Fish Oil Likely Doesn’t Reduce Cancer Risk — But It’s Still Good for You, Since It Reduces Risk of Heart Disease

By Lindsey Tanner Associated Press

CHICAGO – Fish oil, seen as beneficial for reducing heart disease risks, probably doesn’t help prevent cancer, a review of studies involving more than 700,000 patients shows.

Researchers examined data from 38 studies that tracked patients for up to 30 years, and said most showed no cancer protection from omega-3 fatty acids. A few studies found some risk reduction for breast, prostate and lung cancer, but those studies were small and not definitive, said Dr. Catherine MacLean, lead author .

“It doesn’t mean that omega-3 fatty acids don’t have other health benefits – it’s just that reducing cancer risk isn’t one of them,” MacLean said.

The review is unlikely to be the last word. Diet plays a role in cancer, and researchers evaluated observational studies, which give mostly circumstantial evidence.

The reviewed studies examined the effects of fish oil – in both pill form and as food – on 11 kinds of cancer .

The 38 studies involve too many different population groups and levels of fish oil consumption to give a definitive answer about whether fish oil cuts cancer risks, said Julie Buring, a researcher at Harvard’s Brigham and Women’s Hospital not involved in the study.

The study appears in today’s Journal of the American Medical Association.

Omega-3 fatty acids are plentiful in darker, oily fish including salmon, sardines and mackerel. They are mostly thought to help prevent heart disease, not cancer, and American Heart Association guidelines recommend at least two servings of fish per week to help prevent heart disease.

Some animal studies have suggested fish oil might also reduce cancer risks.

The American Cancer Society recommends fish as a source of protein partly because it doesn’t contain high amounts of saturated fats that are in red meat and which some scientists think might increase risks for prostate and colon cancer.