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Laetrile, also referred to as amygdaline or vitamin B17 is a nitriloside and caused quite a furor in America in the 1970s. An active ingredient, which particularly occurs in the seeds of apricots or apples became so well-known as an anti-cancer agent, that first the Sloan Kettering Center in New York, and then even the Mayo Clinic in Rochester performed their own studies. “Naturally” with the result that the predominantly positive studies produced by biochemist, Dr. Kanematsu Sugiura, in which he was could prove that Laetrile was able to particularly stop the growth of smaller tumors, could not be correct. Rubin also proved that patients with breast cancer or bone cancer lived longer.

Only much later was it disclosed that virtually inactive isoamygdaline was used in the Mayo Clinic study. Most of the patients had already undergone chemotherapy and irradiation without success and after stabilization occurred for app. 70% of all patients within 3 weeks, in spite of advanced disease,  the treatment was changed to oral doses of Laetrile instead of intravenous Laetrile.

This is another prime example of how a positive study result, or a negative study result can be generated with any medication in the world. In Germany since the death of the famous cancer physician Dr. Nieper, who treated well-known people like Caroline of Monaco or John Wayne, Laetrile unfortunately has again sunk into oblivion. The current Laetrile center is the Contreras Clinic in Tijuana where Laetrile has been used for more than 25 years.

We have Dr. Ernest Krebs to thank for the discovery of Laetrile. His theory was that trophoblasts (cells that develop at the beginning of fertilization) which normally are destroyed through the enzyme chemotrypsin, survive and years later these cells can develop tumors, if the pancreas no longer functions correctly. Laetrile consists of 2 glucose molecules, a benzaldehyde molecule and a cyanide radical molecule. The glucose molecules are replaced in the body by glucoronic acid. This process has negative effects on cancer cells, however it does not have negative effects on healthy cells, because the enzyme glucoronidase which occurs in high concentrations in cancer cells, splits the glucoronic acid and thus loses the benzaldehyde then cyanide, which kills cancer cells.

As opposed to cancer cells, healthy cells also have the enzyme rhodanase which adds a sulfur atom to each free cyanide,  in order to form harmless thiocyanate. Although there are other studies by Tatsumura (1987) or Kochi (1985) which confirm the positive effect of benzaldehyde on cancer cells, today Laetrile is an almost forgotten cancer medication.

The book by Phillip Day: Cancer: Why we’re still dying to know the truth, has brought Laetrile back into the headlines in Germany. What is less well known is the fact that in 2003, a physician in Hannover,  “was advised” to stop treating his patients with laetrile, and currently I only know of one other doctor in Germany who administers this medication intravenously. Taken orally it is uncertain whether Laetrile can work at all, and unfortunately taken in larger amounts you overtask your gastrointestinal tract very quickly.

Lothar Hirneise

Personal opinion: During my stay at the Contreras Clinic in Mexico, I had the opportunity to speak with many patients and doctors who have had good experiences with laetril. It certainly belongs in the hands of an experienced physician. Unfortunately there are very few of these and it appears as if laetril will disappear from oncology in a few years.

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