5 poisonous foods you love
- pH7 Science Blog
- Oct 4, 2015
- 3 min read
Surprisingly, most kitchens contain all sorts of foods which can actually be toxic to us if we aren’t careful. Did you know that putting too much nutmeg in your curry could kill you? Or that eating too much tuna could be seriously damaging your health?
Here is a list of five foods, much loved foods which are devils in disguise.

FRUIT STONES
Don’t take high fibre dietary advice too far! Eating stones from many popular fruits including apples, cherries, peaches and apricots is very dangerous and can even lead to death. This is because they contain cyanogenic glycosides. When you chew the stones the cyanogenic glycosides come in contact with enzymes in saliva resulting in the release of hydrogen cyanide. Hydrogen cyanide is a potent poison - the same substance that’s in pills that spies carry around in films.
The main way it takes effect is by preventing oxidative phosphorylation which enables us to turn glucose into energy that can actually be used by our cells.
Therefore when oxidative phosphorylation cannot function there is rapid impairment of vital functions due to insufficient energy. Additionally oxidative phosphorylation normally enables pyruvate to be used/removed. However when oxidative phosphorylation is inhibited pyruvate cannot be utilized in this way and is instead reduced to lactic acid. This increases blood acidity, called metabolic acidosis.
Beware: Some health food shops STILL sell products such as apricot kernels. In 1996, a previously healthy woman was found lying on her bathroom floor moaning and unconscious after eating 30 apricot kernels purchased in a health food shop.
POTATOES
Potatoes contain a chemical called glycoalkaloid. When consumed in sufficient quantities they are real hazard to humans. The highest levels of glycoalkaloids are found in potato skin, flowers and sprouts.
Glycoalkaloid poisoning causes both neurological symptoms and gastrointestinal issues. Adverse effects begin after consuming just 3 mg of glycoalkaloids per kg of body weight.
For the top 0.01% of potato consumers in Europe, potatoes ‘fresh off the shelf’ could lead to high enough glycoalkaloid levels to cause adverse effects.
However before those of you on a staple diet of jacket potatoes and baked beans start to panic, it must be noted that the incidence of glycoalkaloid poisonings is very rare and sensitivity is thought to vary significantly.
NUTMEG
Ingesting even small quantities of nutmeg can cause death and some reports consider just 5g of nutmeg (about a teaspoon) to be a toxic dose.
Acute nutmeg intoxication causes mainly gastrointestinal symptoms (nausea, vomiting, and abdominal pain). However it also affects the brain and cardiovascular system. Symptoms vary from giddiness and disorientation to convulsions, anxiety, intense hallucination, euphoria, coma, fast heart rate, feeble pulse, high blood pressure and even death.
The toxic components of nutmeg are myristicin, elemicin and safrole.
We metabolise the myristicin in nutmeg to a compound called 3-methoxy-4,5 methylenedioxyamphetamine (MMDA) and the elemicin in nutmeg to 3,4,5 trimethoxyamphetamine (TMA).
It is the MMDA and TMA that cause the hallucinogenic effects. Myristicin also inhibits an enzyme called monoamine oxidase, This results in some of the cardiovascular symptoms associated with nutmeg toxicity.
So be careful how much nutmeg you put in your curry next time….
RHUBARB LEAVES
Whilst the stalk of a rhubarb plant can be eaten (phew!) the leaves shouldn’t be eaten in large quantities. Although extremely rare, rhubarb leaves can cause death as a result of the oxalic acid they contain.
Symptoms include problems breathing, burning sensation in the mouth and throat, coma, diarrhea, kidney stones, nausea, abdominal pain and vomiting.
Rhubarb leaves contain 0.52 g of oxalic acid per 100g. The lethal oral dose is thought to be somewhere between 15 and 30 grams of oxalic acid. That’s a lot of rhubarb leaves; almost 3 kg in fact!
FISH
It is rarely talked about but surprisingly eating too much fish can actually have adverse effects on health.
Fish absorb mercury from water and many larger fish additionally absorb mercury from the prey they consume.
Therefore it is no surprise that the Robert Koch Institute in Germany found that people who eat more fish have significantly higher mercury levels.
Although the amount of mercury consumed from fish is small, it can still have serious effects. Low doses of mercury can seriously impact the developing nervous system and possibly also harm the reproductive, cardiovascular and immune systems.
US Environmental Protection Agency and US Food and Drug Administration recommend that young children, pregnant women and breast-feeding mothers decrease their fish consumption because of the mercury it commonly contains.
In pregnant women, mercury can cross the placental barrier and affect the developing foetus. This can result in developmental issues not only in the womb but also during childhood.
So enjoy the foods you love, but don’t forget about the toxic dangers which lurk beneath their surfaces!
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