HOUSTON—People who eat meat frequently, especially meat that is well done or cooked at high temperatures, may have a higher chance of developing bladder cancer, according to a study at The University of Texas M. D. Anderson Cancer Center. The research, presented at the American Association for Cancer Research 101st Annual Meeting 2010, noted this risk appears to increase in people with certain genetic variants.
"It's well known that meat cooked at high temperatures generates heterocyclic amines (HCAs) that can cause cancer," said study presenter Jie Lin, Ph.D., assistant professor in M. D. Anderson's Department of Epidemiology. "We wanted to find out if meat consumption increases the risk of developing bladder cancer and how genetic differences may play a part."
HCAs are products of interaction between amino acids, which are the foundation of proteins, and the chemical creatine, which is stored in muscles. Past research has identified 17 HCAs that may contribute to cancer.
This study, which took place over 12 years, included 884 M. D. Anderson patients with bladder cancer and 878 people who did not have cancer. They were matched by age, gender and ethnicity.
Using a standardized questionnaire designed by the National Cancer Institute (NCI), researchers gathered information about each participant's dietary habits. They then categorized people into four levels, ranging from lowest to highest red meat intake.
The group with the highest red-meat consumption had almost one-and-a-half times the risk of developing bladder cancer as those who ate little red meat.
Specifically, consumption of beef steaks, pork chops and bacon raised bladder cancer risk significantly. Even chicken and fish - when fried - significantly raised the odds of cancer.
The level of doneness of the meat also had a marked impact. People whose diets included well-done meats were almost twice as likely to develop bladder cancer as those who preferred meats rare.
Further questioning of a subset of 177 people with bladder cancer and 306 people without bladder cancer showed that people with the highest estimated intake of three specific HCAs were more than two-and-a-half times more likely to develop bladder cancer than those with low estimated HCA intake.
To take the investigation a step further, researchers analyzed each participant's DNA to find if it contained genetic variants in the HCA metabolism pathways that may interact with red meat intake to increase the risk of cancer.
People with seven or more unfavorable genotypes as well as high red-meat intake were at almost five times the risk of bladder cancer.