This is not a comprehensive list, simply some articles I have found along the way.

“High levels of glutamate may increase the survival of unfriendly microbes in the gut and contribute to problems like excess acid and heartburn.” (

“Additionally, Candida produces a toxin called beta alanine that competes with taurine for reabsorption in the kidney, and causes taurine to be wasted in the kidneys and excreted through the urine and beta alanine is absorbed instead. Therefore, taurine levels may be insufficient, which can contribute to less GABA activity. Not only that, taurine can combine with magnesium to form magnesium taurate and the two of them may be eliminated together, which can lead to magnesium deficiency. Insufficient levels of magnesium are going to result in excessive levels of calcium, which as we established earlier, will increase glutamate firing.” (

“Other chronic viral infections interfere with the GAD enzyme and some microbes like streptococcus flourish in a glutamate rich environment, thus many children with pandas and autism carry an ongoing infection with strep.” (

“The toxins created by Candida can stimulate surges of glutamate production. Hundreds of other toxins can produce this same surge in glutamate activity, including mold toxins, bacterial toxins, Lyme, and organic solvents. Dr. Rick Sponaugle, brain expert, states that even the toxins released by bacteria in your mouth that cause gingivitis and periodontal disease can increase glutamate activity and lead to a wide array of symptoms like anxiety. I can attest to this personally, I have experienced high anxiety from a bout with gingivitis. So it’s important to note, that many of the symptoms of Candida overgrowth can be caused by caused by an excess of glutamate.” (

“The glutamine/glutamate ratio was significantly higher in children with ASD. Glutamine and glutamate are further metabolized to gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter. An imbalance between glutamate and GABA transmission has been associated with ASD-like behaviors such as hyper-excitation.” “Correlations between gut bacteria and neurotransmitter-related metabolites are stepping stones for a better understanding of the crosstalk between gut bacteria and autism, which may provide potential targets for diagnosis or treatment of neurological symptoms in children with ASD,” says Kang.” (

Dysregulation of GABAergic Signalling Contributes in the Pathogenesis of Diarrhea-predominant Irritable Bowel syndrome. As we know, when glutamate is high, GABA is low. “Conclusion:
Our sets of data indicate that diminished level of GABA and altered GABAergic signal system contributes to pathogenesis of IBS-D by regulating inflammatory processes. These results provide novel evidence for anti-inflammatory role of GABA in IBS-D patients by altering the expression of pro-inflammatory cytokines.”

“CONCLUSION: Glutamate is involved in the mechanism of intestinal and cerebral inflammation responses. The effects of glutamate on cerebral and intestinal inflammatory responses after ischemia are up-regulated at the transcriptional level, through the NF-kappaB signal transduction pathway.”

The Significance of the Enteric Microbiome on the Development of Childhood Disease: A Review of Prebiotic and Probiotic Therapies in Disorders of Childhood

Propionic acid induces glutamate excitotoxicity. “The results showed that PPA caused multiple signs of excitotoxicity, as measured by the elevation of glutamate and the glutamate/glutamine ratio and the decrease of GABA, glutamine and the GABA/glutamate ratio.”

  • “The central premise of this model is that propionic acid (PPA) and/or related enteric fatty acids may be candidate environmental factors involved in the development of some types of ASD. Propionate and other short chain fatty acids (for example butyrate, acetate) are produced in the body during normal cellular metabolism and following enteric bacterial fermentation of dietary carbohydrates and proteins [13]. PPA producing enteric bacteria, including unique ClostridialDesulfovibrio, and Bacteriodetes species, have been isolated from patients with regressive ASD [2,14]. Propionate is also present naturally in a variety of foods and is a common food preservative in refined wheat and dairy products [15]. Under normal circumstances these short chain fatty acids are primarily metabolized in the liver. However, if there are genetic and/or acquired aberrations in metabolism [7,16], higher than normal levels of short chain fatty acids can be present in the circulating blood, and can cross the gut-blood and blood brain barriers passively and/or actively via high affinity transporters [17]. Under these conditions, short chain fatty acids can concentrate intracellularly, particularly in acidotic conditions [18,19], where they may have deleterious effects on brain development and function [13,20,21]. This could be important in the context of ASD, since PPA is known to affect cell signaling [22], neurotransmitter synthesis and release [20], mitochondrial function/CoA sequestration [16], lipid metabolism [23] immune function [24], gap junction modulation [19], and gene expression [25], all of which have been implicated in ASD [7,25-28].”
  • Clostridia can increase propionic acid
  • Propionic acid often increases with clostridia, gut bacteria imbalances, protein and/or carbohydrate fermentation in the gut & a diet high in grains

Stories of Hope