Fish oil supplements 'should not be used' by those on chemo

By Martin Leggett - 12 Sep 2011 16:1:0 GMT
Fish oil supplements 'should not be used' by those on chemo

One of the food supplements that often tops the list of those seeking to reduce cancer risk - fish oils rich in omega-3,6 fatty acids - may have a dangerous blocking-property, for those undergoing chemotherapy treatment for cancer. The flip-side of fish oil supplements, which are commonly touted as vital to good all-round health, was exposed in a study by the University Medical Center Utrecht, which is published in journal Cancer Cell today.

Health benefits remain

The fatty acids, omega-3 and omega-6, are found in high amounts in predatory fish like swordfish, salmon, mackerel and sharks. They gain them from eating smaller prey fish, who themselves feast on tiny algae that contain these fatty-acids - such oils appear to be passed up the food chain, rather than being broken down. As well as being linked to helping prevent cancer, and to slowing the spread of breast, colon and prostate cancer, these oils are also thought to improve heart health.

That has led to many people suffering from cancer using fish-oil supplements labeled as containing omega-3 or omega-6 - or similar products from algal sources - to help them in their struggle against cancer. But whilst the health-giving benefits of omega fatty acids are not cast into doubt by this new study, the researchers are recommending that those under-going chemotherapy should not take omega-oil enriched supplements, during chemo treatment.

Widely-used chemo halted in its tracks

That recommendation was reached following careful testing of both mice and tumorous human cells. After exposing mice first to fatty acids, and then to a widely used cancer treatment - called cisplatin chemotherapy - the researchers noted that the tumors failed to shrink, as would normally be expected. Cisplatin chemotherapy is one of the most widely-used treatments for cancer, particularly for cancer of the lungs and ovaries.

The team found that the human cells exposed to chemotherapy produced these same fatty acids, in their experiments. It has also been noted that stem-cells in the blood of patients suffering from cancer, who have developed a resistance to chemotherapy, have produced fatty acids. The team thinks the evidence is stacking up for the role omega-3 plays for those suffering from chemotherapy resistance.

Hold back on the fish oil

Team-lead, Professor Emile Voest, said that previous ideas about resistance to chemotherapy looked to the cancer cells for a cause. "Where resistance to chemotherapy is concerned, we usually believe that changes in the cancer cells themselves have occurred." This research may change that outlook.

"Now we show that the body itself secretes protective substances into the blood that are powerful enough to block the effect of chemotherapy. These substances can be found in some types of fish oil. Whilst waiting for the results of further research, we currently recommend that these products should not be used whilst people are undergoing chemotherapy."

Top Image Credit: Omega 3 fish oil capsules © Flynt