JIIMC 2016 Vol. 11, No.3  

137

Ajinomoto Group is one of the leading global 
producers of the flavor enhancer monosodium 
glutamate (MSG). Since early 20th century, 
Ajinomoto has gathered a substantial amount of 
data related to MSG safety and use. Based on that 
database, we are commenting here-below on the 
recent article by Abbasi et al., entitled “Effect of 
Vitamin C on monosodium glutamate (Ajinomoto) 
induced changes in the ovary of rats” (JIIMC 11(2), 
2016, 66-70). 
The article described a rat study with MSG and 
vitamin C. The authors extensively speculated that 
MSG ingestion may cause harmful effects on human 
female fertility and ovarian functions. We argue that 
the study by Abbasi et al. was burdened by 
m e t h o d o l o g i c a l  p r o b l e m s  a n d  a  l a c k  o f  
reproducibility. In addition, we conclude that the 
authors neglected glutamate metabolism in 
mammalian bodies in interpreting the results. 
1) The doses of MSG or the mode of MSG 

treatment were not described, thus one cannot 
conclude if there was any relevance to human 
n u trit io n . If  MSG was  mixed  into  th e 
experimental diet, the authors needed to explain 
how that was achieved since conventional rat 
diets are granulated. If MSG was applied in 
drinking water, the authors needed to describe 
how taste was masked.

2) No data on diet intake, water intake or body 
weight were provided, but the authors 
mentioned that the control group was 
characterized by a lower terminal mean body 
weight when compared to body weight of 
MSG–treated rats. Therefore, the observed 
ovarian differences could have been attributed 
to the changes in body weight and not to the 
treatments per se. In other words, in the absence 
of body weight information, it is impossible to 
toxicologically interpret the observed changes.

3) It is not clear where the tested MSG was 
obtained from, who was the producer and 
whether it contained impurities or other 
substances which may have affected the 
observed results. 

4) The authors indicated that "AJINOMOTO" was a 
common name of all MSG used in Pakistan. 

Indeed, "AJINOMOTO" is a trademark registered 
by Ajinomoto Co., Inc. in more than 170 
countries, including countries in Central and 
South Asia. However, while the “AJINOMOTO” is 
one of the most popular seasoning brands world-
wide, it is not the only MSG brand on the market. 
Mentioning “AJINOMOTO” brand name in a title 
of a scientific article without describing the 
source of the tested MSG, or its purity, was 
disparaging and academically unjustified.

5) As the authors mentioned, a molecule of MSG 
contains glutamate and sodium. However, 
sodium intake from MSG was not controlled for 
even though the authors attributed all observed 
changes to glutamate alone. One cannot 
preclude that at least some effects were 
attributable to sodium. In that respect, we note 
that there was no information on how control 
rats were treated or what control diet was 
composed of. Adult rats ingest standard diet at 
approximately 12% of their body weight, thus we 
suppose the studied female rats ingested daily 
approximately 30 – 40 g of a chaw diet. If that 
diet was based on milk casein, as is usually the 
case, it contained 10% glutamate, so the rats 
were eating 3 – 4 g of glutamate from the diet 
alone without MSG added (i.e., 1). No attention 
was given to that “diet-contained” glutamate 
source.

6) Authors extensively speculated on MSG use in 
humans. Adult humans ingest about > 10 g 
glutamate per day from a normal diet. This 
volume includes 0.5 – 1.0 g per day of glutamate 
added to food as a flavor enhancer, whether in a 
form of MSG or included in other condiments 
rich in glutamate (bouillon cubes, soy sauces, 
mushrooms etc.). In simple words, MSG is only a 
small portion of ingested glutamate. Considering 
that all food free glutamates are metabolized 
identically, it is disproportionate to speculate 
solely on MSG – especially if the speculation is 
based on a rodent study only.

7) Importantly, histopathological evaluation of the 
tissues was not described. Specifically, was the 
evaluation done visually only; and were the 
persons conducting the observations blinded? 

LETTER TO THE EDITOR

Food-added Monosodium Glutamate does not induce Changes
in the Ovaries



8) Finally, the authors selectively used references 
and omitted scientific papers on the lack of 
dietary MSG effect on reproductive functions (2-
4). Instead, the authors used pharmacological 
studies with MSG or non-scientific articles 
published online (See Ref. 17 in the original 
article). At this point, it is appropriate to mention 
that less than 5% of orally ingested glutamate 
from food (including MSG) is absorbed from the 
gut into the systemic circulation. The rest is used 
as an oxidative substrate by the intestinal 
mucosa (5-8). Other food components, which 
are inevitably ingested along with food-added 
glutamate, further suppress circulating 
glutamate levels (9-10) and therefore increasing 
blood glutamate levels by food-added MSG is 
extremely difficult. In the absence of a high 
circulating glutamate, any changes in ovarian 
physiology are impossible to attribute to food-
derived glutamates, such as MSG.

Key Words: Monosodium Glutamate, Metabolism, 
Ovaries.

REFERENCES
1. Seeber RM, Smith JT, Wadell BJ. Plasma leptin-binding 

activity and hypothalamic leptin receptor expression during 
pregnancy and lactation in the rat. Biol Reproduction 2002; 
66: 1762-67.

2. Semprini ME, D'Amicis A, Mariani A. Effect of monosodium 
glutamate on fetus and newborn mouse. Nutr. Metab. 
1974; 1: 276-84.

3. Yonetani S, Matsuzawa Y. Effect of monosodium glutamate 
on serum luteinizing hormone and testosterone in adult 
male rats. Toxicol. Lett. 1978; 1: 207-11.

