This is a topic that we've been queried about before and addressing it is somewhat difficult, simply because a lot of 'science' is required to properly explain everything. Dr. Bill Misner wrote an article entitled, MONOSODIUM GLUTAMATE (MSG), GLUTAMIC ACID (Glutamate), GLUTAMINE REVIEW and if you click on that link it'll take you directly to that article. It is quite technical but we believe it explains the differences between the three substances and the difference between processed glutamic acid and naturally occurring glutamic acid.
Here is some additional information, courtesy of Dr. Misner ...
Glutamic Acid is a naturally occurring amino acid, which exists in other protein foods. Glutamic acid is one of 20 amino acids that make up protein. Our bodies produce roughly 50 milligrams of glutamic acid every day. Of the 20 amino acids in breast milk, glutamic acid is the most abundant. Glycine, Glutamic and Aspartic Acids serve as neurotransmitters within the human central nervous system. Glutamic Acid and Aspartic Acid make up the Acidic Amino Acid Class. Amino acids within the same class compete for absorption through the blood-brain barrier. When one is present with the other, both are incompletely absorbed. Soybeans are typically rich in glutamic acid and its absorptive-competitor, Aspartic Acid. When a soy protein has been specifically processed to contain taste-enhancing excess amounts of free glutamic acid above the aspartic acid content, or has been fortified with monosodium glutamate in proportion to aspartic acid, negative health reactions may potentially result in those allergy-predisposed subjects.
Free Glutamic Acid: Natural vs. Processed
Natural Free Glutamic Acid is glutamic acid that has been freed from whole protein foods during digestion, or a glutamic acid that has been recreated from other amino acids. The parent compound in the glutamate family is glutamic acid, a normal amino acid component in the human metabolism. Glutamic acid exists in two forms: (L)- or (D)- glutamic acid. Humans have a right and left side called chirality, glutamic acid has two sides or enantiomers (chemically identical molecules as the L-enantiomer is a mirror image of the D-enantiomer). Just like most other alpha-amino acids, glutamic acid contains a stereogenic center and typically exists as either an L- or D- enantiomers though some DL- versions occasionally present. Free amino acids found in higher organisms are composed exclusively of the L-enantiomers of amino acids, while the mirror image D-forms are present in some naturally occurring peptide antibiotics and in bacteria. It is also possible that there are some small amounts of natural free glutamic acid associated with intact, unprocessed, unfermented, unadulterated protein. Natural Free Glutamic Acid found in higher organisms is typically presented as L-GLUTAMIC ACID. Natural food-borne protein, as well as protein in the human body, presents a preference for L-form amino acids.
MSG
Monosodium Glutamate is the sodium salt of glutamic acid. It contains 78% free glutamic acid and 21% sodium (the remaining 1% is comprised of 'contaminants'). The glutamic acid component of MSG is comprised of both the D-glutamic acid and the L-glutamic acid forms. The D-glutamic acid component is believed to be the form of glutamic acid responsible for the toxicity associated with MSG.
Summary
None of the maltodextrins formulated in HEED, Perpetuem, Sustained Energy, or Hammer Gel contain flavor-enhancing additives such as MSG. None of the Supro brand soy protein or Lysolecithins soy-derivatives in the Hammer Nutrition soy-containing fuels (Sustained Energy, Perpetuem, Hammer Soy) contain MSG. Additionally, the glutamic acid that is contained in Hammer Whey and Recoverite - as it is with all the soy-based Hammer Nutrition fuels/protein powders - is what occurs naturally in the protein source. There is no processed glutamic acid in any of these products.