Oh No! Not My Fish Oil.

Chances are, you’ve heard of the wonders of fish oil. Filled with rich omega-3 fatty acids, fish oil supplements are known to ward off Alzheimer’s, boost heart health, and prevent arthritis. But now Dutch researchers found fish oil has another, more sinister, power: It may stop chemotherapy drugs from working.

Randy and I have been taking fish oil for years because of the touted benefits of heart health and lower cholesterol claims, and now I'll have to stop temporarily. News of this new correlation between fish oil and chemotherapy broke just last week.

While investigating why a tumor becomes resistant to Cisplatin—a chemotherapy drug that is used to treat many cancers, including testicular, lung, and colorectal—the researchers discovered that a cancer patient’s own cells can start producing platinum-induced polyunsaturated fatty acids, or PIFAs, that protect cancerous cells.

Chemotherapy interferes with DNA and cell division in tumors to stop tumor growth. But it’s not yet clear how PIFAs block the chemo drugs from working. The PIFAs likely create an additional substance in the patient’s blood that effectively prevents the chemo drugs from attacking tumors.

Turns out, some fish oil supplements contain PIFAs as well. Many cancer patients take these products to reduce their risk of heart attack, help maintain muscle mass, and decrease inflammation. When mice with cancer took these supplements, however, the chemo became ineffective against cancerous cells, reports the study published this week in Cancer Cell. Scientists need to conduct further research to see if all fish oil products contain PIFAs and if these products have the same effect on humans.

Researchers warn that until future studies are done, cancer patients undergoing chemo shouldn’t take these supplements unless they consult with their doctor first. They may be able to get the same heart-protecting omega-3 benefits from the alpha-linolenic acid (ALA) found in flaxseeds, chia seeds, and walnuts. Plus, they can still eat whole fish like salmon and tuna, since they contain substantially less PIFAs—if any PIFAs at all—than concentrated fish oil.

There’s no reason for someone who’s not on chemotherapy to discontinue his or her fish oil supplement regimen. And while, I don't use this specific chemotherapy drug, I'm going to stop using just in case. I'm going through this whole process so the drugs going into my body are actually working. Randy on the other hand will continue with his fish oil...