The Neurotransmitter Revolution: Serotonin
Some of the most thrilling discoveries about how the brain works, and how you can influence thought and behavior with food and supplements, come from new knowledge about the activity of neurotransmitter systems. It is these brain chemicals (so far about fifty have been identified) that substantially define who you are at every microsecond of your life.
Flashing through neurons one by one, neurotransmitters lay down biochemical highways that carry your every thought and feeling through the brain’s vast neuronal network. Without neurotransmitters, the lights in the brain would go out; they are the biochemical electrification system of your brain. They are the essence of your memory, intelligence, creativity, and mood.
Until recently, the idea that food might profoundly and rapidly influence brain chemistry was considered scientifically ludicrous. Scientists thought the brain, of all organs, was particularly protected from the random permutations of nutrient invasions. It turns out the brain is uniquely responsive to food chemicals.
The ability of a meal’s composition to affect the production of brain chemicals distinguishes the brain from all other organs. The crucial compounds that regulate other organs are largely independent of whatever was in the last meal we ate—but not the brain.” —Richard Wurtman, research-psychiatrist, MIT
In the late 1970s, a team of researchers at the Massachusetts Institute of Technology, led by Dr. Richard Wurtman, had the first glimmering that food constituents could mimic drugs in regulating neurotransmitters, causing changes in brain activity and behavior. Since then research into the nutritional origins and workings of neurotransmitters and their potential impact on personality and behavior has led to revolutionary findings.
The radical conclusion: The type of neurotransmitters your neurons make and release and their ultimate destiny within the brain depend greatly on what you eat. Obviously, that makes food a very big regulator of the brain.
The thinking goes this way: Your brain cells require certain nutrients as building blocks to make various neurotransmitters. Thus, the availability of a specific nutrient can dictate the levels and potency of a particular neurotransmitter. For example, brain cells need tryptophan, an amino acid in foods, to readily create serotonin, the good-mood messenger. Similarly, choline, concentrated in egg yolk, is required to make the neurotransmitter acetylcholine, critical for memory.
The brain makes the neurotransmitter dopamine, essential for proper motor coordination, from an amino acid, tyrosine, found in high- protein containing foods. Other nutrients such as folic acid and fish oil can help determine the amount, character, and functioning of brain-altering neurotransmitters. When brain cells don’t get enough of the right nutrients, neurotransmitter systems can go awry with disastrous consequences.
One way memory is destroyed, as in dementia and Alzheimer’s, is through a disruption of the neurotransmitter systems. Initially, researchers held neurons responsible for not synthesizing and releasing enough neurotransmitters. The solution: Devise ways to flood brain cells with more neurotransmitters, which is the rationale behind many drug treatments for dementia and mood disorders.
But scientists now know its more complex than neurotransmitter shortage. New research focuses on the receiving apparatus of nerve cells—how plentiful and “sensitive” dendritic receptors are at capturing and processing neurotransmitters. No matter how much of a neurotransmitter roams the brain, if receptors are not “activated” to pass the message on, it stops dead.
Abnormalities in receptors can cause widespread trouble. In the brains of Alzheimer’s patients, for example, the number of receptors for acetylcholine declines as does the receptors’ ability to transmit messages. One new research direction: how to create more receptors and manipulate their sensitivity.
The important point is this: The composition of these neurotransmitters and the functional biochemistry of the receptors are changing all the time—and some of that change is dependent on what you eat and what you do.
Until very recently, we have been imprisoned by a scientifically fallacious view of the brain, proclaiming it beyond our control. The rapid eradication of that concept in the last few years is astonishing. After thirty-five years of pioneering research on the nature of the brain, Marian Diamond, Ph.D., of the University of California at Berkeley, can now say with breathtaking authority:
The brain can decide its own destiny.” The revolutionary new knowledge about the brain is so recent—occurring only in the last six or seven years—that most people don’t even realize the old misconceptions are dead and buried, says leading brain researcher Marilyn Albert of the Harvard Medical School.
Basically, two pivotal notions about the nature of the brain have been nullified. One is that the brain ceases to grow and change after childhood. The second is that the brain steadily loses brain cells after age twenty or so and consequently relentlessly declines in mental capacities. No one questioned that young brains grew, changed, and developed. But scientists thought older brains lost the capacity to grow, and were fixed and static after puberty.
Its now known that brain cells can sprout new dendrites and new synapses, forming new communication networks, at any age! Thus, although everyone is born with a fixed number of brain cells, that innate figure does not define mental capacity; what counts is the proliferation of connections throughout life. Brains with fewer cells can have just as much, or more, mental capacity than larger brains, depending on the lushness of neurons. The idea that a massive and progressive loss of neurons is an inevitable consequence of aging has also been thoroughly disproved.
The process by which the brain is Wired’ and even `rewired’ is referred to as plasticity. This means that the brain is always changing and repairing itself. . . . We now know that even the brains of adults are constantly changing and being rewired.” — Russell L. Blaylock, M.D., University of Mississippi Medical Center
SEROTONIN: ONE MIGHTY MESSENGER
The most extensively studied neurotransmitter is serotonin. It influences practically every aspect of brain life, helping shape your mood, energy level, memory, outlook on life. Antidepressants, such as Prozac, work by enhancing serotonin in the brain. People with low levels of serotonin are more vulnerable to depression, impulsive acts, alcoholism, suicide, aggression, and violence. Scientists can even make lab animals more aggressive by altering their brain serotonin levels.
Interestingly, women synthesize brain serotonin at half the rate of men, which may help explain why women are more prone to depression. Serotonin circuits also grow weaker with age because neurons lose receptors needed to activate serotonin. According to one study, the brains of sixty-five-year olds had 60 percent fewer serotonin receptors of a specific type than the brains of thirty-year-olds. Thus, the effect of serotonin lessens with age, increasing the tendency to depression.
Additionally, serotonin can heighten memory and help protect brain cells from a process called “excitotoxicity” that destroys neurons. Thus, ample serotonin actually helps prevent brain damage as you age! Many supplements, vitamins, nutrients, and fatty acids help enhance and regulate serotonin activity.
“A person’s mood is like a symphony, and serotonin is like the conductor’s baton.” —James Stockard, psychiatrist, Northwestern University