Potassium Prevarications?
June 29, 2013 3:28 PM   Subscribe

FDA recommends 4700mg of potassium intake per day. That translates to appr. 11 bananas or 5 unpeeled potatos, to pick two common and beloved examples among potassium-richest foods. Various other foods (dairy, nuts/seeds, fruit) also offer up to a few hundred mg per serving. But how is anyone able to meet 4700mg without overeating, especially those who are active and lose potassium through exercise/sweat?

Rampant on the internet, meanwhile, are 1) confident shruggy assurances that, sure, a healthy diet delivers enough potassium naturally, so just eat a banana a day or some more spinach and you'll be fine; 2) warnings about the dangers of too much potassium; and 3) few and foggy explanations of whether potassium supplements work and which form (gluconate vs. chloride vs. nitrate vs. salt form) works best.

(Of the previous threads touching on K, I've found some relevant discussion at 1, 2, and 3, but they don't directly address my concerns.)

Perhaps due to my own deficit of the potassium that might quell my restless nerves, all this deficient information is driving me crazy. Please shed more definitive light?
posted by taramosalata to Health & Fitness (12 answers total) 9 users marked this as a favorite
If you actually have potassium deficiency that's a medical issue that should be addressed with intravenous potassium and followed up with a regimen of oral potassium, with regular bloodwork to monitor potassium levels and titrate the dosage appropriate. Moderate-sever hypokalemia can be pretty dangerous.

Has a doctor told you that you have low potassium, or are you getting a lot of Charlie Horses? I'm not making fun of you, but these are very different animals.
posted by telegraph at 3:36 PM on June 29, 2013 [3 favorites]

Well, the biggest single reason they emphasize potassium is because it helps moderate the impact of sodium intake, so reducing your salt could be seen as a proxy for increasing your potassium intake.

Personally, I'm on team "you get enough naturally," unless you've actually got specific symptoms. If you're taking something that reduces potassium, or you have an actual deficiency, your doctor will probably give you a prescription.
posted by SMPA at 3:37 PM on June 29, 2013 [1 favorite]

Unless you have a specific potassium problem that you (or especially your doctor) has noticed, you really are probably getting enough through your diet. I went through a really weird period of hyperkalemia recently (too much potassium, not on purpose, probably brought about by eating nothing but yogurt and spinach and carrots and apricots and bananas for a few days) and it was unpleasant enough to send me to the doctor, so I'd be careful

Whether you are in the normal range is the sort of thing you can determine via basic in-office blood tests. And I don't know about you but for my RDA of calories and everything else, I'm supposed to have 3500mg (I'm a 125lb 5'2" lady) of potassium and I rarely get above 1000 most days.
posted by jessamyn at 3:45 PM on June 29, 2013

Jessamyn's hyperkalemia is interesting. I'm an inch taller than she is, and about 20 lbs. lighter. I was diagnosed with scary low potassium last year.

Prior to being tested by the doc, I'd been tracking my diet on Fitday.com, and I'd noted that my potassium levels were coming in at 70% or less, which seemed mostly okay, because I'd understood that the RDA has padding built in, so really anything over 70% is fine.

But, uh, no.

When my doctor got my results back, he called me at home, on a Saturday, in a frenzy. Among other things potassium directly affects the contraction of muscles. This matters because it's sufficient amounts of potassium that protect your heart. (Low potassium is one of the reasons anorexics sometimes suffer from heart attacks) And, as it turns out, there are a host of murky symptoms if you're running low, which I'd been suffering from for years, but that no one had picked up.

What's confusing is for my age and size I eat really well at between 1500 and 1700 calories a day, which is basically the amount of calories recommended for my demographic. But you absolutely *can't* get enough potassium on 1500 calories a day.

So I did all sorts of research to see how I could maintain a higher potassium level once the doc took me off potassium drugs. OTC supplements supply almost no potassium (because of all the fears of overdose), so I ignore them. Avocados, it turns out, provide more potassium than bananas, so for a while I was making avocado milkshakes. When that got old, I started supplementing with 8 oz. cans of V8, which give you 40% of your RDA, and which beats all other potassium-rich sources of food by a long, long shot.

I'm mighty sick of V8 at this point, but when I don't drink it I note that my symptoms tend to come back. When I do, they go instantly away.

TL;DR: Potassium. Oy!
posted by Violet Blue at 4:25 PM on June 29, 2013 [4 favorites]

If you eat a full zucchini you get 500mg of potassium. It's very easy to eat a lot of zucchini if you roast it.

