Background: The Controversy Over Fish Oil Supplements
Fish oil supplements and omega-3 fatty acids are often touted as a panacea for everything from heart health and brain function to immune systems and overall everyday well-being. But a new study is questioning the supplement's effectiveness.
When part of a person's regular diet, omega-3 fatty acids certainly play a vital role in maintaining health over the long term. A new study suggests that the efficacy of supplements, in particular, may be overstated, especially for those who are at risk of developing Alzheimer's disease.
Study Results: No 'Silver Bullet'
According to a new study out of the Keck School of Medicine at the University of Southern California, omega-3s found in fish oil supplements have no measurable impact on brain health in adults who are at increased risk of Alzheimer's disease.
The placebo-controlled, double-blind study was conducted over two years and included 365 participants, ages 55 to 80, all of whom were at an elevated risk of developing Alzheimer's. What the researchers found, in short, was that high-dose omega-3 supplements did not improve memory, cognitive function or brain cell loss associated with Alzheimer's.
"We all wish there was a silver bullet for preventing Alzheimer's, but our findings showed that fish oil supplements do not appear to protect brain health," said Dr. Hussein Naji Yassine, director of the USC Center for Personalized Brain Health and lead investigator of the study. "While omega-3s play an important role in forming brain cell connections needed for cognition, our results do not support fish oil supplements as a preventive measure against Alzheimer's."
Study Details: Placebo vs. 2,000 mg Supplement
The participants were split into two groups: one received a placebo, and the other took a supplement containing 2,000 mg of docosahexaenoic acid (DHA), an omega-3 fatty acid that plays an important role in brain function.
First, the researchers wanted to ensure that the DHA was successfully reaching the brain. They found that after six months, those taking the supplement showed a 17% increase in the nutrient's presence in the fluid that surrounds the brain and spinal cord.
Armed with this information, they wanted to know whether it was actually affecting a participant's cognitive abilities. The answer, according to two separate analyses, was a resounding no.
- One involved testing all participants' memory and thinking abilities at the start of the study and again at the study's conclusion, two years later. Those who took the DHA supplement failed to perform better than those who took the placebo.
- Meanwhile, brain imaging scans also showed that the hippocampus, a part of the brain associated with memory and used as a barometer for Alzheimer's diagnosis and brain aging, shrank at a similar rate among those who took the supplement and those who didn't.
Looking ahead, the team wants to understand why the DHA, despite reaching the brain, has no impact on brain health.
"We're focused on better understanding how the brain processes omega-3s and whether factors, such as poor health, dietary pattern, genetic risk and age, may change the brain's ability to effectively absorb and use omega-3s," Yassine said. "We are working to develop medications that may help the brain better utilize these nutrients to preserve cognitive function."
Health Advice: Mediterranean Diet and Healthy Habits
According to the researchers, eating a Mediterranean-style diet remains one of the best ways to mitigate Alzheimer's risk, as it is naturally rich in fish and omega-3 fatty acids.
More generally, practicing healthy lifestyle habits — regular exercise, quality sleep and a balanced diet — is the strongest defense against Alzheimer's disease.
"Living a healthy lifestyle is the brain's equivalent of getting regular car maintenance and high-quality oil changes," Yassine said. "The brain is more likely to lose greater function if health issues in other parts of the body go unaddressed, in the same way that car engines stop working if regular maintenance is skipped."