Neurotransmitters |
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Our brains, similar to every organ and tissue in our bodies, consist of cells, billions of them; in fact, there are probably more cells in the human brain than there are stars in the entire galaxy. In the brain, these cells must transmit messages from one to another that ultimately become your mood, which affects how you interact with the world. These messages go from cell to cell by what we call neurotransmitter chemicals, or simply neurotransmitters, for short. There are three neurotransmitters: dopamine, norepinephrine, and serotonin.
Dopamine and norepinephrine are the alertness chemicals. When these alertness chemicals are produced. people are more attentive, think more quickly, and, in general, are what weld call motivated. During these periods people will often tire off ideas or commands, give a stirring speech, and take other actions. which if correctly directed can be very productive.
Serotonin is the calming chemical. Elevating serotonin acts as a brake when your thoughts are racing in all directions and you need to filter the mixed signals coming in. In short, serotonin is the opposite of the alertness chemicals; it eases the effects of stress and tension and helps you focus.
Your brain makes these neurotransmitters from two amino acids, which are the building blocks of protein. It would seem, then, that eating the correct proteins can produce the right balance of the alertness and calming chemicals.
The two amino acids are tyrosine. from which both alertness chemicals (norepinephrine and dopamine) are made, and tryptophan, from which the calming chemical (serotonin) is made.
The ancient Greeks knew that eating protein produced the alertness chemicals. Indeed, their idea that if you ate wildcat meat you'd get the prowess of the wildcat was somewhat correct. Eating protein (and a wildcat is mostly protein) yields an abundance of tyrosine, and since there is a built-in clearinghouse called the blood-brain barrier that makes it hard for tryptophan to get in, the Greek athlete would be more alert. If he was entering a wrestling match, for example, he'd probably do better.
For tyrosine to cross the blood-brain barrier, it simply needs to be in the blood. Tyrosine, along with most other amino acids, is used readily by the brain; these amino acids readily cross the blood-brain barrier. Since there are lots of these amino acids in most protein foods, such as meat, fish, and dairy products, and even in beans and mushrooms, eating protein generally increases alertness.
Tryptophan is the least plentiful of the six essential amino acids that the brain needs. So, when protein is eaten, the amount of tryptophan that can get into the brain is limited. Suppose there are only red and black cars in the world and there are thirty black cars for every red car. Now suppose that to cross a bridge all cars must go through a series of ramps that work by alternative feed. When you look at the bridge, you'd notice that about one in thirty cars was red. In fact, if you looked for only an instant, you'd probably think there were only black cars in the whole world, and it would take awhile before you realized that some cars were colored red. That is the tryptophan problem in a nutshell. There is such an abundance of other amino acids that the small amount of tryptophan is hardly noticed. However, Mother Nature has devised a way around the tryptophan scarcity problem, which enables us to adjust our moods by eating correctly.
You've encountered the hormone insulin more than once in this book. It is responsible for the correct use of blood sugar and works by opening the door in each cell that allows in blood glucose. When insulin opens the door for glucose, it also lets in the other amino acids, except for tryptophan, which is bound to but is not a part of a special blood protein called albumin. Consequently, tryptophan doesn't tag along.
Eat a diet rich in complex carbohydrates along with appropriate protein and the blood level of tryptophan will slowly build. The other amino acids decline because they are entering all cells where they go to the manufacture of bones, muscle, skin, hair, and all the other body structures that are rich in protein. Over time, a diet that is consistently rich in complex carbohydrates will allow tryptophan to build up to a consistent level and go past the blood-brain barrier as required.
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