As for potassium deficiencies, people aren't keeling over right and left from potassium deficiencies, so most non-active people are probably OK. I supplement my intake with "lite" salt, as it's 50% sodium chloride, 50% potassium chloride and a very minimal amount can give you a huge amount of potassium.
posted by schroedinger at 4:31 PM on June 29, 2013

Use "low sodium" salt. Simple as that. A quick glance at the shelf shows that most of them contain 50/50 NaCl/KCl, which at even one teaspoon a day means an extra 3ish grams.

That said, I wouldn't take Jess' admonition lightly. Both low and high potassium levels can really wreak havoc with your body. If you don't have any symptoms of hypokalemia, don't go adding a lot of extra potassium to your diet all at once.
posted by pla at 4:39 PM on June 29, 2013 [1 favorite]

The FDA recommendation is just a recommendation. It doesn't take into account loss of potassium by sweat, urination, and less-than-solid defecation, not to mention any illness that causes vomiting or more excessive diarrhea.

My brother has had transient heart issues, probably due to drinking too much water. Not only does it put you at risk for hyponatremia (low sodium), it also makes you lose more potassium, and in some cases can misbalance your blood/body pH.

The only way to tell if you're "getting" enough potassium is a blood test.

If you really want to meet the FDA's recommendation, keep in mind that everything you eat contains some amount of potassium. Whole grains are better than refined, white starch. A whole lot of fruit is relatively high in potassium. Dried fruit is very high in potassium. Beans, milk, avocado, tomatoes (especially concentrated tomato products like sauce and ketchup), cooked greens, and potatoes especially. Cook them without water (frying, roasting, etc.) to retain the maximum potassium. A medium baked potato has almost 1000 mg of potassium, not counting anything you put on top.

But keep in mind that your body has its own set-point for potassium levels, and you'll pee the extra right out regardless of the amount you "should" be getting. If you're getting too little, it'll hold onto more. That will keep your blood levels in the safe range - I don't know how total consumption affects your body in the long term (e.g. fighting excessive sodium intake).

I have no kidney function. I'm on dialysis. My diet is extremely restricted just so I don't reach dangerous levels of potassium in my blood. You'd be surprised how much potassium is in all the things you might want to eat.
posted by WasabiFlux at 5:11 PM on June 29, 2013 [4 favorites]

The two things I would do are:

- dramatically reduce my sodium intake, as others have suggested. The best way to do this is to stop eating processed foods, and stop salting your food entirely. This takes some getting-used-to, but in fact most people are consuming way too much salt. It only takes a couple of days to adjust; after that, you will find "normally" seasoned foods to be so salty they are unpalatable.

- eat more vegetables. Lots more vegetables (the trouble with V8 is that it's also loaded with sodium, even the low-sodium variety). If you want an excellent insight into the effects of diet on sodium-potassium balance, watch this presentation by Lynda Frassetto, a nephrologist at UCSF who has done a fair bit of work in this area.
posted by rhombus at 5:15 PM on June 29, 2013 [1 favorite]

But how is anyone able to meet 4700mg without overeating, especially those who are active and lose potassium through exercise/sweat?

Vegetables. And fruit (on preview: as rhombus just said)

Sample day:

2 oz raisins - 166 cal, 462 mg K
1 cup yogurt, plain, whole milk - 149 cal, 380 mg K
1 cup coffee, from grounds - 2 cal, 116 mg K

1 peach, medium - 285 mg K, 59 cal

Lettuce, green leaf, 2 cups, shredded - 140 mg, 10 cal
1/3 Cucumber - 147 mg, 15 cal
2 medium stalks celery - 208 mg, 12 cal
1 oz radishes - 65 mg, 4 cal
1 medium tomato - 292 mg, 22 cal
1 medium red bell pepper - 251 mg, 37 cal

6 oz ground beef, 85% lean - 692 mg K, 436 cal
2 slices bread, wheat - 92 mg K, 132 cal
1 slice cheddar cheese - 27 mg K, 113 cal
1 potato, baked - 1600 mg K, 278 cal
1 cup Asparagus - 270 mg K, 27 cal

Total: 5027 mg K, 1462 cal

Which is over on potassium and depending on needs, possibly low on calories.
posted by mountmccabe at 5:21 PM on June 29, 2013 [2 favorites]

WasabiFlux, you have to realize that your case is quite special. It's obviously true that almost all foods contain some measurable quantity of potassium, which poses a problem for your health. But a lot of people with healthy kidney function have added up the numbers and the RDA for potassium is far, far out of reach for most of them.

