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Update on food safety of monosodium L-glutamate (MSG)
Abstract
Objective:
This evidence-based safety review of the flavor enhancer monosodium l-glutamate (MSG) was triggered by its global use and recent studies expressing some safety concerns.
Methodology:
This article obtained information through search of evidence-based scientific databases, especially the US National Library of Medicine NIH.
Results:
(A) MSG is a water-soluble salt of glutamate, a non-essential amino acid, normally synthesized in the body and prevalent in protein foods. (B) MSG is utilized world-wide for its "umami" taste and flavor enhancement qualities, (C) the human body does not discriminate between glutamate present in food and that added as seasoning, (D) glutamate metabolism is compartmentalized in the human body without reported ethnic differences, (E) glutamate does not passively cross biological membranes, (F) food glutamate is completely metabolized by gut cells as energy source and serves as key substrate for other important metabolites in the liver, (G) normal food use of MSG is dose-dependent and self-limiting without elevation in plasma glutamate, (H) the recent EFSA acceptable daily intake (30mg/kg body weight/day) is not attainable when MSG is consumed at normal dietary level, (I) scientists have not been able to consistently elicit reactions in double-blind studies with 'sensitive' individuals using MSG or placebo in food.
Conclusion:
Based on the above observations (A-I), high quality MSG is safe for all life-cycle stages without respect to ethnic origin or culinary background. MSG researchers are advised to employ appropriate scientific methodologies, consider glutamate metabolism and its normal food use before extrapolating pharmacological rodent studies to humans.
... Monosodium glutamate (MSG) consumption has risen dramatically over three decades [5]. People in Asia often eat foods that contain high carbohydrates [6,7] with the addition of MSG as a flavor enhancer [8][9][10][11][12][13][14]. MSG consumption in Southeast Asia is 2-3 times more than people in Europe [13]. ...
... People in Asia often eat foods that contain high carbohydrates [6,7] with the addition of MSG as a flavor enhancer [8][9][10][11][12][13][14]. MSG consumption in Southeast Asia is 2-3 times more than people in Europe [13]. Carbohydrates and MSG can trigger obesity or so-called obesogen [4][5][14][15]. ...
Asians often consume foods high in carbohydrates with the addition of MSG as a flavor enhancer. Foods with high carbohydrates and MSG are predicted to be obesogen. This study aims to explore the effects of high carbohydrate (HC), high MSG (HMSG), and a combination of high carbohydrate and MSG (HCHMSG) intake with the onset of obesity. Seven-week-old male Swiss Webster strain mice (Mus musculus) (n=40) were divided into four groups. The control group consisted of 57% carbohydrates, 9% fiber, and 6.11% fat. The HC group was given food intake consisting of 71% carbohydrate, 4.62% fiber, and 1.81% fat for 14 weeks; the HMSG group's diet consisted of 57% carbohydrates, 9% fiber, 6.11% fat with an additional 10% MSG and group HCHMSG diet consisted of 71% carbohydrates, 4.62% fiber and 1.81% fat with an additional 10% MSG. Significant weight gain (p<0.05) began at the fourth week in HC and HCHMSG groups and the HMSG group in the sixth week. After 14 weeks of study the HC group (BW 45.07±4.41; p<0.05) and the HCHMSG group were obese (42,817±7,149; p>0.05). WAT increases significantly in both HC and HCHMSG groups.
... This body of evidence lacked studies providing MSG at doses <2000 mg/kg bw in food and/or water, long-term duration studies of ≥1 year, developmental and prenatal studies from a range of researchers, and outcomes such as pancreatic changes, cardiac-related changes, gut microbiome, genetic and epigenetic alterations, and toxicokinetic data. More studies that elucidate mechanisms and establish causal links were highly recommended by several authors (Boutry et al., 2011;Chen et al., 2014;He et al., 2008He et al., , 2011Shi et al., 2014), in addition to studies investigating the kinetics of MSG (Al-Mosaibih, 2013;Delibashvili et al., 2018;Henry-Unaeze, 2017). Most of the currently available clinical studies involve acute testing which does not reflect the chronic human exposure, most of the samples were not well-defined in terms of participants' ethnicities and most of the doses used were not justified. ...
... Many reviews and regulatory parties considered that MSG is similar to the naturally occurring amino acid glutamate. However, a rationale or justification for this assumption was absent (Beyreuther et al., 2007;FDA, 2012;Fernstrom, 2009;Henry-Unaeze, 2017;Jinap and Hajeb, 2010;Kazmi et al., 2017). Further investigation in this area is warranted. ...
This scoping review aimed to map and elaborate the heterogenous and inconclusive body of evidence relating monosodium glutamate (MSG) and type 2 diabetes (T2DM). For this reason, multiple health outcomes related to T2DM were included and a systematic search was conducted. Experimental and observational trials between 1995 and January 2021 were collected. The tests were highly heterogenous in their samples, doses, route of exposures, durations, diets and conclusions. There was a pattern of negative effects of MSG at oral doses ≥2,000 mg/kg of body weight, and by gavage or injection at any given dose. Evidence was lacking in many areas and most of the evidence relied on short term tests. Further research should focus on standardizing and justifying methodologies, conducting long term studies and toxicokinetic tests, and avoiding bias. Focusing on the gaps highlighted and investigating mechanisms of action of MSG is crucial. Evidence-based toxicology is encouraged.
... Although commercial foods are time and energy saving, they adversely impacted the health of consumers as their manufacturing needs the addition of food additives to prevent the growth of microorganisms that cause spoilage or foodborne illness and to increase the consumer acceptability (Miyaki et al., 2016;Pasca et al., 2018;Chakraborty, 2019). In this regard, monosodium glutamate (MSG), a sodium derivative of L-glutamate, is still globally incorporated in a broad spectrum of food preparations (Hajihasani et al., 2020) for its umami taste and flavor enhancement properties (Henry-Unaeze, 2017). Many types of food contain MSG, for example, processed meat, soup bases, flavored snacks, spices, gelatin containing substances, and bodybuilding protein powder (Lavine, 2007;Populin et al., 2007). ...
... There are two different research directions in the literature regarding its safety as a food additive. Food safety regulatory agencies generally consider MSG consumption is not associated with health hazard issues (Zanfirescu et al., 2019) based on the fact that glutamate does not passively cross the cellular membranes, and is completely metabolized by enterocytes as an energy substrate (Henry-Unaeze, 2017). Owing to the plenty of polyunsaturated fatty acids in the renal lipid profile, the kidney is supposed to be a high-ranked organ in its vulnerability to free radical attack (Kubo et al., 1997). ...
Monosodium glutamate (MSG) consumption is responsible for a wide spectrum of health hazards including nephrotoxicity. The search for phytochemical strategies having broad safety profile to counter MSG toxicity is worthwhile. Nigella sativa L. seed (NSS) is very promising in this regard owing to its antioxidant and cytoprotective nature. Therefore, we attempted to investigate the potential protective effect of NSS on MSG-induced renal toxicity in rats. To accomplish this objective, fifteen adult Wistar albino rats were randomly and equally divided into three groups for 21 days: the control group received no treatment, MSG group supplemented with MSG at a dose of 30 g/kg feed, and MSG + NSS group supplemented with MSG at the same previous dose in conjugation with NSS at a dose of 30 g/kg feed. MSG and its combination with NSS failed to cause any significant difference in the kidney function parameters in comparison with the control. A significant elevation in lipid peroxides (LPO) level, glutathione-S-transferase activity and total antioxidant capacity (TAC) and a significant reduction in superoxide dismutase activity were found in MSG group. LPO level and TAC in MSG intoxicated rats significantly normalized by NSS ingestion. NO level showed absence of significant difference among all experimental groups. MSG elicited histopathological lesions such as depleted glycogen content and fibrosis however, NSS succeeded in enhancing all these features. MSG group showed positive glutathione reductase and superoxide dismutase two immuno-expression whereas, MSG + NSS group showed weak immunostaining. A significant increase in the number of apoptotic cells was observed in MSG group compared to the control. On the other hand, MSG + NSS group exhibited a significant decrease in the number of apoptotic cells. NSS mitigated MSG-induced renal impairments by ameliorating oxidative stress and exerting anti-apoptotic effect.
... Hence, MSG has been approved approximately in all countries, but the toxicity versus the safety of MSG seems to be controversial. Some studies provided safety reports about that food enhancer [10,11]. However, other studies demonstrate the deleterious impact on laboratory animals [6,8,9,[11][12][13][14][15][16][17][18][19]. ...
... Some studies provided safety reports about that food enhancer [10,11]. However, other studies demonstrate the deleterious impact on laboratory animals [6,8,9,[11][12][13][14][15][16][17][18][19]. Moreover, in humans, the ingestion of repeated high doses of MSG can trigger an elevated frequency of nausea and headaches [20]. ...
(1) Background: Well-known monosodium glutamate (E-621, MSG), originally used as a food flavor enhancer, was approved approximately in all countries, but the toxicity versus the safety of (MSG) are still unclear due to variable scientific toxicological reports. Moreover, it was reported to trigger elevated frequencies of nausea and headaches in humans and provide deleterious effects on laboratory animals. The objectives of the present study were to (i) estimate the possible toxic effects of the food additive MSG (ii) and the ameliorating protective effects of the dietary supplement spirulina (Spirulina platensis) on the biochemical parameters of blood and the damage produced in organs of Swiss mice after applying a supplementary daily dose of MSG for 4 weeks. (2) Methods: The present study was conducted on 20 mature Swiss mice, which were randomly organized into four groups of five Swiss mice. The treatments were (I) the control group, in which Swiss mice were fed only animal feed and drinking water; group II MSG1, which received 1 mL of MSG; group III MSG0.5, which was treated with 0.5 mL of MSG; and (IV) the group MSGS, which was treated with 1 mL of monosodium glutamate and 1 mL of spirulina (aiming to reduce the MSG toxicity). (3) Results: At the end of the experiment, Swiss mice treated with MSG demonstrated a passiveness regarding behavioral aspects. As we hypothesized, the parameters of the spirulina group reached similar values to the control group, and no histopathological observations have been found. Altogether, our findings evidenced that monosodium glutamate leads to histopathological changes in Swiss mice kidneys and caused important modifications for all biochemical parameters of the blood serum. Noticeably, the potential protective effect of Spirulina platensis was proved and was described by using the FTIR spectroscopy technique. (4) Conclusions: A diet rich in antioxidants and other plant-derived bioactive compounds may provide healthy nutrition, alleviating the potential side effects of some food additives.
... In 1908, salts of glutamic acid were discovered in Japan from seaweed as a flavour enhancer by Kikunae Ikeda (Henry-Unaeze, 2017;Ninomiya, 2001). Free glutamate is released depending on protein hydrolysis in fermentation, aging, ripening and cooking process (Wijayasekara and Wansapala, 2017). ...
... Thus, MSG has been allocated an "ADI not specified" by the JECFA. EFSA, as distinct from FDA and JECFA, is stated the "ADI level" as 30 mg/kg body weight (Zanfirescu et al., 2019;Henry-Unaeze, 2017;Maluly et al., 2017). In addition, EFSA indicated that consumption high amounts of MSG containing foods may cause adverse effects on human health. ...
ABSTRACT: The etiology of Moyamoya disease is unknown. It is a cerebrovascular disease which is caused by occlusion or stenosis and can be diagnosed by angiographic methods. Digital Subtraction Angiography (DSA) is the gold standard for diagnosis, especially in cases with mild stenosis and few collateral lesions.The causes of this disease are unknown; it is usually associated with congenital or tumoral defects. This disease is more common in the yellow race, especially woman in Japan. Its prevalence is low in countries other than Japan. The high prevalence of the disease in Japan has given it its name from Japanese. Moyamoya; Meaning of Japanese means smoke dispersing in the air.
The veins in the appearance of smoke scattering in the air giving the name of Moyamoya are, in fact, perforating arteries which are enlarged and angiographically visible to form collateral pathways due to stenosis. The first symptoms in Moyamoya may occur in various forms, including recurrent headache, epilepsy, acute hemiplegia. The clinical picture varies between children and adults.Ischemia in children and early hemorrhage in adults. Angiography is accepted as the gold standard for diagnosis of Moyamoya disease. The criteria for angiographic diagnosis of Moyamoya disease have been determined by the Research Committee for Progressive Obstructive Diseases of Circulus Arteriosus Cerebri of the Ministry of Health of Japan. According to this committee, stenosis or obstruction in the last part of arteriae carotis interna, and / or a. cerebri anterior and / or a. proximal narrowing or obstruction of cerebri media, abnormal collateral vascular network (moyamoya vessels) is observed and these findings are bilateral angiographic diagnosis of moyamoya disease is possible.
In this article, a 38-year-old female patient, who was admitted to the emergency department with complaints of severe headache and vomiting two years ago and whose hemorrhage areas were detected and discharged with conservative treatment, was admitted to the emergency department with sudden onset hemiparesis, nausea, vomiting and left hemiparesis. We present a case of moyamoya disease diagnosed in a 38-year-old female patient presenting with right capsula interna crus posterior and basal core hemorrhage on magnetic resonance angiography (MRA) images.
Keywords: Angiography, Hemorrhage, Hemiparasi, Moyamoya, Digital Subtraction Angiography (DSA).
