Vitamin B17 is not actually a vitamin and can't be classified as one because your body doesn't produce it or need it. The name vitamin B17 was given to a specific component found in plants and identified as amygdalin.
A concentrated synthetic form of amygdalin, called laetrile, was patented in the 1950s, and the two terms are often interchangeable. Laetrile is best known as a controversial treatment for cancer and carries the risk of some dangerous side effects.
What Is B17?
Vitamin B17, or laetrile, is a partly man-made derivative of amygdalin, a natural cyanogenic glycoside plant compound. Amygdalin is made from kernels of apricots and other plant species from the genus Prunus. It hasn't been approved as a vitamin by the American Institute of Nutrition Vitamins, according to the National Cancer Institute.
Laetrile has also been banned by the FDA since the1980s and can't be sold as a medicinal product in the U.S. However, a form of laetrile is made in Mexico from crushed apricot kernels consisting of amygdalin and available illegally on the internet.
Foods Containing Amygdalin
Many plants that contain high amounts of amygdalin, or B17, have been used in traditional food medicines in several cultures for centuries. According to the Marion Institute, these include:
Raw nuts — almonds (bitter and raw) and macadamia nuts
Grasses — wheatgrass, acacia, sprouted alfalfa, milkweed and white Dover
Seeds —** **
flax, chia and sesame
Pits of —
apricot, cherry, apple, peach, nectarine, plum, pear and prunes
Beans — burma, broad, sprouted lentils and mung, lima and scarlet runner
Berries — nearly all wild berries, including blackberry, elderberry, raspberry, cranberry, strawberry and chokeberry
Adverse Effects From Toxins
Foods that contain amygdalin may be part of your daily diet. These foods contain a natural plant toxin called cyanogenic glycosides. They have the potential to generate toxic hydrogen cyanide, which serves as a defense for the plants against herbivores.
If you eat excessive amounts of cyanogenic plants, the hydrogen cyanide produced in your stomach can prevent your cells from using oxygen and eventually kill them, according to a 2014 review by the Research and Development Institute for Bovine Balotesti.
Although generally not a problem with the food you eat, laetrile supplements or medications containing high doses of amygdalin can cause cyanide toxicity. This can lead to symptoms and health problems such as:
- Abdominal pain
- Mental confusion
- Cardiac arrest
- Circulatory and respiratory failure
- Coma and, in extreme cases,
How Much Is Too Much?
Normally, eating small amounts of cyanogenic foods doesn't pose a health risk. However, cases of poisoning have been reported from ingesting amygdalin in bitter apricot kernels. The kernel is the seed from the stone inside the apricot. When the kernel is ground or chewed, it releases hydrocyanic acid. Breaking down 1 gram of amygdalin releases 59 milligrams of hydrocyanic acid.
The European Food Safety Authority set a safe level for cyanide at 20 micrograms per kilogram of body weight. This rating is 25 times below the lowest lethal dose reported. Based on these limits and the amygdalin content of raw apricot kernels, it's estimated that the lethal amount for adults is three small apricot kernels — for children, the amount would be about half of one small kernel.
Read more: Apple Seed Toxicity
Research has found that amygdalin in B17 has antioxidant properties that enhance the immune system and may maximize the benefits of antioxidation cells. A 2014 study used apricot-kernel extract to evaluate the anti-inflammatory and antioxidant effect of chronic inflammatory disorders of the gastrointestinal tract in rats.
The results, published in Research in Pharmaceutical Sciences, showed that the amygdalin present in the apricot kernel, known for its high ability to scavenge free radicals, may be a useful treatment for colitis and a good alternative for alleviating inflammatory bowel disease.
Treatment for Endometriosis
Endometriosis is a painful and often aggressive disorder that develops when the lining of your uterus, referred to as the endometrium, grows outside your uterus. It often causes infertility in women and has the potential risk of recurrence after the recovery period. In an effort to find an effective treatment for this serious condition, researchers examined the effects of amygdalin and leuprolide acetate on endometriosis development and recurrence in rats.
The results of the study, published in the journal Periodicum Biologorum in 2017, found that after three weeks, the group of rats treated with amygdalin and the group treated with leuprolide acetate both had a significantly lower volume of endometriotic cells than the control group, with the amygdalin showing the most positive effect in the treatment of endometriosis.
Read more: Symptoms of Endometriosis Cysts
Alternative Cancer Cure
Many people suffering from cancer hope for an effective therapy with so‐called holistic cures using vitamin B17, although studies haven't revealed enough scientific evidence proving that laetrile or amygdalin can treat cancer. Despite this, vitamin B17 still gets promoted as an alternative and complementary medicine to treat cancer and is used in Mexico and some U.S. clinics. The theory is that, since cyanide kills cells, it can eradicate tumors and stop cancer cells from reproducing.
Laetrile is often administered in combination with special diets, high-dose vitamins and pancreatic enzymes. It's available in several forms: as a tablet, by intravenous or intramuscular injection, as a skin lotion or as a liquid put on the rectum. Taking laetrile orally incurs a much greater toxicity level than other methods of administering the substance. This is due to your digestive system breaking down the laetrile and releasing cyanide.
Even though they can come from questionable sources or be contaminated, there's no government control of vitamin B17 preparations. Cancer patients need to recognize the high risk of developing serious adverse effects due to cyanide poisoning. This risk could increase with intake of vitamin C or in vegetarians with vitamin B12 deficiency.
What Research Says
The Cochrane Library published a systematic review to assess the alleged anti‐cancer effect and possible side effects of amygdalin and laetrile. A group of experts gathered all the evidence and conclusions from a number of databases with searches updated to 2018.
The authors' conclusion was that, in regard to the use of laetrile or preparations containing amygdalin, no claims could be supported by clinical data for the use of either as having any beneficial effect for cancer patients. Findings stressed the considerable risk of serious adverse effects from poisoning, mostly prevalent after oral ingestion of laetrile or amygdalin, both of which have a common structural component that contains cyanide.
The takeaway is that the risk–benefit balance of laetrile or amygdalin as a treatment for cancer is negative and should be discouraged. Furthermore, researchers suggest that there is neither scientific nor ethical justification for further clinical trials with amygdalin or laetrile for the treatment of cancer.
- NIH: National Cancer Institute: Laetrile/Amygdalin (PDQ®)–Patient Version
- WebMD: Is Amygdalin a Safe Cancer Treatment?
- Cochrane Database of Systematic Reviews: Laetrile Treatment for Cancer
- Marion Institute: Amygdalin and Laetrile: History and Current Usage
- Research in Pharmaceutical Sciences: Anti-Inflammatory Effect of Prunus Armeniaca L. (Apricot) Extracts Ameliorates TNBS-Induced Ulcerative Colitis in Rats
- Research and Development Institute for Bovine Balotesti: Natural Plant Toxins – Cyanogenic Glycosides in Plant Foods
- The European Food Safety Authority: Apricot Kernels Pose Risk of Cyanide Poisoning
- European Food Safety Authority Journal: Acute Health Risks Related to the Presence of Cyanogenic Glycosides in Raw Apricot Kernels and Products Derived From Raw Apricot Kernels
- Periodicum Biologorum: Effect of Amygdalin on the Treatment and Recurrence of Endometriosis in an Experimental Rat Study
- NIH PubChem: Amygdalin
- Cancer Research UK: Laetrile (Amygdalin or Vitamin B17)