Celiac.com 02/17/2009 - Texas AgriLife Research scientist Dr. Nancy Turner has recently discovered that a microscopic compound commonly found in plant-based foods reduces inflammation and prevents the formation of cancerous lesions in the colon. The tiny molecule, called quercetin, is easily absorbed when people eat fruits and vegetables, and so requires no specialized supplements or drugs.

Quercetin is a tiny, but powerful compound that is easily absorbed from onions, peppers, tomatoes and most other common produce. According to Turner, nearly all plant-based foods offer "some level of quercetin," including "fun things like wine."

Previous laboratory research has shown quercetin to be effective in reducing rates of colon cancer, but Turner's study is the first to illuminate the mechanism by which quercetin works its magic.

These results offer researchers another line of inquiry into other inflammatory bowel diseases such as Crohn's and celiac disease, as it's quite likely that quercetin can offer some measure of protection against those conditions as well.

According to Turner, the levels of quercetin used in the study are comparable to those "achieved in diets around the world such as...the Mediterranean-style diets." As such, reaching such levels in American diets is "not an unachievable goal," she said.

In the study, Turner's research team observed the responses of rats to quercetin-supplemented diets. Some of the rats were in the early stages of colon cancer formation, while others were cancer-free. In people, as in animal models, early colonic lesions represent some of the very first pre-cancerous changes that can be seen visually. These so called  "aberrant crypts," are thought to mark or predict tumor formation.

Earlier studies have shown quercetin to reduce the number of these crypts, but Turner "wanted to know how it might be protecting."

Cancer is commonly understood as uncontrolled cell growth, but researchers are now realizing that the normal action of cell death, a process called "apoptosis," plays a crucial role in allowing cancer to develop. Healthy bodies generally maintain equilibrium between the generation of new cells and sloughing off cells that have completed their job. Quercetin seems to play a beneficial role in both cases. It decreases the number of cells being generated in the colon [and] increases the number of cells that were undergoing apoptosis. In all, quercetin helps to maintain a normal number of cells.

The research team then turned its attention to the relatively new discovery that inflammation is one of the prime instigators of colon cancer. The team focused on two enzymes, called Cox-1 and Cox-2. Cox-1 is a standard protein that the body usually exhibits. But Cox-2 has a potential role in a number of diseases. Turner explains that Cox-2 is an "inducible protein that is expressed in the body when there is some kind of external stimulus to a cell." Scientists consider high levels of Cox-2 "as being a bad thing."

Research shows that not only are elevated levels of Cox-2 present in colon cancer, but that the Cox-1 levels become elevated before Cox-2 levels rise. According to Turner, it seems that Cox-1 exerts some sort of influence over whether Cox-2 expression.

Both the control groups and the carcinogen-injected groups that consumed dietary quercetin had lower levels of both Cox-1 and Cox-2, suggests that there may be chance for quercetin to prevent tumor growth.

Clearly, further study is needed to better understand the links. But Turner encourages people to consume lots of fruits and vegetables. She points out that, in addition promising benefits for colon cancer, quercetin has demonstrated positive influence in fighting other chronic ailments such as cardiovascular disease.


*Turner's research was funded by the U.S. Department of Agriculture . Source: http://agnews.tamu.edu/showstory.php?id=972

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