Can eating too many bananas kill you?
One well-known figure who has spread this idea around is Karl Pilkington, the grumpy friend of comedian Ricky Gervais.
"Before when you were talking about bananas... I had that fact, about if you eat more than six, it can kill you," he said in one of his conversations with Gervais and fellow comedian Stephen Merchant. "It is a fact. Potassium levels are dangerously high if you have six bananas... I saw a bowl of bananas. There's six bananas there. You know why there's only six? Seven would be dangerous."
So how dangerous is potassium? Actually, it is crucial for survival and can be found "within every single cell of the body," says Catherine Collins, a dietitian at St George's Hospital in London. "We use it to help generate an electrical charge which helps the cell function properly. It helps keep your heart rate steady, it helps trigger insulin release from the pancreas to help control blood sugars, and more importantly keeps blood pressure in check."
On the other hand, if the level of potassium in the body is too low or too high it can result in an irregular heartbeat, stomach pain, nausea and diarrhoea. Potassium chloride is even one of the chemicals used in lethal injections in the US, as extremely high doses can cause cardiac arrest.
But for a healthy person, "it would be impossible to overdose on bananas," says Collins. "You would probably need around 400 bananas a day to build up the kind of potassium levels that would cause your heart to stop beating... Bananas are not dangerous - and in fact they are, and always have been, very good for you."
Adults should consume about 3,500mg of potassium per day, according to the UK's National Health Service. The average banana, weighing 125g, contains 450mg of potassium, meaning a healthy person can consume at least seven-and-half bananas before reaching the recommended level.
There are some people who should steer clear of foods that are high in potassium though, warns Collins - those with kidney disease.
Source: bbc.com
