Chen et al.Citation1 have provided interesting data in their recent article in your esteemed journal. I would like to differ from Chen et al. though, especially in the light of the safety issues related with amygdalin therapy.
Oral administration of amygdalin is especially dangerous. O’Brien et al.Citation2 have recently described the case of a 32-year-old female who developed cyanide poising secondary to amygdalin use as a supplement. The patient developed systemic toxicity and diabetes insipidus but fortunately recovered after appropriate therapy. Patients may also develop neuro-myopathyCitation3. Simultaneous consumption of vitamins especially vitamin C accentuates amygdalin conversion to cyanide thus further augmenting toxicityCitation4. In addition, vitamin C also attenuates cysteine levels in the body that further decreases amygdalin detoxification. Animal studies reveal that oral amygdalin may also cause teratogenic side effectsCitation5. This has not been observed following intravenous administration of amygdalinCitation2. Those on a vegan die with co-existing cynacobalamin deficiency are also at a higher risk of developing overt cyanide toxicity.
These findings have been confirmed by Milazzo et al.Citation6 in a recent analysis of 36 different studies involving amygdalin administration. According to Milazzo et al., amygdalin was not of any clinical benefit in any of these studies. Moertel et al.Citation7 in another study involving 178 cancer patients again refuted the claim that amygdalin is of clinical benefit in these patients. Non-improvement in overall survival or no improvement of symptoms was noted in any of these patients. In addition, the toxic effects are more pronounced in those with the congenital inability to detoxify cyanideCitation2,Citation3.
It is obvious from the above data that clinical use of amygdalin is accompanied by numerous side effects. The risk benefit ratio is not favorable for amygdalin in this regard. Based on the above examples, it is clear that further studies involving amygdalin can cause dangerous side effects as well as mortality.
Declaration of interest
The authors report no conflicts of interest. The authors alone are responsible for the content and writing of this article.
References
- Chen Y, Ma J, Wang F, et al. Amygdalin induces apoptosis in human cervical cancer cell line HeLa cells. Immunopharmacol Immunotoxicol 2013;35:43–51
- O’Brien B, Quigg C, Leong T. Severe cyanide toxicity from ‘vitamin supplements’. Eur J Emerg Med 2005;12:257–258
- Kalyanaraman UP, Kalyanaraman K, Cullinan SA, McLean JM. Neuromyopathy of cyanide intoxication due to “laetrile” (amygdalin). A clinicopathologic study. Cancer 1983;51:2126–2133
- Bromley J, Hughes BG, Leong DC, Buckley NA. Life-threatening interaction between complementary medicines: cyanide toxicity following ingestion of amygdalin and vitamin C. Ann Pharmacother 2005;39:1566–1569
- Willhite CC. Congenital malformations induced by laetrile. Science 1982;215:1513–1515
- Milazzo S, Ernst E, Lejeune S, et al. Laetrile treatment for cancer. Cochrane Database Syst Rev 2011;11:CD005476
- Moertel CG, Fleming TR, Rubin J, et al. A clinical trial of amygdalin (Laetrile) in the treatment of human cancer. N Engl J Med 1982;306:201–206