Dietary influences on membrane function: Importance in protection against oxidative damage and disease

Membrane function is vital to many cellular processes including the role of membrane enzymes and receptors in cell growth and signaling. A number of factors are thought to modulate membrane function including dietary components. Membrane function can either be influenced directly, e.g., by altering fluidity, or indirectly e.g., by modulation of the free radical-mediated process of membrane lipid peroxidation, which can arise from oxidative stress and result in oxidative membrane damage. Vitamins E, C (ascorbic acid), and D, beta-carotene, trace metals, flavonoids, isoflavonoid-type phytoestrogens, food additives, and fatty acids are all dietary, factors that may influence membrane function in one or more of these ways. Modulation of the activity of membrane enzymes and receptors by dietary components may be important in disease states such as cancer. The possibility of dietary protection of membranes (including mitochondrial membranes) against the oxidative damage implicated either directly or indirectly via DNA damage in neurodegeneration, aging, and malignant progression to cancer (e.g., following chronic inflammation) will also be considered. Dietary modulation of the susceptibility of the phospholipid monolayer of low-density lipoprotein (LDL) particles to the oxidative damage implicated in atherosclerosis also appears to be a possibility and thus will be explored.