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23 May 2017 - Nutraingredients - Omega-3 could aid Alzheimer's prevention: Study

Emma Jane Cash

People with high omega-3 intakes have an increased blood flow in the brain, according to research suggesting a link between omega-3 and Alzheimer’s disease.

"What we observed was that higher EPA + DHA status as expressed by the Omega-3 Index is independently correlated with higher perfusion in brain regions important for cognitive function, including the parahippocampal gyrus and precuneus," said the study authors of the new study, published in the Journal of Alzheimer’s Disease.

Omega-3s have been suggested to protect the areas of the brain affected most by ageing - with previous research linking omega-3 fatty acids to anti-amyloid, anti-tau and anti-inflammatory actions in the brains of animal. As a result, research aimed at dietary approaches for the prevention of cognitive decline have become more popular.

The Omega-3 Index measures the percentage of EPA + DHA in red blood cells, with 8% being desirable and less than 4% being a danger zone. Previous studies have also suggested that high doses of omega-3 DHA are more likely to boost  the Omega-3 Index than EPA.

Led by Dr Daniel Amen of the Amen Clinic, the new research suggests a positive relationships between omega-3 EPA (eicosapentaenoic acid) + DHA (docosahexaenoic acid) status, brain perfusion and cognition.

Statistically significant relationships were found between omega-3 EPA +DHA levels in the blood and cerebral perfusion in the right parahippocampal gyrus (a region thought to play an important role in memory encoding and retrieval), the right precuneus (involved with episodic memory, visuospatial processing, and aspects of consciousness) and the vermis subregion (a region associated with bodily posture and locomotion).

Brain study

The research looked at 166 randomly selected participants, drawn from clinics, and studied their brain function using single photon emission computed tomography (SPECT), which measures blood perfusion in the brain. 

Using the Omega-3 Index and SPECT imaging on 128 regions of the brain, researchers collected data on the correlation between omega-3 fatty acid blood levels and blood flow in the brain.

For 'resting-state' scans, participants were asked to sit in a dimly lit room with ambient noise, with their eyes open. Participants were then scanned for 30 minutes. For 'on-task' scans, participants completed Continuous Performance Tests (CPTs) whislt the scans were being made.

No participants were taking omega-3 EPA + DHA supplements, nor were they on specialised omega-3 rich diets. 

“Although we have considerable evidence that omega-3 levels are associated with better cardiovascular health, the role of the ‘fish oil’ fatty acids in mental health and brain physiology is just beginning to be explored," said study co-author William Harris, from the University of South Dakota School of Medicine. "This study opens the door to the possibility that relatively simple dietary changes could favorably impact cognitive function."

The authors also say the study "raises the posibility that higher omega-3 EPA + DHA fatty acid level can improve underlying brain physiology that may in turn translate to better cognitive reserve".