Tuesday, March 31, 2009

Brain Food - #1 Complete Proteins

We know that the foods we eat affect the body. But they may have even more of an influence on how the brain works—it's general tone and level of energy and how it handles its tasks. Mood, motivation and mental performance are powerfully influenced by diet.

The brain is an extremely active organ, making it a very hungry one, and a picky eater at that. It's becoming pretty clear in research labs around the country that the right food - specifically, the natural nutrients that they contain - can enhance mental capabilities—help you concentrate, keep you motivated, magnify memory, speed reaction times, defuse stress, perhaps even prevent brain aging.

The best brain foods are:
  • complex carbohydrates (those with a low glycemic index)
  • complete proteins
  • omega-3 fatty acids
  • antioxidant rich fruits and veggies

Let's look at complete proteins first.

Complete Proteins:
A complete protein (or whole protein) is a source of protein that contains an adequate proportion of all of the essential amino acids for the dietary needs of humans or other animals.
Nearly all whole foods contain protein, and nearly all forms of protein contain all twenty protein-forming amino acids in some quantity. However, proportions vary, and some forms of protein are partly lacking in one or more of the essential amino acids. Meals prepared with a mix of protein foods can provide a better balance of the essential amino acids and therefore a more complete protein source.

Eight amino acids are generally regarded as essential for humans: phenylalanine, valine, threonine, tryptophan, isoleucine, methionine, leucine, and lysine. Cysteine (or sulphur-containing amino acids), tyrosine (or aromatic amino acids), histidine and arginine are additionally required by infants and growing children. Essential amino acids are so called not because they are more important to life than the others, but because the body does not synthesize them, making it essential to include them in one's diet in order to obtain them.

Proteins in the diet affect brain performance because they provide the amino acids from which neurotransmitters are made. Think of neurotransmitters as biochemical messengers that carry signals from one brain cell to another. The better you feed these messengers, the more efficiently they deliver the goods. Some neurotransmitters are neuron turn-ons that perk up the brain. Others have a calming or sedative effect. The two important amino acids, tryptophan and tyrosine, are precursors of neurotransmitters (e.g., the substances from which neurotransmitters are made).

These two amino acids influence the four top neurotransmitters - serotonin, dopamine, epinephrine, and norepinephrine. Serotonin is the neurotransmitter that relaxes the brain; it is made from tryptophan. Serotonin is sometimes called our ‘satisfaction’ brain chemical because, in addition to giving us a sense of well-being, a natural anti-depressant. Tryptophan rich foods may be helpful to relax the body for sleep. By eating tryptophan rich foods we can naturally boost levels of serotonin. Tryptophan is not as widely distributed in our foods as other amino acids, and it is found mainly in: turkey, chicken, fish, pheasant, partridge, cottage cheese, bananas, eggs, nuts, wheat germ, avocados, milk, cheese and the legumes (beans, peas, pulses, soya).

The other three, collectively known as catecholamines, are neurotransmitters that rev up the brain. Two factors influence whether the brain perks up or slows down following a meal: the ratio of protein to carbohydrate, and the ratio of the amino acids tryptophan and tyrosine. High protein, low carbohydrate, high tyrosine foods that are likely to jumpstart the brain are seafood, soy, meat, eggs, and dairy.