When we read the label that shows the ingredients contained in foods, it may happen to come across acronyms or names of little-known substances. In this section we will try to clarify the most common food additives used to improve the flavor, color or texture of foods and we will try to understand their effects on health. Today we will talk about monosodium glutamate, a much debated food additive.
Monosodium glutamate, what is MSG, where is it found and how to recognize it?
Monosodium glutamate, or MSG, is a white powder obtained from glutamic acid, an amino acid that occurs naturally in vegetables, such as tomatoes, in aged cheeses, in mushrooms and in algae and that participates in different processes in the body as a neurotransmitter, capable of increasing brain function (Dutta et al, Saudi Pharm J, 2013). Once monosodium glutamate was obtained by extraction and crystallization from an algae broth, nowadays it is produced through the fermentation of sugar beet, cane sugar or molasses. Monosodium glutamate is then added as an additive to foods to enhance their flavor. For example, MSG can be found in certain types of foods, such as bouillon cubes, canned meat and vegetables, processed meats, soy sauce, and some ready meals. In the European Union it appears on food labels with acronyms ranging from E621 to E625. The label, no added glutamate, may be indicated on the package but other ingredients that are glutamate carriers may be present, such as yeast extract, hydrolyzed yeast, soy extracts, protein isolates. In the United States, however, it is not possible to indicate that a food is glutamate-free if substances that naturally contain glutamate appear among the ingredients.
Glutamate, impact on health
Monosodium glutamate is generally considered safe by all food safety regulators. However, with regard to its long-term consumption, the subject is debated and some scientific studies have questioned its safety with regard to health. Let's try to understand better. First of all, it is believed that the addition of monosodium glutamate improves the palatability of foods and increases appetite, with a possible increase in weight and blood sugar. Then, it was observed that the intake of very high doses of monosodium glutamate led to the development of liver damage due to an increase in oxidative stress. Unfortunately, the study in question only analyzed the effects of acute ingestion of this substance and not what can happen by taking lower amounts of glutamate but for a longer period of time (Eweka et al, Ann Med Health Sci Res., 2011). Not only that, overdoing foods rich in monosodium glutamate has been shown to cause headaches, fatigue and tachycardia. In general, monosodium glutamate appears to increase pain perception (Kraal et al, Neuropsychobiology., 2020). It has also been observed that regular consumption of sodium glutamate can increase the risk of hypertension and asthma over the long term. Finally, some studies indicate that monosodium glutamate also has a neurotoxic action, but the topic is much debated and other studies affirm, instead, that the intake of monosodium glutamate through the diet does not cause an increase of this substance in the brain as it is unable to overcome the blood-brain barrier (Hajihasani et al, Iran J Basic Med Sci, 2010 - Fernstrom et al, Ann Nutr Metab, 2018). However, scientific studies performed on animals seem to indicate that in newborns it is possible that a part of glutamate overcomes this barrier that has not yet been properly formed (Foran et al, Neuroscience, 2017).
The amount of glutamate allowed
The regulatory bodies on food safety have established limits regarding the amount of monosodium glutamate that can be present in a food. For example, EFSA, which is the European Food Safety Authority, has set this limit at 30 mg per kg of body weight, which in any case is considered a value that is not achievable with diet (Henry-Unaeze et al, Pathophysiology, 2017)
Glutamate, conclusions and observations
Science has failed to agree on the safety of monosodium glutamate, as evidenced by studies with conflicting results. While it is true that glutamate is naturally present in various foods that we usually consume, such as aged cheeses and some vegetables, it should also be considered that the prolonged intake of a large amount of foods to which monosodium glutamate has been added from food industry, in addition to the glutamate already present naturally, can lead to an almost chronic intake of this substance with effects that are not clear nowadays. The occasional use of foods containing monosodium glutamate is certainly not to be demonized, indeed, sometimes a bouillon cube can save dinner, but you need to be aware. For example, sometimes it can be a good choice, as well as fun, to prepare the vegetable broth at home without adding additives but only with vegetables and salt. Then the cube can be frozen and used at the moment. In the video blog section we propose a video in which we show step by step how to prepare the vegetable bouillon cube. Then, in general, it is always better to avoid ready-made foods, which, in addition to monosodium glutamate, may also contain sugars to improve their flavor. On the other hand, as far as newborns are concerned, it would be better to avoid the administration of foods containing monosodium glutamate.