The Omega-3 Index measures omega-3 fatty acid concentrations in red blood cells. It provides a reliable assessment of long-term intake and is highly reflective of fatty acid composition in most tissues, with one notable exception – the brain. A recent study suggests that brain-derived neurotrophic factor (BDNF), a protein involved in learning and memory, is a more reliable measure of brain omega-3 concentrations than the Omega-3 Index.
Researchers gave rats and mice different types and amounts of supplemental omega-3 fatty acids, including docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), and dietary fish and krill oils. Then, they measured the fatty acids in the animals' red blood cells (Omega-3 Index) and the BDNF concentrations in their plasma and brain tissues.
They found that increased brain omega-3 levels were positively associated with elevated plasma BDNF but inversely associated with red blood cell concentrations, suggesting that plasma BDNF is a more dependable biomarker than the Omega-3 Index for evaluating the effectiveness of omega-3 supplementation and dietary intake in enhancing brain function.
BDNF is critical for brain function, neurogenesis, neuronal survival, memory, and body weight regulation. Low BDNF concentrations are typical in psychiatric disorders but typically rise after antidepressant treatment and high omega-3 fatty acid doses. Exercise and DHA-rich diets also elevate BDNF, and some evidence suggests that BDNF mediates DHA’s beneficial brain effects.
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