The Relationship of Omega 3 Polyunsaturated Fatty Acids in Red Blood Cell Membranes with Cognitive Function and Brain Structure: A Review Focussed on Alzheimer's Disease

Significant research attention has focussed on the identification of nutraceutical agents for the prevention of cognitive decline as a natural means of cognitive preservation in the elderly. There is some evidence for a reduction of brain omega 3 polyunsaturated fatty acids (n-3 PUFAs) in normal aging and in Alzheimer's disease. n-3 PUFAs exhibit anti-inflammatory and anti-amyloidogenic properties as well as being able to reduce tau phosphorylation. Many observational studies have demonstrated a link between n-3 PUFAs and cognitive aging, and some, but not all, randomized controlled trials have demonstrated a benefit of n-3 PUFA supplementation on cognition, particularly in those subjects with mild cognitive impairment. The identification of a biomarker that reflects n-3 PUFA intake over time and consequent tissue levels is required. In this narrative review we discuss the evidence associating red blood cell membrane n-3 PUFAs with cognitive function and structural brain changes associated with Alzheimer's disease.