Low Serotonin levels in the brain are a contributing factor to depression. Furthermore, Serotonin is produced in larger amounts in the region of the frontal lobe (called the prefrontal cortex) than in any other portion of the brain. And, as might be expected, if the frontal lobe is depressed, Serotonin levels will also be lower. A high level of Serotonin in the brain is an important factor in treading depression, but Serotonin is not found in any food or food supplements. It can on be manufactured within the body.

The body needs certain "raw materials to make Serotonin. One of these materials is the amino acid . Eating foods with adequate amounts of Tryptophan optimizes Serotonin production.

One study considered 15 women who had a past history of depression but were recovered and currently mentally healthy and happy without drug treatment. These women were put on a diet low in Tryptophan. The diet produced a 75% reduction in plasma Tryptophan concentrations. Then of fifteen women experienced temporary but clinically significant depressive symptoms. Some of the women claimed they experienced a "full relapse." The researchers noted that one woman "experienced a sudden onset of sadness, despair, and uncontrollable crying."

This study was highly praised as the first to show a direct link between diet and mood. One of my female patients has noticed that going just one day on a low Tryptophan diet will cause a relapse into depression and anorexia--having no desire to eat--which is a prominent symptom for her when she is depressed.

Serotonin is an important neurotransmitter in the brain, particularly in the frontal lobe. This is an area that needs to be vitally enhanced in depressed patients. (And as stated earlier) The brain can make no Serotonin unless Tryptophan is first present.

Getting enough Tryptophan is not the only nutritional factor in Serotonin production. As stated in the previous chapter, five large Amino Acids compete against Tryptophan in traveling to the brain. A food that contains a large total amount of these five amino Acids will reduce the flow of Tryptophan to the brain. Thus, if our diet is moderate in Tryptophan but high in those five Amino Acids, we may still develop a Tryptophan deficiency in the frontal lobe of the brain. The amount of Tryptophan compared to the amount of the five amino acids is the critical yardstick.