By Allen Studzinski, CN, NOW Foods
Nutritionists at NOW are often asked if our products contain added MSG. We do not add MSG or glutamic acid to our products, including protein powders, nor is it hidden in our products labeled as containing "Natural Flavors."
Glutamic acid or Glutamate is a naturally occurring amino acid, a building block of proteins, and one of the most abundant neurotransmitters in the nervous system. It is commonly added to Asian dishes as a chemical complex called MSG (monosodium glutamate) and it is considered a flavor enhancer and one of the five basic tastes (umami, a savory sensation). Glutamic acid, along with the amino acid Aspartic acid, plays a stimulating or excitatory role in nerve cells while other amino acids such GABA are inhibitory or calming. Some people may be sensitive to MSG as a food additive, experiencing the so-called “Chinese Restaurant Syndrome” that can include headaches, chest tightness, tingling, and nausea. Excess excitotoxicity has been a concern. Excitotoxicity occurs when receptors in the nerve cells become over-stimulated, causing cellular dysfunction, damage, or even death to the cell.
Foods contain a variety of compounds that can have excitotoxic effects. Glutamate is naturally found in protein-rich foods and abundant in milk products and soy sauce, for example. But Glutamate consumed in this way is not considered a problem and the average American consumes about 11,000mg of glutamates per day. Cow’s milk contains about 20 mg/kg of glutamate in its free amino acid form and potentially over 8,000 mg/kg if all of the bound glutamate was freed up during digestion of the amino acid that is contained within the protein. Glutamate can be released during processing and some foods rely on free glutamate for their flavor. Parmesan cheese, for example, contains about 12,000 mg/kg of free glutamate and almost 100,000 mg/kg of bound glutamate. 3 It is interesting to note that breast milk has one of the highest natural concentrations of glutamate.
Of course, any protein - whether Whey, Soy, Pea, or Rice Protein - is a natural source of glutamic acid and will naturally provide this amino acid once digestion begins in the body and the proteins are broken down into their constituent amino acids. All proteins, and all products containing protein would behave similarly.
When we say "Natural Flavors" on our labeled ingredients, we are referring to natural ingredient combinations we’ve put together to give the desired flavor listed on the label. We do not add proteins or amino acids, such as Glutamates or MSG, to enhance these natural flavors. Nor do we add hydrolyzed soy, autolyzed yeast, or other components that may contain free glutamates. Our flavors typically do not contain any added proteins, amino acids, or other significant glutamate or aspartate sources.
The intention is to allow us to use exclusive natural flavor components to optimize the taste of the product while keeping that exact combination of ingredients proprietary. For example, a "natural flavor" in a Chocolate Whey Protein might include a couple types of chocolate flavors sourced from cocoa beans, along with a couple different vanillas sourced from vanilla beans to get exactly the flavor profile that we want, and yet they are simply listed as "Natural Flavors" on the label.
Nutritional help for Glutamate Metabolism
Vitamin B6 plays a key role in Amino Acid metabolism and is fundamental to controlling the effects of glutamate in the body. A study of 155 students found that glutamate reactivity seemed very much related to B6 deficiency and this sensitivity was abolished when corrected via B6 supplementation. 4
Studies suggest the following nutrients may play important protective roles against cellular glutamate toxicity:
Vitamins & Minerals: B2, Folic acid, and B125, Lithium6, Magnesium7, Zinc8, CDP-Choline9
Amino acids: Taurine10, L-Carnitine11
Antioxidants: Coenzyme Q1012, Glutathione13, Vitamin C, Vitamin E, Quercetin14, Tocotrienols15, Lipoic acid16, Melatonin17
Herbs: Magnolia18, Gotu Kola19, Ginseng20, Goji21, Schizandra22, Ginkgo Biloba23, Curcumin24, Green Tea25
1 Olney JW. Excitotoxins in foods. Neurotoxicology. 1994 Fall;15(3):535-44.
2 Glutamate safety: http://www.ific.org/foodinsight/2000/ma/gluamatefi200.cfm
3 Sodium Glutamate: A Safety Assessment". Food Standards Australia New Zealand http://www.foodstandards.gov.au/publications/documents/MSG%20Technical%20Report.pdf
4 Folkers K, Shizukuishi S, Willis R, Scudder SL, Takemura K, Longenecker JB. The biochemistry of vitamin B6 is basic to the cause of the Chinese restaurant syndrome. Hoppe Seylers Z Physiol Chem. 1984 Mar;365(3):405-14.
5 Lin Y, Desbois A, Jiang S, Hou ST. Group B vitamins protect murine cerebellar granule cells from glutamate/NMDA toxicity. Neuroreport. 2004 Oct 5;15(14):2241-4.
6 Nonaka S, Hough CJ, Chuang DM. Chronic lithium treatment robustly protects neurons in the central nervous system against excitotoxicity by inhibiting N-methyl-D-aspartate receptor-mediated calcium influx. Proc Natl Acad Sci U S A. 1998 Mar 3;95(5):2642-7.
7 Poleszak E, Wlaź P, Kedzierska E, Nieoczym D, Wróbel A, Fidecka S, Pilc A, Nowak G. NMDA/glutamate mechanism of antidepressant-like action of magnesium in forced swim test in mice. Pharmacol Biochem Behav. 2007 Dec;88(2):158-64. Epub 2007 Aug 10.
