US researchers say they have found a possible link between red meat consumption and esophageal cancer (esophageal squamous cell carcinoma); there also appears to be a link between DiMelQx intake and cancer in the area of the stomach close to the esophageal opening (gastric cardia cancer). DiMelQx is a compound, a type of heterocyclic amine (HCA) found in red meat after it is cooked at high temperature. They published their findings in the latest issue of the American Journal of Gastroenterology.
The authors explain that we already know that red and processed meats have the potential of increasing cancer risk through several mechanisms involving N-nitroso compounds, polycyclic aromatic hydrocarbons, iron, and heterocyclic amines (HCAs).
The scientists wrote:
Although there have been multiple studies of meat and colorectal cancer, other gastrointestinal malignancies are understudied.
Amanda J. Cross, PhD., from the National Cancer Institute, and team tracked the health of 494,979 Americans aged between 50 and 71 for a period of ten years. At the beginning of the study participants had to complete a questionnaire which included data on their nutritional habits, as well as how they would typically prepare (cook) their meats - how they liked their meat done. The questionnaire also had other details, such as smoking habits, exercise and total bodyweight.
Even though a relatively small proportion of them developed esophagus and stomach cancers - 215 in total, the researchers detected a significantly higher risk among those who consumed lots of red meat, and/or ingested higher quantities of compounds produced when red meat is cooked.
Of the 494,979 people followed, the investigators found that the top fifth who ate the most red meat had a 79% higher risk of developing esophageal squamous cell carcinoma compared to the bottom fifth who ate the least meat. 69 cases of esophageal cancer developed in the top fifth, compared to 28 cases in the bottom fifth.
They also detected a significantly higher risk of gastric cardia cancer among individuals with the highest ingestion of HCA. 113 gastric cardia cancers compared to 57 among the bottom fifth.
After taking into account several factors which could influence their findings, such as age, total bodyweight, smoking habits, and how physically active they were, the authors calculated that the higher meat eaters had a 79% higher risk of developing esophageal squamous cell carcinoma compared to those who ate the least red meat.
This study does not prove that red meat triggers esophageal and/or stomach cancers, the scientists stress. For the moment, they say that their findings add to accumulating evidence of a link. For example, the link they identified which increased gastric cardia cancer was with the intake of DiMelQx rather than the red meat itself.
The scientists were surprised that HCA consumption was not linked to esophageal squamous cell cancer risk, but red intake was. They had presumed before their study that red meat consumption and HCA exposure could not be separated.
In order to determine whether the risk of these two cancers and red meat consumption is real, further large studies are required, the researchers said.
The authors concluded:
We found positive associations between red meat intake and esophageal squamous cell carcinoma, and between DiMeIQx intake and gastric cardia cancer.
"Meat Consumption and Risk of Esophageal and Gastric Cancer in a Large Prospective Study"
Amanda J Cross PhD, Neal D Freedman PhD, Jiansong Ren PhD, Mary H Ward PhD, Albert R Hollenbeck PhD, Arthur Schatzkin MD, DrPH, Rashmi Sinha PhD and Christian C Abnet
Am J Gastroenterol advance online publication 26 October 2010; doi: 10.1038/ajg.2010.415
Written by Christian Nordqvist