... l-glutamic acid was discovered in 1866 by Karl Ritthausen, German scientist who isolated the acid hydrolysate of wheat gluten. Salt of glutamic acid were first revealed in 1908 (Hendry-Unaeze, 2017). Due to the modern lifestyle and addiction to the taste instead of the nutritional quality of food worldwide consumption of readymade and processed food has been increased. ...
Background
Monosodium glutamate (MSG E621) is one of the most popular flavouring agents of modern times and is widely used in many commercially packed food and even in house hold cooking. Previous studies revealed that excessive intake of MSG in diet causes obesity, metabolic defects, nephrotoxicity, neurotoxicity and hepatotoxicity in rats, but no reports are available in the literature about the ecotoxicological assessment of MSG by using fishes as a bioindicators. Since fishes are important consumer in aquatic food chain and directly linked with human health status, the present study was aimed to investigate the impact of MSG in freshwater fish Labeo rohita by using histological biomarkers.
Results
Ninety-six h-LC 50 of MSG to Labeo rohita was determined (1.5 g/L), and fish exposed to sub-lethal concentration of MSG (1/10th of 96 h-LC50 concentration of MSG (150 mg/L)) showed distinguished behavioural changes like erratic movement, loss of appetite and excessive mucous secretion all over the body as an adaptive syndrome to avoid the direct exposure to MSG in the medium. Histopathological analysis clearly depicts severe damages in the vital organs of fish. In gills, epithelial necrosis, hypertrophy, hyperplasia, primary and secondary gill lamellae degeneration, oedema, fusion of adjacent secondary lamellae and rupture of gill epithelium were observed. The intensity of tissue damage was increased as the exposure period was extended. The liver displayed vein congestion, vacuole formation, degeneration in parenchymal cells and bile stagnation, whereas MSG-treated kidney tissue showed high interstitial inflammation. Among the vital organs gill and liver displayed the highest histopathological alterations.
Conclusions
The present study clearly demonstrated that MSG is toxic to fish and able to cause significant damages in the vital organs as the exposure period was extended. Since the studies on the toxicity of MSG to fish are rare, the present investigation may contribute to the scarce literature on sub-lethal toxicity of MSG to freshwater fishes.
... The average intake in the UK is 0.58 g/day, in Germany it is 100 g, and in other European countries it is around 10 g/day (Rhodes et al., 1991). Nigerians consume 0.56-10 g per day on average (Henry-Unaeze, 2017). MSG is marketed in the open market and shops as Ajinomoto or Vedan by West African Seasoning Company Limited (Inuwa et al., 2011). ...
Background
Changes induced by monosodium glutamate (MSG) can negatively impact milk production and secretion, among other adverse effects. This study aimed to investigate the effects of MSG consumption on receptor gene expression and quantification of hormones and receptors, as well as oxidative stress biomarkers and other lactogenic parameters in lactating animals. Twenty-four female Wistar rats, nine weeks of age, were randomly assigned to four groups, each containing six rats, at parturition. The rats in groups II, III, and IV were given varying doses of monosodium glutamate (MSG); while, group I was given distilled water and served as the control. The experimental period lasted two (2) weeks.
Results
The groups administered with MSG showed a significant decrease in mammary PRLR gene expression ( p < 0.05), as well as a marked reduction ( p < 0.05) in mammary PRLR, OXT receptor, AQP-3, brain antioxidant enzymes (SOD, GPx, and CAT), and pituitary SOD compared to the control group ( p < 0.05). Furthermore, there was a significant increase ( p < 0.05) in reactive oxygen species levels in the serum and mammary gland homogenates, erythrocyte osmotic fragility, and elevated ( p < 0.05) brain and pituitary MDA levels in the MSG-administered groups compared to the control group. Daily milk yields were significantly decreased ( p < 0.05) in the MSG-administered groups between days 10 and 14 of lactation.
Conclusion
The findings of this study suggest that prolonged consumption of MSG could interfere with lactation-associated functions via increased ROS production, reduced antioxidants, decreased AQP-3, mammary prolactin and oxytocin receptors, and prolactin receptor mRNA in lactating Wistar rats.
Graphical Abstract
... Classified as a non-essential amino acid, MSG occurs naturally in a myriad of foods, exhibiting its versatility in meats, seaweed, anchovies, molluscs, tomatoes, cheeses, vegetables, and shellfish, as well as human and cow milk, apples, almonds, eggs, onions, carrots, potatoes, walnuts, and garlic. The incorporation of MSG in processed foods such as meats, crackers, frozen meals, soups, salad dressings, baby formula, canned tuna, fast food, frozen dinners, and potato chips adds to its presence in the modern diet [3]. Despite historical safety concerns, MSG remains a regular component, contributing to a perplexing interplay of flavors and textures [4]. ...
Introduction
Monosodium glutamate (MSG), a common global food additive in processed foods, influences flavors and textures due to its chemical complexity and nutritional intricacy. Despite an annual production of 1.9 million tons and historical safety concerns, the multifaceted impact on health, ranging from metabolic disorders to neurological and cardiovascular implications, necessitates ongoing research for informed consumption and balanced dietary practices.
Materials and methods
This cross-sectional study investigates MSG-associated intricacies among Saudi Arabia's urban population. The research included questionnaire development, translation, and cultural adaptation, and was validated by nutrition experts. A sample size of 420 was calculated for a 95% confidence level. Data collection occurred from September 13 to October 31, 2023, and ethical considerations were ensured. Statistical analysis, including chi-square tests, regression analysis, and SPSS, explored intricacy relationships.
Results
The MSG intricacy study in Saudi Arabia's urban population, involving 420 respondents, showed statistically significant correlations (P < 0.05) in demographics. The key findings indicate an awareness of the impact of MSG on health, its associations with various conditions, and strong support for its exclusion from foods. Region, gender, age, and social status correlations highlighted diverse perspectives. The Western province showed the highest response rate at 42.61%, prompting regional awareness questions. Gender dynamics showed that 90.47% of the respondents were females, emphasizing potential gender-specific concerns. Concentration among ages 20-30 (61.9%) underscored generational factors. While commendable baseline awareness was noted, 73.09% of the participants believing MSG is harmful prompts further investigation. Emotional responses, including happiness (25.95%) and frustration (18.33%), highlight the complexity of the individuals' experiences, emphasizing the need for tailored communication strategies.
Conclusion
The MSG intricacy study in Saudi Arabia's urban population reveals insights into knowledge, attitudes, and behaviors, emphasizing the need for nuanced interventions considering regional and emotional differences. The findings underscore health concerns, supporting regulations, and knowledge impact on behavior. This survey serves as a valuable tool for informed public discourse and decision-making in the unique socio-cultural context of urban Saudi Arabia.
... Consumption of MSG has been linked to hypertension and obesity; however, these studies included participants who consumed higher than-average levels of MSG [40,41]. Conversely, it is reported that MSGs dietary element may stimulate the intake of foods high in protein [29] Beef bouillon 3 g MSG in 150 ml beef bouillon Only women in the MSGtreated group had a statistically significant higher headache incidence than the control group* Gore ME and Salmon PR (1980) [30] 150 ml tap water 1. [34] 400 ml Sugar-free lemon soda 150 mg/kg = 9 g/60 kg MSG Significant difference* and bolster several physiological activities, such as intestinal motility [42]. For individuals who worried that MSG could be a trigger for headaches or migraines, an elimination diet might serve as an effective diagnostic method. ...
Purpose of Review
To review the evidence and role of monosodium glutamate (MSG) as a headache and migraine trigger.
Recent Findings
MSG is a common food additive, has widely been linked as a trigger of headache, as well as other symptoms. However, the evidence for MSG as a causative agent for headache is debated. Various clinical trials over the past several decades have reported conflicting results, with studies suggesting that MSG does and does not increase the incidence of headache. However, the dosages of MSG exposure are often inconsistent across studies, with many studies administering a dose significantly higher than the average consumption.. Additionally, there are misconceptions about which foods and cuisines have MSG in them.
Summary
MSG could be a potential trigger for migraine and headaches. It is unclear exactly how MSG plays into the migraine pathophysiology. It’s crucial to accurately determine if MSG is present in one’s diet to evaluate its potential impact on headaches.
... Monosodium glutamate berasal dari asam -glutamat dan termasuk asam amino nonesensial (asam glutamate) disebut juga monosodium -glutamate atau sodium glutamate. Monosodium glutamate secara alami terdapat dalam tubuh dan tidak perlu mendapatkannya dari makanan, merupakan at kristal berwarna putih yang tidak berbau dan kandungannya terdiri atas asam glutamate (78 ), sodium (21 ), kontaminan dan air (1 ) [5][6][7]. Batas maksimum penggunaan bahan tambahan pangan penguat rasa seperti asam glutamat, Mononatrium L-Glutamat maupun Monokalium L-Glutamat termasuk acceptable daily intake (ADI) yang tidak ditentukan (not specified), artinya tidak ada batasan khusus dalam konsumsi MSG dan dapat digunakan secukupnya (Joint FAO/WHO Expert Committee on Food Additives (JECFA)). European Food Safety Authority (EFSA) menetapkan tingkat asupan harian yang dapat diterima sebesar 30 mg/kg berat badan [8]. ...
Kata kunci cerebellum, gambaran histologis, mencit, monosodium glutamate, obesitas Abstract Background. The sodium salt of glutamic acid, monosodium glutamate (MSG), is a white crystalline compound (glutamic acid). MSG was first produced in large quantities in early 1963 by Korea and Japan which then spread to other countries, including Indonesia. The medical profession is concerned about the detrimental consequences of MSG because of its widespread and uncontrolled consumption. The histological differences between the cerebellum of MSG-treated and MSG-free rats are of interest to researchers Method. The Post Test-Only Control Group design was used in this study and used data collected for 14 days. This study used 30 male mice of the Swiss Webster type (Mus Musculus) which were reared as pure strains through inbreeding. The mice taken were 8 weeks old weighing 20-40 grams and divided into three groups, each consisting of nine mice with one tail in reserve for each group. One group as a control and two groups will receive MSG orally, each at a dose of 3 mg and 8 mg. Termination of mice was carried out by means of dislocation of the cervical vertebrae and continued with preparation of mice brain tissue preparations. Data analysis, which was obtained from observing the histological appearance of the mouse brain, used the Paired-Sample T test in the SPSS (Statistical Product and Service Solutions) version 20.0 for Windows with a significance level of 0.05 Results. In this study, there was no difference in the histological appearance of the brain cerebellum of mice in the control group and the administration of 3 mg and 8 mg of MSG. However, there was a greater increase in body weight in mice given 3 mg of MSG compared to the group given 8 mg of MSG and controls, the average weight gain was 2.87 mg. Conclusion. After observing through a microscope on the brain preparations of control mice, MSG 3 mg and MSG 8 mg, no difference in histological appearance was found. But giving MSG to mice affects weight gain.
... Monosodium glutamate (MSG) is an L-glutamate salt well-known as a taste enhancer in instant foods (1). The average MSG consumption in Asia is 1.4-2.3 ...
Introduction: The toxicity of high concentration monosodium glutamate (MSG) has become a controversial issue because of its inconsistent results in human and animal studies. This present study aims to evaluate the effect of subchronic high-doses oral administration of MSG on spatial memory performance and hippocampal pyramidal cells number. Methods: This study involved twenty-eight male Wistar rats, which were divided into a control group of NaCl 0.9% and three intervention groups of MSG 1.0 mg/g bodyweight (M1), 2.0 mg/g bodyweight (M2), and 4.0 mg/g bodyweight (M3) for 30 days. Statistical analysis used a One-way ANOVA test. Results: The result showed significant differences in spatial memory on the Morris Water Maze (MWM) test, including path length (p = 0.020) and escape latency (p = 0.011) according to general linear model repeated measurement analysis. The mean difference of estimated hippocampal pyramidal cells total number among the groups showed volume (p = 0.001), numerical density (p = 0.590), and cells number (p = 0.004). Furthermore, Post-Hoc analysis in both spatial memory and hippocampal pyramidal cells showed that the increasing MSG dose from 1.0 to 4.0 mg/g bodyweight led to a decrease in the results of spatial memory performance on the MWM test and a decrease in hippocampal cells. Conclusion: The present study has provided novel quantitative data that subchronic administration of high-dose MSG caused deleterious effects on the spatial memory function and the volume and number of hippocampal pyramidal cells.
... Monosodium glutamate (MSG) is an L-glutamate salt well-known as a taste enhancer in instant foods (1). The average MSG consumption in Asia is 1.4-2.3 ...
Introduction: The toxicity of high concentration monosodium glutamate (MSG) has become a controversial issue because of its inconsistent results in human and animal studies. This present study aims to evaluate the effect of sub-chronic high-doses oral administration of MSG on spatial memory performance and hippocampal pyramidal cells number. Methods: This study involved twenty-eight male Wistar rats, which were divided into a control group of NaCl 0.9% and three intervention groups of MSG 1.0 mg/g bodyweight (M1), 2.0 mg/g bodyweight (M2), and 4.0 mg/g bodyweight (M3) for 30 days. Statistical analysis used a One-way ANOVA test. Results: The result showed significant differences in spatial memory on the Morris Water Maze (MWM) test, including path length (p = 0.020) and escape latency (p = 0.011) according to general linear model repeated measurement analysis. The mean difference of estimated hippocampal pyramidal cells total number among the groups showed volume (p = 0.001), numerical density (p = 0.590), and cells number (p = 0.004). Furthermore, Post-Hoc analysis in both spatial memory and hippo-campal pyramidal cells showed that the increasing MSG dose from 1.0 to 4.0 mg/g bodyweight led to a decrease in the results of spatial memory performance on the MWM test and a decrease in hippocampal cells. Conclusion: The present study has provided novel quantitative data that subchronic administration of high-dose MSG caused delete-rious effects on the spatial memory function and the volume and number of hippocampal pyramidal cells.
