Banana overdose

[snopes]

Comment: I heard that you'd die from eating 120 bananas, due to the
potassium, I wonder if it's true. And if not then how many bananas it
would take.

[KingDavid8]

Originally Posted by snopes

Comment: I heard that you'd die from eating 120 bananas, due to the potassium, I wonder if it's true.

Definitely false. I'm sure I've eaten hundreds of bananas.

[snopes]

Comment: Is it true that six bananas could kill you because of a potassium
overdose?

[Spam & Cookies-mmm]

Obliquely related anecdote:

Several years ago (pre-internet), a man I knew was prescribed potassium, but something about the pill form made him sick. He asked his doctor, "Can't I just eat a banana?" The doctor went to his books, did a little figuring on the back of his prescription pad, and told my friend exactly how many inches of banana he had to eat every day for his potassium dosage.

[Not_Done_Living]

The whole "7 banana kills you" was brought up on Ricky Gervais "Idiot Abroad".

Karl Pilkington (the idiot who went abroad) said thats why when you see a bunch of bananas in a store, there is only 6 in a bunch. He also commented that he saw 7 bananas in a bowl and thought that was dangerous.

Of course, could a person STAND to eat 7 full size bananas in one sitting?

[Jahungo]

According to this website, each banana has 806 mg of potassium.

According to wikipedia, the oral LD50 of potassium chloride is 2.5 g/kg.
The atomic mass of potassium is 39 mg/mol, while the molecular weight of potassium chloride is about 74.5 g/mol. Therefore, the amount of potassium in 2.5 g/kg of potassium chloride is about 1.3 g/kg.

Since there are 0.806 mg potassium in one banana, this would lead to a banana LD50 of 1.6 bananas / kg (making a huge and largely unwarranted assumption that there is no effect on lethality whether it is taken as KCl or a banana).
So theoretically and 75 kg person could reach LD50 levels of potassium by eating 122 bananas.
I actually suspect that someone did some similar calculations to come up with the OP.

I don't think it would be possible to eat that amount of bananas fast enough to cause a lethal rise in potassium. Maybe someone with renal failure could.

ETA: If you replace the oral LD50 for KCl (2.5 g/kg) with the much lower intravenous LD50 (0.1 g/kg), you would actually get an LD50 of only 0.06 bananas/kg, which for a 75 kg person would be reached with about 5 bananas. That could be where the second comment got their number from, with some slightly different calculations.

But I expect that the oral LD50 would be a much better proxy for potassium in bananas.

ETAA: Crap, the calculations were based on the potassium content in 250 g of banana, not one banana like I thought. It looks like your typical banana weighs about half that, so adjust the numbers to LD50 of 3.2 bananas/kg, which would be 244 bananas for a 75 kg person.

[Beejtronic]

You could also use the Banana Equivalent Dose to determine whether eating bananas will kill you due to radioactivity. 1 banana is equal to about 0.1 μSv, and it takes about 6-8Sv to kill you,* so it would take around 60 million bananas to kill you due to radiation.

(Feel free to check my math, it's Friday night.)

*95-100% mortality without medical treatment.

[purpleiguana]

Originally Posted by snopes

Comment: I heard that you'd die from eating 120 bananas, due to the potassium, I wonder if it's true. And if not then how many bananas it would take.

Yes and no. After eating 120 bananas, you will die, but not from the potassium. Your stomach exploding will take care of it for you.

[TrishDaDish]

That was the alternate version of Cool Hand Luke.

[HelloLlama]

When Neill had dangerously low potassium and taking it orally caused too many unwanted side effects we were told by the doctors that the best way to get high amounts of potassium was to drink milk. A cup has about the same amount as a banana. I'd think it would be much easier to drink too much milk than eat too many bananas, so why no milk overdose rumors?

[Latiam]

My doctor suggested OJ. She knew I didn't like milk.

[Richard W]

The chemistry is all wrong anyway. Everybody should know that potassium combusts violently if you drop it in water. So the real rumour should be that if you eat 7 bananas, you'll explode the next time you have a shower.

[A Turtle Named Mack]

Originally Posted by Jahungo

ETAA: Crap, the calculations were based on the potassium content in 250 g of banana, not one banana like I thought. It looks like your typical banana weighs about half that, so adjust the numbers to LD50 of 3.2 bananas/kg, which would be 244 bananas for a 75 kg person.

So, since I weigh over 100 kg, does that mean I can eat 320 bananas at a sitting?

Of course, with an 'average' banana, sans peel, being about 118 grams, that makes 37.8 kilograms of bananas, or for most Americans, over 83 pounds of bananas.

I think you're at a bigger risk of tarantula attack from having all those bananas around.