¿El glutamato monosódico hace mal a la salud?

It is not new that monosodium glutamate has been considered a villain by health specialists. The ingredient, responsible for giving the Umami taste (one of the five basic tastes of the human palate, alongside sweet, salty, sour, and bitter), has already been linked to diseases such as migraine, allergy, and high blood pressure. But what is truth and what is myth behind monosodium glutamate?

Check below some information about the ingredient and its explanations:

1) Does monosodium glutamate trigger migraine?

Myth. A series of studies was carried out with patients who related monosodium glutamate to headaches, among them one of the double-blind placebo-controlled (DBPC) type. Hellen Maluly, professor of food science and Umami specialist, explains that the studies evaluated by government institutions did not identify this type of relationship.

2) Does monosodium glutamate cause Chinese Restaurant Syndrome?

Myth. In the year 2000, researchers from the four most renowned U.S. universities (Harvard, Boston University, University of California Los Angeles, and Northwestern University) developed a double-blind, placebo-controlled protocol that involved increasing doses of monosodium glutamate.

By consuming different amounts of glutamate, 130 patients who claimed to be sensitive to monosodium glutamate answered some questionnaires. At the end of the study, only two of the analyzed people showed consistency in their responses. With this, the researchers concluded that it is not possible to relate monosodium glutamate to the supposed syndrome.

In addition, the American TV program Food Detectives – which investigates the food safety of certain foods – presented in 2009 an edition called Food Detectives proved MSG is Safe. In that episode, 30 healthy people were invited to have lunch at a Chinese restaurant. Half of the participants received doses of monosodium glutamate in their meals, while the other half did not. At the end of the program, people who had not ingested monosodium glutamate complained of possible symptoms related to the substance. Thus, it was concluded that there is no relationship between the ingredient and Chinese Restaurant Syndrome.

3) Does the human body recognize glutamate molecules and monosodium glutamate in the same way?

Truth. Glutamate (or glutamic acid) is an amino acid naturally present in foods such as meats, cheeses, and mushrooms. The substance is also abundantly present in the human body. Free glutamate is the main substance responsible for giving the Umami taste.

Another possible source of free glutamate is monosodium glutamate. This ingredient is the salt of glutamate and is produced through the fermentation process of some foods, such as sugar cane. When it comes into contact with water (present in food and saliva), it releases free glutamate into the medium.

Thus, both glutamic acid (or glutamate) and monosodium glutamate are converted into free glutamate that results in the perception of the Umami taste. Both are perceived and metabolized in the same way by the taste buds, that is, our body recognizes them in exactly the same way.

4) Does monosodium glutamate cause allergy?

Myth. In the book “Umami and glutamate: chemical, biological and technological aspects”, researcher Joel Faintuch, PhD in digestive system surgery at the University of São Paulo (USP), presents studies that demystify the relationship between the ingredient and allergic reactions. Joel highlights a study in which doses of 1g and 5g of monosodium glutamate were administered to individuals who supposedly suffered from asthma attacks linked to monosodium glutamate. However, none of the analyzed people showed a reduction in forced expiratory volume, a test that determines whether or not there were respiratory dysfunctions.

5) Is monosodium glutamate linked to hypertension?

Myth. Contrary to speculations, the substance could be an alternative to reducing sodium consumption in food. In addition to having approximately 1/3 of the amount of sodium present in conventional table salt, monosodium glutamate could compensate for some sensory losses in foods with less sodium, making their taste pleasant for consumers. Although monosodium glutamate is present in some processed foods, its consumption by the average population is relatively low and would hardly be the main factor in the increase in blood pressure. “The increase in blood pressure depends on several factors related to each individual’s lifestyle and cannot be attributed to a single ingredient or product,” explains Hellen Maluly.

6) Does monosodium glutamate contribute to food acceptance in children and the elderly?

Truth. A study carried out by Professor J. E. Steiner, from the Hebrew University of Jerusalem, published in the book “Umami: a basic taste” (1987), pointed out that newborns can already perceive and accept the Umami taste from the first days of life. “The researcher evaluated the babies’ expression after receiving a solution with a little of each taste and concluded that when feeling the sweet and Umami taste, the babies appeared to be satisfied and showed a ‘happy’ expression. For bitter and sour, they ‘wrinkled their nose,’ and for salty the perception was not very clear. “This is because breast milk contains Umami substances and also sugars, which corresponds to the results of the tests with the solutions,” explains Maluly.

In the case of the elderly, a study developed by researchers from Okanoki Hospital, Japan, divided the elderly into two groups, one formed by 14 people with an average age of 83 years and another with 15 members with an average age of 84 years. The first group had 0.5% monosodium glutamate added to each meal. The second group did not have the substance added to their meals. After three months of analysis, the group that consumed meals with monosodium glutamate showed significant improvements in food acceptance, nutritional status, immunity, and well-being; the control group did not obtain the same results.

7) Can glutamate contribute to the prevention of obesity in babies?

Truth. Researchers from the Monell Chemical Senses Center, Philadelphia, United States, evaluated satiety control, and consequently obesity, in newborns, in a study published in 2012. They found that satiety could be directly linked to glutamate – the main substance that gives the Umami taste – present in breast milk. Therefore, children with a good breastfeeding process would have less chance of developing weight-related disorders. The research was based on the feeding of 30 newborns, up to four months of age, with three different formulas – two with higher concentrations of glutamate (in free form) and one with a lower concentration. It was observed that when fed with the glutamate-rich formulas, the babies reached satiety quickly and, with this, could control food intake.

UMAMI TASTE

The fifth taste was discovered in 1908 by Japanese chemist Kikunae Ikeda. However, it was only recognized by the scientific community in 2000, when researchers at the University of Miami found specific receptors in the taste buds. Parmesan cheese, tomato, mushrooms, and meats in general are the foods that most strongly contain the fifth taste. The two main characteristics of Umami are increased salivation and the persistence of the taste for a few minutes after eating the food.