... Monosodium Glutamate (MSG) is a popular flavor enhancer frequently used in food industry (2). Aside from being used as a food additive, it is also naturally found in many types of food such as cow milk, eggs, cheese, tomatoes, almonds, apple, onion, potato, carrot, garlic and walnut (3,4). Now it is added to many food products such as processed meats, canned food, crackers, soups, salad dressings, infant formula, dietary supplements, fast foods and potato chips (4). ...
... Furthermore, major scientific committees and regulatory bodies, such as the Joint FAO/WHO Expert Committee on Food Additives (JECFA), the European Commission Scientific Committee on Food (SCF), and the U.S. Food and Drug Administration (FDA), have assessed the safety of MSG and all separately came to a conclusion that MSG is safe to consume at a normal intake level and there is no evidence linking the use of MSG to long-term medical problems for the general public [71]. The more recent evidence-based safety reviews of MSG also came to the same conclusions, addressing that some studies speculatively linked animal pharmacology to human food use of MSG, and many are based on excessive dosing that does not meet with levels normally consumed in food products [72,73]. ...
Background
Evidence has demonstrated that excess sodium intake is associated with development of several non-communicable diseases. The main source of sodium is salt. Therefore, reducing salt intake in foods is an important global public health effort to achieve sodium reduction and improve health. This study aimed to model salt intake reduction with 'umami' substances among Japanese adults. The umami substances considered in this study include glutamate or monosodium glutamates (MSG), calcium diglutamate (CDG), inosinate, and guanylate.
Methods
A total of 21,805 participants aged 57.8 years on average from the National Health and Nutrition Survey was used in the analysis. First, we employed a multivariable linear regression approach with overall salt intake (g/day) as a dependent variable, adjusting for food items and other covariates to estimate the contribution of salt intake from each food item that was selected through an extensive literature review. Assuming the participants already consume low-sodium products, we considered three scenarios in which salt intake could be reduced with the additional umami substances up to 30%, 60% and 100%. We estimated the total amount of population-level salt reduction for each scenario by age and gender. Under the 100% scenario, the Japan’s achievement rates against the national and global salt intake reduction goals were also calculated.
Results
Without compromising the taste, the 100% or universal incorporation of umami substances into food items reduced the salt intake of Japanese adults by 12.8–22.3% at the population-level average, which is equivalent to 1.27–2.22 g of salt reduction. The universal incorporation of umami substances into food items changed daily mean salt intake of the total population from 9.95 g to 7.73 g: 10.83 g to 8.40 g for men and 9.21 g to 7.17 g for women, respectively. This study suggested that approximately 60% of Japanese adults could achieve the national dietary goal of 8 g/day, while only 7.6% would meet the global recommendation of 5.0 g/day.
Conclusions
Our study provides essential information on the potential salt reduction with umami substances. The universal incorporation of umami substances into food items would enable the Japanese to achieve the national dietary goal. However, the reduced salt intake level still falls short of the global dietary recommendation.
... A blood assay of Glu should be obtained after an overnight fast, to enhance specificity, avoiding misinterpretation due to nutritional factors, unless dietary management is planned. A preferable practice would be to monitor plasma Glu at the fixed time of the day, if multiple testing is needed, as plasma Glu might fluctuate along the day [168]. For better and more accurate interpretation, multiple factors that can modify blood Glu should be kept in mind, apart from nutritional status mentioned earlier, age, gender [169], body temperature [170], and even blood sampling sites seem confounding factors [171]. ...
The prevalence of aggression has become an increasing problem that threatens lives, from suicidal ideation to homicide. Multiple factors contribute to such issue, including genetic, psychological, familial, economic, environmental, dietary habits, endocrine disturbances, psychiatric disorders, and neurological disturbances, making it resistant to control. If key targets can be identified, it might be possible to find a cure. To date, glutamate has been one culprit involved in aggression, instigated by inflammatory mediators and reactive oxygen species. Monosodium glutamate as well as omega-3 and-6 polyunsaturated fatty acids -components of our modern diet- modulate the inflammatory state, hence, affecting brain and blood glutamate, the latter is an essential neurotransmitter sharing in the antioxidant capacity of erythrocytes.Hence, the erythrocytic or blood glutamate assay, along with members of the inflammatory cascade, might be a cost-effective diagnostic and prognostic tool for aggressive behavior, especially feasible for assessing the efficacy of the intervening dietary and/or pharmacological measures to prevent such potentially devastating behavior.
... Most of the packaged foods such as chips, Jelly, Pastry, Candy, Biscuit, Chocolate, French-fries, Pizza, and Noodles contain MSG, which imparts " Umami" or " Savory" or "Broth-like" or "Meaty taste" [3]. The regular daily consumption of MSG in industrialized country is about 0.3-1g/day, which is alarmingly increasing many times in developing countries [4]. The increased consumption of MSG around the globe is proportional to its increased production, especially major share of production by countries of Asia [5]. ...
Objective: The study was intended to explore whether Monosodium glutamate (MSG) induces oxidative stress on the liver of Wistar albino rats when fed chronically at three different doses, namely, low, mid, and high doses identical to human consumption doses in growing countries. Methods: The acclimatized Wistar albino rats (n=24) were randomly selected and grouped into four groups, namely Control, Low dose MSG (180 mg kg), Mid dose MSG (360 mg/kg), and High dose MSG (720 mg/kg). The animals were orally administered MSG for 120 days. After completion of the experimental period (120 days), euthanized animal liver was homogenized to investigate the oxidative stress marker enzymes such as Superoxide Dismutase (SOD), Glutathione Peroxidase (GPx), Catalase (CAT), and Myeloperoxidase (MPO). Results: The MPO showed a significant increase (p<0.05) in liver homogenate of all MSG induced groups when compared to control group. The SOD, CAT, and GPx activity deteriorated (p<0.05) in monosodium induced groups contrasting to the control group. Conclusion: The effects of MSG on oxidative stress markers on liver homogenate in the current study exhibited erratic abnormal changes in oxidative stress markers of monosodium induced groups which contemplate the harmful effects of MSG consumed chronically. The further studies should confirm the genetic basis of oxidative stress damage and transform the safety regulations of MSG consumption throughout the world.
... Ancak MSG'nin hiperaktivite, obezite, mide rahatsızlıkları, migren gibi sağlık problemlerine yol açma olasılığı nedeniyle kullanımından kaçınılmaktadır. Bu nedenle gıda üreticileri maya özütleri gibi alternatif doğal lezzet arttırıcılarını araştırmaya yönelmektedirler (Kilcast ve Ridder, 2007;Henry-Unaeze, 2017;Mitchell, 2019). ...
Et ürünlerinde kullanılan tuz, su tutma kapasitesini geliştirmesi, etin yumuşaklığını sağlaması, mikrobiyel koruyucu etki göstermesi, uçucu bileşiklerin etkinliğini arttırması, renk pigmentinin gelişiminde rolü olması, lezzete katkısı sebebiyle önemlidir. Ancak yüksek miktarda tuz tüketimi birçok hastalığa neden olmaktadır. Tüketici bilincinin artması ve devlet otoritelerinin sağlık ile ilgili yaklaşımları gıda endüstrisinde tuz kullanımının azaltılmasına yönelik araştırmaların artmasına neden olmaktadır. Et ürünlerinde tuz kullanımını azaltmaya yönelik çalışmaların başında; ürün formülasyonlarında tuza alternatif olabilecek katkıların, örneğin klorür tuzları, laktatlar, fosfatlar, polisakkaritler, deniz yosunları, lezzet arttırıcılar, aminoasitler ve nükleotidler, süt mineralleri karışımlarının geliştirilmesi gelmektedir. Bu çalışmalarda temel amaç, tuzun sağladığı özellikleri üründe koruyacak katkılar geliştirerek sodyum tüketimini azaltmaktır. Bu çalışmada, et ürünlerinde tuz ikamesi olarak kullanılan katkılar ve bu katkıların ürün özellikleri üzerine etkileri derlenerek sunulmuştur.
... Additionally, mammals have the ability to metabolize large dose of MSG; but, glutamate concentrations in plasma fluctuate during the day and lead to an altered diet, metabolism, and protein turnover [54]. In this context, it has been revealed that the application of lower oral doses could produce altered histomorphological architecture of the brain. ...
In this fast-food era, people depend on ready-made foods and engage in minimal physical activities that ultimately change their food habits. Majorities of such foods have harmful effects on human health due to higher percentages of saturated fatty acids, trans-fatty acids, and hydrogenated fats in the form of high lipid diet (HLD). Moreover, food manufacturers add monosodium glutamate (MSG) to enhance the taste and palatability of the HLD. Both MSG and HLD induce the generation of reactive oxygen species (ROS) and thereby alter the redox-homeostasis to cause systemic damage. However, MSG mixed HLD (MH) consumption leads to dyslipidemia, silently develops non-alcoholic fatty liver disease followed by metabolic alterations and systemic anomalies, even malignancies, via modulating different signaling pathways. This comprehensive review formulates health care strategies to create global awareness about the harmful impact of MH on the human body and recommends the daily consumption of more natural foods rich in antioxidants instead of toxic ingredients to counterbalance the MH-induced systemic anomalies.
... Glutamate is also involved in many physiological activities other than taste perception, such as digestion, intermediary metabolism, gut-brain axis activation, and maintaining normal brain function (Kondoh, Mallick, & Torii, 2009). Although it is generally recognized as safe, the use of monosodium glutamate in foodstuffs has always been controversial among the public concerning its potential adverse effects on human health (Henry-Unaeze, 2017;Sugimoto, Murakami, Fujitani, Matsumoto, & Sasaki, 2019). Such as it has also been linked with masking ingredients of poor freshness (Populin, Moret, Truant, & Conte, 2007). ...
In this study, we developed a highly sensitive glutamate biosensor based on Pt nanoparticles (PtNP) decorated two-dimensional nanomaterial MXene-Ti3C2Tx for sensitive analysis of monosodium glutamate (MSG) in food samples. The morphology of [email protected]3C2Tx was characterized by SEM, which confirmed the successful synthesis of the nanocomposite. The electrochemical experiments were carried out after optimizing working conditions, and a linear relationship was established between the current response and MSG content. The biosensor exhibited a good linear relationship with a correlation coefficient (R²) of 0.9948 in a range of 10 to 110 μmol/L, and it also had excellent sensitivity (1.5906 nA/(μmol/L)) and a low detection limit (0.45 μmol/L). The biosensor exhibited high selectivity towards glutamate, and it could hold over 70% of its initial sensitivity for 28 days when stored under optimal conditions. The analytical recovery of added MSG (50 and 100 μmol/L) in the vegetable soup was 87.04 and 106.81 g/100 g, respectively. The biosensor was also used successfully to test MSG content in soy sauce, stock cube, and mushroom seasoning. Hence, the constructed glutamate biosensor would be a suitable method for rapid detection of MSG in foodstuffs.
... It has been reported that more MSG is used in Europe (0.3-0.5 g/day) compared to Asia (1.2-1.7 g/day) (2), and the daily acceptable intake of MSG is proposed to be 30 mg/kg/body weight (BW)/day (3). Despite reports that MSG is safe for consumption (4,5), the results of several studies show its potential toxicity. Excessive MSG consumption may exacerbate asthma (6) and migraine headaches are related to glutamate (7). ...
Monosodium glutamate (MSG) that called "Umami" is a flavor enhancer added as a food additive (E621) in many parts of the world, especially in East Asian countries, but in recent studies began to be used in many studies as a neurotoxin because of the harm on the hypothalamic arcuate nucleus in neonatal animal. Several studies have pointed to the negative effects of injection of this substance on different parts of the hypothalamic-pituitary-gonadal (HPG) axis, besides the inhibition of secretion many reproductive neuropeptides, neurotrophic factors, and hormones, which play a vital role in the regulation of reproductive function. In addition, oral administration or injection in large quantities of MSG to newborns animal leads to a decrease in or an overabundance of the production of many regulatory peptides of the male and female reproductive systems. In this literature review, we summarized the most important studies examined the effect of this substance on the regulatory peptides of HPG axis and whether by oral consumption or injection.
... On the contrary, Henry-Unaeze (2017) proved that during the consumption of MSG, there was no effect on the pituitary hormones in the blood nor the function of the nervous system, noting that it was safe [36]. ...
According to the famous saying of the medieval physician Paracelsus, "There is no substance without poison. Only the dose determines the extent of the toxic effect." Here, the effect of monosodium glutamate (MSG) on human health and the risks to the health of its frequent use in the short term was addressed and the long term was evaluated according to the studies of several researchers specializing in this regard. Monosodium glutamate (MSG) is known as one of the most popular food additives that classified as a flavor enhancer. Parts of the evidence were reviewed from the literature explaining its effect on immune system cells in addition to metabolic disorders by exposing individuals to obesity and what is known as metabolic syndrome, as well as reviewing a lot of evidence indicating the effect of MSG intake on the health of the kidney, liver and other parts of the body through Practical application to laboratory rats and clinical studies in humans.
