MSGs have been used for over centuries in the food production due to its flavour enhancing role in foods. Recently, all over the waves and on social media, there are many claims about the harmful effects of consuming MSGs. Mothers are being advised against the use of MSGs and general consumers have been cautioned against its use. What then is actually the big deal with MSGs?
What are MSGs?
Monosodium Glutamate (MSG) is a sodium salt of the non-essential amino acid L-glutamic acid. This means that it is naturally present in the human body. It can also be gotten from plants and all protein foods. MSG is a white, crystalline powder which is water soluble. It is a food additive belonging to the group known as the flavour enhancers (E621)(Miyaki et al., 2016). Flavor enhancers are additives added to food that brings out the intrinsic characteristic flavour of the food. They do not impact flavors but just amplify the presence of hidden and weak flavors(Henry-Unaeze, 2017). A common flavor enhancer is the common table salt. By bringing out the umami (the fishy/meaty) taste of the food MSGs act as flavor enhancers.
Umami substances are desirable to improve upon the overall diet quality, induces salivary secretion, enhance appetite and overall increase food palatability (Stańska and Krzeski, 2016). MSG based products are highly used by commercial food producers such as restaurants, chop bars and street vendors. It is highly used in several Chinese dishes such as noodles, ramen and kimchi. MSGs have been found to be potential replacer for table salt. There is no significant structural difference between MSGs and the natural glutamic acid. This means that both undergo the same process of metabolism.
What are sources of MSGs?
MSGs can be produced by a fermentation process described as protein hydrolysis, a process by which glutamic acid is freed from protein through enzymatic fermentation or use of chemicals. These protein sources can be from sugar beet molasses, corn and sugar cane etc. The facilitating bacteria is an aerobic bacteria that releases glutamic acid as by product upon culturing. The key difference between MSG and other fermented foods is the crystallization and high purity levels of commercial MSG(Henry-Unaeze, 2017; Airaodion, 2019).
Is it really bad?
There have been several researches that disagree with the consumption of MSGs. Several claims have been made about the health effects of consuming MSGS. This include decrease in fertility, kidney diseases, neural diseases, Increase in blood pressure levels, headaches, fever, vomiting, stomach ache and general body weakness. These studies were initially fueled by the reports of the symptoms referred to as the Chinese restaurant syndrome. A condition described after a report was made to the American Health society when the complainant took ill few minutes after consuming Chinese foods(Airaodion, 2019). This sparked several researches which concluded on several reports. These reports are constantly echoed by some dieticians and health practitioners.
Are the stories true?
Most of the researches conducted were not done on humans and there were several problems with the methodology of the research. The rats were injected with the doses instead of being injested with the MSG. The metabolic pathway for injested products is different from that of injected products. This might have been the cause of such results gotten. Moreover MSGs are usually consumed in meals not alone, but the doses used for the studies were administered without without meals(Henry-Unaeze, 2017). The European Food Safety Authority (EFSA) established an acceptable daily intake of 30mg/kg of body weight. This amount usually cannot be consumed in a single meal (FDA, 2018)
How about those that exhibit the Chinese restaurant syndrome (CRS)? Recent studies have shown that there is no direct linkage between MSGs and the CRS. Previous studies which reported earlier submissions on the link between MSGs and CRS had no robust experimental designs and were characterized by inconsistent results and the frequency of the responses to MSG intake were inadequate to prove that MSG intake results is CRS(Airaodion, 2019). This is also supported by the fact that the body naturally contains glutamic acid which is not harmful to the body. These reactions classified as the CRS might be due to other factors which have not been investigated yet.
Contrary to these believes, it has been found that consumption of MSGs reduces the consumption of non-MSG enhanced, savory and high fatty foods. MSG also increases feelings of fullness when used to enhance protein rich foods.(Henry-Unaeze, 2017) This studies is not the same for carbohydrate rich foods on the other hand. Overall MSGs can help to reduce the calorie intake in meals. Metabolites from MSG does are converted in the gut where it can be used as energy sources, converted to amino acids or used in the synthesis of other bioactive compounds. Also the metabolites are restricted so as almost none of it passes from the gut into the blood or crosses the brain barrier (Stańska and Krzeski, 2016; (Zanfirescu et al., 2019))
How do we regulate MSGs?
