Fish and Brain Food

My dad’s favorite food is fish. On his nights to cook, he whips up his usual salmon dinner. As a kid, I didn’t like salmon but my dad insisted fish was brain food and would make me smarter. Naturally, I didn’t believe him but I ate my dinner in case the fish might help me on my next test. Now, I’ve decided to research my dad’s theory and it so happens that he was right. The oil in fish contains omega-3 fatty acids, abbreviated as n-3 fatty acids, have numerous health benefits; some of which include cardiovascular disease prevention. The n-3 fatty acids reduce high blood pressure, increase lipoprotein or “good cholesterol” amounts, and lower the risk of heart disease (4). However, my dad was referring to neurological properties; therefore, I will focus on the positive effects of omega-3 fatty acids in mood disorders and memory.

As a preliminary note, n-3 fatty acids are polyunsaturated fatty acids or PUFAs. PUFAs are considered to be the building blocks of many neurotransmitters. Eicosaphentaenoic acid, EPA, and docosahexainoic acid, DHA, are two particular types of PUFAs that generate a healthy nervous system. EPA aids mostly in cardiovascular problems while DHA aids in neurological problems. Studies find DHA as a more effective contributor to memory and cognition since the fatty acids better maintain and generate neuron tissue. As a result, DHA is the primary n-3 fatty acid found in salmon, lake trout, herring, sardine, and tuna (1).

Most studies of EPA and DHA examine neurological development usually in infants and children. DHA added to infant milk formulas lead to optimal brain functioning in both premature and full term babies. In the womb, human fetuses subjected to high dosages of ethanol, due to the mother consuming too much alcohol, risk insufficient neurological development. The ethanol and other organic solvents exhaust DHA supplies in the fetus’s brain. Low levels of DHA in a child factor into the biological causes of mild neurological and behavioral problems (2). Deficiencies of DHA are hypothesized to possibly contribute to childhood ADHD, attention deficit hyperactivity disorder. Conflicting evidence forces this hypothesis to continue with further research (2, 3). On the other hand, accepted repercussions of low n-3 fatty acids levels in children are aggression, depression, and other behavior problems (2).

Low omega-3 fatty acid diets diminish dopamine levels, a monoaminegeric neurotransmitter. In 2000, a study by Zimmer et al. observed rats fed an n-3 fatty acid poor diet had a 90% reduction of dopamine released in their brains and mild damage to the dopaminergic synaptic vesicles (2). The neurotransmitter was unable to trigger communication signals to the next neuron. Similarly in a 1998 article in the Journal of Nutrition by Chalon, S. et al., rats fed a fish oil diet had a great grain capacity than those fed a control diet. The rats consuming higher quantities of fish oil had 40% greater dopamine levels in the frontal lobes (2). Scarce dopamine levels in human brain frontal lobes induce neurocognitive functions such as memory, problem solving, and attention are negatively affected (1). Furthermore, if low dopamine levels in humans affect attention, then perhaps this deficiency may be a contributing factor to ADHD. A more examined problem is the susceptibility to depression with low n-3 fatty acid diets and low dopamine amounts. Many animal studies have concluded low dopamine levels, as a result of depleted n-3 fatty acid diets, lead to behavioral problems.

Omega-3 fatty acids not only affect not only dopamine, but also serotonin. Neural membrane tissues contain DHA which facilitate signaling pathways (5). The DHA concentration in neuron membranes has a direct correlation to serotonin levels according to a 1995 study by Hibbeln and Salem. DHA reduction negatively affects either serotonergic receptors or serotonin-reuptake systems (5). Later Olsson et al. concluded a study suggesting a diet low in n-3 fatty acids reduces the amount of serotonin (2). Chronic dietary deficiencies in n-3 fatty acids have also found a 40-75% decrease in dopamine levels (2, DeLion et al). Furthermore, if there are scare amounts of serotonin, then signal relaying is hindered. Only high amounts of serotonin, resulting from a DHA rich diet, tend to facilitate neurotransmission.

A study by Norman Salem, Jr et al focused on the importance of DHA during rat neurological growth and development. The rats were placed in a Morris Water Maze which had four maze quadrants surrounded and separated by water. The rats ran through the mazes and had to reach at a designated platform. A group of rats were fed a DHA rich diet, while a second ground was fed a non-DHA diet. Escape latency, total number of seconds to reach the platform, and memory retention were timed. N-3 fatty acid fed rats demonstrated a faster escape latency and longer memory retention. These rats had a higher memory because of a 7% hippocampus brain level. Scientists noted, however, there was no density or totally number of neuron change (3). There must have been improved patterns of activity in the rat brain.

Numerous brain and behavior studies have provided insight to the beneficial aspects of DHA. Overall, omega-3 fatty acid rich diets seem to improve animal behavior. Since high levels of DHA in fish oil positively affect mammalian animal, perhaps this research may be applied to human behavior. I semi-support my dad’s claim that fish is brain food to make you smarter. I, however, would like to further expand that brain food, such as fish, feeds our mood and biological behaviors.

WORKS CITED

1.) http://en.wikipedia.org; general information about Fish Oil

 2.) http://www.niaaa.nih.gov/NR/rdonlyres/57804B4E-814B-4514-83C3-26489F9F6544/0/Hibbeln2006n3Neurodevelopmentofaggressionreview.pdf; published paper including other studies about aggressive and depressive disorders exacerbated by n-3 fatty acid deficiencies 3.) http://www.niaaa.nih.gov/NR/rdonlyres/6F5D868E-8741-46F6-A582-3D487E5BB58C/0/SalemJMolNeurosci162001299307.pdf; published paper including other studies about rat memory when fed diets with or without n-3 fatty acids 4.) http://medlineplus.gov/; cardiovascular benefits of n-3 fatty acids 5.) http://www.niaaa.nih.gov/NR/rdonlyres/21D42EE8-0DAC-4892-BE75-CD388AB65E83/0/J_mol_neuro2001.pdf; published paper including other studies about DHA content in neuron membranes