Eating Fish May Reduce Colorectal Cancer Risk

A new study suggests that eating fish may reduce the risk for colorectal cancer.

Colon cancer is cancer of the large intestine (colon), which is the lower part of the digestive system. Rectal cancer occurs on the last eight to ten inches of the colon. They are often referred to together as colorectal cancers and are a leading cause of cancer-related deaths in the United States.

In the colon and rectum, the exaggerated growth of cells may cause precancerous polyps (adenomas or adenomatous polyps), which form in the lining of the intestine. Over a period of time some of these polyps may become cancerous. In the later stages of the disease, these cancerous polyps may penetrate the colon walls and metastasize (spread) to nearby lymph nodes and other organs.

In a new study, researchers conducted a comprehensive literature search for studies evaluating the relationship between fish consumption and colorectal, colon or rectal cancer risk. Forty-one studies were ultimately identified for inclusion.

Through analyses of the study results, the researchers found that eating fish reduced the risk of colorectal cancer by 12 percent. The highest reported fish consumption was linked to a 17 percent decreased risk, while the lowest reported fish consumption was linked to a seven percent decreased risk.

The authors concluded that eating fish may reduce the risk of colorectal cancer; however, further research is necessary before firm conclusions can be made.

Fish is a dietary source of both docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). There is supportive evidence from multiple studies that suggests the intake of recommended amounts of DHA and EPA in the form of dietary fish or fish oil supplements lowers triglycerides; reduces the risk of death, heart attack, dangerous abnormal heart rhythms and strokes in people with known cardiovascular disease; slows the buildup of atherosclerotic plaques ("hardening of the arteries") and lowers blood pressure slightly. Several previous population studies have also reported that dietary omega-3 fatty acids or fish oil may reduce the risk of developing breast, colon or prostate cancer. Additional research is needed in this area.

For more information about fish oil, please visit Natural Standard's Foods, Herbs & Supplements Database.

For more information about integrative therapies for colorectal cancer, please visit Natural Standard's Comparative Effectiveness Database.

 

Comments

[MS]

The study mentions that the decrease in risk of rectal cancer was more significant while colorectal cancer was modest. The type of fish and how often it was consumed are important factors to take into consideration. Comparing just omega-3 supplement consumption to fresh fish consumption, which is more effective in reducing cancer risk?

[nb]

I had a family friend who passed away from colon cancer, and the disease was very difficult to manage and painful. I am concerned with consuming a lot of fish though, due to high mercury levels in many types of fish. It would be good to know, as KD mentioned, which types would decrease colorectal cancer risk and low in mercury.

[AB]

Although there are many benefits to eating fish there are also some precautions to be taken into account, such as fish that might contain high levels of mercury and other environmental contaminants. This is seen mostly in large, predatory fish. This article from the American Heart Association gives a brief introduction to Omega-3 Fatty Acids in fish..

http://www.heart.org/HEARTORG/General/Fish-and-Omega-3-Fatty-Acids_UCM_303248_Article.jsp

[JK]

It seems that the benefits of fish are overwhelming. The American Heart Association recommends eating fish at least 2 times per week. I believe people are starting to learn to stay away from red meats and start trying to incorporate fish into their daily diets. When I was working at a children's psychiatry hospital many of the child had Attention Deficit Hyperactivity Disorder. It seems that many doctors are recommending that their patients take fish oil supplements to improve concentration and mood.

[LL]

Always great to hear that a simple lifestyle change could cut your risk of cancer- its not hard at all to increase the amount of fish you consume, or if you just hate seafood, its also simple to incorporate a fish oil supplement into your daily routine. Always remember too, though, to schedule your colonoscopy when you hit 50 years old to screen for colon cancer and other problems!

[EM]

I agree with KD. It seems like there was a lot of heterogeneity in the studies in this analysis, especially regarding the fish, so it would be interesting to see the results stratified based on fish type. Great news regardless!

[Tim Cober]

That's a great point KD, I wonder if certain fish are superior to others when it comes to health benefits? And I bet the style of preparation is important too...grilled must be healthier for you than fried.

