Phenylalanine is a precursor to the synthesis of the neurotransmitters dopamine and norepi-nephrine. Treatment for PKU is a diet low in phenylalanine. Aspartame has also been linked to diketopiperazine, or DKP, an agent associated with brain tumors, and to vertigo and grand mal seizures in airplane pilots. That is why 13 piloting journals and military magazines warn pilots against the use of artificial sweeteners. Readers are encouraged to investigate the debate on the Internet.
Tyrosine travels through the bloodstream to the brain, where it becomes L-dopa.
This conversion takes the child from alertness to agitation and aggression in a matter of seconds. When inadequately nourished, children have great difficulty tolerating frustration and stress because they have no protein stores to draw on. Instead, they exhibit apathy, nonresponsiveness, inactivity, and irritability. When that happens, their attempts to learn are sabotaged. Insulin also enters the bloodstream and pushes glucose and the amino acids, except tryptophan, into muscles for use as energy.