Sodium Glutamate

Modern methods of food production have altered radically from processes used in the past. Many food producing companies have invented their own improved techniques of cooking. Most of these procedures contain numerous different forms of chemical additives and one of the newest chemical substances that will enhance food flavor is monosodium glutamate (MSG). Even though it has no taste of its own, it intensifies considerably the taste of a wide variety of food as well as revealing flavors that could be hidden. While there are numerous reports of its dramatic effects, rigorous experimental evidence of its impact on measured preference is lacking. Moreover, James and Kantrowitz (1952, pp. 573-579) emphasize that MSG can cause definite changes in
the flavor of various foodstuffs and that these changes usually occur in the direction of increased palatability. Moreover, MSG produces a unique flavor that cannot be provided by other foods. Sometimes, Birks (2005, pp. 28–29) implies that MSG elicits a taste described in Japanese as umami, which translates to savory. Raiten, Talbot and Fisher (1995) inform that this property was first described in 1909 with respect to the glutamine content of konbu (a brown seaweed used in Japanese cooking) seaweed. Furthermore, Birks (2005, pp. 28-29) reports that umami taste does not necessarily evoke a flavor itself, despite, umami enhances other flavors. Sake, for example, has significant glutamate content; hence, the Japanese believe that sake enhances a meal. Although food additives can enhance the flavor of food, there is considerable debate about the undesirable effects on humans such as physiological damage, psychological impacts and changes in food palatability. This essay will tentatively conclude that consuming food that contains MSG can be detrimental to one’s health and can cause serious mental and physical health problems.

There are several physiological harms connected to MSG consumption. Therefore Kwok (1968, p. 796) observes that in the case of Chinese food or so-called Chinese restaurant syndrome (CRS), every potential consumer should remember that typical Chinese restaurant meals contain high concentrations of MSG and the symptoms of the CRS may include numbness, radiating to the back, arms, and neck; weakness; and palpitations. Additionally, Geha et al. (2000, pp. 1058–1062) illustrate that other symptoms include tightness, flushing, dizziness and facial pressure. Consequently, it appears that MSG may have numerous adverse effects. Although it is within the realm of biological plausibility that certain individuals experience a hypersensitivity to MSG, there is a lack of information to substantiate this claim. Also, several researches show that MSG attracted the most attention as a possible source of CRS symptoms. However, Tarasoff and Kelly (1993, pp. 1019–1035) raised serious questions about the validity of prior studies. There are significant measurement issues that affect one’s ability to evaluate MSG with a robust experimental design. On the other hand, another study by Kenney (1986, pp. 351–354) suggested that esophageal irritation from MSG was the mechanism that produced MSG symptoms. For example, MSG is not routinely consumed solitarily; instead, it is served with food. Thus, it is prudent for everyone to monitor their diets for potential headache, migraine, and asthma triggers.

Several experiments show that MSG does not instigate headache. However, Radnitz (1990, pp. 51–65) suggested that MSG prompts a generalized vasomotor (relating to or affecting the diameter of blood vessels) reaction, which causes throbbing pain at the temples and a beating sensation across the forehead. In addition, Radnitz’s claim derived not from a clinical trial but from an advice from the Diamond Headache Clinic. She also argued that those who experience migraine headaches are more susceptible to headache triggered by MSG. At the same time Leira and Rodrıguez (1995, pp. 534–538) described how MSG can trigger a migraine headache because of interference with acetylcholine (a compound that occurs throughout the nervous system, in which it functions as a neurotransmitter) synthesis. Consequently, Leira and Rodrıguez (1995, pp. 534–538) cited the Radnitz’s (1990, pp. 51–65) assertion, which, as described above, was not derived from a clinical study and they express their views as:
In the absence of clinical data, it is premature to make any conclusions about MSG as a potential trigger for migraine headaches. With no consistent data to suggest that MSG causes any type of headache, much more extensive clinical research would be required to establish a link between MSG and migraine headache (1995, pp. 534–538).
Therefore, there is no accurate confidence that MSG can cause any type of headache.

More recently, the term MSG symptom complex has been used instead of CRS and some researches show that there is a remote possibility of falling ill with these prodromes.
Therefore, Williams and Woessner (2009, pp. 640-646) state that the Federation of American Societies for Experimental Biology published a report of a comprehensive analysis of the safety of MSG and established a list of symptoms that constitutes the syndrome as shown in table 1. The less pejorative and more inclusive term Monosodium glutamate symptom complex (MSGSC) was also proposed. Additionally, these studies suggest that there may be a small number of people at risk for developing symptoms consistent with the MSGSC when consuming large amounts of MSG on an empty stomach without accompanying food. However, Geha et al. (2000, pp. 1058–1062) argue that approximately 20% of consumers may have at least one disease from MSGSC. On the other hand, Williams and Woessner (2009, pp. 640-646) contradict that the overall incidence of MSGSC appears to be low, even in self-identified MSG-sensitive patients. Thus, current evidence does not suggest that this entity is associated with persistent or serious effects, but numerous experiments show that MSG is not safe for some individuals with
asthma.

