Omega-3 fatty acids improve brain function and structure in older adults.

Alzheimer’s disease is the most common disease of aging, affecting as many as 70 million people worldwide. The pathological processes that contribute to Alzheimer’s disease often precede diagnosis of the condition by several decades, underscoring the importance of identifying strategies that might forestall or even prevent the disease. Findings from a 2017 study suggest that omega-3 fatty acids improve brain function and structure in older adults.

Omega-3 fatty acids are essential nutrients. Found in both plants and fatty fish, they influence cell membrane integrity, affect the function of membrane-bound cellular receptors, and participate in pathways involved in the biosynthesis of hormones that regulate blood clotting, arterial function, and inflammation. The fish-sourced omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), both play important roles in brain health, but DHA in particular regulates transport across the blood-brain barrier, a critical aspect in maintaining the barrier’s integrity.

The study involved 65 healthy adults between the ages of 50 and 75 years. The investigators randomly assigned participants to receive a supplement providing 2.2 grams of fish oil (1320 milligrams EPA + 880 milligrams DHA) or a placebo daily for 26 weeks. Before and after the intervention, participants underwent neuropsychological testing, structural magnetic resonance imaging (MRI) of the brain, body measurement, and blood tests for assessment of metabolic biomarkers (i.e., blood lipids, insulin, glucose, hemoglobin A1c), inflammatory markers, brain-derived neurotrophic factor (BDNF, a protein involved in learning and memory) and the Omega-3 Index, a measure of omega-3 fatty acid concentration in red blood cells.

At the end of the intervention, Omega-3 Index concentrations were approximately 2 percent higher among participants who took the supplemental fish oil, compared to those who took the placebo. The supplemented participants performed better on tests of executive function and exhibited improved white matter microstructural integrity and increased gray matter volume in their brains. In addition, their BDNF increased, and their peripheral insulin decreased.

These findings suggest that supplemental omega-3 fatty acids EPA and DHA increase the Omega-3 Index and improve multiple markers of brain health and cognitive function in older adults. Learn more about the Omega-3 Index in this episode featuring one of its creators, Dr. Bill Harris.

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