The controversy surrounding “Vitamin B17,” also known as Amygdalin and Laetrile, involves its promotion as a natural cancer therapy despite a significant lack of supporting scientific evidence. This compound is not a true vitamin. Its highly contested status involves both the theoretical mechanism of action and the very real dangers associated with its consumption, which stem from a specific chemical reaction occurring within the body.
Defining Amygdalin and Laetrile
Amygdalin is a naturally occurring plant compound classified as a cyanogenic glycoside, meaning it contains a cyanide group bound to a sugar molecule. It is found primarily in the seeds or kernels of fruits from the Prunus genus, such as apricots, peaches, cherries, and bitter almonds. This natural form has been used in alternative medicine practices for centuries.
Laetrile is a semi-synthetic derivative of Amygdalin, often purified and prepared for injection, and was historically marketed as “Vitamin B17.” The term “Vitamin B17” is a misnomer, as this compound is not recognized as a vitamin by any major scientific body. Vitamins are substances the body cannot synthesize and must be obtained through diet to prevent deficiency diseases. This designation was a marketing strategy employed by its proponents in the 1950s to circumvent stringent regulatory approval processes for pharmaceutical drugs.
The Mechanism Behind the Cancer Claim
The rationale behind Laetrile’s supposed cancer-fighting ability centers on the release of hydrogen cyanide, a potent toxin, within the body. Proponents claim that the enzyme beta-glucosidase breaks down Amygdalin, releasing the cyanide. The theory posits that this toxic action is selectively targeted toward malignant cells while leaving healthy tissue unharmed.
This selective action is theorized because cancer cells purportedly contain significantly higher concentrations of the beta-glucosidase enzyme than non-cancerous cells. This concentration at the tumor site supposedly causes Amygdalin to break down there, killing the cancer. Healthy cells, conversely, are thought to possess the detoxifying enzyme rhodanese, which quickly neutralizes any released cyanide, protecting the rest of the body.
Regulatory Status and Scientific Evidence
Decades of scientific investigation and regulatory action have addressed whether Amygdalin or Laetrile works as a cancer treatment. Clinical trials have consistently failed to demonstrate any therapeutic benefit for Laetrile in treating or preventing any type of cancer. A major systematic review conducted by the Cochrane Collaboration concluded that the claims of beneficial effects for cancer patients are not supported by any sound clinical data.
A significant investigation into Laetrile’s efficacy was a clinical trial sponsored by the National Cancer Institute (NCI) in the late 1970s. This study found that patients receiving Amygdalin showed no objective tumor responses, with only one out of 175 evaluable patients meeting the criteria for a minimal response. Crucially, the study also documented cases of severe toxicity among the participants, reinforcing the compound’s danger.
Based on the lack of efficacy and documented safety risks, the United States Food and Drug Administration (FDA) has banned the sale and use of Laetrile for cancer treatment. It is not approved for any medical use in the U.S. or most other developed countries, including the European Union. Major health organizations, such as the American Cancer Society, also stand against its use due to the absence of scientific support and the associated risk of harm. The consensus among the medical and scientific community is that Amygdalin and Laetrile offer no therapeutic value against cancer. The continued promotion of this substance occurs outside of regulated medical practice, often in alternative medicine clinics advertising unproven “metabolic therapies.”
Understanding Cyanide Toxicity
The primary and most severe safety concern associated with Amygdalin and Laetrile is the risk of cyanide poisoning. When the compound is metabolized by enzymes in the gut, it releases hydrogen cyanide, a rapidly acting and highly dangerous poison. Cyanide interferes with cellular respiration by inhibiting a mitochondrial enzyme complex, which prevents the body’s cells from utilizing oxygen to produce energy.
Symptoms of acute cyanide poisoning can manifest rapidly:
- Nausea
- Vomiting
- Headache
- Dizziness
- Difficulty breathing
- Abnormally low blood pressure
- Neurological damage, confusion, and difficulty walking
In high doses, cyanide exposure can quickly lead to coma and death. The risk of toxicity is significantly amplified when Amygdalin is consumed orally, such as by eating apricot kernels, compared to intravenous administration. Oral intake interacts directly with digestive tract enzymes, resulting in a much higher release of hydrogen cyanide.