“People who rarely eat fish may experience health benefits in a variety of areas – heart disease, reproductive and now colon cancer – by increasing their fish consumption somewhat,” Dr Michael Gochfeld, a professor of environmental and occupational medicine at University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School said in a Reuters Health report.

For the report, researchers pooled data from 41 studies from the US, Norway, Japan, Finland and elsewhere, published between 1990 and 2011, that measured fish consumption and tracked cancer diagnoses.

Overall, regularly eating fish was tied to a 12% lower risk of developing or dying of colon or rectal cancer. The protective effect tied to fish consumption was stronger for rectal cancer than colon cancer.

People who ate the highest amounts of fish had a 21% lower risk of rectal cancer than those who ate the least. That compared to just a 4% lower risk of colon cancer, which was not statistically significant.

Food preparation

“Cooking temperatures might affect the risk of colorectal cancer,” said Dr Jie Liang of Xijing Hospital of Digestive Diseases in Xi’an, China, who worked on the study. Dr Liang cited recent evidence that suggests eating lots of meat and fish barbecued or grilled over high heat may actually be tied to an increased cancer risk.

Dr Liang’s team did not investigate why eating fish may have a positive effect on colorectal cancer risk. The study also can’t prove that it’s the fish, itself, that was responsible for a lower cancer risk in some participants.

“It doesn’t tell us whether the benefit you get from fish has to do with specific nutrients in the fish, or with the fact that people who tend to eat fish tend to adopt other healthful lifestyles, such as avoiding red meat or processed meats,” said Dr Gochfeld, who was not involved in the research.

If fish indeed is behind the lower colorectal cancer risk, the added benefit could be coming from the omega-3 essential fatty acids found in certain fish such as salmon and sardines, Dr Gochfeld said.

Source: Reuters Health