really is extremely hard through normal diet. Most foods have a few percent of it at most. The question of why the RDA is so difficult to achieve is one that I have wondered as well. Few people apparently approach it so why is that the recommended level? Other nutrients aren’t like that to the best of my knowledge.
Why don’t they sell potassium supplements that are say 25 - 50% of the recommended daily value if there is little danger? My guess based on some knowledge of pharmacology is that it is a rapid absorption risk that concentrated potassium in pills pose that regular foods do not.
Probably because those levels were determined to be the most optimal for long-term health; similar to how you hear 75% of people worldwide have Vitamin D deficiency, even those that get plenty of sunlight (there was a discussion a while ago about this, where I said that the recommended blood levels were perhaps set too high and I got a similar explanation). Also, there are in fact other nutrients that people don’t get enough of, at least according to the set RDA, like magnesium (on the other hand, how come some nutrients, like calcium, have so much attention paid to them, I get more than enough from milk alone so I don’t need all of this calcium-fortified food (I know some people don’t drink milk but then most of the world is lactose intolerant as adults), and why not fortify it with nutrients like magnesium, especially processed wheat flour which loses it when they remove the germ and bran but isn’t added as enrichment?).
That said, potassium apparently isn’t restricted from food; I have seen reduced sodium canned soup with over 1,000 mg per serving (2,000 mg per can, a more realistic serving size, at least I eat the whole can at once, being only 200-400 calories total). Some people don’t like the taste though, but I hardly notice any difference.
Also, on nutrition labels that show the recommended RDA/maximum intake of nutrients (as shown here), I note that they say 3,500 mg for potassium, not 4,700 mg; similarly, sodium is set at 2,400 mg but I often seen 2,300 as a recommended limit.
My guess is this is it. At least with IV forms, they absolutely pound it into us in nursing school that you do NOT “push” potassium, even in an emergency. Always on a pump, always slow. Potassium push=Kevorkian.
While absorption is going to be slower through the gut, it seems that you still want to go slow. It’s not that too much potassium in a day from natural sources is absolutely impossible, it’s that you can’t get it in you fast enough to cause a problem. Unless you concentrate it in a pill. (Even then, I’m pretty sure someone asked something about this recently, and I did the math and discovered you’d have to work pretty hard to take enough of even prescription potassium pills to overdose.)
Again, the DRI (or what used to be RDA) is set to cover the needs of 98% of the population. It is impossible to know any one individual’s true need, so individual recommendations can’t be made. That’s why they set the DRIs high. Your true need may be significantly less and if you get 50% of the DRI it may be just right for you.
From the text:
On the basis of available data, an Adequate Intake (AI) for potassium is set at 4.7 g (120 mmol)/day for all adults. This level of dietary intake (i.e., from foods) should maintain lower blood pressure levels, reduce the adverse effects of sodium chloride intake on blood pressure, reduce the risk of recurrent kidney stones, and possibly decrease bone loss. Because of insufficient data from dose-response trials demonstrating these effects, an Estimated Average Requirement (EAR) could not be established, and thus a Recommended Dietary Allowance (RDA) could not be derived.
At present, dietary intake of potassium by all groups in the United States and Canada is considerably lower than the AI. In recent surveys, the median intake of potassium by adults in the United States was approximately 2.8 to 3.3 g (72 to 84 mmol)/day2 for men and 2.2 to 2.4 g (56 to 61 mmol)/day for women; in Canada, the median intakes ranged from 3.2 to 3.4 g (82 to 87 mmol)/day for men and 2.4 to 2.6 g (62 to 67 mmol)/day for women (Appendix Tables D-5 and F-3). Because African Americans have a relatively low intake of potassium and a high prevalence of elevated blood pressure and salt sensitivity, this subgroup of the population would especially benefit from an increased intake of potassium.
It’s not difficult for a healthy adult to get the recommended amount of potassium if you are eating a balanced diet. The problem is that the typical American diet is short on fruits, vegetables and dairy, which are good sources of potassium. There can be concerns for people with kidney issues, but for most people too much potassium isn’t something they should lose any sleep over.
Cecil’s column is not what I’d expect given the LD50s. As mentioned, the uptake rates may be key here, although I had heard that the body is very good at NOT absorbing too much potassium from the gut – that or it was very good at excreting excess; I can’t remember. Wiki tells me hyperkalemia is often due to inhibited excretion.
I have to wonder if the folks mentioned in the column had kidney problems.