Aspartate and glutamate act as neurotransmitters in the brain by facilitating the transmission of information from neuron to neuron. Too much aspartate or glutamate in the brain kills certain neurons by allowing the influx of too much calcium into the cells. This influx triggers excessive amounts of free radicals which kill the cells. The neural cell damage that can be caused by excessive aspartate and glutamate is why they are referred to as 'excitotoxins'. They 'excite' or stimulate the neural cells to death.
Aspartic acid is an amino acid. Taken in its free form (unbound to proteins) it significantly raises the blood plasma level of aspartate and glutamate. The excess aspartate and glutamate in the blood plasma shortly after ingesting aspartame or products with free glutamic acid (glutamate precursor) leads to a high level or those neurotransmitters in certain areas of the brain.
The blood brain barrier (BBB) which normally protects the brain from excess glutamate and aspartate as well as toxins;
- is not fully developed during childhood,
- does not fully protect all areas of the brain,
- is damaged by numberous chronic and acute conditions, and
- allows seepage of excess glutamate and aspartate into the brain even when intact.
The excess glutamate and aspartate slowly begin to destroy neurons. The large majority (75%+) of neural cells in a particular area of the brain are killed before any clinical symptoms of a chronic illness are noticed. A few of the many chronic illnesses that have been shown to be contributed to by long-term exposure excitatory amino acid damage include:
- multiple sclerosis(MS)
- ALS
- memory loss
- hormonal problems
- hearing loss
- epilepsy
- Alzheimer's disease
- Parkinson's disease
- hypoglycemia
- AIDS
- dementia
- brain lessons
- neuroendocrine disorders
The risk to infants, children, pregnant women, the eldery, and persons with certain chronic health problems from excitotoxins are great. Even the Federation of American Societies For Experimental Biology (FASEB), which usually understates problems and mimics the FDA party-line, recently states in a review that "it is prudent to avoid the use of dietary supplements of L-glutamic acid by pregnant women, infants, and children. The Existence of evidence of potential endocrine responses, i.e., elevated cortisol and prolactin, and differential responses between males and female, would also suggest a neuroendocrine link and that supplemental L-glutamic acid should be avoided by women of childbearing age and individuals with affective disorders." Aspartic acid from aspartame has the same deleterious effects on the body as glutamic acid.
The exact mechanism of acute reactions to excess free glutamate and aspartate is currently being debated. As reported to the FDA, those reactions include:
- headaches / migraines
- nausea
- abdominal pains
- fatigue (blocks sufficient glucose entry into brain)
- sleep problems
- vision problems
- anxiety attacks
- depression
- asthma / chest tightness
One common complaint of persons suffering from the effect of aspartame is memory loss. Ironically, in 1987, G.D. Searle, the manufacturer of aspartame, undertook a search for a drug to combat memory loss caused by excitatory amino acid damage. Blaylock is one of many scientists and physicians who are concerned about excitatory amino acid damage caused by ingestion of aspartame and MSG. A few of the many experts wo have spoken out against the damage being caused by aspartate and glutamate include Adrienne Samuels, Ph.D., an experiemental psychologist specializing in research design. Another is Olney, a professor in the department of psychiatry, School of Medicine, Washington University, a neuroscientist and researcher, and one of the world's foremost authorities on excitotoxins. (He informed Searle in 1971 that aspartic acid caused holes in the brain of mice.)