... Namely, some reactions associated with the monosodium glutamate are commonly known as MSG-symptom complex (headaches, numbness, flushing, tingling, palpitations, and drowsiness), but so far there is no strong evidence associating MSG and these symptoms. The US Food and Drug Administration (FDA), classify it as 'generally recognized as safe' (GRAS) and whenever it is added as an additive, it must be referred (E621) on the product label (Geha et al., 2000;Choudhury and Sarkar, 2017;Henry-Unaeze, 2017). Recently, the European Food Safety Authority (EFSA) established an acceptable daily intake level of 30 mg (kg) − 1 body weight (EFSA, 2017). ...
The fifth basic taste - umami, described as the essence of deliciousness, was discovered more than a century ago in Japan, after extraction of free glutamate from dashi, the Japanese broth prepared with brown seaweed Saccharina japonica (konbu). Although umami was accepted as a basic taste in the Eastern world a long time ago, umami gained recognition in the Western world very slowly. However, as the consumer's longing for delicious food is constantly growing, umami taste can be an important choice criterion. Moreover, in recent years, there has been an increasing demand for vegetarian and vegan products and edible seaweeds are a resource that has been used in the development of new food products. Consumption of edible seaweeds is becoming popular worldwide, not only due to their abundance and unique flavors but also because of their nutritional benefits and umami taste.
In this review, the basic concepts of umami in seaweeds are described. The traditional consumption of seaweeds in the Eastern world, but also the more innovative approach in Western countries, are referred. The quantification of compounds responsible for the umami taste in aqueous extracts (broths) based on edible seaweeds was reviewed. Also, the influence of seaweed conservation techniques (drying techniques applied) and extraction conditions on umami potentials have been discussed, as well as the latest studies on metabolic pathways, including the biochemical reactions between glutamate and umami receptors.
... The increase in monosodium glutamate percentage, which has less sodium than salt (approximately 123 and 393 mg of sodium, respectively) (Maluly et al., 2017), results in similar sensory effects to salt considering the salty taste (Table 2), measured through intensity and JAR scales, this can be a way of reducing sodium in this type of product. This is an interesting result because monosodium glutamate is scientifically recognized as safe (Beyreuther et al., 2007;Henry-Unaeze, 2017). Figure 4 shows the TDS curves for the snacks selected from the experimental design (Table 1), which were assays 5 to 8. Assays 5 and 6, which present the minimum and maximum percentages of salt, respectively, and assay 7, which presents the minimum percentage of monosodium glutamate, had the umami taste as the dominant attribute, since this attribute is above the significance level. ...
The effects of salt and monosodium glutamate on the sensory characteristics of cheese‐flavored corn grits expanded snacks, looking to reduce the sodium content of these products, were studied. An increase in the percentage of salt increased the ideal of the intensity of salty taste, the degree of liking of salty taste, and the degree of liking of flavor, while an increase in the monosodium glutamate percentage increased only the first two previous sensory responses. No interactions were observed between salt and monosodium glutamate considering results from Response Surface Methodology. From the experimental design, four samples were selected and submitted to the Temporal Dominance of Sensations analysis. In general, the snacks presented umami taste as a dominant attribute. Among the snacks studied, that with 1.2% salt and 0.6% monosodium glutamate stands out, since this was sensorially accepted, presented umami taste as its dominant attribute, and still had estimated sodium content below the average for commercial snacks. Nowadays there are efforts for reducing the salt consumption in reason to relations of such ingredient with some non‐communicable chronic diseases. However, the reduction of salt content in food is not a simple task because sodium compounds play an important role in the flavor of foods. Therefore, studying how some compounds rich in sodium, such as salt and monosodium glutamate, influence the sensory characteristics of products, in this case, of expanded snacks of cheese‐flavored corn grits, is relevant for providing alternatives for reducing the sodium content on products, reduction that must be gradual so as not to negatively affect consumer acceptance.
... The amount of sodium in MSG (12.28 g/100 g) is one third of the sodium in salt (39.34 g/100 g), which makes it a promising salt alternative in sodium reduction strategies. The majority of glutamate intake is from that naturally present in food, with only a small amount derived from MSG seasoning (Henry-Unaeze, 2017). Ever since the discovery of glutamate's unique, umami taste by Dr. Ikeda in 1908 (Kawamura & Kare, 1987), MSG has been widely used as a flavor enhancer in savory foods. ...
We tested the hypothesis that reduced‐salt versions of four “better‐for‐you” dishes enhanced with monosodium glutamate (MSG) through a “Salt Flip” in an amount that still substantially reduced total sodium matched the consumer acceptance of normal‐salt versions. Three versions each—standard recipe with normal salt, reduced salt, and reduced salt with MSG, of four dishes—roasted vegetables (RV), quinoa bowl (QB), savory yogurt dip (SD), and pork cauliflower fried rice (CR) were evaluated by 163 consumers for overall liking and liking of appearance, flavor, and texture/mouthfeel on the nine‐point hedonic scale, preference, adequacy of flavor, saltiness, and aftertaste on just‐about‐right (JAR) scales, likeliness to order, and sensory characteristics by check‐all‐that‐apply. For each dish, the MSG recipe was liked the same (or significantly more for SD, P < 0.05) than the standard recipe, and better than the reduced salt recipe for QB and CR. The same was true of likeliness to order. MSG recipes of QB and SD were significantly preferred to the standard recipes, with no difference for RV and CR. MSG recipes were consistently described as “delicious,” “flavorful,” and “balanced.” Penalty‐lift analysis showed that “delicious,” “flavorful,” “balanced,” “fresh,” and “savory”; and “bland,” “rancid,” and “bitter,” were positive and negative drivers of liking, respectively. Two of three uncovered preference clusters, accounting for 68% of consumers, consistently liked MSG recipes, and the same or more so than standard recipes. We conclude that MSG can successfully be used to mitigate salt and sodium reduction without compromising consumer acceptance of better‐for‐you foods.
Practical Application
The Salt Flip offers a promising dietary sodium reduction strategy through the addition of monosodium glutamate (MSG) to reduced‐salt, savory, better‐for‐you foods that does not compromise consumer acceptance of their sensory profile.
Tilapia (Oreochromis niloticus) is one of the leading freshwater fish commodities in Indonesia. The problem often faced by tilapia farmers is the low level of feed utilization, especially protein, which is still low, resulting in suboptimal growth. The glutamate content in monosodium glutamate (MSG) can act as a precursor for the formation of arginine and glutamine, which can increase the production of protease and lipase enzymes that are excreted into the intestines during the feed hydrolysis process, which is useful in increasing the absorption of nutrients in the form of protein and fat. This research was conducted using fingerling tilapia as a test fish with an average individual length of 6.59 ± 0.21 cm/fish and an average individual weight of 5.33 ± 0.27 g/fish. This research was carried out in an aquarium container measuring 40x30x30 cm with a water volume of 27 l and a density of 15 fish/aquarium. The aim of this research was to determine the effect of MSG in fish feed on total feed consumption (TKP), feed utilization efficiency (FUE), protein efficiency ratio (PER), protein retention, relative growth rate (RGR), and survival (SR) in fingerling tilapia. This research used an experimental method with a completely randomized design (CRD) of 4 treatments with 3 replications. Treatments A, B, C, and D are fed with the addition of 0 MSG in commercial feed; 0.75; 1.5; and 2.25 g/kg. Variables observed included TKP, FUE, PER, protein retention, RGR, and SR. The research results showed that MSG in feed had a significant effect (P < 0.05) on the FUE, PER, protein retention, and RGR values but had no effect (P < 0.05) on the TKP and SR values. FUE value; PER, protein retention; The highest RGR was obtained in treatment D (2.25 g/kg); FUE (87.21±2.28); PER(1.83±0.05); protein retention (50.47±0.76); The RGR (3.06 ± 0.03) and survival value for all treatments were found to be 100%. The water quality during the research was in optimal condition.
Flavor enhancers are pivotal in numerous food products in the commercial markets. Among these enhancers, umami flavor compounds stand out for their ability to elicit a pleasurable taste response and elevate the overall sensory characteristics of food. This short review offers insights into incorporating natural ingredients as sources of umami, a cornerstone in enhancing savory flavors while shedding light on emerging trends within the food industry concerning the utilization of these natural ingredients. Furthermore, this review delves into the intricacies of umami taste, encompassing its constituent elements and characteristic profile. In addition to exploring the essence of umami, the study also delves into various technologies instrumental in their creation and processing. These technologies encompass a range of methods, including fermentation, enzyme hydrolysis, acid hydrolysis, the Maillard reaction, water-based extraction, and drying techniques.
Monosodium glutamate (MSG) is one of the most popular food additives in the world and is often ingested with commercially processed foods. It can be described as a sodium salt of glutamic acid with the IUPAC name - Sodium 2-aminopentanedioate and is ionized by water to produce free sodium ions and glutamic acid. MSG use has significantly increased over the past 30 years, its global demand stands huge at over three million metric tons which is worth over $4.5 billion. Asia was responsible for more than three quarter of world MSG consumption with the country China also leading in global consumption as well as production and export to other countries. Prior to year 2020, global demand for MSG increased by almost four percent each year with the highest significant increase in demand for MSG predicted to rise in Thailand, Indonesia, Vietnam and China, followed by Brazil and Nigeria. However, several researches featured in this review has identified MSG consumption as a major contributor to the development and progression of some metabolic disorders such as obesity, which is a risk factor for other metabolic syndromes like hypertension, diabetes mellitus and cancer initiation. The mechanism by which MSG induce obesity involves induction of hypothalamic lesion, hyperlipidemia, oxidative stress, leptin resistance and increased expression of peroxisome proliferator-activated receptors (PPARs) Gamma and Alpha. Similarly for induction of diabetes mellitus, MSG consumption resulted in decreased pancreatic beta cell mass, increased oxidative stress and metabolic rates, reduced glucose and insulin transport to adipose tissue and skeletal muscles, insulin insensitivity, reduced insulin receptors and induced severe hyperinsulinemia. Dietary salt, an active component of MSG is also found to be a major risk factor for high blood pressure (which may lead to hypertension). MSG is used to enhance the taste of tobacco, causing smokers to consume the product in excess and thereby increasing the risk of cancer development. Depending on the amount consumed, MSG has both positive and negative effects. Despite the controversy surrounding MSG's safety and its probable contribution to risk of development and progression of metabolic disorders, its global consumption is still very high. Therefore, this article will sensitize the public on the need for cautious use of MSG in foods and also aid regulatory agencies to further review the daily MSG consumption limit based on metabolic toxicities observed at the varied dosages reported in this review.
The purpose of this study was to determine the effects of dietary glutamate supplementation on the growth performances, feed utilization efficiency and hematological parameters of carp (Cyprinus carpio L.). Two hundred carps were allocated to four experimental groups, each consisting of five replicates. The four treatments were dietary glutamate supplementation of 0.0, 0.5, 1.0 and 1.5%, respectively, each with 10 fish in one experimental unit. The initial weight of the trial fish ranged between 2.54 to 2.61 g fish-1 (P<0.05). Each group of fish was cultured in a 10 L aquarium container of (60x45x45) cm 3 for 42 days. The fish were fed on the test diets three times a day by at satiation method. The experiment was carried out to study the effects of glutamate supplementation on the final weight gain, total feed consumption, feed utilization efficiency, relative growth rate, survival and hematological parameters (i.e. consisting of aspartate aminotransaminase (AST), alanine aminotransaminase (ALT), bilirubin, blood glucose) of the carp. The data obtained on growth performances were analyzed by ANOVA and followed by Duncan's test using SPSS 22.0. Hematological and water quality data were analyzed descriptively. This study showed that dietary glutamate supplementation resulted in the increase of feed utilization efficiency and relative growth rate. Dietary glutamate affected the concentrations of AST, ALT, bilirubin and blood glucose, but had no impact on the fish survival. Based on the ECR and RGR regression, it was found that the optimal level of dietary monosodium glutamate (MSG) varied from 0.99 to 1.16%. The maximum value of feed utilization efficiency and relative growth rate were 59.79 and 3.48% day-1 , respectively.
Monosodium glutamat (MSG) 1800’lü yıllardan beri lezzet artırıcı katkı maddesi olarak, işlenmiş ve paketlenmiş tuzlu veya tatlı gıdalarda kullanılmaktadır. Yapılan birçok çalışma MSG kullanımının çok sayıda yapısal ve fonksiyonel bozukluklara yol açabileceğini ortaya çıkarmıştır. Son yıllarda MSG kullanımının çok artması gıda güvenliği konusunda endişelerinde artmasına neden olmuştur.
