Umami helps in the control of babies’ weight

Science has already proven that breast milk is the essential food source for babies. The World Health Organization recommends that babies receive exclusively breast milk during the first 6 months of life¹. However, for various reasons, some mothers are unable to breastfeed their babies, which increases the demand for the production of infant formulas.

The infant formulas currently available on the market are theoretically designed to “mimic” the composition of breast milk in their macro and micronutrient content, providing babies without access to breast milk with an equally nutritious and protective option. However, the few studies that have analyzed the composition of commercial formulas identified a large gap in the concentration of some nutrients present in breast milk, such as free amino acids, for example, which appear in significantly lower amounts in some formulas. Moreover, especially glutamate, which is the most abundant amino acid in breast milk, is present in much lower concentrations. It is known that this difference in free amino acid concentration could alter important physiological functions in the body, such as the protection of the intestinal mucosa²,³.

The Monell Chemical Senses Center, in Philadelphia, raised questions related to the control of food intake and satiety regulation. It was found that some babies fed infant formulas had greater and faster weight gain than babies fed breast milk. Disorders in these systems can lead to weight gain as early as the first year of life, which may increase the risk of obesity, metabolic syndrome, and mortality due to cardiovascular diseases. For this reason, the hypothesis emerged that the amount of proteins and free amino acids in the formula could influence the increase in weight gain. To confirm this fact, researchers evaluated whether the higher concentration of free glutamate in infant formulas could reduce consumption, and consequently weight gain, using a control formula with lower amounts of glutamate for comparison⁴.

The formula with the highest amount of protein hydrolysate (FESP) contained almost 120 times more free amino acids, among them, in greater amounts, leucine, glutamate, lysine, and valine, respectively. The control formula had few detectable free amino acids, with taurine being the most abundant⁴.

A total of 30 babies up to 4 months of age participated in the research. All of them had already consumed the control formula used in the study, but had never ingested the protein hydrolysate-rich formula. A third formula was also created, adding free glutamate to the control formula, in an amount slightly lower than that of the protein hydrolysate formula. This formula served as a second parameter for comparison and confirmation of the results⁴.

During the 3-day intervention, the babies randomly received hydrolyzed protein formula, or control formula, or control formula + glutamate. Satiety development (the process during feeding that leads to the end of intake) was investigated through the evaluation of the amount of formula consumed, and satiety, identified by the prolonged effect caused by the first formula ingested until the onset of hunger and subsequent consumption of the next formula⁴.

As results, the researchers confirmed their hypotheses. Babies who received the protein hydrolysate formula and the one enriched with glutamate consumed smaller amounts, that is, they reached satiety faster than the control formula babies, and the feeling of satiety after the first meal did not differ from that of babies who received the control formula, even though they ingested smaller amounts. After ruling out hypotheses that could have influenced the reduced consumption of the formulas with more glutamate, it was possible to confirm that the presence of free glutamate helps regulate the intake of energy, proteins, and amino acids, and may also serve as a satiety signal for the central nervous system⁴.

Until now it was well established that only breastfeeding allowed babies to self-regulate their intake. In fact, breastfeeding is indisputably the best form of nutrition for babies and should be encouraged and practiced whenever possible. However, this recent research took a step forward in investigating another benefit of the amino acid glutamate in its free form in the human diet, and opened up a range of hope and opportunity also for babies deprived of breast milk. The next step is to make commercial infant formulas as close as possible to the composition of breast milk. Thus, even artificially fed babies will be more protected against various metabolic disorders that may arise in adulthood as a reflection of excess weight caused by malnutrition already established early in life.

Authors:
Marília Esteves
Hellen Maluly

References:

¹ Organização Pan-americana de Saúde / Organização Mundial da Saúde. Amamentação. 2003. [acesso 28 mai 2012]. Disponível em: http://www.opas.org.br/sistema/fotos/amamentar.pdf

² Baldeon M, Flores N. O glutamato no leite materno e no desenvolvimento do intestino do lactente. In: Reyes FGR. Umami e glutamato: aspectos químicos, biológicos e tecnológicos. São Paulo: Editora Plêiade, 2011. 195p.

³ Chuang CK, Lin SP, Lee HC, Wang TJ, Shih YS, Huang FY, Yeing CY. Free amino acids in full-term and pré-term human Milk and infant formula. J Pedriatr Gastroenterol Nutr. 2005; 40:496-500.

⁴ Ventura AK, Beauchamp GK, Mennella JA,. Infant regulation of intake: the effect of free glutamate content in infant formulas. Am J Clin Nutr. 2012; 95:875-881.