WASHINGTON (dpa-AFX) - Fish oil supplements were able to deliver omega-3 fatty acids to the brain, but a new study found that this alone did not improve memory or thinking skills in older adults who were at high risk of developing Alzheimer's disease.
'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 lead author Hussein Naji Yassine. '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.'
The two-year study included 365 adults between the ages of 55 and 80. All participants had a higher-than-average risk of Alzheimer's, and nearly half carried the APOE4 gene, the strongest known genetic risk factor for late-onset Alzheimer's disease. Participants were randomly assigned to take either a daily fish oil supplement or a placebo. The supplement contained 2,000 mg of docosahexaenoic acid (DHA), an omega-3 fatty acid that plays an important role in brain health.
Researchers first wanted to find out if the DHA from the supplements could actually reach the brain. They measured DHA levels in the cerebrospinal fluid, which surrounds the brain and spinal cord. After six months, DHA levels had increased by an average of 17%, confirming that the omega-3 had reached the brain.
The researchers then looked at whether this increase improved brain health. Participants completed memory and thinking tests at the beginning of the study and again after two years. The results showed no difference between those who took DHA supplements and those who received a placebo. Brain scans also found that the supplements did not slow shrinkage of the hippocampus, the part of the brain involved in memory that often shrinks with aging and Alzheimer's disease.
Yassine and his team are now trying to understand why omega-3 supplements can reach the brain without providing clear cognitive benefits. Based on previous research, they believe omega-3s may work better when they come from a Mediterranean-style diet, which is naturally rich in omega-3s and has been linked to a lower risk of Alzheimer's, rather than from supplements alone.
'Staying healthy throughout life remains the most powerful tool we have for reducing Alzheimer's risk, including regular exercise, quality sleep, and a balanced diet,' said Yassine. 'Living a healthy lifestyle is the brain's equivalent of getting regular car maintenance and high-quality oil changes. 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.'
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