Fruits That Contain Cyanide: They Aren’t So Sweet Revealed.” Cyanide is a chemical compound that is found in some of the most common fruits. In small amounts it’s completely harmless, but in larger amounts it can kill you. So for people who are scared about eating fruits like apples, cherries, peaches and plums here is a list of fruits that contain cyanide to calm your fears down.
Cyanide in fruit seeds: how dangerous is an apple?
You’re highly unlikely to manage to eat enough apple seeds to poison yourself, so you can rest easy if you occasionally swallow one. Apples contain a compound called amygdalin in their seeds, which is a cyanide-and-sugar based molecule. If the seed is chewed or otherwise broken, human or animal enzymes come into contact with the amygdalin and effectively cut off the sugar part of the molecule. The remainder can then decompose to produce the poisonous gas hydrogen cyanide.
Cyanide toxicity is experienced by humans at doses of around 0.5–3.5 milligrams per kilogram of body weight. Symptoms of cyanide poisoning include stomach cramps, headache, nausea and vomiting, and can culminate in cardiac arrest, respiratory failure, coma and death. A fatal dose for humans can be as low as 1.5 milligrams per kilogram of body weight. In a recent study, the amygdalin content of apple seeds was found to be approximately 3 milligrams per gram of seeds (one seed is approximately 0.7g).
As not all of this mass would be converted into hydrogen cyanide (some of it will constitute the sugar part of the molecules that is cleaved off), it’s apparent that you’re going to need to eat a huge number of apple seeds to succeed in poisoning yourself, and there don’t appear to be any cases of someone having succeeded in doing so.
Natural toxins in fresh fruit and vegetables
Fresh fruit and vegetables are an important part of a healthy diet, however several fruits and vegetables consumed in Canada contain small amounts of natural toxins. These natural toxins help protect the plants and create resistance to diseases and certain types of insects. The public should be aware of the presence of natural toxins in these fruits and vegetables. The following safety tips can help reduce or avoid exposure to toxins, which could potentially have harmful effects on human health.
Fruit and vegetables that produce cyanide
The kernels within the pits of some stone fruits contain a natural toxin called cyanogenic glycoside. These fruits include apricots, cherries, peaches, pears, plums and prunes. The flesh of the fruit itself is not toxic. Normally, the presence of cyanogenic glycoside alone is not dangerous. However, when kernels are chewed cyanogenic glycoside can transform into hydrogen cyanide – which is poisonous to humans. The lethal dose of cyanide ranges from 0.5 to 3.0 mg per kilogram of body weight. This is why it is not recommended to eat the kernels inside the pits of stone fruits.
Although it is not recommended, some people use ground or whole bitter apricot kernels to flavour foods, as a health food, or for medicinal purposes. More information on bitter apricot kernels is available from Health Canada.
Cassava root and bamboo shoots
Cyanogenic glycoside toxin is also found in the cassava root and fresh bamboo shoots, making it necessary for them to be cooked before canning or eating. Cassava is classified into two main types – sweet and bitter. Sweet cassava is defined as having a concentration of cyanide less than 50 mg per kilogram of fresh weight, while bitter cassava has a concentration greater than 50 mg per kilogram. The sweet cassava only requires cooking in order to reduce the cyanide content to non-toxic levels. However, the bitter cassava contains more toxins and should be prepared and cooked properly prior to consumption. Grating the root and prolonged soaking of the gratings in water will leach out the cyanide, reducing the levels of toxin. In addition to soaking, cooking will further detoxify the roots before consumption.
Cyanogenic glycoside found in fresh bamboo decomposes quickly when placed in boiling water, rendering the bamboo shoots safe for consumption. It has been found that boiling bamboo shoots for 20 minutes at 98 C removes nearly 70 percent of the cyanide, while higher temperatures and longer intervals remove up to 96 percent. The highest concentrations are detoxified by cooking for two hours.
