Apples can be a healthful snack or ingredient. However, it is not advisable to eat the core or apple seeds, as they contain small amounts of cyanide, which is highly toxic.
Apples have five seed pockets, with varying numbers of seeds in each pocket. Some believe that apple seeds are poisonous, while others consider them to be healthful.
Most people avoid the seeds, which have a bitter taste, but a person may occasionally eat one or a few by accident and not bother to spit them out. Or, a person may drink juice that contains pulverized seeds.
This article explores scientific research into the safety and risks of eating apple seeds.
Apples contain plenty of healthful compounds, including antioxidants, vitamins, and dietary fiber.
Apple seeds, however, contain a plant compound called amygdalin, which can have a toxic effect.
Amygdalin is a part of the seeds’ chemical defenses. It is harmless when a seed is intact, but when a seed is chewed or otherwise damaged, the amygdalin degrades into hydrogen cyanide. This is very poisonous and even lethal in high doses.
Amygdalin exists in relatively high amounts in the seeds of fruits in the Rosaceae family, which includes apples, almonds, apricots, peaches, and cherries.
People have used cyanide as a poison throughout history. It works by interfering with cells’ oxygen supplies, and high doses may lead to death within minutes.
Eating or drinking cyanogenic plant compounds can cause cyanide poisoning in humans. These compounds exist in apricot seeds, almonds, cassavas, and apple seeds.
Mild symptoms of cyanide poisoning can include:
Acute poisoning can lead to decreased consciousness, high blood pressure, paralysis, and coma. In some cases, it is fatal.
The exact amount needed to make someone sick depends on their body weight. Young children have a greater risk.
For the toxic compounds in apple seeds to be lethal, the number of seeds would depend on a person’s body weight, their tolerance, and the type of apple.
The amount of amygdalin in an apple varies, depending on the variety of apple and its growing environment.
It is important to keep in mind that when amygdalin is not lethal, smaller amounts can still make a person sick.
Eating a few apple seeds is safe. However, eating or drinking large quantities of ground or crushed seeds could be fatal.
According to a 2015 review, the amygdalin content in 1 gram of apple seeds ranges from 1–4 milligrams (mg), depending on the variety of apple. However, the amount of cyanide derived from the seeds is much lower.
A lethal dose of hydrogen cyanide may be around 50–300 mg.
Apple seeds have the potential to release 0.6 mg of hydrogen cyanide per gram. This means that a person would have to eat 83–500 apple seeds to develop acute cyanide poisoning.
In other words, consuming cups of ground apple seeds might be fatal, or at least cause illness. However, eating the seeds in one apple would not pose a problem.
That said, researchers recommend avoiding eating apple seeds and removing them before juicing apples because of their high amygdalin content.
Other scientists confirm that the amygdalin content in apple seeds can be high and that eating the seeds can be a cause for concern.
Swallowing whole apple seeds is unlikely to cause any symptoms. The seed coating protects it from digestive enzymes, and the seeds can pass through the digestive system undamaged.
Nevertheless, it is probably a good idea to remove the seeds before giving apples to young children or pets.
Apple juice and smoothies often contain entire crushed apples, including the core and seeds.
Because the apple seeds get crushed during processing, they could release some cyanide, which remains in the juice.
However, when researchers investigated how much amygdalin was in commercial apple juice brands, they found very low amounts, ranging from:
- 0.01–0.04 mg per milliliter (ml) in pressed apple juice
- 0.001–0.007 mg per ml in long-life apple juice
The authors of the review concluded that the amounts of amygdalin in commercially available apple juice were unlikely to cause harm.
Still, they recommend avoiding eating apple seeds and removing them before juicing apples, due to the amygdalin content.
Apple flesh and peel are very healthful and pose no risks. Yet chewed or crushed apple seeds release small amounts of cyanide, which is highly toxic.
Someone would probably need to thoroughly chew and swallow at least 85 seeds before they experienced any adverse effects.
If a person accidentally eats a few apple seeds, there is no need to worry.