It is true that chocolate have some health benefits but too much of this yummy, chocolate-y goodness is fatal.
One of the key components of chocolate is theobromine, or theobromide, also known asxantheose. It has the chemical formula C7H8N4O2 and it is a bitter alkaloid of the cacao plant – although it’s also found in tea leaves and the kola (or cola) nut. Despite its name, the compound does not contain the element bromine (Br). The name comes from Theobroma, meaning “food of the gods”, the genus of the cacao tree.
It also comes from caffeine: when caffeine is metabolized in the liver, 12% of it is turned into theobromine. This theobromine is a vasodilator (which widens blood vessels), a diuretic (makes us urinate) and a heart stimulant. As a result, it can be poisonous.
The first signs of theobromine poisoning are nausea, vomiting, diarrhea, and frequent urination. In high doses it goes on to cardiac arrhythmias, epileptic seizures, internal bleeding, heart attacks and eventually death. The half-life of theobromine in dogs is 17.5 hours, and if they’ve eaten enough of it the symptoms can persist for 72 hours.
Fortunately, the median lethal dose of chocolates for humans is 1000 milligrams per kilogram of body weight. That means that an 80 kg human would have to eat 5.7 kg of unsweetened dark chocolate for it to kill them (going by a theobromine content of 14 milligrams per gram of dark chocolate, although it varies). For milk chocolate, you’d have to eat around 40 kg.
On the other hand, in the case of domestic animals they metabolize chocolates much more slowly than humans do. Unfortunately, dogs are the most vulnerable, with a median lethal dose of only 300 milligrams per kilogram of body weight. Although cats do have a lower toxic dose – 200 mg/kg – they’re unable to taste sweetness and so are much less likely to eat enough chocolate.
A typical 20 kg dog will normally experience intestinal distress after eating less than 240 g of dark chocolate, but won’t necessarily experience brachycardia or tachyarrhythmia unless it eats at least 500 g of milk chocolate.
Remember though that humans aren’t totally immune, and the elderly are particularly vulnerable to consumption of large quantities. That’s why we should all be mindful of what we are eating.
via Lost in Science