Excitotoxicity – Step 1

Another wonderful word – excitotoxicity – and a possible key to relief of fibromyalgia symptoms through diet.  Everything, according to Holton et al (see library) may hinge on glutamate and aspartate, but they are just the beginning of a twisting and interconnecting puzzle of nutrients, amino acids, and lots of initials.  I’m not sure if I’ll be able to make sense of this for you, but here we go…

Glutamate and aspartate are non-essential amino acids found in a large variety of foods. While some studies indicate that reducing foods that have these amino acids in them helps with fibromyalgia symptoms, others say pretty unequivocally no.  Looking at how glutamate and aspartate interrelate with other nutrients and the body, however, makes the conclusion a bit equivocal.

  1. Noxious stimuli (pain) causes the release of glutamate into the system – glutamate that has NOT been ingested.
  2. Prolonged pain (activation of nociceptors) causes the continuous release of glutamate into the system (again not through eating)
  3. Magnesium is a natural block of NMDA (N-methyl-D-aspartate) receptors – all I’m sure about is NMDA helps cause chronic pain, and NMDA antagonists help relieve chronic pain.
  4. Continuous release of glutamate breaks down the magnesium block.
  5. Add to that Substance P (a very mysterious substance related to chronic pain), the combination is the perfect storm for fibromyalgia.
  6. In addition, high levels of glutamate overexcites postsynaptic neurons which then die.  This is “excitotoxicity.”

High levels of glutamate and Substance P also increases the permeability of the blood-brain barrier (great image with that one…).  I don’t know exactly what that means yet, but when permeability increases, then DIETARY glutamate (stuff you eat) can enter the brain easier.  It would seem like this is the point that the spiral of fibro symptoms may start, and changing diet may help break the circuit.

At the same time, vitamin B6 assists development of an enzyme (glutamate decarboxylase) which converts glutamate into GABA (gamma-aminobutyric acid), which is an inhibitory neurotransmitter and blocks the negative effects of glutamate.

Therefore, it seems like eliminating foods is not necessarily the way to go, but making sure a proper balance of nutrients is in place is key to diet helping to relieve symptoms.  One thing to keep in mind (for me) is the idea of people having different “normals.”  One person’s B6 levels may need to be higher or lower than the next person’s.  Coming up with a diet is going to require some experimentation.


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