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SALT LAKE CITY — They lower your cholesterol and help your brain. Now research suggests that omega-3 and omega-6 polyunsaturated fatty acids — found in fatty fish, nuts and some oils — may also help prevent a variety of cancers.
The study by researchers at the University of Georgia is published in the International Journal of Cancer. It found that higher levels of the fatty acids in blood were associated with lower levels of cancer, with some variations. The researchers found of site-specific cancers, just ovary, breast, uterus and lymphoid and hematopoietic tissues were not associated at all with either omega-3 or omega-6.
"Higher omega-3 and omega-6 levels were associated with lower rates of cancer," said Yuchen Zhang, lead author of the study and a doctoral student in the university's College of Public Health, quoted in a news release. "These findings suggest that the average person should focus on getting more of these fatty acids in their diets."
Having a high level of omega-3 was associated in the study with lower rates of colon, stomach and lung cancer, as well as other digestive tract cancers. Having a higher omega-6 level was associated with fewer cases of brain, malignant melanoma, bladder and 11 other cancers. The omega-6 benefit was stronger in younger participants, especially women, the study found.
The study design
Using data from more than 250,000 people who were part of the United Kingdom Biobank, the researchers found about 1 in 8 developed cancer of some sort in the average of nearly 13 years they were followed in this analysis. While other research has suggested fatty acids and cancer might be linked, the researchers said they were able to show the benefits were associated with high levels of the polyunsaturated fatty acids and not due to possibly confounding factors like a person's body mass index, alcohol use, smoking status or level of physical activity.
They did note some limitations to the research, including that the biobank samples "skewed heavily toward European ancestry and white ethnicity," so the findings might not be universally generalizable. And some of the types of cancer occurred in comparatively small numbers. Nor could they account for individual genetics, they noted. The researchers called for further study to verify the finding and expand on it.
Healthy fats
The two types of fatty acids are "healthy fats," per the release, which calls them "essential for human health." Fish oil supplements are an omega-3 fatty acid and are often touted as offering several health benefits in a form that's an easy way to boost omega-3 fatty acid levels. But the University of Georgia researchers noted the benefits aren't one-size-fits-all all.
Omega-6 comes from plant oils and seeds, not fatty fish. And the supplements are not interchangeable. Other research has shown that people who have chronic obstructive pulmonary disease or diabetes should not take high levels of omega-6 fatty acids. In the latter case, it can increase the risk of developing high blood pressure, per MedlinePlus.
Despite the link to lower levels of certain cancers from having more of the two fatty acids, the new study found an exception in prostate cancer. Having higher levels of omega-3 was associated with slightly higher rates of prostate cancer.
Still, "for women, it's an easy decision: Eat more omega-3," said Kaixiong Ye, the study's corresponding author and an associate professor in the university's Franklin College of Arts and Sciences.