[SM]

Its always great when a simple lifestyle change could help to lower our risk for disease. Looking through Natural Standard's database, I was amazed to see how many indications were associated with omega-3 fatty acids. Many had an evidence grade of A as well, so a good deal of strong evidence has shown how beneficial omega-3 fatty acids are in disease states from hypertension to rheumatoid arthritis.

[Scooby]

a. The increase in prevalence of colorectal cancer can be attributed to a number of things, some of which could possibly include a person’s diet, others could be that more and more people are getting screenings done. Even with the increased amount of screenings, the possibility of a progression from a polyp to a cancerous mass can still arise before a screening is performed; therefore, having dietary options as preventative measures are valuable. Researchers have shown that diets rich in vegetables and fiber have reduced the risk of developing colorectal cancer. Adding fish just broadens the preventive care so that people can further optimize their health. However, with increased consumption of fish, this would create the question of should people then be cautious of how much fish to consume due to its mercury content? The FDA has guidelines on fish consumption because of its mercury content, so people would have to take this into consideration.

[CC]

It is great to hear that Fish Oil supplements would work just as effectively as consuming fish as it’s something I could recommend to my patients who have a family history of colon cancer. I live in a rural part of the country with limited access to fresh seafood; most of the people in the area don’t eat seafood. I will definitely do further research on the Mediterranean diet and Fish Oil supplements on the Natural Standard database.

[Carrie]

It is interesting to me that the risk for colorectal cancer seems to be very dependent on diet. While it would be difficult to do, I would be intrigued by a study that looked at the comparison of high fiber diets to diets with high amounts of fish. I wonder which diet would actually be more beneficial overall.

[DM]

In response to KD’s comment, I do think the type of fish is important in helping to reduce colorectal cancer. Since reducing the risk of colorectal cancer is linked to omega-3 fatty acids, it is important to eat fish that have high EPA and DHA content. Some fish that have the highest omega-3 levels are tuna, mackerel and rainbow trout.

[MN]

I believe it's the omega-3 fatty acids (EPA and DHA) that helps reduce the risk of colorectal cancer. Fish high in omega-3 fatty acids include anchovy, black cod, bluefish, halibut, kipper, mackerel, menhaden, mullet, herring, pilchard, sable fish, salmon, sardine, seal blubber, sturgeon, trout, and tuna. This is a great excuse to go out and eat more sushi!

[MW]

It is nice to hear positive news about cancer instead of all the negative news. Fish has long been under looked in it's ability to prevent certain diseases. It's common knowledge now that fish contains omega-3's which help prevent heart disease, hopefully information like this becomes common knowledge and we see an increase in fish consumption. If you are new to eating fish or want to try some new recipes the Natural Standard is doing a really nice job compiling recipes. Check it out they've been updating it all the time with new tasty recipes.

[DM]

It is great to hear about new alternative and natural ways to prevent cancer. Since different types of cancer are being linked more and more to lifestyle habits, it is great to hear about ways to cut cancer risk with diet. I wonder how eating fish compares to eating a high fiber diet in reducing colorectal cancer risk. I also wonder how fish oil compares to certain high risk populations who take a low-dose aspirin to help reduce the risk of colorectal cancer. Hopefully some studies will come out that can directly compare the effects of these therapies.

[Charles]

This is good news - colorectal cancer is one of the leading causes of cancer-related deaths in the US (National Library of Medicine). Natural Standard has some great recipes for fish so it won't be hard to incorporate these beneficial nutrients into your diet.

[JR]

It sounds like I should really increase the amount of fish in my diet! The more information I read about eating fish, the more health benefits I discover.

[EM]

I wonder if we'll see more people taking part in the Mediterranean diet after the recent research on omega-3 fatty acids. The Mediterranean diet is rich in heart-healthy fiber and nutrients including omega-3 fatty acids and antioxidants, and seems to be associated with health benefits. More information is available on Natural Standard's diet database.

[KD]

These results are very interesting and emphasize the importance of fish in a healthy diet. However I would like to know which type of fish reduces the risk of colorectal cancer more than other types of fish. Or if they type of fish has no bearing on the health benefits.