Docosahexaenoic acid

About: Docosahexaenoic acid is a research topic. Over the lifetime, 14412 publications have been published within this topic receiving 620852 citations. The topic is also known as: all-cis-DHA & all-cis-docosa-4,7,10,13,16,19-hexaenoic acid.

Dietary fats and membrane function: implications for metabolism and disease

Abstract: Lipids play varied and critical roles in metabolism, with function dramatically modulated by the individual fatty acid moities in complex lipid entities. In particular, the fatty acid composition of membrane lipids greatly influences membrane function. Here we consider the role of dietary fatty acid profile on membrane composition and, in turn, its impact on prevalent disease clusters of the metabolic syndrome and mental illness. Applying the classical physiological conformer-regulator paradigm to quantify the influence of dietary fats on membrane lipid composition (i.e. where the membrane variable is plotted against the same variable in the environment--in this case dietary fats), membrane lipid composition appears as a predominantly regulated parameter. Membranes remain relatively constant in their saturated (SFA) and monounsaturated (MUFA) fatty acid levels over a wide range of dietary variation for these fatty acids. Membrane composition was found to be more responsive to n-6 and n-3 polyunsaturated fatty acid (PUFA) levels in the diet and most sensitive to n-3 PUFA and to the n-3/n-6 ratio. These differential responses are probably due to the fact that both n-6 and n-3 PUFA classes cannot be synthesised de novo by higher animals. Diet-induced modifications in membrane lipid composition are associated with changes in the rates of membrane-linked cellular processes that are major contributors to energy metabolism. For example, in the intrinsic activity of fundamental processes such as the Na+/K+ pump and proton pump-leak cycle. Equally, dietary lipid profile impacts substantially on diseases of the metabolic syndrome with evidence accruing for changes in metabolic rate and neuropeptide regulation (thus influencing both sides of the energy balance equation), in second messenger generation and in gene expression influencing a range of glucose and lipid handling pathways. Finally, there is a growing literature relating changes in dietary fatty acid profile to many aspects of mental health. The understanding of dietary lipid profile and its influence on membrane function in relation to metabolic dysregulation has exciting potential for the prevention and treatment of a range of prevalent disease states.

Docosahexaenoic acid provides protection from impairment of learning ability in Alzheimer's disease model rats.

Abstract: Docosahexaenoic acid (C22:6, n-3), a major n-3 fatty acid of the brain, has been implicated in restoration and enhancement of memory-related functions. Because Alzheimer's disease impairs memory, and infusion of amyloid-beta (Abeta) peptide (1-40) into the rat cerebral ventricle reduces learning ability, we investigated the effect of dietary pre-administration of docosahexaenoic acid on avoidance learning ability in Abeta peptide-produced Alzheimer's disease model rats. After a mini-osmotic pump filled with Abeta peptide or vehicle was implanted in docosahexaenoic acid-fed and control rats, they were subjected to an active avoidance task in a shuttle avoidance system apparatus. Pre-administration of docosahexaenoic acid had a profoundly beneficial effect on the decline in avoidance learning ability in the Alzheimer's disease model rats, associated with an increase in the cortico-hippocampal docosahexaenoic acid/arachidonic acid molar ratio, and a decrease in neuronal apoptotic products. Docosahexaenoic acid pre-administration furthermore increased cortico-hippocampal reduced glutathione levels and glutathione reductase activity, and suppressed the increase in lipid peroxide and reactive oxygen species levels in the cerebral cortex and hippocampus of the Alzheimer's disease model rats, suggesting an increase in antioxidative defence. Docosahexaenoic acid is thus a possible prophylactic means for preventing the learning deficiencies of Alzheimer's disease.