Fish oil supplements have long been touted for their health benefits, especially for chronic diseases. However, a recent study conducted by researchers from the University of Michigan and University of Texas MD Anderson Cancer Center has shed light on the potential limitations of these supplements for certain cancer patients.
The study, published in Cellular and Molecular Gastroenterology and Hepatology, focused on the role of the gene 15-lipoxygenase-1 (ALOX15) in the effectiveness of fish oil supplements containing omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in suppressing colorectal cancer. The researchers found that ALOX15 is essential for the anti-cancer properties of EPA and DHA.
Previous large clinical studies on the association between fish oil supplements and cancer risk have yielded inconsistent results. While some studies have shown a reduction in cancer risk with fish oil supplementation, others have shown no benefit or even an increased cancer incidence.
In the current study, mice were fed diets supplemented with fish oil to observe the effects on colon tumor formation. Surprisingly, fish oil increased the number of colon tumors in mice exposed to inflammatory chemicals, accelerating tumor formation. The breakdown of EPA and DHA into molecules called resolvins, which prevent chronic inflammation, depends on the enzyme ALOX15. This enzyme is typically turned off in various cancers.
The researchers also found that mice lacking ALOX15 responded differently to fish oil supplements compared to control mice. The loss of ALOX15 increased colorectal tumors in mice fed fish oil, with varying results depending on the type of omega-3 acid. EPA diets resulted in fewer tumors compared to DHA diets.
The study highlighted that not all fish oil supplements are the same, and the presence of ALOX15 is crucial for the effectiveness of EPA and DHA in inhibiting tumor growth. The researchers are now working on developing drugs that can increase ALOX15 expression in cancer cells, potentially enhancing the benefits of EPA and DHA supplementation for preventing colon cancer development.
It is important for individuals considering fish oil supplements to consult with their physicians, especially if they have a history of colon polyps or other risk factors for colorectal cancer. The findings of this study suggest that ALOX15 status may play a significant role in the response to EPA and DHA supplementation in cancer prevention.
Overall, this research provides valuable insights into the complex relationship between fish oil supplements, omega-3 fatty acids, and cancer risk. By understanding the role of ALOX15 in mediating the effects of EPA and DHA on colorectal tumorigenesis, future prevention strategies can be tailored to individual patients based on their genetic makeup and enzyme activity levels.
