Approximately 19 million adults across the United States regularly consume fish oil supplements. These supplements are packed with omega-3 fatty acids, primarily eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Individuals often turn to these products expecting benefits such as decreased inflammation and a reduced likelihood of developing chronic illnesses.
A Critical Gene’s Role in Safeguarding Against Colon Cancer
Scientists from the University of Michigan and the University of Texas MD Anderson Cancer Center conducted research to clarify the inconsistent findings surrounding omega-3 supplements and cancer. Their work, featured in the journal Cellular and Molecular Gastroenterology and Hepatology, pinpointed a gene known as 15-lipoxygenase-1, or ALOX15, as a vital element determining whether EPA and DHA can effectively inhibit colorectal cancer progression.
These discoveries highlight the potential value of screening cancer patients for ALOX15 expression when formulating preventive approaches that incorporate omega-3 supplementation.
Unexpected Outcomes Observed in Mouse Experiments
In an effort to investigate the influence of fish oil on tumor formation, researchers compared groups of mice: one group received a diet enriched with fish oil, while the other followed a conventional diet. Surprisingly, the fish oil diet resulted in a higher count of colon tumors among mice that had been exposed to chemical agents promoting inflammation and accelerating tumor development.
Under typical conditions, the body metabolizes ingested EPA and DHA into specialized compounds called resolvins. These substances play a key role in alleviating chronic inflammation, a significant contributor to cancer onset. The transformation into resolvins depends on the enzyme produced by ALOX15. Notably, this enzyme is frequently inactivated in various cancer types.
The study further analyzed the effects in mice genetically deficient in ALOX15 who were administered fish oil. In these cases, the lack of ALOX15 correlated with an elevated incidence of colorectal tumors, though the degree of impact differed based on the specific omega-3 fatty acid involved.
Comparing EPA and DHA Across Various Supplement Formats
Mice provided with EPA-rich diets exhibited fewer tumors compared to those given DHA-rich diets. Both EPA and DHA are offered in multiple formulations, such as free fatty acids, ethyl esters, and triglycerides.
Lovaza, a prescription drug featuring the ethyl ester versions of EPA and DHA, has received approval from the Food and Drug Administration for managing elevated blood triglyceride levels.
Within this research, Lovaza, along with the ethyl ester and free fatty acid versions of EPA, significantly diminished both the quantity and dimensions of tumors, especially in mice expressing functional ALOX15. Conversely, DHA forms failed to curb tumor growth in ALOX15-deficient mice. However, when ALOX15 was active, DHA also contributed to reduced tumor progression.
‘Not every fish oil supplement operates identically,’ explained Imad Shureiqi, a professor of internal medicine at the University of Michigan and an affiliate of the Rogel Cancer Center.
‘It’s equally essential to consider if the individual using the supplement possesses the necessary enzymes to properly convert these compounds, thereby mitigating chronic inflammation and lowering the risk of cancer.’
Implications for Patient Care and Future Directions
While the bulk of the evidence stems from animal models, these results pose significant considerations for human health. They indicate that individuals with colon polyps who lack functional ALOX15 might not derive the full protective effects from EPA and DHA, rendering the supplements less potent in hindering tumor advancement.
Shureiqi recommends that patients consult their healthcare providers prior to initiating fish oil supplementation.
Concurrently, the investigative team is working on pharmaceutical interventions aimed at elevating ALOX15 activity within cancer cells. Their objective is to improve the body’s capacity to utilize EPA and DHA, thereby bolstering strategies for colorectal cancer prevention.