Natural toxins found in ackee fruit
Ackee, akee or achee – Blinghia sapida – is a food staple in many Western Africa, Jamaican and Caribbean diets. There are two main varieties, hard and soft ackees, that are available for consumption. Both canned and fresh forms of this fruit are consumed. However, unripe fruit contains natural toxins called hypoglycin that can cause serious health effects. The only part of this fruit that is edible, is the properly harvested and prepared ripe golden flesh around the shiny black seeds. The fruit is poisonous unless ripe and after being opened naturally on the tree.
Potatoes that can cause burning sensations
Several different glycoalkaloids are produced naturally by potatoes, the most common being solanine and chaconine. Low levels of glycoalkaloids produce desirable flavour in potatoes. However, exposure to elevated levels of glycoalkaloids when eating potatoes can cause a bitter taste or a burning sensation in the mouth – indicating a state of toxicity. Glycoalkaloids are not destroyed by cooking; even by frying in hot oil. The majority of this natural toxin found in potatoes is in the peel, or just below the peel. Greening of the potatoes may be indicative of the presence of the toxin. Red skinned or russet potatoes may camouflage the greening.
Consumers should avoid eating potatoes that show signs of greening, physical damage, rotting or sprouting. Potatoes should be stored in a cool, dark, dry place at home, such as a basement, and away from the sun or artificial light. Wash potatoes before cooking and peel or cut away green areas prior to cooking. Potatoes with pronounced greening or damage should be discarded. If potatoes taste bitter or cause a burning sensation after cooking, do not consume them.
Poisoning from fiddleheads
There have been documented reports of poisoning from consuming raw or undercooked fiddleheads. Symptoms usually begin 30 minutes to 12 hours subsequent to consumption and may include diarrhea, nausea, vomiting, abdominal cramps and headaches. Illness generally lasts less than 24 hours. Studies to date have not determined the cause of these illnesses. More information on Fiddleheads is available from Health Canada.
Fresh fiddleheads must be carefully washed in several changes of cold water. They should then be thoroughly cooked, either through steaming for 10 to 12 minutes – until tender – or in boiling water for at least 15 minutes. Water used for boiling or steaming fiddleheads should be discarded. Fiddleheads should also be boiled or steamed prior to sauteing, frying or baking.
Off-flavour in fresh carrots
Off-flavours such as a bitter taste, aftertaste and/or petroleum-like flavour have been associated with the consumption of fresh carrots. In contrast to sweet flavour, these off-flavours are usually as a result of stored carrots being exposed to ethylene. Ethylene is a normal fruit ripening hormone that may react with natural chemical compounds found in carrots creating off-flavour sensory attributes. Thus, carrots should not be stored with ethylene-producing commodities such as apples, avocados, bananas, pears, peaches, plums, cantaloupes, honeydew melons and tomatoes. Carrots properly handled and stored in perforated plastic bags at a low temperature retain the most acceptable taste.
Foods That Could Kill You (If You Eat Enough of Them)
Eat enough of these toxic fruits and vegetables, and you’ll suffer the consequences.
We’re not trying to say that the world is out to get you, but at times you might want to exercise caution. Each of these eight otherwise delicious and healthy fruits and vegetables have naturally occurring toxins that, while safe to ingest every so often (the body is pretty resilient that way), can definitely kill you depending on how, and how much of it you decide to eat. We’ve also done some quick math* to figure out how much you can eat before things get…lethal. Now go forth and satisfy that morbid curiosity:
*Note: Numbers are by no means a strong suit of ours, so while we’re reasonably confident in the algebra used to come up with these quantities, please excuse any calculation errors!
