Food Cooked at High Temps May Pose Cancer Risk

A new study suggests high-temperature cooking damages food's DNA, which could ultimately lead to genetic damage when consumed.

According to the National Cancer Institute, animal studies have found links between meat cooked at high temperatures and an increased risk of several types of cancer. Scientists suggest that the health risks from high-temperature cooking likely come from the small molecules produced during the cooking process that interacts with the consumer's healthy DNA.

However, when consuming foods like meat, vegetables, and grains, a person ingests not only protein, fat, and vitamins but also the food's DNA. And not much is known about whether heat damages the DNA in food.

Recently, Stanford University scientists, in collaboration with the National Institute of Standards and Technology (NIST), the University of Maryland, and Colorado State University, decided to investigate whether high-temperature cooking could cause damage to the DNA in food. And if so, could this damaged DNA make its way into the consumer's DNA?

To test their hypothesis, the scientists cooked ground pork, ground beef, and potatoes either by boiling at 212°F for 15 minutes or roasting at 430°F for 20 minutes. They extracted and examined the DNA from the food and found that all the foods showed DNA damage when cooked, especially when cooked at higher temperatures. However, the potatoes exhibited less cooking-related DNA damage than the meat.

Moreover, the DNA damage found was genotoxic — meaning it can impair gene functions and potentially cause mutations that could result in uncontrollable cell replication as observed in cancer.

The team then exposed lab-grown cells to the heat-damaged food DNA and found that the cells took up the DNA, resulting in cellular DNA damage.

Moreover, when the researchers fed mice the DNA-damaged food components, the cells lining the rodent's small intestine also showed DNA damage.

Because the researchers used lab-grown cells and mice in the study, whether foods cooked at high temperatures could impact human DNA is unknown. Nonetheless, their findings indicate the possibility of a previously unrecognized pathway where high-temperature cooking may contribute to genetic risks.

The team plans to conduct future studies looking at different cooking methods and whether long-term low doses of heat-damaged DNA — similar to what humans might consume — might have the same effects as high doses used in this study.

In a Stanford news release, senior author Eric Kool, the George A. and Hilda M. Daubert Professor in Chemistry in the Stanford School of Humanities and Sciences says, "Our study raises a lot of questions about an entirely unexplored, yet possibly substantial chronic health risk from eating foods that are grilled, fried, or otherwise prepared with high heat."

"We have shown that cooking can damage DNA in food, and have discovered that consumption of this DNA may be a source of genetic risk," Kool explains. "Building upon these findings could really change our perceptions of food preparation and food choices."