Share on PinterestIf you’re taking a fish oil supplement to improve your health, it may not be having as much of an effect as you think. Getty Images
- New research finds fish oil may provide little benefit in preventing cancer.
- However, it may slightly lower the risk of cardiovascular disease events or death.
- Fish oil contains omega-3 fatty acids, which are important for health and must be obtained through diet.
- It’s thought that the benefits of omega-3 fatty acids might come from their effects on inflammation, oxidative stress, or cell membrane composition.
- It’s important to consult with your physician about whether fish oil supplementation is right for you.
According to researchers from the University of East Anglia in Norwich, England, supplementing with fish oil offers little to no benefit against cancer.
In fact, it seems to be associated with a slightly increased risk of one particular type of cancer: prostate.
However, a group of researchers from China and the United States found that habitual fish oil use was linked to lower risk of death from cardiovascular disease (CVD) as well as death from all causes.
In addition, it seemed to provide a small benefit against CVD events among the general population.
Fish oil supplements contain omega-3 fatty acids, which are important for health.
It’s available both over the counter and by prescription.
Omega-3 fatty acids can also be found in foods such as nuts, seeds, and fatty fish like salmon or mackerel.
These fatty acids have been thought to be potentially protective against several conditions, including cancer and cardiovascular disease, perhaps due to their effects on inflammation, oxidative stress, or cell membrane composition.
The researchers used the data from 47 different randomized, controlled trials that included 108,194 people.
The studies involved adults who didn’t have cancer, those who were at increased risk for cancer, or those who had previously received a cancer diagnosis.
All of the studies compared higher consumption of omega-3, omega-6, or total polyunsaturated fatty acids (PUFA) with usual intake.
Omega-3 and omega-6 fatty acids are types of PUFAs.
Both are essential fatty acids, meaning the human body can’t manufacture them. Instead, they must be obtained through diet.
Having the correct ratio of omega-3 and omega-6 fatty acids is thought to be important to health.
In addition to examining fatty acid intake, the studies assessed cancers over a period of a least 1 year.
The studies looked at how many people either died or received a cancer diagnosis by the end of their respective studies.
After conducting statistical analyses of the data, the team found that increased omega-3 fatty acid consumption was associated with little or no positive effects on cancer prevention.
However, it was associated with a slight increase in the risk of prostate cancer.
According to the lead author Lee Hooper, PhD, RD, a professor of research synthesis for nutrition and hydration at Norwich Medical School, if 1,000 people took omega-3 supplements for 4 years, three extra people would develop prostate cancer over what would have occurred otherwise.
The researchers involved in this study used data from the U.K. Biobank, which is a large population-based study involving 427,678 British women and men between the ages of 40 and 69 years old.
The study participants, who didn’t have CVD or cancer, took part in the study between the years 2006 and 2010.
Each filled out a questionnaire related to their use of supplements, such as fish oil.
The team used death certificates and hospital records to follow deaths due to any cause or CVD as well as any heart attacks or strokes that occurred up to the year 2018.
The researchers found during the follow-up period that those who had been regularly taking fish oil at the onset of the study had a 13 percent lower risk for death from all causes.
They also had a 16 percent lower risk for death from CVD.
Further, they had a 7 percent lower risk for having a heart attack or stroke.
The association between fish oil use and CVD seemed to be strongest for those with high blood pressure.
Hooper states that, based on her work, the risks of cancer and the benefits for CVD are both very small.
“Generally, we are interested as individuals in staying healthy,” she explained. “Whether we are struck down by heart/vascular disease or cancer is not the key thing, the issue is to prevent both.”
If you have an increased risk for cardiovascular disease, these small benefits may make it worthwhile to take fish oil supplements, Hooper says.
However, if you have a high risk for cancer, then taking them wouldn’t be logical.
“A conversation with your doctor is a sensible idea,” she added.
Timothy Richard Rebbeck, PhD, a researcher at Dana-Farber Cancer Institute, who wasn’t a part of either study, agrees with the idea that certain high-risk populations might benefit from fish oil supplementation.
However, it’s not yet possible to make any strong recommendations, he notes.
So far, the data doesn’t provide strong evidence that fish oil supplementation has positive effects for either CVD or cancer death.
Further, he adds he wasn’t sure there was actually an increase in prostate cancer risk, noting that none of the individual studies showed a statistically significant effect.
Based on these studies, it appears that fish oil supplementation has little to no benefit in cancer prevention. In fact, it may slightly increase the risk of prostate cancer.
However, fish oil supplementation may provide some benefit for people who have a risk for cardiovascular disease.
It’s important to speak with your doctor about what’s best for you as an individual.