Omega-3 Fatty Acids and Neurodegenerative Diseases: New Evidence in Clinical Trials

Abstract

A nutritional approach could be a promising strategy to prevent or slow the progression of neurodegenerative diseases such as Parkinson's and Alzheimer's disease, since there is no effective therapy for these diseases so far. The beneficial effects of omega-3 fatty acids are now well established by a plethora of studies through their involvement in multiple biochemical functions, including synthesis of anti-inflammatory mediators, cell membrane fluidity, intracellular signaling, and gene expression. This systematic review will consider epidemiological studies and clinical trials that assessed the impact of supplementation or dietary intake of omega-3 polyunsaturated fatty acids on neurodegenerative diseases such as Parkinson's and Alzheimer's diseases. Indeed, treatment with omega-3 fatty acids, being safe and well tolerated, represents a valuable and biologically plausible tool in the management of neurodegenerative diseases in their early stages.

Keywords: Alzheimer’s disease; Parkinson’s disease; clinical trials; omega-3 polyunsaturated fatty acids.

Figure 1

Endogenous synthesis of omega-3 polyunsaturated fatty acids and their involvement in inflammation. 15-LOX: 15-Lipoxygenase, 5-LOX: 5-Lipoxygenase, 12/15-LOX: 12/15 Lipoxygenase, CYP-450: Cytochrome P450.

Figure 2

Amyloid precursor protein (APP) processing pathways. The non-amyloidogenic pathway (a) occurs upon sequential cleavage by α- and γ-secretases (non-pathological situation). The amyloidogenic pathway route (b) occurs when cleavage is carried out sequentially by β- and γ secretases (pathological situation). Letters α, β, and γ represent each type of secretase. APP: Amyloid precursor protein, APPsα: Soluble α-APP, APPsβ: Soluble β-APP. Omega-3 polyunsaturated fatty acids, proposed to inhibit APP processing, are shown in orange dashed lines.