Allergic response – MSG is not a true allergen but may directly affect immune response by stimulating or damaging the nervous system. In studies done recently on animals, food allergies may be caused by a lack of Interleukin 12. This substance is made by cells in the body - oligodendrocytes, that are killed by excess glutamate. Also - Over 85% of individuals with Type 1 Diabetes have antibodies to the enzyme the body uses to turn Glutamate into GABA - glutamic acid decarboxylase (GAD). Their immune system attacks the means by which glutamate is metabolized, even though it does not attack glutamate itself. Because of their immune response to GAD, Type 1 diabetics are at risk of having an excess of glutamate in their systems already.
Blood Pressure - may create taurine deficiency – calcium channels stay open – causing high blood pressure and counteracting calcium channel blocking medication.
Blood vessels – Glutamate is vasoactive - it changes the diameter of the blood vessels - one reason why it may cause headaches.
Brain – during periods of hypoglycemia where low blood glucose levels leave the brain with low defenses, or allergy response where the blood vessels become "leaky", MSG may cross the blood brain barrier and damage brain cells by excitatory neurotoxicity. By affecting the pancreas and creating a situation of hypoglycemia, MSG may bring down the brain’s barriers, carrying it’s own key, in a sense, to get to the brain.
Digestive system – may create taurine deficiency due to its effect on cysteine. Cysteine competes with glutamate for uptake. Unfortunately, cysteine is used to make taurine, and taurine is used to make bile. Bile, which is made by the liver and stored in the gall bladder is used to break up fats into managable pieces for digestion. If bile formation is compromised - diarrhea and "gall bladder attacks" may occur.
Endocrine System - GABA (gamma amino butyric acid) is created by feedback mechanism from MSG. GABA may be addictive. Related to the date-rape drug GBH. GABA stimulates the pituitary to produce growth hormone. Research has shown that MSG can also overstimulate prolactin production by the pituitary and cause sterility in female animals. Nearly half of all pituitary tumors are prolactin secreting.
Hearing - The hair cells of the ear use glutamate as a neurotransmitter. Over-stimulation of these cells by glutamate can result in ringing in the ears. Glutamate opens calcium channels.
Heart Rate - May create taurine deficiency – (taurine regulates heartbeat) causing irregular or racing heartbeat.
Hypoglycemia – MSG’s stimulation of pancreas decreases blood glucose, making hypoglycemia (low blood sugar) worse.
Hypothalamus – part of the brain most susceptible to attack because it is the "sensor" of the brain, out in the open so to speak, not protected by the blood brain barrier because it needs to monitor levels of hormones in the blood. This part of the brain directs the action of the pituitary gland which directs the action of the entire endocrine system. Many MSG sensitive persons become diagnosed with thyroid disfunction and are put on synthetic hormone due to hypothyroidism. This would suggest that the hypothalamus may be compromised and unable to effectively direct the pituitary gland and consequently the thyroid. The hypothalamus also regulates hunger, and body temperature. The hypothalamus is also responsible for rage and panic as well...
Lungs - Asthma - due to MSG’s stimulatory effect on the nervous system (See Johns Hopkins research) would explain why asthma is induced in some by MSG.
Nervous system - MSG stimulates nerves in tongue and elsewhere directly (that’s why they use it). Glutamate in excess can overstimulate nerve cells until they die. Certain cells called oligodendrocytes which are found in the nervous system and make MYELIN are killed by excess glutamate. It is the inability to make myelin which defines the disease Multiple Sclerosis. In those patients, Interleukin 12 is low. IL 12 is also made by the oligodendrocytes - a clue that these cells are probably being killed by something. We firmly believe that something may be MSG and aspartame in the diet.
Pancreas – glutamate stimulates the pancreas and may cause Type II diabetes, obesity, and insulin resistance. In individuals with Type 1 diabetes, it may cause an excess of glutamate since 85% of those with Type 1 diabetes have antibodies which attack GAD - the enzyme responsible for converting glutamate into GABA.
Thyroid function – See Hypothalamus above
Vision - There are glutamate receptors in the retina. Laboratory studies on animals have shown the retina to be damaged by MSG.
Source
msgtruth.org