About 19 million adults in the U.S. take fish oil supplements. These supplements contain omega-3 fatty acids, mostly EPA and DHA, which are believed to help with chronic diseases.
However, studies on whether they help prevent cancer, especially colon cancer, have shown mixed results.
A new study from the University of Michigan and the University of Texas MD Anderson Cancer Center has found that a gene called ALOX15 is key to making EPA and DHA effective in preventing colon cancer.
This research, published in Cellular and Molecular Gastroenterology and Hepatology, suggests that testing for ALOX15 may be important before recommending EPA and DHA for cancer prevention.
In their study, researchers fed mice diets with and without fish oil and exposed them to substances that cause colon tumors. Surprisingly, the fish oil diet increased the number of tumors in some mice.
EPA and DHA can be broken down into compounds that reduce inflammation, a major cause of cancer. But this breakdown depends on the ALOX15 gene. In many cancers, this gene is turned off.
To test its role, scientists used mice that didn’t have ALOX15. In these mice, fish oil didn’t help prevent cancer. In fact, tumors increased, especially with DHA. EPA still showed some protective effect.
Fish oil supplements come in different forms. One FDA-approved product, Lovaza, contains EPA and DHA as ethyl esters. The study found that Lovaza and similar EPA products reduced tumor growth, but only in mice that had the ALOX15 gene.
In contrast, DHA supplements didn’t help mice without the gene. But when ALOX15 was present, even DHA reduced tumor growth.
This means not all fish oil supplements are equally effective, and whether they help may depend on a person’s genes.
Professor Imad Shureiqi, one of the researchers, stressed that people should talk to their doctors before taking fish oil. His team is now working on new drugs to boost ALOX15 in cancer cells, hoping this will help EPA and DHA prevent colon cancer more effectively.
If you care about gut health, please read studies about how high blood pressure medicine might affect your gut and origin of Parkinson’s disease is in the gut.
For more about gut health, please read studies that your gut can help lower your blood pressure: here’s how and from shock to awe: a zap in the gut could be the new insulin for people with diabetes.
The study is published in Cellular and Molecular Gastroenterology and Hepatology.
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