Docs and nutritionists tout fatty acids found in fatty fishes such as sardines and salmon as a healthy nutrient that can lower triglycerides and prevent heart disease, ease arthritis, prevent eye degeneration and focus the mind.
Some studies have even shown it can help with depression and other brain conditions, such as attention deficit hyperactive disorder.
But new research published in the Journal of the National Cancer Institute raises the question as to whether fish oil causes prostate cancer.
The study, Plasma Phospholipid Fatty Acids and Prostate Cancer Risk in the SELECT Trial, suggests men with high levels of omega-3 fatty acids have higher rates of prostate cancer.
In the epidemiological study, which compared 834 men diagnosed with prostate cancer to a control group of 1,400 without the disease, those with high blood concentrations of long-chain omega-3 polyunsaturated fatty acids had a 43 percent increase in the risk for all grades of prostate cancer, compared with men who had the lowest concentrations.
Researchers theorized that high doses of omega-3 fatty acids could cause oxidative stress, which can lead to DNA damage, possibly increasing the risk for prostate cancer, study lead author Theodore Brasky, a research assistant professor at Ohio State University Comprehensive Cancer Center, told HealthDay.
But other scientists aren’t rushing to throw fish oil under the bus just yet.
Duffy MacKay, a naturopath and vice president of scientific and regulatory affairs with the supplement industry trade group Council on Responsible Nutrition, points out the study does not show fish oil caused the cancer, it only reveals an association between omega-3s in the blood and prostate cancer.
MacKay said it is not known whether the men took fish oil or simply ate a lot of fatty fish. Also, only one blood sample was taken, and the general health of the population at the time of the draw was not considered.
“There are so many problems — not with the study itself but with the conclusions batting about. If this were the case, people who study the Inuit Eskimos and Japanese fisherman, high fish eating populations, they would have found [an increase in prostate cancer]. But instead, they find the exact opposite,” MacKay said.
He recommends consumers talk to their dieticians and pharmacists about the general scientific conclusions on fish oil supplements to decide whether they should take them.
MacKay said the prostate cancer link needs to be thoroughly studied before any concrete conclusions can be drawn.
“It’s still prudent to make sure you are eating either cold water fatty fish or supplementing with omega-3s. Not mega-dosing, not going crazy with it, just making sure you get this essential nutrient,” he said.
To get the recommended amount of omega-3s, nutritionists recommend eating two servings of fatty fish a week or a daily supplement.
Patricia Kime is the health reporter for Military Times. She can be reached at pkime@militarytimes.com.
