Do Lemons Prevent Cancer?

Caroline Novas

A widely circulating e-mail claiming to be from the Institute of Health Sciences (or the Health Sciences Institute) in Baltimore states that lemons are a “proven remedy against cancers of all types” and that lemons are 10,000 times stronger than chemotherapy.  The e-mail also says that pharmaceutical companies have kept the truth from us because lemons are much less expensive than the less effective synthetic versions that companies can sell for a large profit.

Although there is an “Institute of Health Sciences” in Baltimore that is “dedicated to uncovering and researching most urgent advances in modern underground medicine,” the Institute’s web site has no article about the cancer-fighting properties of lemons. It does, however, contain numerous articles promoting unproven alternative medicines and treatments. Most certainly, is not a credible scientific or medical source.

Regardless of the source, the claims the e-mail makes are NOT correct. Lemons are not a “proven remedy against cancers of all types,” and no studies have ever been done that would compare the effectiveness of a lemon to chemotherapy.

A few studies indicate that lemons and other citrus fruits have naturally occurring substances that may have cancer fighting properties, namely modified citrus pectin and limonoids.  These properties have not been tested in humans.

Modified Citrus Pectin (MCP)

Modified citrus pectin is a carbohydrate found in the peels of citrus fruits modified to be absorbed into the intestinal tract for easier human consumption. In its natural state, pectin is an indigestible dietary fiber.  Animal studies have found that MCP can inhibit the spread of prostate, breast, and skin cancer to other organs. MCP makes it difficult for cancer cells to break off and spread, although it has no impact on the initial tumor.

However, there is almost no information about whether MCP is effective in humans.  One study that measured prostate cancer in humans treated with MCP after standard treatment failed, showed a slowing in the progression of the disease, as measured by doubling time for prostate specific antigen (PSA). The longer the doubling time for PSA in patients with prostate cancer, the better their prognosis is expected to be. Patients taking MCP for 12 months showed a statistically significant increase in prostate specific antigen doubling time (PSADT), when compared to the 12 month period before they began taking MCP.  Unfortunately, the study used no control group (men that did not take MCP after standard treatment failed) and therefore could not compare the survival rates of men who took MCP after standard treatment failed, with those who did not.

Limonoids

Limonoids are chemicals found in citrus peels that are responsible for lemons’ bitter taste. Research has found that at very high levels, limonoids are capable of slowing cancer cell growth and inducing apoptosis (cell death). However, studies have focused on animals and in vitro human breast cancer cultures (breast cancer cells removed from the human body and studied in a laboratory). As a result, there is little information about limonoids’ effectiveness in preventing or combating cancer in humans.

The Bottom Line

Although lemons have health benefits, the claims that “lemons are a proven remedy against cancer of all types” and “lemons are 10,000 times stronger than chemotherapy” are certainly false.  Furthermore, while a few studies have looked into the anti-carcinogenic properties of modified citrus pectin and limonoids and found some promising results, not enough research has been done to prove its effects on humans. It’s possible that in the future, after more research, a medicine will be developed to prevent or fight cancer using these ingredients; if so, it will probably be in much higher concentrations than found in nature

MCP and limonoids are not unique to lemons; they are found in all citrus fruits, which have many known health benefits and should be part of any healthy diet.

References:


The Health Sciences Institute. http://hsionline.com/

Glinksy Vladislav and Avraham Raz. (2009). Modified citrus pectin anti-metastatic properties: one bullet, multiple targets. Carbohydrates Research. 28;344(14):1788-91

BW Guess et. al (2003). Modified citrus pectin (MCP) increases the prostate-specific antigen doubling time in men with prostate cancer: phase ll pilot study. Prostate Cancer and Prostatic Diseases. 6, 301-304

Polouse SM, Harries ED, and Patil BS. (2005) Citrus limonoids induce apoptosis in human neuroblastoma cells and have radical scavenging activity.  Journal of Nutrition. 135(4): 870-7