MSG, or Monosodium Glutamate is a salt of the amino acid - Glutamic Acid (glutamate). A salt is the chemical name for a molecule held together by opposite charges. Basically one (mono) sodium atom is "stuck" to the amino acid glutamate.
What is an amino acid?
Amino acids are often called the building blocks of life because it takes many of them linked together in a chain to create a protein. DNA tells the body how to make the chain and in what order the amino acids must line up. Some amino acids must be eaten because the body cannot make them (essential), some the body can make (non-essential), and yet others are able to be made during some times, but not others (conditionally essential). The life processes are all dependent on proteins which play critical roles in the body as structure, messengers, enzymes, and hormones.
Proteins are globular and clumpy because the amino acid chains fold in on themselves. This is how the immune system recognizes proteins. They are large compared to single amino acids, and they are uniquely shaped. The immune system does not recognize tiny MSG as an allergen. However, trouble can begin because the body can attack the larger enzymes like GAD, responsible for turning excess MSG into GABA.
What is an enzyme?
Enzymes are simply proteins with interesting day jobs. Enzymes help make things happen by helping to create other proteins and by helping break them down too. Enzymes are not straight chains, they are globular and clumpy, because they are folded into intricate shapes like other proteins. It is these shapes that help them create and break down other proteins and compounds.
What is a hormone?
Hormones are extremely potent protein based messengers that travel around the body connecting the lines of communication between glands of the endocrine system. These glands direct important functions like metabolism, growth, and sexual development. It has been found lately that smaller amounts of hormones are more effective than larger amounts because the body has feedback mechanisms that don't take kindly to overdoses of hormone. Things shut down because it is considered a trouble signal if there is too much hormone present. By affecting the part of the brain - the hypothalamus, that controls the master gland of the body - the pituitary, MSG may affect hormone production in the body.
Glutamate - Protein Building Block and Excitatory Neurotransmitter....
Glutamate is just one of many amino acids used by the body and linked into the chains of protein in the body. However some amino acids are free to float around by themselves as well as being found linked into proteins because they serve vital functions - some are neurotransmitters which carry nerve cell impulses throughout the body. Amino acid neurotransmitters are like chemical messengers carrying news from nerve cell to nerve cell. Some amino acid neurotransmitters like glutamate trigger nerve cells to fire, others like taurine and gamma amino butyric acid tell those firing nerve cells to cease firing. It is a delicate balance. An important balance. Researchers are finding out just what happens when that balance tips. In patients who suffer a stroke, for example, an excess of glutamate in the brain causes the nerve cells to die from overstimulation. Glutamate blocking drugs are being used to prevent some of this damage.
How does the body usually deal with excess amino acids?
Most amino acids if not used right away, are not stored as amino acids. The body has elaborate means of changing extra amino acids into other amino acids, and removing nitrogen and changing amino acids into fuel to be stored. There are processes such as "transamination" and "deamination" which occur mostly in the liver. In patients with compromised livers, however, they may have trouble transaminating cysteine, for example, into taurine, the amino acid that acts counter to glutamate. Also, an excess of the amino acid aspartate (found in Nutrasweet) may result in excess glutamate, since the body can convert aspartate directly to glutamate. Aspartate and glutamate affect some of the same receptors. In a different example, there is an enzyme that the body uses to convert excess glutamate into another neurotransmitter called GABA. In many patients with Type II Diabetes, their bodies view the enzyme responsible for turning MSG into GABA as an enemy and create antibodies to attack it so that it cannot do its job. This is a problem. The body is compromised in its job of getting rid of excess glutamate. It again is a question of balance, and what tips it.
Is manufactured MSG a problem?
According to some MSG opponents the glutamate added to foods is "bad" and the natural glutamate in our bodies is "good". MSG sellers argue that MSG is exactly like the glutamate in the human body, therefore it must always be "good". It is not so simple. There are contaminants in processed MSG. An anology that can be used is that there are right-handed amino acids and left handed ones. They are like mirror images of each other. Processed MSG contains not only the kind of amino acids the body is used to handling, but mirror image ones too. This may cause problems because it is like putting the wrong glove on your hand. It's not quite the same. We don't exactly know what problems this may cause. On the other hand (so to speak) the fact that glutamate the body is used to handling is also in MSG may present a problem because an excess of naturally occurring glutamate is well known by neuroscientists to be a problem in many disease states. Natural glutamate can cause problems we already know about. The reason food processors "free" glutamate from its bound form, is that it acts as a neurotransmitter in its free form. The food industry's claim that free glutamate is as harmless as bound glutamate is disingenuous at best. If it was exactly the same, they wouldn't need to hydrolyse vegetable protein (split the amino acids apart).
How do they make MSG or Free Glutamic Acid?
The following links explain exactly how the food industry can make free glutamic acid by hydrolyzing vegetable protein or by fermentation of glucose from starchy foods. In essence, MSG manufacturers can not only free bound glutamic acid from foods, but create it chemically.
Why do food companies add MSG to foods?
There are several reasons: