Ginger root supplement is worth investigating as a potential strategy for colon cancer prevention, according to a phase II study published in the 11 October issue of Cancer Prevention Research. Researchers from the University of Michigan Medical School and colleagues, found that ginger root supplement reduced levels of prostaglandin E2 (PGE2) and other biomarkers of colon inflammation in a select group of patients.

The authors write that studies using drugs that inhibit the enzyme cyclooxygenase (COX) indicate that up-regulation of inflammatory eicasanoids, and in particular prostaglandin E2 (PGE2) are early events in the development of colon cancer.

Eicosanoids are short-lived signalling molecules that act locally on cells nearby. They are not stored in cells but synthesized when required.

There is also evidence that ginger downregulates COX in cultures, and is linked to lower incidence and number of colon polyps in rats.

This phase II study set out to test the effect of a daily dose of ginger supplement on levels of PGE2 and other eicosanoidal biomarkers (13-hydroxy-octadecadienoic acids, and 5-, 12-, and 15-hydroxyeicosatetraenoic acid, HETE) on the colons of 30 healthy human volunteers.

The researchers randomly assigned 30 participants to take either 2.0 g a day of ginger supplement or placebo for 28 days.

Flexible sigmoidoscopy was used to take biopsy colon samples from the participants at the start of the study and then again on day 28.

The researchers then used liquid chromatography mass spectrometry to determine the eicosanoid levels in the biopsies.

They found that when normalized to protein, there were no significant differences between the before and after treatment levels of any of the eicosanoids.

But when they normalized to free arachidonic acid (there is a pathway where eicosanoids are sythesized from arachidonic acid), they found a “significant decrease in the mean percent change in PGE2 (P = 0.05) and 5-HETE (P = 0.04), and a trend toward significant decreases in 12-HETE (P = 0.09) and 15-HETE (P = 0.06)”.

The researchers conclude:

“On the basis of these results, it seems that ginger has the potential to decrease eicosanoid levels, perhaps by inhibiting their synthesis from arachidonic acid.”

“Ginger also seemed to be tolerable and safe,” they add, and call for further investigation in people at high risk for colorectal cancer.

First author Suzanna M. Zick is a naturopathic doctor (ND) and a research assistant professor at the University of Michigan Medical School. She said in a statement that prior studies have shown inflammation to be a precursor to colon cancer but another trial would be needed to see how ginger root might affect the risk.

“We need to apply the same rigor to the sorts of questions about the effect of ginger root that we apply to other clinical trial research,” said Zick:

“Interest in this is only going to increase as people look for ways to prevent cancer that are nontoxic, and improve their quality of life in a cost-effective way.”

The National Cancer Institute and University of Michigan Clinical Research Center and the Kutsche Family Memorial Endowment paid for the study and Pure Encapsulations of Sudbury, Massachusetts donated the ginger extract.

Written by Catharine Paddock PhD