Cancer Gene Dances With Coffee and Tea

Cancer linked gene p53 activated in presence of certain foods and flavorings

(RxWiki News) Is anything safe? We’ve been told that grilled meats contain cancer-causing chemicals. So do some plastic food containers. Scientists have now found some flavorings may be harmful.

A recent laboratory study found black and green teas, coffee and liquid smoke flavoring activated higher levels of a well-known gene called p53.

This gene activates only when there’s been some DNA damage.

"Eat fresh vegetables and fruits."

Lead investigator, Scott Kern, MD, the Kovler Professor of Oncology and Pathology at the Johns Hopkins University School of Medicine, said the study isn’t suggesting that people stop drinking tea or coffee or using flavorings.

“We don't know much about the foods we eat and how they affect cells in our bodies," Dr. Kern said in a statement. "But it's clear that plants contain many compounds that are meant to deter humans and animals from eating them, like cellulose in stems and bitter-tasting tannins in leaves and beans we use to make teas and coffees, and their impact needs to be assessed."

The Johns Hopkins researchers mixed different food products and flavorings with human cells and grew them in the laboratory for 18 hours. 

In these experiments, liquid smoke, which gives foods a smoky flavor, along with coffee and green and black teas, produced a nearly 30-fold increase in p53 activity.

That kind of activity is the same as what’s caused by the chemotherapy agent etoposide (brand names – Etopophos and Toposar). Chemotherapy works by damaging the DNA of cancer cells.

Delving deeper, postdoctoral fellow Zulfiquer Hossain identified two chemicals - pyrogallol and gallic acid – that are thought to be responsible for the uptick in p53.

Both chemicals are found in teas and coffee. Pyrogallol, which is commonly seen in smoked foods, is also in cigarette smoke, hair dye, tea, coffee, bread crust, roasted malt and cocoa powder.

Previous animal studies showed liquid smoke, which is a distilled version of natural smoke, caused DNA damage in animal models.

Tests on other flavorings - fish and oyster sauces, tabasco, soy and black bean sauces – had only minimal impact on p53 activity. Soybean paste, kim chee, wasabi powder, hickory smoke powders and smoked paprika didn’t excite p53 much either.

Dr. Kern says more study is needed to hone in on the exact nature of DNA damage that pyrogallol and gallic acid cause. He added that these chemicals might be able to be removed from foods and flavorings.

This study was published recently in the journal Food and Chemical Toxicology.

This work was supported by the National Institutes of Health and the Everett and Marjorie Kovler Professorship in Pancreas Cancer Research.  No author declared potential conflicts of interest.

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Review Date: 
March 29, 2013