Monosodium glutamate (MSG) is a flavor enhancer and food additive with a unique umami taste. Due to its widespread use in humans, this study focused on the cytotoxicity, anti-diabetic effect, and interaction with protein digestion by performing a standardized static in vitro digestion model and lipid digestion by estimating free fatty acids released from 0.5 g of olive oil during intestinal lipolysis. The study showed that monosodium glutamate has an apparent cytotoxic effect on the Caco-2 cell line in a dose-dependent manner. MSG glutamate also showed low inhibitory activity on alpha-glucosidase enzyme even at high concentrations (16.3 % at 1800 ppm). By performing simulated in vitro digestion to study the interaction between MSG and protein digestion, followed by MTT study, total protein determination, and pH drop method, all results concluded that MSG affected proteolysis. Finally, the impact of MSG on lipolysis was studied through a free fatty acid release test. The results of the study demonstrated that MSG harmed fat digestibility in a concentration-dependent manner. As a result, it is essential to conduct further studies, especially in vivo studies, to determine the potential negative effects of MSG on human health.
This study aimed at reducing the amount of salt added to potato chips by decreasing the size of salt particles. First, a selected panel ( n = 15 assessors) evaluated the saltiness of potato chips added with refined and microparticulated salt using the magnitude estimation. The amount of 1.6% of refined salt, previously determined as just‐about‐right in potato chips, was equivalent to 1.2% of microparticulated salt. Afterward, an acceptance test ( n = 115 consumers) was performed with six samples of potato chips added with microparticulated salt, with successive reductions from 1.2% to 0%, combined with a seasoning made of powdered parsley and onion. Results showed that it is possible to reduce salt by up to 65% without a significant decrease ( p > .05) in acceptance. In conclusion, microparticulated salt associated with the flavor‐enhancing power of traditional seasonings proved to be a valuable strategy to reduce sodium in snacks.
Practical Applications
Previous studies have proposed strategies to reduce salt added topically to snacks without combining sodium chloride (NaCl) with additives such as potassium chloride (KCl) and monosodium glutamate (MSG). This study demonstrated, using a trained panel on magnitude scale, that decreasing the size of salt particles by a simple sieving process made it possible to reduce 25% of the salt added to potato chips. Further reduction was possible by combining microparticulated salt with powdered onion and parsley without a significant ( p > .05) drop in consumer's acceptance ( N = 115). The strategy not only makes snacks healthier but also improves flavor and keeps the product's clean label, which is a demand of the consumer.
Introduction: Monosodium glutamate (MSG) is known as a flavor-enhancing compound and also the fifth basic taste (umami). About the safety of using MSG as a food additive, some studies show indications that there is no threat and others show the opposite. There is no consensus about the advantages and disadvantages of using MSG. Objective: To systematically review studies in the international literature on the knowledge of the pros and cons of using glutamate in food. Methods: Systematic review of studies published in journals indexed in ScienceDirect and PubMed databases. Articles published until 2020 were included. The aspects involving the advantages and disadvantages were discussed, as well as the health risks related to the MSG intake from diet. Results: The revised studies showed that MSG can reduce the amount of sodium in foods without modifying flavor. Although authorities indicate that MSG is safe for human consumption, some studies highlight that health risk is real. The use of MSG is still controversial because there are some misunderstandings in the applied amounts of MSG absorption and metabolism. Conclusion: MSG is widely applied in industrial and homemade food. The need for further studies is crucial, and aspects such as metabolism and amounts of MSG effectively consumed must be better evaluated.
Monosodium glutamate (MSG) is a food flavor enhancer used widely for its umami potency in different cultures. This chapter documents the biological importance of MSG and found that it constitutes sodium, glutamate, and water and occurs richly in protein foods and in the human body. As a major nonessential amino acid in the human body, it performs several functions including energy for gut cells, material for protein metabolism and key metabolites, and also a neurotransmitter in the central nervous system. It can be found free or bound to proteins and the free form has the unique taste quality (umami) that translates savory taste in foods. This umami taste is distinct to other basic tastes. Human beings have been shown to adequately metabolize food glutamate and flavor-enhancing glutamate. Double blind placebo-controlled studies reported that flavor-enhancing glutamate at normal dietary levels found in umami foods can considerably improve health of older population and poses no risk for other age groups. The European established acceptable daily intake of 30 mg/kg body weight is well above the no adverse effect level. Proper labeling is specified for MSG on product labels. More work on MSG as consumed in human diet is encouraged.
Monosodium glutamate (MSG) is a flavor enhancer commonly used in modern nutrition. In this study, it was aimed to determine the effect of in ovo administered MSG on the embryonic development of thymus, bursa of Fabricius, and percentages of alpha-naphthyl acetate esterase (ANAE) positive lymphocyte by using histological, histometrical, and enzyme histochemical methods in chickens. For this purpose, 410 fertile eggs were used. The eggs were then divided into five groups: group 1 (control group, n = 40 eggs), group 2 (distilled water-injected group, n = 62 eggs), group 3 (0.12 mg/g egg MSG-injected group, n = 80 eggs), group 4 (0.6 mg/g egg MSG-injected group, n = 90 eggs), and group 5 (1.2 mg/g egg MSG-injected group, n = 138 eggs), and injections were performed via the egg yolk. On the 18th and 21st days of the incubation, the eggs were randomly opened from each group until six live embryos were obtained. The embryos of each group were sacrificed by decapitation, and blood, thymus, and bursa of Fabricius tissue samples were taken from the obtained embryos. The MSG-treated groups were found to be retarded embryonic development of thymus and bursa of Fabricius tissue compared to the control and distilled water groups. MSG treatment also resulted in reduced lymphoid follicles count and follicle diameters in bursa of Fabricius (P < 0.05). The percentage of peripheral blood ANAE positive lymphocytes was significantly lower in the MSG-treated groups than in the control and distilled water groups (P < 0.05). In conclusion, it has been found that in ovo administered MSG can adversely affect the embryonic development of thymus and bursa of Fabricius and decrease percentage of ANAE positive lymphocyte.
Bu çalışmada, dünyada en yaygın kullanılan lezzet arttırıcı gıda katkı maddelerinden biri olan monosodyum glutamat (MSG)’ın, medulla spinalis’in embriyonik gelişimi üzerine etkilerinin histolojik ve histometrik yöntemler kullanılarak belirlenmesi amaçlanmaktadır. Çalışmada 410 adet döllü tavuk yumurtası kullanıldı. Yumurtalar kontrol, distile su, 0,12, 0,6 ve 1,2 mg/g yumurta MSG olmak üzere beş gruba ayrıldı ve enjeksiyonlar kuluçka başlangıcında yumurta sarısına yapıldı. Kuluçkanın 15, 18 ve 21. günlerinde her gruptan 10 yumurta açılarak elde edilen embriyolardan medulla spinalis doku örnekleri alındı. Doku örnekleri %10'luk formolde tespit edildikten sonra rutin histolojik yöntemlerle parafinde bloklandı. Bloklardan alınan 6 μm kalınlığındaki kesitler Hematoksilen Eozin, Kluver-Barrera, Toluidine Blue, Periyodik Asit Schiff ve Crossmon’ın üçlü boyama yöntemi ile boyandı. Preparatlar ışık mikroskop altında incelendi ve medulla spinalis dokusunda histometrik ölçümler yapıldı. 15. gün elde edilen embriyolarda yapılan histometrik ölçümler sonucunda substantia grisea yüzey alanının medulla spinalis’in kesitlerdeki toplam yüzey alanına oranı dikkate alındığında kontrol ve MSG grupları arasında anlamlı bir farklılık olmadığı tespit edildi. 18. günde substantia grisea yüzey alanının medulla spinalis’in kesitlerdeki toplam yüzey alanına oranı açısından özellikle 0,6 mg/g yumurta dozunda MSG uygulanan grupta kontrol grubuna kıyasla arttığı tespit edildi. 21. günde ise substantia grisea yüzey alanının medulla spinalis’in kesitlerdeki toplam yüzey alanına oranının 0,6 mg/g ve 1,2 mg/g dozunda MSG uygulanan grupta kontrol ve distile su grubu ile karşılaştırıldığında azalmış olduğu tespit edildi. Kanalis sentralis’in enine ve boyuna çapları üzerinde yapılan değerlendirmelerde ise MSG uygulanan gruplarda, kontrol ve distile su grubuna göre kanalis sentralis’in enine ve boyuna çaplarının azaldığı dikkati çekti. Medulla spinalisin ventral kornusunda bulunan motorik nöronlarda MSG uygulanan gruplarda 15., 18. ve 21. günlerde nekroz ve nöronofaji gibi histopatolojik değişikliklere rastlandı, MSG grupları kontrol ve distile su grupları ile karşılaştırıldığında motor nöronlardaki nekrozda önemli bir artış dikkati çekti (p<0.05). Sonuç olarak inkübasyondan hemen önce döllü tavuk yumurtasına verilen MSG’nin medulla spinalisin embriyonik gelişimini olumsuz yönde etkilediği ve motor nöronlarda nekroza neden olduğu tespit edilmiştir.
According to the European Food Safety Authority (EFSA),the allowed level of Monosodium glutamate (MSG)consumption is 30 mg / kgbw per day. Several studies show that long-term MSG is toxic to the kidneys bycausingoxidative stress and decreasing thekidney function.This study was based on the potential for impaired kidneyfunction and structure caused by excessive consumption of MSG and basil leaves (Ocimum basilicum L.) asantioxidant plants with flavonoid content. To find out the effect of basil (Ocimum basilicum L.) leaves’ ethanolextract dose 175 mg / kgbw, 350 mg / kgbw and 700 mg / kgbw against kidney tubular injury on white rats WistarStrain induced by MSG.This study was a quasi-experimental study with a randomized post-test only controlledgroup design. The number of samples was 25 ABM, divided into five groups, the positive control group (K+), thenegative control group (K-) and the treatment group (K1,K2 and K3).In the group given basil leaves ethanol extractdoses of 175, 350 and 700 mg / kgbw, there was a decrease in tubular injury in the kidney of the white rat (Rattusnorvegicus) Wistar strain induced by MSG 1.6 g/day orally. The optimal dose in this study was 700 mg / kgbw. Teststatistics indicated significant differences in all five groups (p < 0.05).The administration of ethanol extract of basilleaves (Ocimum basilicumL.) was able to prevent tubular injury in the kidney of the white rat (Rattus norvegicus)Wistar strain induced by MSG. Kadar konsumsi MSG yang diperbolehkan menurut Europian Food Safety Authority (EFSA) yaitu 30 mg/kgBB per hari. Beberapa studi pada hewan coba menunjukkan bahwa pemberian MSG jangka panjang bersifat toksik padaginjal dengan menyebabkan stress oksidatif dan menurunkan fungsi ginjal. Penggunaan tanaman yang mengandungantioksidan dapat meningkatkan mekanisme dalam tubuh untuk mencegah stres oksidatif. Penelitian ini didasarkanoleh potensi terjadinya gangguan fungsi dan struktur ginjal akibat stres oksidatif yang disebabkan oleh konsumsiMSG berlebih serta daun kemangi (Ocimum basilicum L.) sebagai tanaman antioksidan dengan kandunganflavonoid.Mengetahui pengaruh pemberian ekstrak etanol daun kemangi (Ocimum basilicum L.) dosis 175,350 dan700 mg/kgBB terhadap cedera tubulus pada BBT ginjal tikus putih (Rattus norvegicus) galur Wistar yang diinduksiMSG.Penelitian ini merupakan jenis penelitian quasi-experimental dengan rancangan randomized post test onlycontrolled group. Jumlah sampel sebanyak 25 BBT, terbagi menjadi lima kelompok, yaitu kontrol positif (K+),kontrol negatif (K-) dan kelompok perlakuan ekstrak daun kemangi (K1, K2 dan K3).Pada kelompok pemberianekstrak etanol daun kemangi terjadi penurunan cedera tubulus pada ginjal tikus putih (Rattus norvegicus) galur Wistar yang diinduksi MSG 1,6 g/hari secara oral. Dosis optimal ekstrak etanol daun kemangi padapenelitian iniyaitu 700 mg/kgBB. Uji statistik menuunjukkan perbedaan yang signifikan pada kelima kelompok (p<0,05). Pemberian ekstrak etanol daun kemangi (Ocimum basilicum L.) dapat mencegah terjadinya cedera tubulus padaginjal tikus putih (Rattus norvegicus) galur Wistar yang diinduksi MSG.
Although monosodium glutamate (MSG) is a widely used food additive, its safety and systemic side effects have not been fully clarified. The intestinal flora is closely associated with human health; however, it remains unclear whether MSG consumption can affect health by acting on the intestinal flora. In this study, serum biomarkers, intestinal structure, intestinal immunity, and intestinal flora were examined to investigate the effects of different doses of sodium glutamate on the body, intestinal function, and intestinal flora of mice. The results showed that 30 mg/kg MSG had no significant effect on serum C-reactive protein, trimethylamine N-oxide, angiotensin II, intestinal interleukin (IL)-1β, IL-6, tumor necrosis factor-α, secretory IgA and fecal albumin in mice, but also promoted intestinal development and regulated the intestinal flora. Moreover, 1500 mg/kg MSG increased the risk of cardiovascular disease and damaged the intestinal structure and flora. In this study, MSG was also found to be healthier than salt at the equivalent sodium concentration. Collectively, these findings suggested that low doses of MSG were safe for mice and may have some health benefits as a probiotic by promoting intestinal development and regulating the intestinal flora.
