Docosahexaenoic Acid in Neural Signaling Systems

Abstract

Docosahexaenoic acid has been conserved in neural signalling systems in the cephalopods, fish, amphibian, reptiles, birds, mammals, primates and humans. This extreme conservation, despite wide genomic changes over 500 million years, testifies to a uniqueness of this molecule in the brain. The brain selectively incorporates docosahexaenoic acid and its rate of incorporation into the developing brain has been shown to be greater than ten times more efficient than its synthesis from the omega 3 fatty acids of land plant origin. Data has now been published demonstrating a significant influence of dietary omega 3 fatty acids on neural gene expression. As docosahexaenoic acid is the only omega 3 fatty acid in the brain, it is likely that it is the ligand involved. The selective uptake, requirement for function and stimulation of gene expression would have conferred an advantage to a primate which separated from the chimpanzees in the forests and woodlands and sought a different ecological niche. In view of the paucity of docosahexaenoic acid in the land food chain it is likely that the advantage would have been gained from a lacustrine or marine coastal habitat with access to food rich in docosahexaenoic acid and the accessory micronutrients, such as iodine, zinc, copper, manganese and selenium, of importance in brain development and protection against peroxidation. Land agricultural development has, in recent time, come to dominate the human food chain. The decline in use and availability of aquatic resources is not considered important by Langdon (2006) as he considers the resource was not needed for human evolution and can be replaced from the terrestrial food chain. This notion is not supported by the biochemistry nor the molecular biology. He misses the point that the shoreline hypothesis is not just dependent on docosahexaenoic acid but also on the other accessory nutrients specifically required by the brain. Moreover he neglects the basic principle of Darwinian evolution. The well documented greater efficiency of preformed docosahexaenoic acid for brain incorporation during development would have conferred a distinct survival advantage over those without it. All terrestrial mammals lost brain capacity in relation to advancing increase in body size. The rise in mental ill health and brain disorders, to replace all other costs in the European list of burdens of ill health, (Andlin Sobocki et al., 2005) raises interesting questions as to its association with the reduced availability and consumption of marine and fresh water products. The threat posed by the continued rise in brain disorders also raises questions of importance to present and future food and agricultural policies.

Exercise and DHA Prevent the Negative Effects of Hypoxia on EEG and Nerve Conduction Velocity

“…In the current study, exercise and DHA increased alpha and beta activities. Similarly, in previous studies it was shown that exercise (Youngstedt et al, 1993) and DHA (Crawford 2006;Takeuchi et al, 2002) increased alpha and beta activities. While an increase in alpha activity is related to alertness (Nerad and Bilkey, 2005), vigilance (Olbrich et al, 2009), and semantic memory in humans (Klimesch, 1999), increase in beta activity is related to alertness (Nerad and Bilkey, 2005), attention (Makeig and Jung, 1995), emotion (Cole and Ray, 1985), anger (Rusalova et al, 2003), and sensorimotor cortex (Parkes et al, 2005) activities.…”

“…Similarly, previous studies reported that exercise (Li et al, 2008;Youngstedt et al, 1993) and DHA (Crawford, 2006;Takeuchi et al, 2002) decreased delta activity. Also, in our results, delta activity was found to be high in all groups.…”

“…In another study, it was reported that hypoxia reduced theta activity (Budzinska and Ilasz, 2007). In other studies, it was shown that, unlike hypoxia, exercise and DHA reduced the delta activity and increased alpha and beta activities (Crawford, 2006;Li et al, 2008;Takeuchi et al, 2002;Youngstedt et al, 1993) and NCV (Balducci et al, 2006;Coste et al, 2003). Exercise and/or DHA can be suggested to prevent either partially or completely the effects of hypoxia on nervous system functions.…”

Eicosapentaenoic Acid (EPA) Reduces Cardiovascular Events: Relationship with the EPA/Arachidonic Acid Ratio

“…ω3 deprivation reduces the blood DHA levels by 89% and the brain DHA levels by 37% 44) . EPA to DHA conversion may be restricted in order to maintain constant DHA levels for nervous system signaling 45) . Although the reason for this phenomenon is unknown, the following may be a potential cause.…”

Improved spatial learning performance of fat-1 mice is associated with enhanced neurogenesis and neuritogenesis by docosahexaenoic acid

“…DHA serves not only as a building block for neural development, but also as a functional molecule to maintain proper fluidity of neuronal membranes and modulate neurochemical, gene expression, and memory processes (2). Clinical evidence indicates that term infants given formula supplemented with either DHA plus arachidonic acid or DHA alone have substantially better visual acuity (3) and improved cognitive ability (4).…”