According to a study by the Netherlands Cancer Institute, fish and fish oil may decrease the effectiveness of chemotherapy by half, New York Daily News reported.
Researchers found that the fatty acids found in particular fish and fish oil supplements halted the cancer-fighting properties of drugs in mice suffering from tumors. Diets rich in oily fish, such as sardines, mackerel and salmon, offer protection against dementia, vision loss, prostate cancer and cardiovascular disease. In addition, these fish contain good amonts of omega-3 fatty acids, selenium, B vitamins and vitamin
Dutch researchers analyzed exposure to the fatty acid 16:4(n-3) after taking fish oil supplements or consuming fish. Experiments in mice have indicated that the fatty acid 16:4(n-3) makes cancer cells immune to chemotherapy, according to Cancer Therapy Advisor.
The study analyzed the rate of fish oil consumption among people undergoing cancer therapy. Researchers measured fatty acid blood levels after healthy participants consumed fish and fish oils.
Thirty percent of cancer patients out of 118 used supplements on a regular basis and 11 per cent of cancer patients used supplements containing omega-3 fatty acids.
The research team found elevated blood levels of the fatty acid 16:4(n-3) in healthy volunteers after they administered the recommended daily amount of 10 ml of fish oil in volunteers.
Moreover, consuming 100 grams of mackerel and herring increased blood levels of the fatty acid 16:4(n-3) compared with salmon and tuna.
Researchers said that people who are undergoing chemotherapy should not take fish oil supplements or eat oily fish in the day before and after treatment.