What is Amygdalin and How Does it Work?
Apple seeds, along with the pits of other fruits like peaches and apricots, contain a compound called amygdalin. Amygdalin is a cyanogenic glycoside, meaning it contains a cyanide and sugar molecule. When the seed is chewed or crushed, digestive enzymes break down the amygdalin and release hydrogen cyanide (HCN), a highly toxic substance.
The human body can detoxify small amounts of cyanide. The enzyme rhodanese in the liver converts cyanide into thiocyanate, which is then excreted through the urine. This natural detoxification process is highly efficient, which is why accidentally swallowing a few intact apple seeds poses virtually no risk.
The Importance of the Seed Coating
The reason swallowing a few whole seeds is not dangerous is due to their hard, protective outer coating. This shell is resistant to stomach acids and digestive enzymes, allowing the seeds to pass through the digestive tract largely intact without releasing the amygdalin inside. It is only when the seeds are physically broken—by chewing, crushing, or blending—that the amygdalin becomes bioavailable and releases cyanide.
How Many Apple Seeds Are Dangerous?
For cyanide poisoning to occur, a person would need to ingest a significant amount of crushed seeds. Experts and studies have provided different estimations, but the consensus is that it takes a substantial quantity far beyond what anyone would consume under normal circumstances.
- One study suggests that a person would have to consume somewhere between 83 and 500 crushed seeds to risk acute cyanide poisoning.
- Other estimations suggest that a lethal dose could be higher, with some sources claiming up to 2,500 seeds are necessary for a fatal amount.
- An average apple contains only about 5 to 8 seeds, meaning you would need to consume the seeds of dozens, if not hundreds, of apples in a short period to approach toxic levels.
- The lethal oral dose of cyanide for a human is approximately 0.5–3.5 mg per kilogram of body weight. The concentration of amygdalin varies by apple variety, but it is a minuscule amount per seed.
What are the Symptoms of Cyanide Poisoning?
While the risk is low, knowing the symptoms of cyanide poisoning is important. Initial, milder symptoms can appear within minutes to hours after ingestion and include headaches, dizziness, confusion, and nausea. In severe cases, symptoms can escalate to difficulty breathing, seizures, loss of consciousness, and potentially death.
Comparing Cyanogenic Glycosides in Different Seeds
Apple seeds are not the only part of a plant containing cyanogenic glycosides. This is a common defense mechanism in many members of the Rosaceae family. The table below compares the risks of apple seeds with other common fruit pits and seeds.
| Fruit/Seed | Presence of Amygdalin | Relative Risk of Poisoning (Crushed) | Key Factor |
|---|---|---|---|
| Apple Seeds | Yes | Very Low | Quantity needed for risk is extremely high, protective coating prevents release if swallowed whole. |
| Apricot Pits | Yes | Low to Medium | Contains a higher concentration of amygdalin than apple seeds. Can be promoted as alternative medicine, leading to dangerous overconsumption. |
| Cherry Pits | Yes | Very Low | The hard pit must be crushed to release amygdalin, similar to an apple seed. |
| Peach Pits | Yes | Low to Medium | Like apricot pits, these have a higher concentration of cyanogenic compounds. |
| Sweet Almonds | Minimal | Negligible | Cultivated sweet almonds contain very low levels of amygdalin. |
| Bitter Almonds | High | High | Bitter almonds contain significantly more amygdalin and are therefore a much higher risk. |
Can Apple Seeds Accumulate Cyanide in the Body?
This is a common misconception. The body's detoxification process for cyanide is very efficient, meaning that small, non-lethal doses are quickly processed and excreted. Therefore, the cyanide released from a few accidentally chewed seeds does not accumulate over time to dangerous levels.
What about Apple Juice or Smoothies?
Commercially produced apple juice is generally pasteurized, and since cyanide has a low boiling point, the heating process effectively vaporizes the toxin. However, if you are making a smoothie at home using a powerful blender that crushes whole apples, including the core and seeds, a small amount of amygdalin might be released. The quantity is still unlikely to be dangerous, but it is a good practice to core apples before blending them.
Conclusion: Dispel the Fear, Practice Caution
The urban myth about the fatal danger of apple seeds is largely unfounded. While it is true that apple seeds contain a compound called amygdalin, which can release cyanide when crushed, the quantity is so small and the body's natural defense mechanisms are so effective that accidental ingestion is not a cause for concern. To reach a toxic dose, a person would need to intentionally and thoroughly crush and consume an extremely large number of seeds in one sitting, an unlikely and unpleasant scenario. The delicious, nutritious fruit is perfectly safe to eat, and the best practice is simply to avoid deliberately chewing or consuming the seeds, especially for children and pets. In the rare case of symptoms of poisoning after consuming a large quantity, contact poison control immediately.
Resources for Further Reading
Key Takeaways
- Amygdalin in Apple Seeds: Apple seeds contain the natural chemical amygdalin, which can break down into hydrogen cyanide when crushed.
- Whole Seeds Are Harmless: Swallowing a few whole, unchewed apple seeds is not dangerous because their protective outer coating prevents the release of amygdalin.
- Lethal Dose Requires Many Crushed Seeds: A person would need to thoroughly chew and ingest an enormous quantity of apple seeds—potentially hundreds—in one sitting to reach a toxic level of cyanide.
- Body Detoxifies Small Amounts: The human body is capable of detoxifying the minuscule amounts of cyanide released from a few accidentally chewed seeds.
- Other Seeds Contain Similar Compounds: Other fruit pits and seeds, such as those from peaches, apricots, and cherries, also contain amygdalin.
- Remove Seeds from Blended Foods: It is best practice to remove cores and seeds before blending whole apples for smoothies, as crushing them can release the compound.
FAQs
Q: What is amygdalin? A: Amygdalin is a natural compound in apple seeds and other fruit pits that can release hydrogen cyanide (a poison) when the seeds are crushed or chewed.
Q: Is it dangerous to swallow a whole apple seed? A: No, swallowing a few whole seeds is not dangerous. The hard shell protects the amygdalin from being released, and the seeds will simply pass through your digestive system.
Q: How many apple seeds are lethal? A: It is highly unlikely for accidental ingestion to be lethal. A toxic dose would require a person to thoroughly chew and consume hundreds of seeds in one short sitting.
Q: Do apple seeds accumulate cyanide in the body over time? A: No, small amounts of cyanide are quickly processed and detoxified by the liver. Cyanide does not accumulate in the body.
Q: Are other fruit seeds like cherry or peach pits also dangerous? A: Yes, pits from cherries, peaches, apricots, and other stone fruits also contain amygdalin. The risk is the same: the compound is only released if the pit is crushed, and a large quantity would be required for poisoning.
Q: Is it safe to make smoothies with whole apples, seeds included? A: It is best to remove the core and seeds before blending. Powerful blenders can crush the seeds and release amygdalin. While a small amount is not likely to be dangerous, it's safer to discard them.
Q: What should I do if I suspect someone has eaten a large quantity of apple seeds? A: If you suspect a person or pet has consumed a large amount of crushed seeds and is showing symptoms of poisoning like dizziness or vomiting, seek immediate medical attention.