In my previous question, which the OP linked to, I asked about the health consequences of switching to a "low-sodium salt," which is the supermarket name for potassium chloride. Several people there had chimed in with "nooo, that kind of potassium is baaad." Then again, several people in this thread have chimed in with "have you tried potassium chloride?"

The fact that table salt substitute remains on store shelves suggests that it is not a hazard to public health. A number of "low-sodium" versions of food products are, in fact, heavily seasoned with potassium chloride (like the aforementioned V8). Again, no health scares there.

Many people embark on radical diets, eating almost nothing but fatty red meat or almost nothing but raw vegetables. Some of them end up developing nutritional deficiencies or other health issues. Popular culture remains very gung ho about radical diets. I think that switching to "low-sodium salt" isn't any worse than those. Whether it's better or has any noticeable effect at all depends on individual medical circumstances.
posted by Nomyte at 5:34 PM on June 29, 2013 [1 favorite]

Nomyte, I never meant to imply that eating too much potassium was harmful to a healthy person. In fact, it's very very difficult for a healthy person, who's not on drugs that could increase potassium levels (ACE inhibitors, potassium-sparing diuretics, etc.) to have too much potassium. The kidneys are simply too good at getting rid of the extra.

I suspect that even if one did consume an entire bulk package of potassium chloride, the result would be their gastrointestinal system getting rid of it ASAP, in one direction or another. It would act like an osmotic laxative if it didn't come back up.

I did explain that it's possible for a healthy person to end up with a dangerous potassium deficiency, just as with sodium - but that almost always happens as a result of drinking way too much water without also consuming replacement electrolytes. If you're eating a regular diet, and not chugging gallons of water, you are not in danger from lack of potassium.

But this is all besides the point. The FDA recommendation for potassium is, in part, reactionary to the high sodium consumption of the general American population. The questions are 1) whether 4,700 mg of potassium are necessary to combat the negative health effects of the average American's sodium intake; and 2) whether a normal, healthy diet comes close to the amount of potassium to have that effect, whether it's 4,700 mg or more or less.

There are numerous studies, but it seems the panel is split on conclusions, and even what outcomes to look at.

As far as getting 4,700 mg of potassium every day, it seems doable, but difficult - just like any other major dietary change. Keeping an otherwise healthy and varied diet while increasing potassium intake without supplements would seem to imply increasing caloric intake as well. Dumping a healthy diet in favor of potatoes with ketchup at every meal could get you to your goal, but has plenty of other consequences.
posted by WasabiFlux at 8:30 PM on June 29, 2013

WasabiFlux, thanks for being patient and gracious. My point was only that an amount of potassium that someone in your position considers non-negligible may, in fact, appear quite negligible to someone with healthy kidney function.

I think one of the factors feeding this potassium question is the outstanding nature of the RDA for potassium. An adult can meet the RDA for vitamin C by eating a serving of cabbage. For almost all micronutrients, doses that meet or even far exceed the RDA can be reached with a simple, harmless multivitamin. And, obviously, everyone gets plenty of sodium every day.

Only potassium, I think, stands out by (a) not being available as an OTC supplement, except disguised as table salt substitute, and by (b) having an RDA that can only be met through major changes in diet. It's more complicated than eating a cup of cruciferous vegetables or popping a vitamin pill.

It's possible that this is a matter of the tricky mechanisms the human body uses to keep its sodium and potassium in homeostasis and how those mechanisms relate to overall health, lifestyle, and diet. I'm sure it's very complicated. The potassium question is probably also related to how an RDA is established and what exactly it means. For example, reading AskMe suggests that a lot of people have diagnosed vitamin D deficiency. A lot fewer people seem to have diagnosed hypokalemia, even though the test for it is routine.

I think we agree that simply supplementing one's diet with a single micronutrient is probably not going to have much of an effect by itself, except in uncommon cases. Health outcomes seem to show substantial improvement after far-ranging changes in diet, lifestyle, and fitness level. But that kind of advice is outside the scope of the potassium question.

A lot of people can get into the habit of taking a daily vitamin. Many fewer people are willing or able to sustain far-ranging changes like complete diet makeover or a schedule of strenuous regular exercise. Anecdotally, that habit seems to be an order of magnitude harder to establish.
posted by Nomyte at 10:27 PM on June 29, 2013

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