The Risks of Eating Well-done Meat

The study involves mice, which are often used to test whether substances in food are harmful to humans. Norwegian researchers adopted a mouse type where human enzymes have been inserted to examine whether people may be more sensitive to certain carcinogenic substances from heat-treated foods. “Carcinogenic,” of course, means “cancer-causing.” Through this better mouse model, they may better assess negative health effects in humans from substances in food.

The key results were this: intestinal tumors increased to 80% from 31% in the mice that ate substances from meat “crust.” The crust refers to the surface of the meat formed while being cooked.

Now, when certain foods are cooked, it can lead to the formation of carcinogenic substances. These “food mutagens” usually occur at high temperatures when frying or grilling.

There are enzymes called “sulfotransferases” (SULT) in the human body. These are only found in the livers of normal laboratory mice. SULT-enzymes can make some substances in food less harmful, but they can also transform harmless substances into carcinogenic substances.

In the new study, researchers made the extra step and used mice with the same amount of SULT-enzymes in the intestines as humans would have. The mice received the food mutagen often found in highest quantities in the crust of meat and fish. The researchers wanted to study tumor development in the intestines of the “human-like” mice, and compare this with tumor development in normal mice given the same food mutagen.

It is there they discovered the rate of cancer in the intestinal tract rose to 80% from 31%. This, because of meat crust. While we have a long way to go before these results can be applied to humans, it is another reason why limiting the amount of red meat you consume each week is a positive step for a healthy lifestyle.