Vitamin B17, also known as laetrile and amygdalin, is another controversial "vitamin," as its source, the apricot kernel, becomes a focus of increasing interest. As with pangamic acid, B17 was also discovered by Dr. Ernest T. Krebs Sr., who thought it a vitamin essential to health, and who first tried amygdalin therapeutically. Laetrile is a nitriloside compound composed of four molecules: two sugar, one benzaldehyde, and one cyanide. It is likely the cyanide that accounts for the controversy over this substance, particularly in regard to cancer therapy. Using laetrile—amygdalin, vitamin B17, nitriloside, whatever we call it—as a treatment for cancer is now illegal in the United States. Some people seeking such treatment go to Mexico or other laetrile-supportive countries.
Arguments against laetrile as a therapy cite concerns about possible cyanide toxicity as well as studies that show it is not effective as a cancer treatment. Studies, however, cannot be completely objective, especially on a subject as complex as cancer, which is influenced by so many factors. The proponents of laetrile claim that cyanide is a natural molecule found in food and is not toxic in normal doses; laetrile treatment itself is not known to have any side effects in usual dosages. But, obviously, considering Western medicine’s use of chemotherapy, radiation, and surgery, side effects are not the main concern when treating a life-threatening disease. The proof in any treatment is, ultimately, whether it works.
Amygdalin is not digested in the stomach by hydrochloric acid, but passes into the small intestine where it is acted on by enzymes that split it into various compounds, which are then absorbed.
Sources: Laetrile is found primarily in apricot kernels and comprises about 2–3 percent of the kernel. It is also available in the kernels of other fruits, such as plums, cherries, peaches, nectarines, and apples. The fruit kernels or seeds generally have other nutrients as well—some protein, unsaturated fatty acids, and various minerals. B17 is not found with other B vitamins in yeasts. Many plants do, however, contain some B17, with the sprouting seeds, especially mung bean sprouts, containing the highest amount.
Functions: The specific theoretical function of laetrile is its effect on cancer cells. Normal cells have an enzyme, rhodanase, that inactivates the cyanide molecule of the laetrile compound. Cancer cells do not possess this enzyme. In fact, they have an enzyme, beta-glucosidase, that releases the cyanide, which then poisons the cancer cells.
Uses: The main use for laetrile is in the treatment of cancer, particularly to reduce tumor size and further spread, and to alleviate the sometimes severe pains of the cancerous process. As I stated, more well-designed research needs to be done to determine whether this compound in its natural form is effective. Other uses reported for laetrile have been in the treatment of high blood pressure and rheumatism.
Deficiency and toxicity: There are no known problems caused by not consuming this "vitamin," other than, theoretically, a deficiency could increase the likelihood of developing cancer. There are, however, concerns over toxicity, due to the cyanide within the vitamin or possibly from other metabolic effects. Usually, treatment amounts are limited to 1 gram to reduce potential side effects, which initially are most likely gastrointestinal in nature. Toxicity of this molecule must be researched further.
Requirements:This nutrient is not required as far as we know; in fact, it is against the law in the United States. When used, laetrile is administered at 250–1,000 mg. (1 gram) daily. Higher amounts—up to 3 grams per day—have been used, but divided into several smaller dosages, each usually limited to 1 gram. If the source is whole apricot kernels, the quantity is usually about 10–20 kernels per day; 1–2 cups of fresh mung bean sprouts may provide an equivalent amount. If apricot kernels are blended or pulverized, it is suggested that they be consumed immediately