SMART STUFF FOR YOUR BRAIN: TO BOOST YOUR BRAIN, REACH FOR PROTEIN FIRST

You can actually control your own level of mental performance—or relaxation—by choosing the right combination of foods that contain smart nutrients.

Two amino acids compete with one another to control the way your brain works. One is L-tyrosine, which your brain uses to synthesize the neurotransmitters norepinephrine and dopamine, both of which are critical to lucid, swift thinking; long-term memory; and feelings of alertness and stability. The other is L-tryptophan, which the brain uses to make the— neurotransmitter serotonin, which is responsible for slowing down reaction time, imparting satiety after a meal, and inducing sleep. L-tyrosine, found in protein-rich foods like meat, poultry, seafood, beans, tofu, and lentils, thus serves as a nutritional stimulant to the brain, whereas L-tryptophan, found in such foods as bananas, sunflower seeds, and milk (and whose effects are augmented when consumed with carbohydrate-rich foods), behaves as a mental downer.

If L-tyrosine gets into your brain ahead of L-tryptophan, it will prime your brain to function at maximum performance levels all day (or all night, depending upon when you eat the meal or snack). But if L-tryptophan reaches the brain first, it will stimulate the production of serotonin, and your mental performance will ebb and your brain will begin to shut down, even in the middle of the day.

Where do you get these amino acids, and how do you get them into your brain? The answers to these two questions reveal how easy it is to begin a program of mental fitness and how you can exert a good measure of control over your own levels of mental performance, memory, relaxation, and even depression.

Judith Wurtman, Ph.D., a researcher at the Massachusetts Institute of Technology (MIT) advises that when you want the mental lift from L-tyrosine, you should eat the protein portion of a meal (turkey or shrimp, for example) before you take a single bite of any food that contains carbohydrates (the same applies to beverages). I recommend 100 grams (3.5 ounces) of animal protein, such as a boneless chicken breast or a small can of water-packed tuna fish. Vegetarians can use textured vegetable protein (TVP), tofu, or legumes (such as beans, peas, or lentils) in place of meat to get their L-tyrosine.

Animal and vegetable protein is chock-full of L-tyrosine, but contains only modest amounts of L-tryptophan. Thus, L-tyrosine will crowd-out L-tryptophan and cross the BBB in greater amounts. Your brain will wake up as a result.

Another reason that L-tyrosine prevails over L-tryptophan is that L-tryptophan also needs carbohydrates to get into the brain. Several ounces of protein-rich food, such as turkey, will send plenty of L-tyrosine to your brain; L-tryptophan, however, cannot readily cross the BBB until you eat the carbohydrate-rich foods—breads, pastas, and vegetables— you left on your plate (carbohydrates stimulate the release of insulin, which drives other competing amino acids into muscles, leaving L-tryptophan to cross the BBB into the brain unopposed).

Do you sometimes feel lethargic after lunch? One of the most common complaints I hear is, "By mid-afternoon, I can't concentrate very well. I could use more energy!" Actually, the type of energy most people want is mental energy, exactly the kind you'll get from a high-protein power lunch (and the choline "cocktail" I'll tell you about shortly). If you hold off on the pasta until dinner, you'll enjoy peak mental energy when you need it most—during the workday—and benefit from the relaxation effects of L-tryptophan in the evening, when it's time to wind down, relax, and fall asleep.

L-tyrosine's ability to rev up your brain may even help overcome stress and depression. The U.S. Army discovered that L-tyrosine was able to counter the effects of mental stress and depression on the performance of soldiers. Two dozen soldiers were tested with and without supplemental L-tyrosine before a stressful maneuver, half of them receiving L-tyrosine and half of them receiving a placebo, an inert substance free of L-tyrosine. The stressful operation was repeated again, this time so that those who received the placebo got L-tyrosine and those who received L-tyrosine the first time got the placebo.

During the two maneuvers, the soldiers were tested to determine their ability to perform military tasks that required clear thinking and quick decisions. The result was that those who normally experienced stress or depression that adversely affected their thinking and performance (as well as headaches, fatigue, and muddled thinking) found that L-tyrosine reduced their stress and depression while improving their performance. It is interesting that soldiers who normally experienced little, if any, stress or depression found that L-tyrosine did not make much difference in their performance. This finding may imply that people who consume enough L-tyrosine-rich foods, such as chicken, turkey, and seafood, won't enjoy the same degree of brain stimulation from L-tyrosine supplements as will those who have not ingested optimal amounts of this smart amino acid.

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