Written by Dr. Adam McLeod
On a daily basis I will hear from patients who have been encouraged by someone to try apricot seeds to treat their cancer. When writing this article I made a deliberate attempt to approach this subject with an open mind. The more that I researched this therapy the more that it solidified the undeniable conclusion that not only is this approach completely unsupported by evidence and it also has the potential to be dangerous.
I consider myself to be a very open minded Naturopathic physician and my clinical practice is completely focused on integrative oncology. Prior to becoming a Naturopathic doctor I obtained a degree in Molecular Biology and Biochemistry which gave me a firm understanding of the molecular pathways that influence our health. I have also had incredible experiences with energy healing which have profoundly influenced my perspective on life. As a result of these experiences I feel comfortable discussing a wide range of therapies with my patients and giving them a balanced perspective.
Since the Truth about Cancer was aired it seems that patients have been left with an inaccurate and polarized view of cancer care. This series aims to scare patients away from all conventional cancer treatments which is not only dangerous it is simply untrue. Not all cancers are the same, not all drugs are the same. Some cancers are very treatable with conventional care and often an integrative approach is the most effective plan rather than choosing one extreme or the other. Oddly enough, one of the therapies that is routinely emphasized in this series and on other alternative cancer websites is apricot seeds.
One of the reasons that I find it so perplexing that this therapy is the focus of such a popular series is that there are virtually no Naturopathic physicians experienced with cancer who use this approach. I regularly attend integrative oncology conferences around North America and I have literally never heard of any of my colleagues using this as a core therapy. There are still some clinics in Mexico that promote this therapy but it has been widely debunked as an ineffective cancer treatment4,2.
To understand why this is not a recommended cancer therapy we need to look at the proposed mechanism of action of this therapy. Laetrile (often referred to as Vitamin B17 even though it is not a Vitamin) is a man made form of a natural substance amygdalin which is found in apricots. Since Laetrile declined in popularity many people have consequently turned their attention to consuming apricot seeds. The proposed mechanism of action is that “healthy cells” contain the enzyme rhodanese which neutralizes benzaldahyde and hydrogen cyanide in B17. It converts them to “useful nutrient compounds” thyiocyanate and benzoic acid. Glucose delivers B17 to the cancer cells, but cancer cells do not have rhodanese to neutralize the cyanide. Instead, they have an enzyme called β-Glucosidase. This enzyme, found only in cancer cells, releases the benzaldahyde and cyanide from the glucose and each other to create a targeted poison that kills the cancer cell.
There are a number of serious problems with this theory. First of all rhodanese is present in cancer cells as it is a mitochondrial enzyme. Although cancer cells may be less dependent on their mitochondria for energy they certainly still have mitochondria which carry out many critical reactions for the cancer cells1. The second major assumption is that cancer cells have significant expression of β-Glucosidase to release the cyanide within cancer cells. The β-Glucosidase enzyme is present in small amounts in all cells in a small oraganelle known as lysosomes. It is also expressed in higher levels in the liver to help break down various sugars. β-Glucosidase is certainly not an enzyme that is unique to cancer. Even if this was an enzyme “unique to cancer”, every cancer is different in every individual and they all have unique genetic expression patterns. For example, if you gathered a dozen patients with the same type of cancer such as colon cancer and if you did a genetic analysis on the cancer you would find that there are significant variations between each person. There are even variations between different cells within the same tumour of one patient! These genetic variations are what makes the battle against cancer so complicated.
Here is the conclusion from an article in the prestigious journal Cancer about Laetrile:
“The evidence for the claims that laetrile (amygdalin) can prevent or control cancers has been reviewed. The beta-glucosidase content of cancer tissues is low compared to that of normal liver and small intestine. Cancer tissues contain the enzyme rhodanese in amounts comparable to that of liver and kidney and hence, cannot be attacked selectively by cyanide release through beta-glucosidase action on amygdalin…The claims for cure and control of cancers in humans have been refuted by distinguished physicians who specialize in the treatment of cancer patients. The writings of laetrile proponents are filled with erroneous and absurd statements. The propaganda for the doctrine of “freedom of choice in cancer treatment” deludes many individuals with treatable cancer to reject proven methods of treatment.”2
There are several case studies that describe serious toxicity concerns with consuming large amounts of amygdalin or Laetrile3. (Note: Technically Laetrile, Amygdalin and B17 are often used interchangeably but they are technically different compounds. The proposed mechanism of action however is the same5). Just because something is considered natural, that does not mean that it is safe.
Cancer patients need professional guidance from a Naturopathic doctor experienced with oncology. If you are battling cancer or if you of someone who is battling cancer and they are using therapies such as Laetrile without professional guidance then please take the time to find a Naturopathic physician with a special focus in oncology. There are many natural therapies that are not only safe, they are effective when it comes to the fight against cancer. Do not waste your precious time and money focusing on “alternative therapies” which are not even indicated for your cancer type. The integrative oncology approaches used by any Naturopathic doctor skilled with cancer have significant scientific evidence to support their use.
Dr. Adam McLeod is a Naturopathic Doctor (ND), BSc. (Hon) Molecular biology, Motivational Speaker and International Best Selling Author. He currently practices at a clinic in Vancouver, British Columbia where he focuses on integrative oncology. http://www.yaletownnaturopathic.com
1) Rossignol, Rodrigue, et al. “Energy substrate modulates mitochondrial structure and oxidative capacity in cancer cells.” Cancer research 64.3 (2004): 985-993.
2) Greenberg, David M. “The case against laetrile: the fraudulent cancer remedy.” Cancer 45.4 (1980): 799-807.
3) Smith, Frederick P., et al. “Laetrile toxicity: a report of two cases.” JAMA 238.13 (1977): 1361-1361.
4) Milazzo, Stefania, Stephane Lejeune, and Edzard Ernst. “Laetrile for cancer: a systematic review of the clinical evidence.” Supportive care in cancer 15.6 (2007): 583-595.
5) Complementary, PDQ Cancer, and Alternative Medicine Editorial Board. “Laetrile/Amygdalin (PDQ®).” (2015).