High Fibre Diets and Alzheimer’s Disease

The understanding of cholesterol and its pathogenesis to Alzheimer’s disease (AD) pathogenic process is important for the possible prevention of AD. High fibre diets that contain phytosterols have been shown to lower LDL and increase HDL cholesterol and are implicated in membrane cholesterol and amyloid beta (Aβ) homeostasis. The convergence of diet and AD may be related to the effects of phytosterols since plasma cholesterol is closely linked and regulated by phytosterols. Dietary fibre modifications that are low in fat and glucose reduce the risk for AD by not only effecting cell membranes and nutrient sensing G coupled receptors but also by regulating number of nuclear receptors such as histone deacetylases (HDAC) and peroxisome proliferator activated receptors (PPAR) that control glucose, fatty acids and cholesterol and have significant effects on the brain cholesterol homeostasis and amyloidosis. The peripheral sink Aβ hypothesis indicates that the peripheral clearance of Aβ and its regulation by dietary phytosterols is of substantial interest since it may delay hypercholesterolemia and the early onset of amyloid plaque development. Liver disease has been of central importance with aging and programmed cell death pathways. Nutritional therapy has emerged as a novel approach to control appetite and the role of nutrigenomics as an early nutritional therapy may assist genes to delay liver and brain diseases such as Parkinson’s disease (PD) and Huntington’s disease (HD) that are associated with aging. The understanding of phytosterols and the role of these lipids in drug therapy such as cholesterol lowering drugs may provide molecular mechanisms that are involved in the regulation of cell Aβ clearance and metabolism. High fibre diets also contain various fatty acids such as the short chain fatty acids (SCFA) and the understanding of synergistic effects of SCFA and phytosterols in glucose regulation and cholesterol homeostasisis important to our understanding of diet, lifestyle and drugs in relation to peripheral amyloidosis and gene expression that play an early role in the development of AD.