Potassium, Killer Bananas, and the Periodic Table of DEATH and Mystery

Isn’t it interesting how we’ve turned food into 💊 “medicine” ?

• Omega-3 fatty acids found in foods like fatty fish help regulate inflammation and are linked to improved heart and immune health (1).
• Raspberries are high in antioxidant polyphenols, while black raspberries may benefit heart health (2).

And a perpetual favorite:

• Dark chocolate contains flavanols which may help your heart health (3).

 

Yes, you must acknowledge the weasel words—linked to, promote, may benefit—which tell you that no definitive research is available on the food and its effects. Maybe some research has shown the extracted and purified molecules found in the food (omega-3-fatty acids, polyphenols, flavanols) have a statistically significant health effect at some level—in rats or monkeys or cell cultures, etc. Ultimately, these claims make us feel better about our food choices and “eating healthy.” Food marketers know that, too, and tend to exploit, er, capitalize on our thirst for healthy longevity. Nutritional claims can be seriously confusing.

 

But enough cynical snarkiness, because there is one piece of advice that seems to dominate the annals of healthy food:

 

• Eat bananas because they are an excellent source of potassium.

In fact, one NLEA (Nutritional Labeling and Education Act (4)) serving (one medium sized banana) contains ~450 mg of potassium, about 15% of your daily requirement (~3000 mg average for adults (5)) for this mineral element of the periodic table (6, 7). 

 

Potassium (K) is a necessary component of life

 

Humans need potassium to stay alive. Because it is an element, we can’t make it, nor can any other organism on Earth. Like (most) all the other periodic table elements, it was created at the beginning of the universe and makes up about 2.4% of the Earth’s crust (8). 

 

In pure form, K (Latin for kalium) is a buttery soft silvery metal that tarnishes quickly in air.

 

Potassium is named for potash, a grouping of potassium-containing fertilizers that can either be mined or manufactured. Historically, potassium fertilizer was made in an iron pot by leaching wood ash (9). The white residue left over? Pot. Ash.

 

With an atomic number of 19 and an atomic mass of 39.098, potassium is an alkali metal at the far left end of the periodic table, along with lithium, sodium, rubidium, cesium, and francium. Based on their electron shell configuration, alkali metals easily lose an electron to become positively charged cations. For potassium, that means it becomes K+. K+ can then combine with negatively charged anions to form salts, like KCl. In fact, potassium is only found naturally as potassium salts or alkali salts, like potassium hydroxide, KOH, a strong base (the opposite of an acid) (10).

 

So why is potassium necessary for life? Because of that positive charge and its concentration across the membrane of our cells. K+ is an electrolyte found in relatively high concentrations inside most living cells as compared to the outside of a cell, while another electrolyte, sodium (Na+), is found in higher concentrations outside a cell than inside (11, 12). This sets up a charge (+/-) and [concentration] gradient across the living cell’s membrane that is strictly maintained by the cell and thus the whole organism. In fact, most of the food we eat and turn into chemical energy—from 30% up to 70% of our daily energy in nerve cells (13)—is used to maintain this strict Na+/K+ gradient. Controlled collapse of the charge and concentration gradient creates electrical currents that propagate things like nerve impulses and muscle contraction. Which means K+ has a profound effect on the heart and heartbeat.

 

Too little K+ (hypokalemia) and too much K+ (hyperkalemia) cause heart arrhythmias that can lead to heart attack and death. The incorrect dose of certain medications and natural poisons (like aconite from the plant Monkshood (14)) can also alter the concentration and recovery of K+ inside the heart muscle cells, leading to heart attack and death.

 

In fact, ingestion of potassium-chloride tablets (hyperkalemia) has been used in suicides, while intravenous administration of KCl, has been used in assisted suicide and judicial death (15) (which is a nice way of saying the death penalty).

 

Can you eat enough bananas a day to kill yourself? Short answer – impossible

 

Let’s do the math. If a person eats 6 ½ bananas a day, that would be the approximate recommended daily allowance of K+ for an adult: ~3000 mg or 3 grams or 0.1 oz. Some countries use 4500 mg as their daily dose of potassium, which would be 10 bananas a day. By scouring the internet, I found a banana expert who actually answered this question, although I doubt she’s done the research. She said EATING 400 BANANAS A DAY would probably kill someone (16). That would be like ingesting 180 grams of potassium.

 

Or did she mean having 400 bananas fall on your head? That would weigh 40 kg or 88 lbs. Or maybe slipping on 400 banana peels.

 

Did you know bananas are berries?

 

And have you heard of the Banana Equivalent Dose or BED, the measure of radiation exposure you get from eating one banana (17) because each banana contains a few molecules of radioactive potassium?

 

Or that bananas—

Oh, forget it. I’m gonna go bake some banana bread.

 

Should I add walnuts (424 mg K/100 gr) or pecans (360 mg K/100 gr)? Both are heart-healthy.