A study on physiological taste threshold in hyperthyroidism

Background: Taste is the perception produced when a substance in the mouth reacts chemically with taste receptors located on taste buds in the oral cavity. The five basic taste modalities are sweet, salt, sour, bitter, and umami. Disorders of taste can result from various diseases and use of various drugs. Hyperthyroidism is one among them which affects the taste sensation and threshold. Aim and Objectives: The study was conducted to assess the physiological taste threshold for the five primary taste modalities in hyperthyroid patients and to compare their taste thresholds with that of the normal healthy controls. Materials and Methods: Investigations were carried out in 30 hyperthyroid patients aged between 20 and 50 years and in age, sex, and anthropometrically matched control groups of 30, who were apparently healthy. The statistical analysis was done by student’s t-test. Results: There is no difference in the physiological threshold of the all the basic tastes but salt. A significant (P < 0.05) increase in the taste threshold for salt taste can be seen in hyperthyroid patients compared to that of controls. Conclusion: The threshold for salt taste was altered in hyperthyroidism, which can be detected by proper screening. Taste dysfunction leads to reduced food intake and poor nutrition. Proper treatment and counseling can help them to get back their normal taste threshold along with normal thyroid status.

Development of a Gustatory Function Test for Clinical Application in Korean Subjects

PURPOSE: To obtain validated clinical values suitable for developing a gustatory function test, including umami taste, in a Korean population. MATERIALS AND METHODS: The investigation involved 297 participants with self-reported normal sense of taste and smell. Liquid solutions were used for the assessment of gustatory function. The test consisted of 30 taste solutions [six concentrations of five tastants (sweet, bitter, salty, sour, and umami)]. For evaluation of overall gustatory function, the number of detected or correctly recognized taste thresholds was combined to form a “taste score.” RESULTS: Mean values of each detection and recognition threshold for the five tastes in men were consistently lower than those of women. The 10th percentile of taste score for recognition was used as the cut-off value for distinguishing normogeusia from hypogeusia. In subgroup analysis, total taste score from recognition thresholds revealed a significant negative correlation with age, indicating lower scores for increasing age. Taste score for non-smokers was significantly higher than that of smokers, in terms of detection and recognition of taste sensitivities. CONCLUSION: This gustatory function test was easy to perform, affordable, and time-saving, with the capacity to self-produce and obtain reliable data. Gustatory function was more sensitive in young people, women, and non-smokers.

L-Glutamato: un aminoácido clave para las funciones sensoriales y metabólicas / L-glutamate: a key amino acid for sensory and metabolic functions

El ácido glutámico como tal o en su forma ionizada L-glutamato (GLU) es uno de los aminoácidos más abundantes en la naturaleza debido a que cumple funciones importantes a nivel celular y sistémico. En el intestino y el hígado, por ejemplo, el GLU constituye fuente de energía y es precursor de moléculas de relevancia biológica. Mientras que en el sistema nervioso central de los mamíferos actúa como neurotransmisor excitatorio, debido a la interacción con receptores específicos distribuidos en el cerebro. Además al GLU se le ha relacionado con la potenciación a corto y largo plazo de la memoria y el aprendizaje. Por otro lado, el consumo de GLU o de su sal monosódica (GMS) como aditivo alimentario genera el gusto umami, palabra japonesa que significa sabroso. El consumo de GMS ha sido considerado seguro por diferentes organizaciones que evalúan la inocuidad de uso de los aditivos alimentarios, razón por la cual han establecido una ingesta diaria admisible (IDA) "no especificada" y lo clasifican como un ingrediente reconocido como seguro o sustancia GRAS (por sus siglas en inglés, Generally Recognized Safe Substance). En esta revisión se presentan los aspectos del metabolismo del GLU, su papel en la degustación de los alimentos y la inocuidad del uso del GMS(AU)

Glutamic acid or its ionic form L-glutamate (GLU) is one of the most abundant amino acids in nature and it plays important functions at the cellular and systemic levels. For instance, in the intestine and liver, GLU is a source of energy and is the precursor of key biological molecules. At the central nervous system of mammals, GLU acts as an excitatory neurotransmitter due to the interaction with specific receptors. In addition, GLU has been related with short- and long-term potentiation, memory and the learning. Furthermore, consumption of GLU or its monosodium salt (monosodium glutamate, MSG) as a food additive is responsible for the umami taste. The consumption of MSG has been considered safe for different agencies responsible for the evaluation of the safe use of food additives, which have establish an Acceptable Daily Intake (ADI) “not specified”, or classified as Generally Recognized Safe Substance (GRAS). This review focuses on important metabolic aspects of GLU and its role in food tasting and MSG safety(AU)

La cuestión de las sensaciones gustativas básicas / The question of basic taste sensations

RESUMEN Antecedentes existe interés en conocer la posible influencia de la percepción del gusto, y su efecto sobre la elección de la dieta y la conducta alimentaria. Objetivo conocer los factores que modulan la percepción de los gustos básicos y su relación con el consumo de alimentos Materiales y métodos se hizo una búsqueda bibliográfica en bases de datos: Science Direct, Medline y Pubmed, sobre la sensación del gusto, sin considerar lo que se denomina el flavor. Resultados se ha avanzado en las bases fisiológicas de los gustos básicos: dulce, salado, ácido, amargo y umami, recientemente se ha propuesto el gusto graso, pero aún no hay consenso al respecto. El gusto y la selección de alimentos dependen de factores genéticos, las primeras experiencias con estímulos sápidos, incluso antes de nacer, factores culturales, sociales, individuales y otros relacionados con el alimento. No se ha podido demostrar asociación entre consumo excesivo de alimentos hipercalóricos con la sensibilidad gustativa, ni sobre esta última con la obesidad. Conclusión el efecto de la percepción del gusto sobre el consumo de alimentos y su relación con la obesidad, aun es motivo de controversia. Se recomienda educar en la infancia sobre las percepciones gustativas, con el fin de adquirir buenos hábitos alimentarios.

ABSTRACT Background There is interest in discovering more about the possible influence in taste perception and its effect in dietary selection and food behaviors. Objective Explore the factors that alter perceptions of taste and their relationship with food consumption. Materials and methods A literature review was performed using scientific databases: Science Direct, Medline y Pubmed on the subject of taste, regardless of dominant flavors. Results Progress has been made on the physiological basis of the basic tastes: sweet, salty, sour, bitter and umami. It has recently been proposed to add a ''fatty'' taste but as of now no consensus exists. Taste and food selection depend on genetic factors, first experiences with sapid stimuli, even before birth, as well as cultural, social, individual and other factors related to food. An association between consumption of high-calorie foods and taste sensitivity has not been demonstrated, nor taste sensitivity with obesity. Conclusion The effect of taste perception on food consumption and any relation with obesity continues to be controversial. It is recommended to educate from a young age on taste perception, with the goal of acquiring healthy food habits.