Williams and Woessner (2009, pp. 640-646)

According to some researches, MSG can be the reason for respiratory, skin, nasal and oral diseases. Consequently, Kwok (1968, p. 796) outlines that dietary ingestion of MSG might be responsible for a variety of clinical conditions including the MSGSC, asthma, itching and rhinitis (inflammation of the mucous membrane of the nose), has received a great deal of attention from investigators, clinicians, and the general public. In addition, Williams & Woessner (2009, pp. 640-646 ) have suggested that large doses of MSG (approximately >43 g) ingested on an empty stomach without concomitant food ingestion may elicit some of the symptoms of the MSGSC and it would be inappropriate to conclude that MSG consumed as a part of a typical diet would be likely to induce such symptoms. Also, Reif-Lehrer (1977, pp. 1617–1623) confirms that the case for MSG as a clear cause of asthma, urticaria or rhinitis is much less convincing. Nevertheless, Kenney (1986, pp. 351–354) refutes that MSG has a widespread reputation for eliciting a variety of symptoms, ranging from headache to dry mouth to flushing. Since the first report of the so-called Chinese restaurant syndrome, clinical trials have identified a consistent relationship between the consumption of MSG and the constellation of symptoms that comprise the syndrome. In addition, Hanon (2007) reports that like the brain, there are glutamate receptors in the human eye. According to an experiment conducted in Japan, a group of rats were put on a diet high in MSG for six months. The rats’ retinal nerve layers thinned by up to 75 percent. At the end of the six months, all of the rats had severe vision impairment, simply because their diet was high in MSG. Therefore, it can be seen that MSG has been described as a possible trigger for the loss of vision, asthma, urticaria, rhinitis and migraine headache exacerbations in the case of overconsumption.

The consumption of MSG has negative long-term health effects as well, including neuronal, brain and psychological damage.
Therefore, Olney, Adamo and Ratner (1971, p. 294) estimate that larger numbers of adult rats after multiple MSG treatments in infancy and have consistently found that average weights of the adenohypophysis (the glandular, anterior lobe of the pituitary gland) are about one-half those of control animals. In addition, Young and Ajami (2000, pp. 892-900) argue that in infant retina and hypothalamus (a neural control centre at the base of the brain), susceptible nerve cells undergo rapid necrosis (the death of most or all of the cells in an organ) and are phagocytized (the cellular process of engulfing solid particles), degraded, and evacuated from affected areas within 24 to 48 hours after MSG treatment. Consequently, it is clearly shown that MSG may have several hostile effects on brain work possibilities. Although Arees, Mayer, Burde, Shainker and Kayes, J. (1970, p. 549) have found both the rat and mouse susceptible to MSG-induced brain damage, Olney’s at al. (1971, p. 294) study was the first report to suggest the possibility that a single subcutaneous injection of MSG may not produce neuronal necrosis in the arcuate nucleus of infant rats. Additionally, Sampson (2003, pp. 701-706) reported failure to detect brain damage in infant rats injected subcutaneously with monosodium glutamate (MSG). However, Hanon (2007) states that normal neural components can
be found in the adult brain of an animal treated with MSG in infancy does not constitute a valid basis for claiming that MSG lacks effect on infant brain. Therefore, a large body of data indicates that MSG may impel permanent cerebral diseases despite several contradictions.

Excitotoxicity (the pathological process by which nerve cells are damaged and killed by excessive stimulation by neurotransmitters such as glutamate and similar substances) is one of the detrimental illnesses which can be caused by MSG consumption. Thus, Hanon (2007) persuades that, when brain cells communicate, neurotransmitters are secreted in small amounts in order to excite nearby brain cells and transmit a message. Moreover, most scientists believed all neurotransmitters to be relatively benign until 1969, when neuroscientist John Olney discovered two neurotransmitters that are harmful to the brain and one of them is monosodium glutamate (Sampson, 2003, pp. 701-706). These excitotoxins, in essence, overexcite brain cells to death by causing them to be excessively stimulated, resulting in brain damage. Besides, Young and Ajami (2000, pp. 892-900) point out that excitotoxicity is something that is connected with virtually everything pernicious that can happen to the brain-strokes, brain injury, brain tumors, severe hypoglycemia (deficiency of glucose in the bloodstream), multiple sclerosis, asphyxia (a condition arising when the body is deprived of oxygen), heavy metal poisoning, and most of the neurodegenerative diseases, including Alzheimer’s, Parkinson’s and Lou Gehrig’s disease. Hence, it may appear possible to assume that MSG can be used as a psychotropic food additive which can cause serious problems with cognitive functions. Even though Arees and Mayer (1970, pp. 549-550) reported that brain lesions were found also in albino rats after MSG treatment in the neonatal period, Olney at al. (1971, p. 294) have emphasized that glutamic acid which consists in MSG is converted to the acid amide (an organic compound containing the group - CONH2) and glutamine (a hydrophilic amino acid which is a constituent of most proteins), in which form it may be used by brain tissue as a source of energy. Furthermore, in clinical trials with moderate doses given to mentally retarded children, it has been reported to increase the IQ and produce other beneficial effects (ibid). Tentatively, we could possibly argue that MSG may have several beneficial effects to our thinking abilities, but Sampson (2003, pp. 701-706) postulates that injections of glutamate in laboratory animals have resulted in damage to nerve cells in the brain. Therefore, it would seem rather likely that MSG can cause more noxious results than wholesome consequences.