Monosodium Glutamate (MSG) is used as flavour enhancer, with potential beneficial effects due to its nutritional value. Given the decline in kidney functions during aging, we investigated the impact of MSG voluntary intake on the kidney of male mice, aged 6 or 18 months. For 2 months, they freely consumed water (control group), sodium chloride (0.3% NaCl) or MSG (1% MSG) in addition to standard diet. Young animals consuming sodium chloride presented signs of proteinuria, hyperfiltration, enhanced expression and excretion of Aquaporin 2 and initial degenerative reactions suggestive of fibrosis, while MSG-consuming mice were similar to controls. In old mice, aging-related effects including proteinuria and increased renal corpuscle volume were observed in all groups. At an advanced age, MSG caused no adverse effects on the kidney compared to controls, despite the presence of a sodium moiety, similar to sodium chloride. These data show that prolonged MSG intake in mice has less impact on kidney compared to sodium chloride, that already in young animals induced some effects on kidney, possibly related to hypertension.
Latar Belakang: Monosodium glutamat merupakan suatu garam natrium dari asam glutamat yang merupakan salah satu asam amino paling banyak ditemukan di alam. Meskipun monosodium glutamat mempunyai kemampuan untuk meningkatkan nafsu makan, sebuah kasus melaporkan bahwa monosodium glutamat dapat bersifat racun terhadap manusia dan hewan percobaan. Korteks cerebellum mengandung sel purkinje dan lapisan sel granular. Akumulasi glutamat yang berlebihan di sinapsis sel purkinje pada korteks cerebellum dapat menyebabkan penurunan kemampuan neuronal untuk mempertahankan kadar normal dari glutamat sehingga terjadi kematian sel purkinje dan gangguan fungsi sinapsis. Tujuan: Mengetahui pengaruh pemberian monosodium glutamat terhadap jumlah sel purkinje cerebellum pada tikus. Metode: Menggunakan studi literatur dari jurnal baik nasional maupun internasional dengan cara meringkas topik pembahasan dan membandingkan hasil yang disajikan dalam artikel. Hasil: Pemberian monosodium glutamat pada tikus dengan dosis 3,5 mg/gBB per hari selama 10 hari dengan administrasi parenteral mengakibatkan penurunan jumlah sel purkinje pada cerebellum tikus. Kesimpulan: Akumulasi monosodium glutamat yang berlebihan dengan glutamat sebagai komponen utama menjadi penyebab penurunan jumlah sel purkinje cerebellum pada tikus.
An alternative use of shiitake stipes, usually treated as waste, was proposed for the production of a powder ingredient, rich in umami compounds, aiming its application in food. The extraction of umami compounds was optimized through the Response Surface Methodology (RSM), in order to obtain an extract with high umami taste intensity. From the optimized condition, a comparative analysis of shiitake stipes dehydration method was performed. Stipes were dehydrated by hot air drying (HD) and freeze drying (FD), submitted to extraction and the umami compounds in the extracts were compared. The comparative analysis showed that the 5' - nucleotides are more sensitive to prolonged heating, while the release of free amino acids (FAA) was favored by hot air drying. The HD samples extract showed higher Equivalent Umami Concentration (EUC). The spray drying of the HD samples extract allowed the production of a newly powder ingredient rich in umami compounds (Umami Ingredient) that can be applied in in diverse food matrices. Due to the presence of umami compounds, Umami Ingredient can be a potential alternative to help in the process of sodium reduction by enhancing food flavor.
Os aditivos alimentares são substâncias adicionadas aos alimentos intencionalmente sem o objetivo de nutrir, mas de modificar as características do alimento, aumentar sua vida útil e alterar direta ou indiretamente suas características ao desempenhar funções tecnológicas, como a finalidade de colorir (corantes), adoçar (edulcorantes), preservar (conservantes) e/ou conferir sabor e odor (aromatizantes).
Diante da multiplicidade de aditivos hoje presentes no mercado, da pluralidade de formas de apresentação e da quantidade em que são misturados a somente um tipo de alimento, começaram a surgir suspeitas, depois acompanhadas de evidências científicas, que os aditivos possam causar toxicidade aguda ou crônica em mamíferos, incluindo nos seres humanos. As evidências científicas relatam: i) a nível sistêmico: alergias, hipersensibilidade, diarreia, redução do peso fetal, enjoos e alterações no comportamento; ii) a nível tecidual: nefrotoxicidade, hepatotoxicidade, hipoproteinemia, aumento sérico de transaminases, mielossupressão, diabetes tipo II e bronquiolite obliterante; iii) a nível celular e molecular: embriotoxicidade, indução de morte celular por apoptose, quebra de cromátides, ativação de caspases, e aumento de micronúcleos, da peroxidação lipídica e da fragmentação de DNA, o que sugere riscos de indução de instabilidade genética e de carcinogenicidade. Porém, alguns desses efeitos de exposição podem ser observados somente a longo prazo, o que dificulta sobremaneira o entendimento dos mecanismos farmacotoxicológicos, a relação de causalidade e os impactos ambientais.
Portanto, nasceu, recentemente, uma maior preocupação, inclusive entre leigos, sobre a falta de determinações legislativas e da padronização de limites para a fiscalização e controle da adição de aditivos aos alimentos, já que em muitos países foram registradas violações ao se acrescentar tais substâncias acima do limite estabelecido. Evidentemente, tudo isso exige o aperfeiçoamento constante das ações sanitárias de controle alimentar e a atualização de regulamentos técnicos governamentais sobre uso e limites diários, o que denota a grande importância da aplicação da lei para assegurar ao consumidor uma segurança alimentar efetiva, sempre visando melhor qualidade de vida e proteção da saúde da coletividade.
Esse livro então relata, do ponto de vista científico, as descobertas sobre os impactos celulares e orgânicos dos aditivos diante da substituição de alimentos in natura por produtos processados, e levanta questionamentos a serem discutidos e desafios a serem enfrentados perante o empobrecimento da dieta associado ao crescimento de doenças crônicas não transmissíveis.
In India, eating Chinese food has become very popular. We hereby report a case who presented with angioneurotic edema of the uvula and the surrounding structures, after eating Chinese food, which resulted in severe difficulty in swallowing saliva and inability to speak.
A facilitative transport system exists on the blood–brain barrier (BBB) that has been tacitly assumed to be a path for glutamate entry to the brain. However, glutamate is a non-essential amino acid whose brain content is much greater than plasma, and studies in vivo show that glutamate does not enter the brain in appreciable quantities except in those small regions with fenestrated capillaries (circumventricular organs). The situation became understandable when luminal (blood facing) and abluminal (brain facing) membranes were isolated and studied separately. Facilitative transport of glutamate and glutamine exists only on the luminal membranes, whereas Na+-dependent transport systems for glutamate, glutamine, and some other amino acids are present only on the abluminal membrane. The Na+-dependent cotransporters of the abluminal membrane are in a position to actively transport amino acids from the extracellular fluid (ECF) into the endothelial cells of the BBB. These powerful secondary active transporters couple with the energy of the Na+-gradient to move glutamate and glutamine into endothelial cells, whereupon glutamate can exit to the blood on the luminal facilitative glutamate transporter. Glutamine may also exit the brain via separate facilitative transport system that exists on the luminal membranes, or glutamine can be hydrolyzed to glutamate within the BBB, thereby releasing ammonia that is freely diffusible. The γ-glutamyl cycle participates indirectly by producing oxoproline (pyroglutamate), which stimulates almost all secondary active transporters yet discovered in the abluminal membranes of the BBB.
Monosodium Glutamate (MSG) is consumed as food additive around the world, studies has revealed some deleterious effect of MSG on different body organs and tissues. This work was undertaken to determine the effect of MSG on the gross weight of albino rats. A total of 30 male rats were at random divided into five groups (A-E) of six rats each. Group A served as control and received normal saline, while rats in group B were administered 4mg/kg body weight of MSG for 28days, rats in group C received 8m/kg body weight of MSG for 14days, group D rats were administered 8mg/kg body weight of MSG for 28days. Rats in group E received 8mg/kg body weight of MSG for 28days and allowed to stay for another 28days post treatment to observe for reversibility, persistence or delayed occurrence of any effect. At the end of the experimental period, each animal was sacrificed and the heart was carefully removed and weighed. Administration of MSG to rats showed a significant increase in heart weight when compared with those in the control group. Withdrawal of MSG for 28days showed some degree of recovery by a reduction in weight of the heart. The findings suggest that the gross weight of the heart can significantly be increase with continuous and/or increased use of MSG.
This study investigated the effects of administration of monosodium L-glutamate (MSG) on serum gonadotrophin-releasing hormone (GnRH), luteinis-ing hormone (LH), testosterone and total cholesterol (TC), cauda epididymal sperm reserves (CESR) and testicular histomorphology of adult male albino rats. Eighty-four rats, randomly assigned to 7 groups of 12 rats each, were used for the study. Varying low doses (0.25, 0.50 or 1.00 g/kg body weight) of MSG were administered orally or subcutaneously at 48-h intervals for six weeks. Serum GnRH, LH, testosterone and TC, and CESR were evaluated on days 14, 28 and 42 of MSG administration. Testicular histomorphology was evaluated on day 42. The results showed that the mean serum GnRH, LH and testosterone levels, and the CESR of all the treated groups were significantly (P < 0.05) lower than those of the untreated control on days 14, 28 and 42 of MSG administration. The mean serum TC levels of all the treated groups were also significantly (P < 0.05) lower than those of the control group on days 14 and 28. No lesions were observed on sections of the testes. It was concluded that MSG administration for 14, 28 and 42 days led to significantly lower serum levels of GnRH, LH, testosterone and TC, and significantly lower CESR.
The effects of oral administration of varied doses of monosodium glutamate (MSG) on the morphology of the testes and cauda epididymal sperm reserves of rats were studied using 28 four-week-old (young) male Sprague-Dawley rats and 28 twelve-week-old (adult) male Sprague-Dawley rats. Increasing doses (1 mg/g body mass, 2 mg/g body mass, and 4 mg/g body mass) of a 40% aqueous solution of monosodium glutamate were administered to the male Sprague-Dawley rats every 48 hours for 6 weeks, using a rat gavage needle. The results showed that age variation did not influence the effect of MSG on the parameters studied in male rats. There was a significant reduction in the cauda epididymal sperm reserves (P<0.05) and the serum testosterone levels (P<0.05) of the rats that received monosodium glutamate relative to the control rats. The histomorphology of the testes of the rats that were given monosodium glutamate did not differ from those of the rats in the control group. No overt pathological lesions were seen in the testicular sections. These observations suggest that monosodium glutamate may have adversely affected spermatogenesis by disrupting the hypothalamic-pituitarytestis regulatory axis, and not through any direct toxic effect on the testis.
Animal studies suggest that chronic monosodium glutamate (MSG) intake induces kidney damage by oxidative stress. However, the underlying mechanisms are still unclear, despite the growing evidence and consensus that α-ketoglutarate dehydrogenase, glutamate receptors and cystine-glutamate antiporter play an important role in up-regulation of oxidative stress in MSG-induced renal toxicity. This review summaries evidence from studies into MSG-induced renal oxidative damage, possible mechanisms and their importance from a toxicological viewpoint.
Background
The amount of dietary monosodium glutamate (MSG) is increasing worldwide, in parallel with the epidemics of metabolic syndrome. Parenteral administration of MSG to rodents induces obesity, hyperglycemia, hyperlipidemia, insulin resistance, and type 2 diabetes. However, the impact of dietary MSG is still being debated. We investigated the morphological and functional effects of prolonged MSG consumption on rat glucose metabolism and on pancreatic islet histology.
Methods
Eighty adult male Wistar rats were randomly subdivided into 4 groups, and test rats in each group were supplemented with MSG for a different duration (1, 3, 6, or 9 months, n=20 for each group). All rats were fed ad libitum with a standard rat chow and water. Ten test rats in each group were provided MSG 2 mg/g body weight/day in drinking water and the 10 remaining rats in each group served as non-MSG treated controls. Oral glucose tolerance tests (OGTT) were performed and serum insulin measured at 9 months. Animals were sacrificed at 1, 3, 6, or 9 months to examine the histopathology of pancreatic islets.
Results
MSG-treated rats had significantly lower pancreatic β-cell mass at 1, 6 and 9 months of study. Islet hemorrhages increased with age in all groups and fibrosis was significantly more frequent in MSG-treated rats at 1 and 3 months. Serum insulin levels and glucose tolerance in MSG-treated and untreated rats were similar at all time points we investigated.
Conclusion
Daily MSG dietary consumption was associated with reduced pancreatic β-cell mass and enhanced hemorrhages and fibrosis, but did not affect glucose homeostasis. We speculate that high dietary MSG intake may exert a negative effect on the pancreas and such effect might become functionally significant in the presence or susceptibility to diabetes or NaCl; future experiments will take these crucial cofactors into account.
The peritoneal injection of monosodium glutamate (MSG) can induce kidney injury in adult rats but the effects of long-term oral intake have not been determined.
We investigated the kidney histology and function in adult male Wistar rats that were fed ad libitum with a standard rat chow pellet and water with or without the addition of 2 mg/g body weight MSG/day in drinking water (n=10 per group). Both MSG-treated and control animals were sacrificed after 9 months when renal function parameters, blood and urine electrolytes, and tissue histopathology were determined.
