In a laboratory study pairing food chemistry and cancer biology, scientists at the Johns Hopkins Kimmel Cancer Center tested the potentially harmful effect of foods and flavorings on the DNA of cells. They found that liquid smoke flavoring, black and green teas and coffee activated the highest levels of a well-known, cancer-linked gene called p53.
The p53 gene becomes activated when DNA is damaged. Its gene product makes repair proteins that mend DNA. The higher the level of DNA damage, the more p53 becomes activated.
"We don't know much about the foods we eat and how they affect cells in our bodies," says Scott Kern, M.D., the Kovler Professor of Oncology and Pathology at the Johns Hopkins University School of Medicine. "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."
Kern cautioned that his studies do not suggest people should stop using tea, coffee or flavorings, but do suggest the need for further research.
The Johns Hopkins study began a year ago when graduate student Samuel Gilbert, working in Kern's laboratory, noted that a test Kern had developed to detect p53 activity had never been used to identify DNA-damaging substances in food.
For the study, published online February 8 in Food and Chemical Toxicology, Kern and his team sought advice from scientists at the U.S. Department of Agriculture about food products and flavorings. "To do this study well, we had to think like food chemists to extract chemicals from food and dilute food products to levels that occur in a normal diet," he says.
Using Kern's test for p53 activity, which makes a fluorescent compound that "glows" when p53 is activated, the scientists mixed dilutions of the food products and flavorings with human cells and grew them in
|Contact: Vanessa Wasta|
Johns Hopkins Medicine