Many researches state that monosodium glutamate may have the ability to change flavors of food. Hence, Melnick (1949, pp. 64-65) instructs that MSG acts, not by adding its own savor, but by serving as a stimulant which increases the acuity of the taste receptors and thus accentuates the natural taste characteristic of the food. Also, Melnick (1950, pp. 199-204) exemplifies this point of view: “…the advantage of adding glutamate to food products is not for imparting a flavor of its own but for physiologically promoting and prolonging sensory acuity for the natural flavor…”. Similarly, Logan (1949) states that: “…MSG has the unique and unexplainable ability to create a keener sense of taste in the human taste buds…”. The only thing that seems certain from existing data is that MSG can change the flavor of food, usually in the direction of increased palatability.
Nonetheless, if MSG acts on taste acuity, it is difficult to see how it could increase sensitivity when the original taste is pleasant and yet depress it when the original taste is unpleasant. However, Cairncross and Sjostrom (1948, p. 982) clarify that MSG accentuates sweet and salty tastes in food when they are present in near optimal amounts, but if these tastes are greatly below the amount required for optimal palatability, the needed remainder will not be supplied. Subsequently the above findings contradict the contention that MSG serves simply to intensify the original natural flavor, since a differential modification of acuity would most certainly change the configuration or relative balance of the original taste components.

It may suggest substantial to argue that MSG can have not only detrimental effects in taste changes, but also beneficial properties. So, Cairncross (1948, pp. 32-38) observes that MSG suppresses acuity to certain undesirable flavors naturally present in some foods, for example, sharpness in onion flavor, rawness in many vegetables, a fishy taste in lima beans and bitter tastes present in a few freshly opened vegetables. Additionally, Crocker and Sjostrom (1948, pp. 450-455) reveal that the effect after consumption of MSG is pleasant and mild, and attended by definite tactile sensations: a slight tingling or furriness on the tip of the tongue and mild stimulation in the throat and back of the mouth. Moreover, Mosel and Kantrowitz (1952, pp. 573-579) articulate that while consuming MSG both taste and tactile sensations are very persistent, lasting several hours after exposure and the total effect is a feeling of mouth satisfaction. On the contrary, Cairncross and Sjostrom (1948, p. 982) accuse that if a food is slightly deficient in the amount of saltiness required for optimal palatability, MSG could supply the remainder; but if the deficiency were great, glutamate could not adequately overcome the difference. This data states that MSG is not always having positive effects on palatability. However, Win (2008, pp. 43-49) scrutinizes that MSG enhances the flavor of basically bland and tasteless foods, such as many low-fat and vegetarian foods may become tasty. Consequently, it may be probably assumed that MSG may have several advantageous influences on human tasting receptors despite numerous unfavorable comments.

In conclusion, it appears that there are serious problems with monosodium glutamate and it can influence differently on our health. Although moderate doses of MSG can enhance flavor of food, increase the IQ of mentally retarded children and produce other beneficial effects, it may cause several undesirable outcomes connected to physical diseases and mental abilities. Firstly, from a physiological point of view, MSG can generate Chinese restaurant syndrome, causing serious paralysis and can induce monosodium glutamate symptom complex, consisting of burning sensations, nausea and drowsiness. In addition, MSG has been described as a possible trigger for the loss of vision, asthma and migraine headache exacerbations in the case of overconsumption. Secondly, from a psychological research, MSG can have a number of injurious effects on intellectual abilities and be connected with practically everything maleficent that can happen to the brain harm, severe hypoglycemia (deficiency of glucose in the bloodstream), multiple sclerosis, and most of the neurodegenerative diseases, including Alzheimer’s, Parkinson’s and Lou Gehrig’s disease. Hence, some of the evidence shows that MSG may aggravate some chronic diseases, so people who are susceptible to headache, asthma and weakness are not recommended to consume it. Also, parents should restrict their children’s consumption of MSG consisting food, which can cause an addiction. Moreover, if they consume excessively high doses of monosodium glutamate and do it often, a possible worsening of their tasting abilities may occur. Therefore, the most appropriate solution for all these problems could be keeping limitations and temperate dosages in MSG consumption or renouncing radically from MSG consisting foodstuffs. However, further research on this topic is needed for more accurate safety information.

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