A Facebook post claims “Vitamin B17 is banned because it kills cancer cells” and says the substance can be found in apricot seeds.
Vitamin B17 is a common name for a substance called amygdalin which indeed is found in apricots, as well as raw nuts and beans. A synthetic form of the substance, called Laetrile, has been marketed unofficially as a cancer treatment since the middle of the 20th century.
The substance is not actually a vitamin, and can be harmful.
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Is it banned?
The Medicines and Healthcare products Regulatory Agency regulates the substance in the UK, and “it is an offence to sell, supply or advertise products containing Amygdalin without a marketing authorisation”. It also notes that the product has been restricted since the 1980s.
Clearly, buying food that contains amygdalin such as apricots and beans is not illegal.
Does it kill cancer cells?
Cancer Research UK says “There isn’t any scientific evidence that laetrile is an effective treatment for cancer or any other illness.”
A Cochrane review, often considered the best form of evidence for medical treatments, found that anti-cancer claims are “not currently supported by sound clinical data”, and carry a significant risk of harm.
Studies looking at the action of the substance in lab conditions and in animals have generally not found an effect, according to an evidence summary by the US National Cancer Institute. While some effect was seen in lab tests on cancer cells, this tells us little about the usefulness in treating actual cancers.
The results in animals were even less positive. Six of the seven studies examined found no effect, and the seventh showed only a small slowing of cancer growth in mice injected with amygdalin.
What’s the harm?
Amygdalin is partly converted into the poison cyanide once in the body, and has a long list of side effects as a result.
Cyanide is present in many forms, but can kill in large enough doses and is considered a poison. Cyanide poisoning can occur acutely (with one exposure) or over time.
The Cochrane review found there to be a “considerable risk of serious adverse effects from cyanide poisoning after laetrile or amygdalin, especially after oral ingestion.”
It added: “The risk–benefit balance of laetrile or amygdalin as a treatment for cancer is therefore unambiguously negative.”
The European Food Safety Authority has in fact warned against the over consumption of apricot kernels and given advice on avoiding consuming unsafe levels of cyanide.
Bad information about cancer cures can cause harm if people use it to make decisions about their treatment, and in this instance the substance itself may also be harmful. We have written several times about false claims in this area.
As Cancer Research UK says, alternative therapies “may be harmful or could interact with other treatments you're having” and that while the decision to use an alternative therapy is down to the individual, it cautions: “you could harm your health if you stop your cancer treatment for an unproven treatment.”
Image courtesy of Polina Tankilevitch