8 Kitamura Y, Iida Y, Abe J, Ueda M, Mifune M, Kasuya F, Ohta M, Igarashi K, Saito Y, Saji H. Protective effect of zinc against ischemic neuronal injury in a middle cerebral artery occlusion model. J Pharmacol Sci. 2006 Feb;100(2):142-8. Epub 2006 Feb 11.
9 Mir C, Clotet J, Aledo R, Durany N, Argemí J, Lozano R, Cervós-Navarro J, Casals N. CDP-choline prevents glutamate-mediated cell death in cerebellar granule neurons. J Mol Neurosci. 2003 Feb;20(1):53-60.
10 Leon R, Wu H, Jin Y, Wei J, Buddhala C, Prentice H, Wu JY. Protective function of taurine in glutamate-induced apoptosis in cultured neurons. J Neurosci Res. 2009 Apr;87(5):1185-94.
11 Felipo V, Miñana MD, Cabedo H, Grisolía S. L-carnitine increases the affinity of glutamate for quisqualate receptors and prevents glutamate neurotoxicity. l-Neurochem Res. 1994 Mar;19(3):373-7.
12 Sandhu JK, Pandey S, Ribecco-Lutkiewicz M, Monette R, Borowy-Borowski H, Walker PR, Sikorska M. Molecular mechanisms of glutamate neurotoxicity in mixed cultures of NT2-derived neurons and astrocytes: protective effects of coenzyme Q10. J Neurosci Res. 2003 Jun 15;72(6):691-703.
13 Chen CJ, Liao SL, Kuo JS. Gliotoxic action of glutamate on cultured astrocytes. J Neurochem. 2000 Oct; 75(4):1557-65.
14 Farombi EO, Onyema OO. Monosodium glutamate-induced oxidative damage and genotoxicity in the rat: modulatory role of vitamin C, vitamin E and quercetin. Hum Exp Toxicol. 2006 May;25(5):251-9.
15 Khanna S, Roy S, Ryu H, Bahadduri P, Swaan PW, Ratan RR, Sen CK. Molecular basis of vitamin E action: tocotrienol modulates 12-lipoxygenase, a key mediator of glutamate-induced neurodegeneration. J Biol Chem. 2003 Oct 31;278(44):43508-15. Epub 2003 Aug 13.
16 Kobayashi MS, Han D, Packer L. Antioxidants and herbal extracts protect HT-4 neuronal cells against glutamate-induced cytotoxicity. Free Radic Res. 2000 Feb;32(2):115-24.
17 Espinar A, García-Oliva A, Isorna EM, Quesada A, Prada FA, Guerrero JM. Neuroprotection by melatonin from glutamate-induced excitotoxicity during development of the cerebellum in the chick embryo. J Pineal Res. 2000 Mar;28(2):81-8.
18 Lin YR, Chen HH, Ko CH, Chan MH. Neuroprotective activity of honokiol and magnolol in cerebellar granule cell damage. Eur J Pharmacol. 2006 May 10;537(1-3):64-9. Epub 2006 Mar 24.
19 Ramanathan M, Sivakumar S, Anandvijayakumar PR, Saravanababu C, Pandian PR. Neuroprotective evaluation of standardized extract of Centella asiatica in monosodium glutamate treated rats. Indian J Exp Biol. 2007 May;45(5):425-31.
20 Bao HY, Zhang J, Yeo SJ, Myung CS, Kim HM, Kim JM, Park JH, Cho J, Kang JS. Memory enhancing and neuroprotective effects of selected ginsenosides. Arch Pharm Res. 2005 Mar;28(3):335-42.
21 Ho YS, Yu MS, Yik SY, So KF, Yuen WH, Chang RC. Polysaccharides from Wolfberry Antagonizes Glutamate Excitotoxicity in Rat Cortical Neurons. Cell Mol Neurobiol. 2009 Jun 5. [Epub ahead of print]
22 Cheng HY, Hsieh MT, Wu CR, Tsai FH, Lu TC, Hsieh CC, Li WC, Lin YT, Peng WH. Schizandrin protects primary cultures of rat cortical cells from glutamate-induced excitotoxicity. J Pharmacol Sci. 2008 May;107(1):21-31.
23 Chandrasekaran K, Mehrabian Z, Spinnewyn B, Chinopoulos C, Drieu K, Fiskum G. Bilobalide, a component of the Ginkgo biloba extract (EGb 761), protects against neuronal death in global brain ischemia and in glutamate-induced excitotoxicity. Cell Mol Biol (Noisy-le-grand). 2002 Sep;48(6):663-9.
24 Wang R, Li YB, Li YH, Xu Y, Wu HL, Li XJ. Curcumin protects against glutamate excitotoxicity in rat cerebral cortical neurons by increasing brain-derived neurotrophic factor level and activating TrkB. Brain Res. 2008 May 19;1210:84-91. Epub 2008 Apr 16.
25 Lee H, Bae JH, Lee SR. Protective effect of green tea polyphenol EGCG against neuronal damage and brain edema after unilateral cerebral ischemia in gerbils. J Neurosci Res. 2004 Sep 15;77(6):892-900.