4. Yonetani S, Ishii H, Kirimura J. Effect of dietary 
administration of monosodium L-glutamate on growth and 
r e p r o d u c t i v e  f u n c t i o n s  i n  m i c e .  O y o  Ya k u r i  
(Pharmacometrics) 1979; 17: 143-52.

5. Neame KD, Wiseman G. The transamination of Glu and Asp 
during absorption by the small intestine of the dog in vivo. J. 
Physiol. 1957; 135: 442-50.

6. Reeds PJ. Enteral glutamate is almost completely 
metabolized in first pass by the gastrointestinal tract of 
infant pigs. Am. J. Physiol. 1996; 270: 413-18.

7. Reeds PJ. Intestinal glutamate metabolism. J. Nutr. 2000; 
130: 978S-82S.

8. Reeds PJ. Dispensible and indispensible amino acids in 
humans. J. Nutr. 2000; 130: 1835S-40S.

9. Stegink LD, Filer LJ, Baker GL, Bell EF. Plasma glutamate 
concentrations in 1-year-old infants and adults ingesting 
monosodium L-glutamate in consommé. Pediatr. Res. 1986; 
20: 53-8.

10. Stegink LD, Pitkin RM, Reynolds WA, Filer LJ Jr, Boaz DP, 

138

Brummel MC. Placental transfer of glutamate and its 
metabolites in the primate. Am. J. Obstet. Gynecol. 1975; 
122: 70-8.

Correspondence:
Miro Smriga 
Department of External Scientific Affairs Group
and Intellectual Property Rights
Ajinomoto Co. Inc. 
1-15-1 Kyobashi, Chuo-ku, 104-8315 Tokyo, Japan
E-mail: miro_smriga@ajinomoto.com

Miro Smriga, Kosuke Tomori, Tatsuo Igarashi
Department of External Scientific Affairs Group
and Intellectual Property Rights
Ajinomoto Co. Inc. 

Received: July 13, 2016; Accepted: Aug 19, 2016

JIIMC 2016 Vol. 11, No.3  

The dose of MSG was 0.08 mg per kg body 
1-3

weight.  And it was mixed in their pallet diet. 
Daily diet intake of one rat is 10-12grams. Weight 
of one rat is approximately 300grams. So the 
weight of fifteen rats in experimental group A 
was 15 * 300 = 4500gm/4.5kg. The estimated 
dose of MSG for fifteen rats was 0.08 * 4500 = 
0.036grams. Approximate dose of MSG per rate 
per day will be 0.024grams. The dose of MSG for 
four weeks was 0.024 * 30 = 0.72grams.
High quality MSG free from impurities was 
obtained from Asia Scientific Traders, Rawalpindi 
manufactured by Zinef Company China.
I followed the tradition in academic literature 

 4-6
where MSG is commonly known as Ajinomoto.
The major component of MSG is glutamate that 

7
is 78%  and literature showed that glutamate is 
harmful component of MSG not the sodium.5 
Indeed glutamate is a major component of 
protein rich food like tomatoes, fermented 
beans, soya sauce and fish sauce. 
H i sto p at h o l o g i ca l  eva l u at i o n  wa s  d o n e  
microscopically under the supervision of 
histopathologist.

REFERENCES
1. Eweka AO, Eweka A, Om’Iniabohs FA. Histological studies of 

the effects of monosodium glutamate of the fallopian tubes 
of adult female Wistar rats. North American journal of 
medical sciences. 2010; 2: 146.

2. Zia MS, Qamar K, Hanif R, Khalil M. Effect of monosodium 
glutamate on the serum estrogen and progesterone levels 

COMMENTS BY AUTHOR

Effect of Vitamin C on MSG
induced Changes in the Ovaries
of Rat

Letter to the Editor



7. Afeefy AA, Mahmoud MS, Arafa MA. Effect of Honey on 
Monosodium Glutamate Induced Nephrotoxicity 
(Histological and Electron Microscopic Studies). Journal of 
American Science. 2012;8:146–156. 44.

JIIMC 2016 Vol. 11, No.3  

in female rat and prevention of this effect with diltiazem. 
Journal of Ayub Medical College, Abbottabad: JAMC. 2014; 
26: 18.

3. Zia M, Qamar K, Butt S. Effect of Monosodium Glutamate on 
the Epithelial Height of Fallopian Tube of Rat and its 
Prevention with Diltiazem. 2013.

4. Eweka A, Adjene J. Histological studies of the effects of 
monosodium Glutamate on the medial geniculate body of 
adult Wister rat. Electron J Biomed. 2007; 22: 9-13.

5. Osman HEH. Study of the role of antioxidant (vitamin c) on 
modulation toxicity of chronic use of monosodium 
glutamate in liver of albino rats: Faculty of Medicine, Taif 
University; 2012.

6. Eweka A, Om’Iniabohs F. Histological studies of the effects 
of monosodium glutamate on the ovaries of adult wistar 
rats. Annals of medical and health sciences research. 2013; 
1:37-44.

Correspondence:
Dr. Sumaira Abbasi
Department of Anatomy
Islamic International Medical College
Riphah International University, Islamabad
E-Mail: sumaira.abbasi@gmail.com

Sumaira Abbasi, Rehana Rana, Kaukab Anjum
Department of Anatomy
Islamic International Medical College
Riphah International University, Islamabad

Funding Source: NIL ; Conflict of Interest: NIL
Received: July 13, 2016; Accepted: Aug 19, 2016

139

Letter to the Editor


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