- 1/5Cherries, Apricots, Plums, Peaches: CyanideDon’t freak out if you accidentally swallow a cherry pit—they’re rarely poisonous when eaten whole—but whatever you do, don’t eat a broken pit. Because aside from tasting really bitter and generally being impossible to chew, the stones of certain stone fruits, like cherries, apricots, plums and peaches, contain cyanogenic compounds—science talk for “stuff that your body can turn into cyanide.” So, how many cherry pits is a lethal amount of cherry pits? After some quick Googling, we found that hydrogen cyanide is lethal at about 1.52 milligrams per kilogram, meaning that it takes little more than 0.1 grams (a dime weighs about one gram) of the toxin to dispatch a 150-pound human. A single cherry yields roughly 0.17 grams of lethal cyanide per gram of seed, so depending on the size of the kernel, ingesting just one or two freshly crushed pits can lead to death. (Credit: sk8geek / Flickr, MissMessie / Flickr, kudumomo / Flickr)
- 2/5Rice: ArsenicRice (especially rice grown in Texas) contains arsenic, a toxin that can cause bad things like vomiting, abdominal pain, and vertigo when consumed in large quantities. The highest levels are found in brown rice, the lowest in instant rice. Despite the toxin’s presence, it would be incredibly difficult to poison yourself by eating too much rice in one day. That’s not to say nothing bad will happen; consistent exposure to even low doses of arsenic over time can lead to heart disease and bladder cancer. According to the FDA, there is anywhere from 2.6 to 7.2 micrograms of inorganic (vs. organic, which is much easier for your body to metabolize) arsenic in one serving of rice. Given that it would take about 50 grams of arsenic to kill the average 150-pound adult, you’d have to eat nearly 7 million servings of rice—in one sitting—to achieve death by rice. If we assume that one serving is about 1/4 cup, that’s almost 1,800 cups of rice!
- 3/5Rhubarb: Oxalic AcidBrightly colored rhubarb stalks are great in cocktails and for making tangy-sweet pie fillings, but the plant’s leaves contain oxalic acid, a chemical that’s also used in household bleach and anti-rust products (yikes!). If that wasn’t enough, eating the leaves can cause burning sensations in the mouth and throat, nausea, vomiting, convulsions, and even death. Even cooking the leaves won’t get rid of the acid. If, despite this, you still want to try eating rhubarb leaves, you’ll be glad to know that they’re not severely toxic. According to a study from the Hampshire College (.pdf), a 130-pound woman would have to eat around 10 pounds of rhubarb leaves to show symptoms of oxalic acid poisoning.
Common Foods That Can Be Toxic
The hard stone in the center of cherries is full of prussic acid, also known as cyanide, which is poisonous. But there’s no need to freak out if you accidentally swallow one — intact pits just pass through your system and out the other end. Avoid crunching or crushing pits as you nosh on your cherries.
Apple seeds also have cyanide, so throwing back a handful as a snack isn’t smart. Luckily, apple seeds have a protective coating that keeps the cyanide from entering your system if you accidentally eat them. But it’s good to be cautious. Even in small doses, cyanide can cause rapid breathing, seizures, and possibly death.
You may take elderberry as a syrup or supplement to boost your immune system and treat cold or flu symptoms or constipation. But eating unripe berries, bark, or leaves of elderberry may leave you feeling worse instead of better. They have both lectin and cyanide, two chemicals that can cause nausea, vomiting, and diarrhea.
Nutmeg adds a nice, nutty flavor when you add it in small amounts to baked goods. But eaten by the spoonful, it can cause big problems to your system. Even as little as 2 teaspoons can be toxic to your body because of myristicin, an oil that can cause hallucinations, drowsiness, dizziness, confusion, and seizures.
The leaves, sprouts, and underground stems (tubers) of potatoes contain a toxic substance called glycoalkaloid. Glycoalkaloids make a potato look green when it’s exposed to light, gets damaged, or ages. Eating potatoes with a high glycoalkaloid content can cause nausea, diarrhea, confusion, headaches, and death.
Raw Kidney Beans
Of all the bean varieties, raw red kidney beans have the highest concentration of lectins. Lectins are a toxin that can give you a bad stomachache, make you vomit, or give you diarrhea. It only takes 4-5 raw kidney beans to cause these side effects, which is why it’s best to boil your beans before eating.
