Americans spend more than\u00a0$1 billion\u00a0annually on fish oil supplements, in part due to purported cognitive benefits from the omega-3 fatty acids they\u00a0contain, essential nutrients that help form brain cell connections\u00a0needed for cognition.\u00a0<\/p>\n
However, a new\u00a0Keck Medicine of\u00a0USC\u00a0study\u00a0published today in\u00a0eBioMedicine\u00a0suggests that increasing omega-3 levels via supplements has\u00a0little effect\u00a0on brain health despite showing evidence that the nutrients directly reach the brain.\u00a0<\/p>\n
The two-year, placebo-controlled, double-blinded study of older adults with an elevated risk of developing Alzheimer’s showed that high doses of omega-3s did not improve memory, cognitive function or brain cell loss in areas of the brain related to Alzheimer’s.\u00a0<\/p>\n
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We all wish there was a silver bullet for preventing Alzheimer’s, but our findings\u00a0showed\u00a0that fish oil\u00a0supplements do not\u00a0appear\u00a0to\u00a0protect brain health. 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.”\u00a0<\/p>\n
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Hussein Naji Yassine, MD, director of the USC Center for Personalized Brain Health and lead investigator of the study<\/p>\n
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How the study was conducted\u00a0<\/p>\n
Researchers recruited 365 adults, ages 55 to 80 who rarely ate fish, which is rich in omega-3s, and who study authors considered at risk for Alzheimer’s. About half (47%) carried\u00a0an\u00a0APOE4 gene, the strongest genetic risk factor\u00a0for late-onset Alzheimer’s. Participants were randomly chosen to receive either daily fish oil supplements or a placebo. The supplements\u00a0contained\u00a02,000 mg\u00a0of docosahexaenoic acid (DHA), a key omega-3 involved in brain function.\u00a0<\/p>\n
Researchers were first interested\u00a0to learn\u00a0whether the omega-3\u00a0in the\u00a0supplement was able to reach the brain.\u00a0<\/p>\n
They measured DHA levels in cerebrospinal fluid, which surrounds the brain, and found an average 17% increase of DHA levels in patients’ brains after six months,\u00a0confirming\u00a0the omega-3 reached its intended target.\u00a0<\/p>\n
Next, researchers tested participants’ memory and cognitive abilities at the beginning of the study and again two years later. Study participants who took DHA supplements did\u00a0no\u00a0better on the tests than those who took a placebo. Brain scans also showed that supplements did not prevent shrinkage of the hippocampus, a brain region important for memory that is often used as a marker of brain aging and Alzheimer’s risk.\u00a0<\/p>\n
Now, Yassine and his team are focused on solving why omega-3 supplements can reach the brain but not affect brain health.\u00a0Based on their\u00a0previous\u00a0research, they believe\u00a0omega-3s may work better as a part of a\u00a0Mediterranean-style diet,\u00a0which is\u00a0naturally rich in omega-3s\u00a0and\u00a0linked with lower Alzheimer’s\u00a0risk,\u00a0than\u00a0in\u00a0a\u00a0standalone supplement.\u00a0<\/p>\n
“We’re focused on better understanding how the brain processes\u00a0omega-3s\u00a0and whether factors,\u00a0such as poor health,\u00a0dietary\u00a0pattern,\u00a0genetic risk\u00a0and\u00a0age,\u00a0may change the brain’s ability to effectively absorb and use omega-3s,” said Yassine. “We\u00a0are\u00a0working to\u00a0develop medications that\u00a0may\u00a0help the brain better utilize these nutrients to preserve cognitive function.”\u00a0<\/p>\n
Holistic\u00a0lifestyle\u00a0remains\u00a0the best prevention\u00a0<\/p>\n
While out of scope of the study, the researchers stress that overall healthy living – rather than\u00a0relying on\u00a0fish oil supplements alone\u00a0-is\u00a0the best way to protect brain health.\u00a0<\/p>\n
“Staying healthy throughout life remains the most powerful tool we have for reducing Alzheimer’s risk,\u00a0including regular exercise, quality sleep and a balanced diet,” said Yassine.\u00a0“Living a healthy lifestyle\u00a0is the brain’s equivalent\u00a0of getting\u00a0regular car\u00a0maintenance\u00a0and\u00a0high-quality\u00a0oil 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\u00a0regular maintenance is skipped.”\u00a0<\/p>\n
Other USC authors for the study include\u00a0Lina D’Orazio, PhD, a clinical psychologist and neuropsychology specialist with Keck Medicine; Lon Schneider, PhD, a professor of psychiatry<\/a> and behavioral sciences at the\u00a0Keck School of Medicine of USC; Michael Harrington, MD, a professor of research neurology at the Keck School; and Meredith Braskie, PhD, an assistant professor of neurology at the Keck School.\u00a0<\/p>\n Source:<\/p>\n University of Southern California – Health Sciences<\/a><\/p>\n Journal reference:<\/p>\n