MSG-treated rats were more prone to kidney stone formation, as represented by the alkaline urine and significantly higher activity product of calcium phosphate. Accordingly, 3/10 MSG-treated rats developed kidney stones over 9 months versus none of the control animals. Further, 2/10 MSG-treated rats but none (0/10) of the controls manifested hydronephrosis. MSG-treated rats had significantly higher levels of serum creatinine and potassium including urine output volume, urinary excretion sodium and citrate compared to controls. In contrast, MSG-treated rats had significantly lower ammonium and magnesium urinary excretion.
Oral MSG consumption appears to cause alkaline urine and may increase the risks of kidney stones with hydronephrosis in rats. Similar effects in humans must be verified by dedicated studies.
Acetyl-CoA carboxylase (ACC) catalyzes the formation of malonyl-CoA, an essential substrate for fatty acid biosynthesis and
a potent inhibitor of fatty acid oxidation. Here, we provide evidence that glutamate may be a physiologically relevant activator
of ACC. Glutamate induced the activation of both major isoforms of ACC, prepared from rat liver, heart, or white adipose tissue.
In agreement with previous studies, a type 2A protein phosphatase contributed to the effects of glutamate on ACC. However,
the protein phosphatase inhibitor microcystin LR did not abolish the effects of glutamate on ACC activity. Moreover, glutamate
directly activated purified preparations of ACC when protein phosphatase activity was excluded. Phosphatase-independent ACC
activation by glutamate was also reflected by polymerization of the enzyme as judged by size-exclusion chromatography. The
sensitivity of ACC to direct activation by glutamate was diminished by treatment in vitro with AMP-activated protein kinase or cAMP-dependent protein kinase or by β-adrenergic stimulation of intact adipose tissue.
We conclude that glutamate, an abundant intracellular amino acid, induces ACC activation through complementary actions as
a phosphatase activator and as a direct allosteric ligand for dephosphorylated ACC. This study supports the general hypothesis
that amino acids fulfill important roles as signal molecules as well as intermediates in carbon and nitrogen metabolism.
The present study is aimed at investigating the potentials of low concentration administration of monosodium glutamate in inducing hepatotoxic effects in male albino rats. Thus, monosodium glutamate at a dose of 5 mg/kg of body weight was administered to adult male albino rats by oral intubation. Treatment was daily for 28 days. The monosodium glutamate treatment significantly (p<0.05) decreased the serum alkaline phosphatase activity by 71.97% but increased (p<0.05) the serum enzyme activities of aspartate aminotransferase by 66.86% and alanine aminotransferase by 9.15%. The treatment also increased (p<0.05) the serum malondialdehyde concentration by 287.15% and the serum aspartate aminotransferase-to-alanine aminotransferase ratio by 56.59%. Thus, treating rats with monosodium glutamate at a low concentration (5 mg/kg of body weight) could be hepatotoxic without significant cholestasis or pathologies of the bone.
A single intake of monosodium glutamate (MSG) may cause headache and increased muscle sensitivity. We conducted a double-blinded, placebo-controlled, crossover study to examine the effect of repeated MSG intake on spontaneous pain, mechanical sensitivity of masticatory muscles, side effects, and blood pressure.
Fourteen healthy subjects participated in 5 daily sessions for one week of MSG intake (150 mg/kg) or placebo (24 mg/kg NaCl) (randomized, double-blinded). Spontaneous pain, pressure pain thresholds and tolerance levels for the masseter and temporalis muscles, side effects, and blood pressure were evaluated before and 15, 30, and 50 min after MSG intake. Whole saliva samples were taken before and 30 min after MSG intake to assess glutamate concentrations.
Headache occurred in 8/14 subjects during MSG and 2/14 during placebo (P = 0.041). Salivary glutamate concentrations on Day 5 were elevated significantly (P < 0.05). Pressure pain thresholds in masseter muscle were reduced by MSG on Day 2 and 5 (P < 0.05). Blood pressure was significantly elevated after MSG (P < 0.040).
In conclusion, MSG induced mechanical sensitization in masseter muscle and adverse effects such as headache and short-lasting blood pressure elevation for which tolerance did not develop over 5 days of MSG intake.
Monosodium glutamate (MSG) is a commonly used food additive and there is growing concern that excitotoxins such as MSG play a critical role in the development of several hepatic disorders.
The histochemical effect of monosodium glutamate was investigated on the liver of adult Wistar rats.
Adult male Wistar rats (n = 24), with an average weight of 230 g were randomly assigned into two treatment groups, (A & B) (n=16) and Control (C) (n=8). The rats in the treatment groups (A & B) received 0.04mg/kg and 0.08mg/kg of monosodium glutamate thoroughly mixed with the grower's mash, respectively on a daily basis for forty-two days. The 0.04mg/kg and 0.08mg/kg monosodium glutamate doses were chosen and extrapolated in this experiment based on the previous work done with the additive. The control group (C) received equal amount of feed (Growers' mash) without monosodium glutamate added for the same period. The rats were given water ad libitum. Both the treatment and control rats were sacrificed by cervical dislocation on day forty-three of the experiment. The Liver was carefully dissected out and quickly fixed in Bouin's fluid for histochemical studies, while blood was collected for estimation of total protein, albumin, transaminasese (aspartate aminotransferase (AST) and alanine aminotransferase (ALT).
The histological findings showed changes like dilatation of the central vein, which contained lysed red blood cells, cyto-architectural distortions of the hepatocytes, atrophic and degenerative changes on the liver of the animals that received feed incoporated with monosodium glutamate. Furthermore, the biochemical parameters were significantly higher in the test than control groups (P < 0.0001). These changes were more severe in the group that had 0.08 mg/kg of monosodium glutamate mixed in their feed.
These findings showed that monosodium glutamate consumption may have some deleterious effects on the liver of adult Wistar rats at higher doses and by extension may affect the functions of the liver.
Traditional fermented condiments (dawadawa, iru, ogiri) based on vegetable proteins, and consumed by different ethnic groups in Nigeria have been the pride of culinary traditions for centuries. It is evident that these products have played a major role in the food habits of communities in the rural regions serving not only as a nutritious non-meat proteins substitute but also as condiments and flavouring agents in soups. These condiments are being increasingly marketed throughout the country and beyond in informal ways. Differences in the chemical composition of fermented condiments are evident mainly because different ingredients have been used in their preparation. Traditional methods of manufacture should take advantage of biotechnological progress to assure reasonable quality and at the same time assure safety of these products. The requirements for a sustainable biotechnological development of Nigerian condiments are discussed in the scope of the microbiology and biochemical changes of the raw materials. Schemes to standardize the manufacturing stages are proposed. Emphasis is placed on the relevance of the role of starter cultures in the traditional methods of manufacture to ascertain appropriate nutritional quality and physical properties of the final product. Fermented vegetable proteins have potential food uses as protein supplements and as functional ingredients in fabricated foods. Relevant research and development activities are suggested.
Epidemiology and animal models suggest that dietary monosodium glutamate (MSG) may contribute to the onset of obesity and the metabolic syndrome.
Families (n = 324) from a rural area of Thailand were selected and provided MSG as the sole source for the use in meal preparation for 10 days. Three hundred forty-nine subjects aged 35-55 years completed the study and were evaluated for energy and nutrient intake, physical activity, and tobacco smoking. The prevalence of overweight and obesity (BMI ≥ 25 kg/m2), insulin resistance (HOMA-IR >3), and the metabolic syndrome (ATP III criteria) were evaluated according to the daily MSG intake.
The prevalence of the metabolic syndrome was significantly higher in the tertile with the highest MSG intake. Further, every 1 g increase in MSG intake significantly increased the risk of having the metabolic syndrome (odds ratio 1.14, 95% confidence interval-CI- 1.12 - 1.28) or being overweight (odds ratio 1.16, 95% CI 1.04 - 1.29), independent of the total energy intake and the level of physical activity.
Higher amounts of individual MSG consumption are associated with the risk of having the metabolic syndrome and being overweight independent of other major determinants.
Umami is the term that identifies the taste of substances such as L-glutamate salts, which were discovered by Ikeda in 1908. Umami is an important taste element in natural foods; it is the main taste in the Japanese stock “dashi,” and in bouillon and other stocks in the West. The umami taste has characteristic qualities that differentiate it from other tastes, including a taste-enhancing synergism between two umami compounds, L-glutamate and 5′-ribonulceotides, and a prolonged aftertaste. The key qualitative and quantitative features of umami are reviewed in this paper. The continued study of the umami taste will help to further our general understanding of the taste process and improve our knowledge of how the taste properties of foods contribute to appropriate food selection and good nutrition.
When normal adults were fed 150 mg MSG per kg body weight (WHO/FAO Acceptable Daily Intake level) with a typical Chinese meal, rice porridge, at lunchtime, mean serum glutamate level was elevated approximately 1.3 times over baseline level 15 to 60 minutes after eating. The increase in serum glutamate level of 11 term infants and 2 premature infants given MSG at 150 mg/kg body weight in infant formula was about 2 times baseline level. No adverse reactions were observed following ingestions of the meal with MSG in either age group. These results indicate that human infants, as do adults, metabolize large amounts of free glutamate added to a meal.
The International Glutamate Technical Committee (IGTC) comments on a recent publication in "Pathophysiology" entitled "Evidence of alterations in brain structure and antioxidant status following "low-dose" monosodium glutamate ingestion" (authored by Onaolapo, Onaolapo, Akanmu and Gbola) [1]. In particular, IGTC highlights that, in the view of published scientific literature [2-12], the methods of this study were inappropriate and did not support conclusions drawn by the authors.
Fasting male subjects received each of four treatments on different days: a large oral dose of monosodium L-glutamate (MSG; 12.7 g), the MSG vehicle, an iv injection of TRH, or a high protein meal. Blood samples were drawn via an indwelling venous line before and at 20-min intervals after each treatment for 4 h. Plasma glutamate levels rose 11-fold within 1 h of MSG ingestion, but did not change appreciably with any of the other treatments. Plasma PRL levels rose 10-fold after TRH infusion and 2-fold after the protein meal, but did not rise significantly after MSG ingestion. No effects resulted from any of the treatments on plasma LH, FSH, testosterone, GH, or cortisol concentrations. Plasma levels of TSH, T4, and T3 showed minimal changes after any of the treatments except TRH; TRH elevated plasma TSH and T3 levels. Self-rating instruments of mood and side-effects revealed no treatment-related effects on mood or physical state for up to 48 h after each treatment. Together, these results suggest that acut...
Objective:
The study investigated the effects of low dose monosodium glutamate (MSG) on the brain, with a view to providing information on its effects on neuronal morphology and antioxidant status in mice.
Methodology:
Sixty male mice (20-22 g) were divided into six groups of ten animals each. Vehicle (distilled water), a standard (l-glutamate at 10mg/kg body weight) or MSG (10, 20, 40 and 80mg/kg body weight) were administered orally for 28days. Sections of the cerebrum, hippocampus and cerebellum were processed and stained using hematoxylin and eosin, examined under a microscope and captured images analysed. Plasma and brain levels of glutamate, glutamine, and antioxidants were assayed. Data obtained were analysed using descriptive and inferential statistics.
Results:
MSG ingestion did not significantly alter body weight. Relative brain weight increased at 40 and 80mg/kg compared to vehicle. Histological and histomorphometric changes consistent with neuronal damage were seen in the cerebrum, hippocampus and cerebellum at 40 and 80mg/kg. Plasma glutamate and glutamine assay showed significant increase at 40 and 80mg/kg while no significant difference in total brain glutamate or glutamine levels were seen. Levels of brain superoxide dismutase and catalase decreased with increasing doses of MSG, while nitric oxide (NO) increased at these doses.
Conclusion:
The study showed morphological alterations consistent with neuronal injury, biochemical changes of oxidative stress and a rise in plasma glutamate and glutamine. These data therefore still support the need for cautious consideration in the indiscriminate use of MSG as a dietary flavor enhancer.
Multi-generation study of monosodium L-glutamate (MSG) was conducted in mice of IVCS and Swiss albino strains. Parents and offspring (F1) were fed the diets containing 0.2% (approx. 4 g/kg b.w./day) and 4% (approx. 8 g/kg b.w./day) MSG. No significant abnormality was observed on growth, food consumption, estrous cycle, date of sexual maturation, organ weight, litter size and body weight of the offspring, and histopathology of major organs (including the brain and retina) of the parent and F1 generation. Mice of the F2 generation showed normal day of eye opening and external and skeletal characteristics at 20 days of age.
No hypothalamic lesions were found in weanling Sprague-Dawley (SD) rats or in golden hamsters deprived of water and/or food overnight (ON 19.00–09.00 h) and offered monosodium l-glutamate monohydrate (MSG) in up to 10% solution for 30 min subsequently.
