Many a grandmother has warned her grandkids against eating "poisonous" apple seeds. Perhaps you've had the experience of accidentally swallowing a few and wondering if you'd soon fall to the floor, gasping for breath.
Then there are those individuals who've been eating apples whole — seeds and all — for decades with no ill effects.
Many did not even know there were supposed "ill effects" to speak of. Are there? This is the question of the day, and, to answer it in a nutshell, or shall I say in an apple core, there's little to be afraid of.
Apple Seeds Release Cyanide When Crushed
Apple seeds contain amygdalin, a plant compound known as a cyanogenic glycoside. It's part of the seeds' chemical defenses, but when apple seeds are chewed or crushed and metabolized, the amygdalin turns into hydrogen cyanide.
Hydrogen cyanide, in turn, is a poisonous substance that prevents your cells from using oxygen properly, leading to death within minutes at high-enough exposure levels.
It's perhaps most known for its use as a chemical warfare agent by the Germans during World War II, but it was also reportedly used during the Iran-Iraq War in the 1980s, also as a chemical weapon.1
Apple seeds aren't the only food to contain cyanide precursors. Amygdalin is also found in apricot, peach and cherry pits, for instance, and much more (over 2,500 plant species in all2).
But consuming a few apple seeds is not the same thing as being exposed to straight hydrogen cyanide, and here's why: apple seeds have a protective coating that's resistant to digestion.
If you've ever eaten whole apple seeds, you may have noticed that they pass through your body basically unharmed. The cyanide is only produced if the seeds are damaged (i.e., crushed or chewed), so swallowing a few seeds whole is likely to be of little consequence.
It's one of mother nature's ingenious protections, as the seeds' ability to produce cyanide when crushed discourages animals from chewing them, thus allowing for the whole undamaged seeds to return to the Earth and grow new apples.
You'd Have to Eat a Lot of Crushed Apple Seeds for Them to Be Dangerous
While consuming the number of apple seeds in one apple (the average apple contains 5 seeds, according to the Washington State Apple Commission3) is not cause for alarm, it is possible to be harmed by apple seeds — if you crush them and consume a large enough quantity.