MSGs have been declared as Generally Recognized as Safe(GRAS) by the Food and Drugs Authority , the European Food Safety Authority and the Joint FAO/WHO Expert Committee on Food Additives (JECFA). The European Food Safety Authority (EFSA) established an acceptable daily intake of 30mg/kg of body weight (FDA, 2018). Usually this amount cannot be consumed in a single meal but it must be enforced to ensure its use does not surpass its limit.
In order not to cause sodium influx in the body which can lead to high blood pressure, when MSGs are used in foods, the amount of salt added to foods must be greatly reduced so as to ensure there is a balance. Spices such as ginger, turmeric should also be included in MSG enhanced meals as they have been found to mitigate some of the diseases reported to have been caused by MSGs in rats. Fermented locust beans (dawadawa) can be used as a natural substitute for MSGs as it also gives the Umami flavoring that is derived from MSGs.
What is the way forward?
MSGs are used by producers in the production of several foods such as soups, stews and sauces. Its also added to noodles, fried chickens and several Chinese dishes. In developing countries it is used domestically to enhance the flavour of food since the natural spices are quite expensive. How do we harness this great market of consumers?
MSGs can be used as vehicles for food fortification. Micronutrients can be used to fortify MSG related products to curb micronutrients deficiencies (hidden hunger) among children and adults. Intake of MSGs have also been linked to increased hemoglobin levels in humans. MSGs can be fortified with irons and other trace minerals to help combat their deficiencies in humans.(Muhilal et al., 1988; Shi et al., 2012; US department of Commerce, 1991).
Natural alternatives including Vegetables such as ;tomatoes, onions, cabbage, green peas, spinach, mushrooms, broccoli and Animal-based protein such as; salmon, chicken, beef, mackerel, crab, shrimp can be used to enhance foods.
References
Airaodion, A.I. (2019) ‘Toxicological Effect of Monosodium Glutamate in Seasonings on Human Health’, Global Journal of Nutrition & Food Science, 1(5). Available at: https://doi.org/10.33552/gjnfs.2019.01.000522.
Henry-Unaeze, H.N. (2017) ‘Update on food safety of monosodium L-glutamate (MSG)’, Pathophysiology, 24(4), pp. 243–249. Available at: https://doi.org/10.1016/j.pathophys.2017.08.001.
Miyaki, T. et al. (2016) ‘Monosodium l-glutamate in soup reduces subsequent energy intake from high-fat savoury food in overweight and obese women’, British Journal of Nutrition, 115(1), pp. 176–184. Available at: https://doi.org/10.1017/S0007114515004031.
Muhilal et al. (1988) ‘Vitamin growth , A-fortified monosodium and survival of children : glutamate a controlled’, The American journal of clinical nutrition, 48(March), pp. 1271–6.
Shi, Z. et al. (2012) ‘Monosodium glutamate intake increases hemoglobin level over 5 years among Chinese adults’, Amino Acids, 43(3), pp. 1389–1397. Available at: https://doi.org/10.1007/s00726-011-1213-7.
Zanfirescu, A. et al. (2019) ‘A Review of the Alleged Health Hazards of Monosodium Glutamate’, Comprehensive Reviews in Food Science and Food Safety, 18(4), pp. 1111–1134. Available at: https://doi.org/10.1111/1541-4337.12448.
Stańska, K., & Krzeski, A. (2016). The umami taste: from discovery to clinical use. Otolaryngologia polska = The Polish otolaryngology, 70(4), 10–15. https://doi.org/10.5604/00306657.1199991
US Department of Commerce, 1991. US Direct Investment Abroad: 1994 Benchmark Survey, Preliminary Results.
This is very educative. Thank you for this eye-opener, Elikem