Laetrile: An Unproven Cancer TreatmentEn Español (Spanish Version)
Laetrile is a pure form of the chemical amygdalin. This compound occurs naturally in many fruit pits and nuts. French chemists first identified it in 1830. They found that when amygdalin breaks down, it produces the poison cyanide.
Vitamin B17 is another name for laetrile. But, it is not a vitamin. Some advocates believe cancer results from a vitamin deficiency that laetrile can presumably correct. Opponents think the term was coined to avoid federal drug safety and efficacy requirements.
During the 1800s, doctors tried using amygdalin to treat cancer. It proved too toxic. In the 1950s, a semi-synthetic form, called laetrile, was produced and promoted as a cancer cure. Several theories exist about its anticancer action. In addition to the "vitamin" theory, some supporters believe an enzyme found primarily in cancer cells, but lacking in healthy cells, breaks down amygdalin. The amygdalin is broken down to cyanide, which then kills the cancer.
"Every cancer cell has a prodigious quantity of beta-glucosidase, or the unlocking enzyme," says G. Edward Griffin, who maintains that laetrile works. He wrote
World Without Cancer: The Story of Vitamin B17
. He adds, "It's a beautiful mechanism of nature that couldn't have been accidental."
None of these theories has held up well under scientific scrutiny.
Laetrile gained notoriety during the 1970s, a time when doctors had fewer effective cancer treatments in their arsenal. Chemotherapy
side effects were hard to control. Patients began looking for other options. Approximately 75,000 Americans had tried laetrile by 1978. That year, the National Cancer Institute (NCI) reviewed 93 cases submitted by doctors touting laetrile's benefits. Out of those 93 cases, only 6 actually showed benefits of tumor shrinkage.
The NCI then sponsored research to evaluate laetrile. Two of the six patients in the first study died of cyanide poisoning after eating almonds. During the second study, patients received an infusion of amygdalin, followed by laetrile pills. Some patients reported feeling better while taking the drug. But cancer progressed in all 175 patients by the end of treatment. The NCI concluded that laetrile did not have any effect on treating cancer.
The US Food and Drug Administration (FDA) has not approved the use of laetrile and has taken action against US companies to halt Internet laetrile sales. It is illegal to bring the drug into the country for personal use.
"This product has not been found to be safe and effective, so they're in violation of US drug laws," says FDA spokesperson Susan Cruzan of companies that try to sell laetrile.
Adverse reactions to laetrile are similar to those that occur with cyanide poisoning. Eating raw almonds or some fruits and vegetables when taking laetrile can increase the risk of having adverse reactions, which may include:
- Nausea and vomiting
- Bluish skin color
- Liver damage
- Droopy eyelids
- Trouble walking
Some patients have died from laetrile treatment.
Many cancer patients want to try alternative therapies. Talk with your doctor if you are considering laetrile or other therapies. Herbal remedies can interfere with drugs ordered by your doctor.
"Some people choose to go the alternative route. Other people do both," Dr. Brown concludes. "Openly discuss with your doctor the value or lack thereof of these treatments. Do not be afraid to tell us."
Food and Drug Administration
National Cancer Institute
General information: laetrile/amygdalin. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/pdq/cam/laetrile/HealthProfessional/page2. Accessed September 19, 2011.
Griffin E. World Without Cancer: The Story of Vitamin B17. Westlake Village, CA; 1997.
Laetrile. American Cancer Society website. Available at:http://www.cancer.org/docroot/ETO/content/ETO_5_3x_Laetrile.asp. Accessed September 19, 2011.
Questions and answers about laetrile/amygdalin. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/pdq/cam/laetrile/HealthProfessional/page2. Accessed September 19, 2011.
Last Reviewed September 2011