Vitamin B17 – “Laetrile” - in Cancer Therapy
Vitamin B17 (Laetrile) – found in bitter almonds and certain other natural foods - is one of a group of naturally occurring compounds known as “cyanogenic glycosides”; they are “cyanogenic” because they break down to release the compound cyanide after interacting with certain types of enzymes. In case of amygdalin, it yields cyanide and the volatile compound benzaldehyde when it is cleaved by the enzyme beta-glucosidase. Under the trade-name “Laetrile”, amygdalin has been used in cancer therapy for over 40 years.
It is conceivable that amygdalin can have a subtle but worthwhile impact on cancer growth and spread, especially in the context of other effective anti-cancer measures. Of particular interest in this regard are various rodent studies, primarily from Japan, indicating that benzaldehyde – a product derived from amygdalin cleavage – can have favorable impact on cancer growth. In these reports, since benzaldehyde per se is too irritative for direct administration, it was administered either as a complex with cyclodextrin or various glycosides (sugars).
Decreases in size of established tumors, prevention of lung metastases, and an increase in natural killer cell activity ( a type of immune cell that plays a key role in prevention of metastases) were reported in rodents, and a couple of clinical reports also suggested that benzaldehyde complexes might be useful in cancer therapy (1-7).
Could amygdalin function clinically as a source of cancer-retardant benzaldehyde? When amygdalin is ingested, the beta-glucosidase activity of gut bacteria has the potential to cleave it, releasing cyanide and benzaldehyde. Conceivably, the modest amounts of benzaldehyde released in this way could have a physiological impact.
Although the utility of amygdalin in cancer therapy can rightly be considered “unproven”, this agent has long been in use at Oasis of Hope Hospital as a component of a more comprehensive “metabolic therapy” developed under the direction of Dr. Ernesto Contreras.
In light of this tradition, the theoretical possibility that amygdalin could be be acting as a “time-release” source of benzaldehyde, and the fact that many patients coming to Oasis wish to receive amydalin therapy, we are continuing to employ amygdalin, both intravenously and orally. There is no reason to think that this is doing any harm – when administered in proper doses, systemic cyanide toxicity is not an issue – and it possibly is doing some good.
References
1. 1. Kochi M, Takeuchi S, Mizutani T, Mochizuki K, Matsumoto Y, Saito Y. Antitumor activity of benzaldehyde. Cancer Treat Rep 1980 January;64(1):21-3. 2. 2. Banks AR, Cloran JA, Jones T, Kerry DB, Parks RC, Thurlow SM. A benzylidene mannopyranoside derivative with antitumor activity in the spontaneous mammary tumor system. Neoplasma 1982;29(5):589-95. 3. 3. Kochi M, Isono N, Niwayama M, Shirakabe K. Antitumor activity of a benzaldehyde derivative. Cancer Treat Rep 1985 May;69(5):533-7. 4. 4. Ochiai H, Niwayama S, Masuyama K. Inhibition of experimental pulmonary metastasis in mice by beta-cyclodextrin-benzaldehyde. J Cancer Res Clin Oncol 1986;112(3):216-20. 5. 5. Masuyama K, Ochiai H, Niwayama S, Tazawa K, Fujimaki M. Inhibition of experimental and spontaneous pulmonary metastasis of murine RCT (+) sarcoma by beta-cyclodextrin-benzaldehyde. Jpn J Cancer Res 1987 July;78(7):705-11. 6. 6. Balazova E, Koza I. Therapy of P388 leukemia with benzaldehyde. Neoplasma 1988;35(6):725-8. 7. 7. Kuroki Y, Ochiai H, Kurokawa M, Niwayama S, Kishimoto C, Tazawa K, Fujimaki M. Augmentation of murine lymphokine-activated killer cell cytotoxicity by beta-cyclodextrin-benzaldehyde. J Cancer Res Clin Oncol 1991;117(2):109-14.