The sodium salt of glutamate (monosodium glutamate; MSG) imparts a savory/meaty taste to foods, and has been used as a flavoring agent for millennia. Past research on MSG/glutamate has evaluated its physiologic, metabolic and behavioral actions, and its safety. Ingested MSG has been found to be safe, and to produce no remarkable effects, except on taste. However, some recent epidemiologic and animal studies have associated MSG use with obesity and aberrations in fat metabolism. Reported effects are usually attributed to direct actions of ingested MSG in brain. As these observations conflict with past MSG research findings, a symposium was convened at the 13th International Congress on Amino Acids, Peptides and Proteins to discuss them. The principal conclusions were: (1) the proposed link between MSG intake and weight gain is likely explained by co-varying environmental factors (e.g., diet, physical activity) linked to the "nutrition transition" in developing Asian countries. (2) Controlled intervention studies adding MSG to the diet of animals and humans show no effect on body weight. (3) Hypotheses positing dietary MSG effects on body weight involve results from rodent MSG injection studies that link MSG to actions in brain not applicable to MSG ingestion studies. The fundamental reason is that glutamate is metabolically compartmentalized in the body, and generally does not passively cross biologic membranes. Hence, almost no ingested glutamate/MSG passes from gut into blood, and essentially none transits placenta from maternal to fetal circulation, or crosses the blood-brain barrier. Dietary MSG, therefore, does not gain access to brain. Overall, it appears that normal dietary MSG use is unlikely to influence energy intake, body weight or fat metabolism.
This review provides extensive presentation and evaluation of data relative to flavor potentiation, including the historical, chemical, organoleptic, metabolic, physiological, and consumptive properties of the commonly available flavor potentiators, which are primarily monosodium glutamate and 5'‐nucleotides. In addition, their food occurrences, mode of action, manufacturing procedures, and methods of analyses will be discussed. Also, attention will be given to miscellaneous compounds that possess flavor potentiating properties.
A number of studies were performed in Beagle dogs to assess the clinical, biochemical and histological effects of administering monosodium glutamate (MSG) by oral gavage. Serum glutamate levels were markedly raised irrespective of the dose administered. Vomiting consistently occurred at the time of the serum glutamate peak. There was no difference between control and MSG-treated dogs with regard to glutamate concentration in cerebrospinal fluid (CSF) or brain tissue taken from the region of the third ventricle. MSG did not accumulate in the liver, kidney, duodenum or intestinal fluid of dosed dogs. At the time of peak glutamate concentration there was a relative drop in serum potassium concentration, with a subsequent increase in sodium concentration.
Repeated s.c. injections of high doses of monosodium-l-glutamate (MSG) to neonatal female rats caused precocious puberty, disturbed oestrous cycle and small ovaries and pituitary. Pituitary LH and FSH were low but the basal serum levels were unchanged from control values. Serum E2 level was significantly low in the early stages. Cyclic regulation of gonadotrophin release and follicular maturation was inadequate. Pituitary-gonadal function in males was less affected. Females treated with high doses of MSG as infants showed normal onset of puberty and regular oestrous cycles, but subsequent earlier oestrous cycle irregularity was observed than in controls. Gonadal weights in both sexes were slightly reduced. Serum hormone levels and the pituitary contents were not changed from those of controls except for reduced FSH. Males and females, given subneurotoxic doses of MSG, or fed large amounts of MSG ad libitum, presented no abnormalities. MSG administration therefore induces marked abnormalities in reproductive endocrine function after maturation only when injected parenterally, early in postnatal life, in repeated, very large doses.
Behavioural observations were made on rats given repeated high, subneurotoxic doses of monosodium l-glutamate (MSG), or large amounts of MSG in the diet, during the early stages of life. Multiple injections of 4 g/kg MSG to neonates caused low grip strength, hypoactivity, changes of spontaneous motor activity pattern in a day, deficit of learning ability and tail mutilation. The same treatment at the infant stage resulted in only slight behavioural abnormalities at a later stage of life, or yielded nothing at all. Administration of subneurotoxic doses either by s.c. injection or forced intubation, or at high levels in a diet provided ad libitum, were without behavioural effect. Adverse behavioural effects were not induced when the brains were free from histological evidence of damage.
The administration of monosodium glutamate (MSG) to an infant (2-day-old) rhesus monkey at a dose level of 4 g/kg, in 10 ml SMA baby milk, failed to induce any pathological change in the hypothalamus.
This study tested the hypothesis that infants metabolize glutamate more slowly than adults. Eight 1-yr-old infants ingested 160 ml of a beef consomme providing monosodium L-glutamate at 0, 25, and 50 mg/kg body weight. Plasma glutamate and aspartate concentrations were measured sequentially for the next 2 h. The results were compared to values noted in nine adult subjects ingesting equivalent doses of monosodium L-glutamate in consomme. In adults, mean (± SD) peak plasma glutamate concentrations were 5.59 ± 1.56, 10.2 ± 2.08, and 17.0 ± 8.06 µmol/dl, respectively; the area under the plasma glutamate concentration time curves were 96 ± 42, 257 ± 80, and 442 ± 303 µmol/dl x min, respectively. In infants, the mean (±SD) peak plasma glutamate concentrations were 6.94 ± 1.43,10.6 ± 2.36, and 12.0 ± 1.16 µmol/dl, respectively; the plasma glutamate area under the curve values were 47 ± 28, 191 ± 85, and 358 ± 105 µmol/dl x min, respectively. The data indicate that the plasma glutamate concentration response in 1-yr-old infants ingesting MSG at these glutamate doses is no higher than values observed in adult subjects.
Charles River CD rats were fed diets containing either 2.05% w/w sodium propionate or 1, 2 or 4% w/w monosodium glutamate (MSG) for 104 weeks. There were no adverse effects upon bodyweight gain, economy of food consumption, haematology, blood chemistry, organ weights or mortality by comparison with control rats receiving the basal diet. Water consumption, urinary volume and sodium excretion were increased at 2.05% sodium propionate or 4% MSG, and this appeared to be reflected in an increased incidence and earlier onset of spontaneous subepithelial basophilic deposits in the renal pelvis among treated rats. Focal mineralization at the renal corticomedullary junction occurred with equal frequency in all groups, including untreated controls. There were no other histological findings of significance.
The use of monosodium glutamate (MSG) as a flavor enhancer spans more than 100 y and there are many studies indicating the safety of general use of MSG. Recently, however, Collison et al. (2010) reported a two-generation study with a low dose of MSG that caused abdominal obesity, insulin resistance and dyslipidemia in mice. Due to public health concerns over metabolic syndrome, their report merits careful analysis. The present study attempted to repeat the Collison et al. findings. Groups of male or female C57BL/6J mice were fed a control diet or one supplemented with high-fructose corn syrup (HFCS) at a level of 20%. Drinking water control was provided or treatment groups were given 0.064% MSG solution (w/v). Diets and MSG administration continued throughout mating and during gestation and lactation periods. To further investigate the effects of ingestion of MSG, the offspring were continued on the same dosing conditions until they reached 32 wk of age. MSG administration in mice fed a normal or a HFCS diet throughout gestation and for 32 wk after birth, did not affect growth, girth size, abdominal fat weight or body composition. This study reports that MSG did not trigger insulin resistance, dyslipidemia or hepatic steatosis, regardless of the diet, not reproducing the results of the above-mentioned study (Collison et al., 2010).
Subcutaneous administration of monosodium glutamate (MSG), to normal adult male mice, for six consecutive days at dose levels of 4 and 8 mg/g body weight, significantly increased the level of free radical initiating enzyme, xanthine oxidase, whereas the activity of free radical scavenging enzymes, like catalase and superoxide dismutase was significantly decreased in hepatic tissue. These observations suggested that ingestion of MSG at dose level of 4 mg/g body weight and above, induced oxidative stress in the hepatic tissue of adult male mice.
Administration of monosodium glutamate (MSG) to rhesus monkeys caused a dose-related increase in serum glutamate concentration, and Na+ concentration is also increased when large quantities of MSG are ingested. Vomiting occurs in 50% of treated monkeys but is not precisely correlated with serum glutamate levels. The concentration of glutamate in vomitus reflects the dosage of MSG given. Monkeys with enteritis have high basal serum glutamate levels.
Monosodium l-glutamate (MSG) is known to influence the endocrine system and gastrointestinal (GI) motility. The mechanism of postprandial glycemic control by food in the GI tract is mostly unknown and of great interest.
To investigate the effect of MSG on glucose homeostasis, incretin secretion and gastric emptying in humans after a lipid-containing meal.
Thirteen healthy male volunteers (mean age, 25.5 years) and with no Helicobcter pylori infection were enrolled. A 400 mL (520 kcal) liquid meal with MSG (2 g, 0.5% wt:vol) or NaCl (control) was ingested in a single-blind placebo-controlled cross-over study. Blood glucose, serum insulin, plasma glucagon, plasma glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide were measured. Gastric emptying was monitored by a 13C acetate breath test. Postprandial symptoms were assessed on a visual analogue scale.
The 30-min postprandial glucose concentration was significantly reduced by adding MSG to the test meal. The area under the glucose concentration vs. time curve (0–60 min) was also significantly reduced by adding MSG (40.6 ± 3.51 mg·1 hr/dL with MSG vs. 49.2 ± 3.86 mg·1 hr/dL with NaCl, P = 0.047), whereas, the 30-min postprandial plasma GLP-1 level was significantly increased (58.1 ± 15.8 pmol/L with MSG vs. 13.4 ± 15.8 pmol/L with NaCl, P = 0.035). MSG did not affect the half gastric emptying time or postprandial symptoms.
Monosodium l-glutamate improved early postprandial glycaemia after a lipid-containing liquid meal. This effect was not associated with a change in gastric emptying, but was possibly related to stimulation of glucagon-like peptide-1 secretion.
Monosodium glutamate (MSG) is pervasively consumed as a flavor enhancer so there are important implications to understanding its physiological actions, particularly its effects on body weight. Previous studies suggest that MSG increases, decreases, or has no effect on the body weight of rodents. However, most of these studies involved administration of MSG to immature rodents and consequently may not be relevant for understanding human obesity. We report here five experiments in which we measured the body weights of a total of 32 groups of 10-12 adult rats or mice given various diets to eat and MSG to eat or drink. We found no evidence that MSG influenced body weight, energy intake, or body composition. To the extent that experiments in rodents illuminate mechanisms involved in human obesity and body weight control, our results suggest that MSG is unlikely to be a useful anti-obesity supplement but neither is it responsible for exacerbating obesity.
l-Monosodium glutamate (l-MSG), dl-monosodium glutamate (dl-MSG) and l-glutamic acid (l-GA), each at dietary concentrations of 0.1 and 0.4%, were administered from 12 weeks of age to Sprague-Dawley rats for periods of up to 2 years and combined with a multigeneration reproduction test. There were no adverse effects upon clinical signs, motor activity, food consumption, bodyweight gain, haematology, tumour incidence, fertility, survival, organ weights or histopathological findings, compared with control animals receiving a basal Ralston Purina diet.
The effect of materials administered simultaneously with monosodium l-glutamate (MSG) was studied in 10-day-old mice to assess the histological brain lesion. By gavage, sodium chloride did not promote glutamate-induced brain damage, while the mono- and disaccharides glucose, fructose, galactose, sucrose and lactose significantly reduced the number of necrotic neurons in the arcuate nucleus (AN) of the hypothalamus.
The enzymic activities and biochemical changes in the principal food constituents of African locust bean were investigated. The reducing sugar level increased from 63 mg/g to 134 mg/g during the first 24 hr but subsequently decreased. Amylase activity was not detected. The lipase activities were detectable with the peak at 48 hr after the start of fermentation. The most significant activity during the fermentation is the rapid and steady increase in the quantity of free amino acids throughout the fermentation. This is due to a consistently active proteinase activity by the fermentative microorganisms. The number and quantities of each amino acids analysed also increased in the fermented beans. Glutamic acid, valine, aspartic acid and alanine were rapidly liberated during the fermentation. The changes observed are compared with the fermentation of other protein rich seeds.
Purpose: This article reviews the literature from the past 40 years of research related to monosodium glutamate (MSG) and its ability to trigger a migraine headache, induce an asthma exacerbation, or evoke a constellation of symptoms described as the “Chinese restaurant syndrome.”
Data sources: Literature retrieved by a search using PubMed, Medline, Lexis-Nexus, and Infotrac to review articles from the past 40 years.
Conclusions: 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 40 years ago, clinical trials have failed to identify a consistent relationship between the consumption of MSG and the constellation of symptoms that comprise the syndrome. Furthermore, MSG has been described as a trigger for asthma and migraine headache exacerbations, but there are no consistent data to support this relationship. Although there have been reports of an MSG-sensitive subset of the population, this has not been demonstrated in placebo-controlled trials.
Implications for practice: Despite a widespread belief that MSG can elicit a headache, among other symptoms, there are no consistent clinical data to support this claim. Findings from the literature indicate that there is no consistent evidence to suggest that individuals may be uniquely sensitive to MSG. Nurse practitioners should therefore concentrate their efforts on advising patients of the nutritional pitfalls of some Chinese restaurant meals and to seek more consistently documented etiologies for symptoms such as headache, xerostomia, or flushing.
Oligosaccharides were the most abundant carbohydrates in the unfermented African locust beans. Flatus-forming oligosaccharides — stachyose, raffinose and sucrose — were the main constituents. During the first 24 h of fermentation, the quantities of the oligosaccharides decreased significantly. The reducing sugars increased during the first 12 h of fermentation but then decreased. The reducing sugars detected in the unfermented and fermented locust beans were similar; these were galactose, glucose and fructose. The activities of -galactosidase were highest at 24 h from the start of fermentation while the peak of sucrose activity was at 36 h.