Eating the stalk is OK, but leave out the leaf. Rhubarb leaves contain oxalic acid, which binds to calcium and makes it harder for your body to absorb it. In turn, your bones can’t grow the way they should, and you’re at risk for kidney stones, blood clotting problems, vomiting, diarrhea, and coma.
Cyanide, Arsenic, and Other Toxins in Fruit: Apple Seeds, Peach Pits, Cherry Pits, etc.: Facts, Mythes and Old Wive’s Tales. Find Out ther Truth!
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Cyanide, Arsenic, and Other Toxins in Fruit: Apple Seeds, Peach Pits, Cherry Pits, etc.: Facts, Mythes and Old Wive’s Tales. Find Out ther Truth!
With the popularity of juicers and food grinders, some people seem to think that grinding up entire fruit (skin, seeds, pits, stems and all) is somehow healthier than tradition methods. This is not always the case. Some parts of some fruit are not only unpleasant to eat, they can even be dangerous. Here are the facts about toxic parts of fruit.
Cyanide in Apple Seeds, Cherry Pits, Peach Pits and Apricot Pits
Apple and crabapple seeds (and seeds of some other fruits, like cherries, peaches, apricots) contain amygdalin, an organic cyanide and sugar compound that degrades into hydrogen cyanide (HCN) when metabolized. Cyanide itself is a poison that kills by denying blood the ability to carry oxygen and thereby causes its victims to die. It’s not an urban legend that apple seeds contain cyanide; even Snopes.com has an article about it. “The Dr. Oz Show” did an episode in which they talked about the amount of arsenic in children’s apple juice.
Apple seeds also have a tough protective coating seals the amygdalin inside, unless the seeds are crushed, chewed or otherwise ground up. Whole apple seeds have hard, durable shells that allow them to pass intact through the digestive systems of people and animals.
The National Institute of Health says:
“The edible portions of dietary plant species commonly used in the United States contain relatively low levels of cyanogen glycosides, although some pits and seeds of common fruits, apple, apricot, peach, contain significantly higher concentrations.”
The Bottom Line
Don’t worry: It would take a bushel’s worth of ground up apple’s seeds (about 1 cup of seeds) to create enough cyanide to poison someone. Grinding apples and pressing them for apple juice or apple cider wouldn’t release enough cyanide to be a problem. Neither does cooking apples and straining them to make a sauce. Richard E. Barrans Jr., Ph.D. Assistant Director PG Research Foundation in Darien, Illinois says “About the only way you can actually run into a problem with the toxicity of apple seeds is if you save the seeds from about a bushel of apples, grind them and eat them all at once.”
Still, I don’t think I would intentionally group up the seeds and include them in foods. When we make homemade applesauce or juice, the seeds are exclude in the process and most are not even broken nor ground.
Cyanide Toxicity in Fruit Seeds
Cyanide toxicity is experienced by humans at doses of around 0.5-3.5 milligrams per kilogram of body weight. Symptoms of cyanide poisoning include stomach cramps, headache, nausea and vomiting, and can culminate in cardiac arrest, respiratory failure, coma and death. A fatal dose for humans can be as low as 1.5 milligrams per kilogram of body weight.
Cherry, peach, and apricot pits, on the other hand, also contain amygdalin, a form of cyanide. Peach and apricot have it in potentially harmful amounts. Of course, few people intentionally swallow or chew them. This NY Times article explains more.
The UK newspaper, The Guardian, reports the following levels of cyanide in various fruit:
Amygdalin in other fruits, in mg/g of seeds:
- Greengage: 17.5
- Apricot: 14.4
- Red cherries: 3.9
- Black cherries: 2.7
- Peaches: 2.2
- Plums: 2.2
- Pears: 1.3
- Nectarines: 0.1