Eating fish regularly may reduce colorectal cancer risk

May 24, 2012 in Cancer Prevention, Nutrition Topics in the News

Eating fish regularly may reduce colorectal cancer risk
The advice to eat fish, especially fatty fish like salmon and trout, is based on evidence that doing so can help prevent heart disease.

Now, it seems there's another reason to make fish a regular part of your diet.  According to an analysis of international studies, people who eat fish often have a lower risk of colorectal cancer.

For the study, researchers pooled the results from 41 studies that measured fish intake and tracked cancer diagnoses.  Studies included were from Canada, United States, United Kingdom, Australia, Italy, Japan, China, Norway, Finland, Sweden and The Netherlands.

Overall, people who ate fish regularly were 12 percent less likely to be diagnosed with colon or rectal cancer even after accounting for family history, body weight, physical activity, smoking, alcohol use and other dietary factors.

The protective effect of fish was stronger for rectal cancer. Compared to participants who ate consumed the least fish, those who ate the most had a 21 percent lower risk of rectal cancer.

Whether the beneficial effects of fish have to do with omega-3 fatty acids or other nutrients found in fish is unclear.   However, omega-3 fats have been demonstrated to reduce the size and number of colorectal cancer cells in experimental studies.  

Omega-3 fats might also reduce the formation of colon polyps through their anti-inflammatory actions.  In a study published earlier this year, women who ate three servings (3.5 ounces each) of fish per week - versus less than half a serving - were one-third as likely to develop colorectal adenomas.  (Adenomas in the colon are polyps that have the potential to become cancerous.)

It's also possible that a diet plentiful in fish is one that's low in red and processed meat, two dietary factors known to increase colorectal cancer risk.

How much fish should you eat to lower the risk of colorectal cancer? Based on the current analysis, it's impossible to say since the ranges of fish intake for low and high consumers varied considerably across studies.  However, it's likely prudent to include at least two servings per week.  

Fish that offer the most omega-3 fatty acids include salmon, herring, mackerel, trout, sardines, and anchovies.  Whether a daily fish oil supplement offers the same benefit remains unclear.

All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.