Vitamin B17, also known as laetrile, is a chemical compound derived from amygdalin, a substance that occurs naturally in bitter almonds and apricot and peach pits. Its use as an alternative cancer therapy is controversial, and several studies since the mid-1970s have found no proof that laetrile is effective in treating cancer. The FDA has sanctioned against the sale, use and transportation into the United States of products labeled as vitamin B17, laetrile or amygdalin.
Russians first used amygdalin as a cancer treatment in 1845. By the early 1920s, Californian physician Ernst T. Krebs Sr. had begun using the substance to treat his cancer patients, but the pills he created proved toxic. His son, biochemist Ernst T. Krebs Jr., invented a chemically modified version of amygdalin in 1952 that he called laetrile. Both father and son promoted laetrile as an effective cancer treatment, claiming it contained a substance that targeted and attacked cancerous cells.
Krebs Jr. first theorized that cancer is caused by a deficiency in vitamin B17, and claimed that laetrile was the “missing” vitamin B17. Following this theory, proponents of B17 say that not only does it treat cancer but it also can prevent it. Laetrile cancer treatments involve metabolic therapy, including a specified diet, high doses of vitamins and weeks of injections followed by maintenance pills. Laetrile also is an ingredient in anti-cancer enemas and skin creams.
According to the American Cancer Society, laetrile is not a vitamin because it doesn’t fit the scientific definition of a vitamin, in that it’s not essential for reaching or sustaining good health. Further, the National Cancer Institute states that while it knows of no clinical trials of laetrile, all case reports and anecdotal reports do not provide sufficient proof that laetrile is an effective method of treating cancer.
Proponents of laetrile have sought FDA approval several times since the 1970s. The FDA always has rejected the application for human testing, concluding that there isn’t sufficient evidence that laetrile is effective enough in animal tests to warrant clinical trials in humans. Advocates of laetrile claim that the government’s sanctions against it amount to a kind of censorship that dictates the type of treatments that cancer patients can seek. They suggest that the FDA and the medical profession are motivated by the profits of conventional medicine.
The FDA describes laetrile as “a highly toxic product that has not shown any effect on treating cancer.” Laetrile contains cyanide, which its supporters contend is its anti-cancer agent, but laetrile pills have been linked to cyanide poisoning, with side effects including headaches, dizziness, nausea, vomiting, fever, confusion, blue skin due to oxygen depletion, low blood pressure, droopy eyelids and nerve and liver damage. Eating raw almonds, carrots, celery, peaches and bean sprouts can exacerbate these effects. According to the American Cancer Society, cyanide toxicity due to laetrile treatments has led to death in a few cases.