Autoimmune Thyroid Disease

An Unfortunate and Lengthy Adventure in Misdiagnosis

GABA fermentation

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Last week I was interested to read an article about the Japanese company Yakult, who have launched “GABA yoghurt” in Japan, “a new type of fermented milk containing GABA by using two kinds of starters—Lactobacillus casei strain Shirota, and Lactococcus lactis YIT 2027. The Lb. casei strain hydrolyzes milk protein into glutamic acid, and the Lc. lactis converts glutamic acid into GABA.”

I’ve been investigating the various different actions of bacteria in the formation of amines and neurotransmitters, including glutamic acid and GABA. So far I have the following:

Produces free glutamic acid (glutamate hydrolysation):

Lactobacillus casei

Converts free glutamate into GABA:

Lactococcus lactis subspecies lactis
Lactobacillus brevis

Some strains that appear to convert free glutamate into GABA:

Lactobacillus plantarum particularly strain WCFS1
Listeria monocytogenes
Escherichia coli particularly strain UT481
Saccharomyces cerevisiae strain S288C (Baker’s or pudding yeast)
Clostridium perfringens strain 13 (Note: clostridium infection may be involved in autism!)
Candida albicans strain SC5314 (Shock!)
This article contains more information, or search the PubMed gene database.

Does NOT produce GABA:

Lactococcus lactis subspecies cremoris

The GABA producing activity of these bacteria is via the enzyme glutamate decarboxylase, which requires the cofactor PLP (P5P), the active form of vitamin B6.

With this kind of experimentation, we always run the risk of producing many other amines. But where might we find such yeasts and bacteria?

Bread and Beer

Saccharomyces cerevisiae is also known as baker’s or brewer’s yeast. It produces GABA during long leavening of bread. Store bought bread is not leavened in this way but homemade sourdough bread is. Wheat and other grains are disproportionately high in bound glutamic acid, so it seems logical that a sourdough starter that includes L. casei, L. lactis and L. brevis, as well as saccharomyces cerevisiae will result in the production of glutamate and GABA. Saccharomyces cerevisiae lives happily with gut microflora.


Lactobacillus brevis OPK-3, having 84.292mg/L/h of gamma-aminobutyric acid (GABA) productivity, was isolated from Kimchi.” Am I correct in thinking that is 84 milligrams of GABA per litre per hour? GABA is not very active – you seem to need a lot of it to cause reactions compared to other amines. But after a 24 hour fermentation, that gives us over two grams of GABA to one litre of kimchi, a biologically active dose.


Cheese cultures fall into two main categories, thermophilic and mesophilic. Thermophilic cheeses are made mainly with streptococcus thermophilus and lactobacillus bulgaricus, and mesophilic cheeses are made mainly with a variety of lactococcus lactis subspecies and streptococcus thermophilus. Cheese – as well as containing a variety of other neurotransmitters like serotonin and tyramine – also contains GABA. More about cheese cultures.


A number of people who consume kefir say they ‘feel relaxed’ after eating it. There could be a number of reasons for this, including opioid-like peptide liberation.

A total of 21 strains of Lactobacillus species were isolated from Turkish kefir samples, in order to select the most suitable strains according to their metabolic activities including probiotic properties. As a result of the identification tests, 21 Lactobacillus isolates were identified as L. acidophilus (4%), L. helveticus (9%), L. brevis (9%), L. bulgaricus (14%), L. plantarum (14%), L. casei (19%) and L. lactis (28%). Metabolic activities of Lactobacillus spp. strains isolated from kefir

Lactobacillus brevis appears to be at least partially responsible for kefiran, the polysaccharide that forms around kefir grains.

In an investigation of the changes in the microflora along the pathway: kefir grains (A)–>kefir made from kefir grains (B)–>kefir made from kefir as inoculum (C), the following species of lactic acid bacteria (83-90%) of the microbial count in the grains) were identified: Lactococcus lactis subsp. lactis, Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus helveticus, Lactobacillus casei subsp. pseudoplantarum and Lactobacillus brevis. Yeasts (10-17%) identified were Kluyveromyces marxianus var. lactis, Saccharomyces cerevisiae, Candida inconspicua and Candida maris. In the microbial population of kefir grains and kefir made from them the homofermentative lactic streptococci (52-65% and 79-86%, respectively) predominated. Within the group of lactobacilli, the homofermentative thermophilic species L. delbrueckii subsp. bulgaricus and L. helveticus (70-87% of the isolated bacilli) predominated. Along the pathway A–>B–>C, the streptococcal proportion in the total kefir microflora increased by 26-30% whereas the lactobacilli decreased by 13-23%. K. marxianus var. lactis was permanently present in kefir grains and kefirs, whereas the dominant lactose-negative yeast in the total yeast flora of the kefir grains dramatically decreased in kefir C. Lactic acid bacteria and yeasts in kefir grains and kefir made from them

Kefir grains vary considerably in their bacterial makeup, but these particular species seem to be present all or most of the time. Unfortunately such cultures are often an unknown quantity.

Other Amines

Lactococcus lactis produces tyramine. I’ve tried kefir before, and it seemed quite pleasant but it kept me awake at night because of the tyramine content. I was unable to eat it regularly for this reason.

Histamine is also present in cheese cultures. It is largely formed by enterococci.


Written by alienrobotgirl

11 May, 2006 at 9:12 am

Posted in Probiotics Don't Work

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