The following are studies done by researchers warning that manufactured free glutamate (MfG) in food might contribute to adverse events. They are often done by scientists with interest in identifying drugs to use as interventions in glutamate-related maladies. They almost invariably come from researchers working outside of the United States.
Hermanussen M, García AP, Sunder M, Voigt M, Salazar V, Tresguerres JA. Obesity, voracity, and short stature: the impact of glutamate on the regulation of appetite. Eur J Clin Nutr. 2006 Jan;60(1):25-31. doi: 10.1038/sj.ejcn.1602263.
https://pubmed.ncbi.nlm.nih.gov/16132059/
Hermanussen M, Tresguerres JA. Does high glutamate intake cause obesity? J Pediatr Endocrinol Metab. 2003 Sep;16(7):965-8. doi: 10.1515/jpem.2003.16.7.965.
https://pubmed.ncbi.nlm.nih.gov/14513871/
Stover JF, Kempski OS. Glutamate-containing parenteral nutrition doubles plasma glutamate: a risk factor in neurosurgical patients with blood-brain barrier damage? Crit Care Med. 1999 Oct;27(10):2252-6. doi: 10.1097/00003246-199910000-00031.
https://pubmed.ncbi.nlm.nih.gov/10548216/
Nakanishi Y, Tsuneyama K, Fujimoto M, Salunga TL, Nomoto K, An JL, Takano Y, Iizuka S, Nagata M, Suzuki W, Shimada T, Aburada M, Nakano M, Selmi C, Gershwin ME. Monosodium glutamate (MSG): a villain and promoter of liver inflammation and dysplasia. J Autoimmun. 2008 Feb-Mar;30(1-2):42-50.
https://pubmed.ncbi.nlm.nih.gov/18178378/
Chakraborty SP. Patho-physiological and toxicological aspects of monosodium glutamate. Toxicol Mech Methods. 2019 Jul;29(6):389-396. doi: 10.1080/15376516.2018.1528649. Epub 2019 May 6.
https://pubmed.ncbi.nlm.nih.gov/30273089/
Hernández Bautista RJ, Mahmoud AM, Königsberg M, López Díaz Guerrero NE. Obesity: Pathophysiology, monosodium glutamate-induced model and anti-obesity medicinal plants. Biomed Pharmacother. 2019 Mar;111:503-516. doi: 10.1016/j.biopha.2018.12.108. Epub 2018 Dec
https://pubmed.ncbi.nlm.nih.gov/30597304/
Sharma A. Monosodium glutamate-induced oxidative kidney damage and possible mechanisms: a mini-review. J Biomed Sci. 2015 Oct 22;22:93. doi: 10.1186/s12929-015-0192-5.
https://pubmed.ncbi.nlm.nih.gov/26493866/
Ataseven N, Yüzbaşıoğlu D, Keskin AÇ, Ünal F. Genotoxicity of monosodium glutamate. Food Chem Toxicol. 2016 May;91:8-18. doi: 10.1016/j.fct.2016.02.021. Epub 2016 Feb 27.
https://pubmed.ncbi.nlm.nih.gov/26929995/
Kayode OT, Rotimi DE, Kayode AAA, Olaolu TD, Adeyemi OS. Monosodium Glutamate (MSG)-Induced Male Reproductive Dysfunction: A Mini Review. Toxics. 2020 Jan 22;8(1):7. doi: 10.3390/toxics8010007.
https://pubmed.ncbi.nlm.nih.gov/31979139/
Hajihasani MM, Soheili V, Zirak MR, Sahebkar A, Shakeri A. Natural products as safeguards against monosodium glutamate-induced toxicity. Iran J Basic Med Sci. 2020 Apr;23(4):416-430. doi: 10.22038/IJBMS.2020.43060.10123.
https://pubmed.ncbi.nlm.nih.gov/32489556/
Dixit SG, Rani P, Anand A, Khatri K, Chauhan R, Bharihoke V. To study the effect of monosodium glutamate on histomorphometry of cortex of kidney in adult albino rats. Ren Fail. 2014 Mar;36(2):266-70. doi: 10.3109/0886022X.2013.846865. Epub 2013 Nov 4.
https://pubmed.ncbi.nlm.nih.gov/24188378/
Onaolapo OJ, Onaolapo AY, Akanmu MA, Gbola O. Evidence of alterations in brain structure and antioxidant status following ‘low-dose’ monosodium glutamate ingestion. Pathophysiology. 2016 Sep;23(3):147-56. doi: 10.1016/j.pathophys.2016.05.001. Epub 2016 May 24.
https://pubmed.ncbi.nlm.nih.gov/27312658/
Niaz K, Zaplatic E, Spoor J. Extensive use of monosodium glutamate: A threat to public health? EXCLI J. 2018 Mar 19;17:273-278. doi: 10.17179/excli2018-1092.
https://pubmed.ncbi.nlm.nih.gov/29743864/
Gürgen SG, Sayın O, Çeti N F, Sarsmaz HY, Yazıcı GN, Umur N, Yücel AT. The Effect of Monosodium Glutamate on Neuronal Signaling Molecules in the Hippocampus and the Neuroprotective Effects of Omega-3 Fatty Acids. ACS Chem Neurosci. 2021 Aug 18;12(16):3028-3037. doi: 10.1021/acschemneuro.1c00308. Epub 2021 Jul 30.