Seeds, spuds and cyanide—poisonous pantry favourites
Is anyone else sick of seeing preachy health food articles? We’re told to be afraid of fat and scared of sugar. “Soft drinks will kill you, and bacon causes cancer.”
It gets a bit tiring having all my poor lifestyle choices judged by society. If loaded brownie milkshakes are wrong, then I don’t want to be right.
But now it turns out those fruits and vegetables they keep harping on about could be the real killers.
Some of those so-called ‘healthy foods’ are actually concealing toxic chemicals. And they may try to slip you some poison in your next meal.
So are you harbouring any food fugitives in your crisper? Let’s take a look.
You don’t need a wicked stepmother to be poisoned by an apple.
Apples can kill you all on their own, using their secret deadly weapon.
A mother lion may maul the face of anything that comes between her and her cubs, and it turns out plants have their own clever way of defending their offspring.
Seeds of some fruiting plants, like apples, cherries and peaches, contain amygdalin. Amygdalin is a cyanide and sugar compound. When it mixes with digestive enzymes, it degrades into toxic hydrogen cyanide.
In other words, when you swallow an apple’s precious seeds, they fight back by turning to poison in your tummy.
But don’t let that put you off your next red delicious. Apple seeds are built tough and resistant to digestive juices. So to release any cyanide at all, you’d have to chew the seeds first.
Let’s say you did chew the seeds (please don’t do this at home)—how many would it take to kill you?
According to a report by the World Health Organization, death by cyanide ingestion usually occurs after absorption of 1.4mg per kilogram of body weight. The New Zealand Food Safety Authority reports the cyanogen content of an apple seed is around 700mg/kg.
So let’s do some maths. If one apple seed weighs 0.7g and the average apple contains eight seeds, that’s around 5.6 grams of seeds. Together, these seeds could contain 3.92mg of cyanide.
It would take 98mg of cyanide to kill a 70kg person—that’s the equivalent of 25 apples or 200 apple seeds.
You’re unlikely to ever consume this number of seeds at once. And if you happen to chew and swallow a couple, the few milligrams of released cyanide will just be processed the natural way without dramas.
Put it this way—you’re more likely to choke on the seeds than be poisoned by them, but it’s still not a good idea to smash an apple seed smoothie.
Potatoes are a firm family favourite. They bring us joy in the form of hash browns, fries and cheesy potato bakes. How could something so delicious ever betray us? Well it turns out if you neglect your potatoes, they just might turn on you.
I’m sure everyone’s had that moment of finding a forgotten potato in their pantry. It’s started growing sprouts and has a greenish tinge to it. Is it still safe to eat?
In this case, green does not mean go. It’s actually a warning sign that toxins may be present.
In the plant world, potatoes are a strong, independent vegetable that don’t need no soil. They are still living and metabolising well after they’re dug out of the ground.
They’re also producing chemicals—depending on what sort of light they’re exposed to. Some light causes spuds to produce chlorophyll.
Chlorophyll is a pigment found in all green plants, and it’s what gives old potatoes that green tinge. But it’s not the chlorophyll you have to worry about.
The same processes that make chlorophyll can also make a toxic chemical called solanine. Solanine exists naturally in the stem and leaves of potatoes. It’s commonly found in the nightshade family, which includes potatoes, eggplants and tomatoes. Solanine is a natural pesticide, designed to deter animals coming over for a munch.
When you abandon your potatoes and expose them to unflattering light, they get mad. And they start plotting your doom in the form of potato poisoning. The solanine they produce can cause a whole host of problems for humans that consume them. This can include diarrhoea and vomiting, and—while rare—death by potato is not unheard of!
But how much solanine is dangerous? This one is harder to work out, because fewer people die from solanine poisoning than cyanide. And it’s difficult to know the concentrations of solanine in a green potato.
A report by the University of Nebraska estimates a 10-fold increase in solanine when a potato is exposed to UV light. And that a 90kg person would need to eat 450g of an affected spud to reach toxic levels. That’s the equivilent of one large baked potato.
That’s why it’s best to store your spuds in a cool, dark place and try to eat them within 3 weeks of purchase. And if they start to go green—throw them out.
The final verdict
OK, so maybe fruits and vegetables aren’t quite as dangerous as I made them out to be. I may have been a tad salty, like the delicious fries my doctor says are giving me high blood pressure.
If the experts say we should have a healthy diet, we should probably listen to them.
But keep your wits about you. Plants have made it pretty clear they’re not going down without a fight. Avoid the poisonous parts, and remember, you can have too much of a good thing.