Physiology & Behavior, Vol. 48, pp. 801-804. ©Pergamon Press plc, 1990. Printed in the U.S.A.
0031-9384/90 $3.00 + .00
Umami and Appetite: Effects of Monosodium Glutamate on Hunger and Food Intake in Human Subjects P E T E R J. R O G E R S l A N D J O H N E. B L U N D E L L
Biopsychology Group, Psychology Department, University o f Leeds, Leeds LS2 9JT, UK
ROGERS, P. J. AND J. E. BLUNDELL. Umami and appetite: Effects of monosodium glutamate on hunger and food intake in human subjects. PHYSIOL BEHAV 48(6) 801-804, 1990.--Subjects consumed soup (beef consomme) preloads of a fixed size conraining different concentrations of monosodinm L-glutamate (MSG). Effects on appetite following these preloads, and when no soup was consumed, were assessed in 3 studies. The soups supplemented with MSG were rated as more "pleasant," more "savoury" and more "satisfying" than soup with no added MSG. Compared with the no preload condition, consumption of the soups initially reduced appetitive motivational ratings and increased fullness ratings, but did not alter food intake in a test meal begun either 2 or 30 minutes later. This immediate inhibition of subjective motivation to eat was unaffected by MSG concentration. The failure of the soups to reduce subsequent food intake is presumably due to their low energy content (< 10 kcal) and indicates that sensory stimulation alone is insufficient to reduce appetite. Indeed, the most important finding concerning MSG showed that motivation to eat recovered more rapidly following a lunchtime meal in which MSG-supplemented soup was served as the first course (compared both with the effect of unsupplemented soup and no preload). It is suggested tentatively that MSG through its stimulation of orosensory receptors and/or by improving the palatability of the soup may have influenced the metabolic disposal of nutrients consumed in the previous meal. Monosodium glutamate
Hunger
Food intake
Taste
Human eating behaviour
Caloric compensation
METHOD
G L U T A M A T E has long been used to improve the taste quality of food. The taste of glutamate has been named umami which is derived from the Japanese word meaning "deliciousness," and several umami substances, including monosodium L-glutamate (MSG), sodium 5'-inosinate and 5'-guanylate, are now widely available as "flavour enhancers" (5). However, despite the importance of umami taste in many foods and much research on, for example, the physiological mechanisms of umami taste perception, there appears to be little information on the relationship between umami and appetite control (5). Umami taste substances may be expected to influence appetite in a number of ways, such as through effects on palatability, and because of their natural association with protein containing foods: to British palates umami taste may best be described as " s a v o u r y . " Some evidence indicates that protein is more satiating calorie for calorie than carbohydrate or fat [see (3)1. Three studies are reported here in which subjects consumed soup preloads of a fixed size containing various concentrations of MSG. Effects on appetite following these preloads, and when no soup was consumed, were assessed by tracking motivation to eat and by measuring the amount of food eaten in test meals.
Subjects A total of 36 undergraduate volunteers, 23 women and 13 men, took part in the 3 studies. All were of normal weight for height (mean Body Mass Index = 21.1), and all reported that they were not currently dieting to lose weight. Four subjects, however, were excluded from the fmal data analysis because they failed to complete all of their scheduled experimental sessions.
Design and Preloads An outline of the 3 studies is given below: STUDY 1 Soup preload STUDY 2 Soup preload STUDY 3 Soup preload
--, Motivational ratings for 60 minutes ---, 30-minute interval --* Test meal 2-minute ~ interval
Test----~ Postmeal meal motivational ratings for 3 hours
IRequests for reprints should be addressed to Peter J. Rogers at his current address: Department of Food Acceptability, AFRC Institute of Food Research, Shinfield, Reading, RG2 9AT, UK.
801
802
ROGERS AND BLUNDELL
TABLE 1 COMPOSITION OF THE BEEF CONSOMME* Component
Percentage by Weight
TABLE 2 MEAN (+ SE) SENSORY AND AFFECTIVE RATINGS OF TWO MSG-SUPPLEMENTED SOUP PRELOADS: COMBINED DATA FROM STUDIES 1 AND 3 Rating
Crude protein Fat Sugar Ash Water Umami compounds: MSG Disodium inosinate Disodium guanylate
0%-MSG
20%-MSG
t(20)
p
0.55 0.75 0.61 3.19 1.51 1.75 2.70 3.67
ns ns ns
0031-9384/90 $3.00 + .00
Umami and Appetite: Effects of Monosodium Glutamate on Hunger and Food Intake in Human Subjects P E T E R J. R O G E R S l A N D J O H N E. B L U N D E L L
Biopsychology Group, Psychology Department, University o f Leeds, Leeds LS2 9JT, UK
ROGERS, P. J. AND J. E. BLUNDELL. Umami and appetite: Effects of monosodium glutamate on hunger and food intake in human subjects. PHYSIOL BEHAV 48(6) 801-804, 1990.--Subjects consumed soup (beef consomme) preloads of a fixed size conraining different concentrations of monosodinm L-glutamate (MSG). Effects on appetite following these preloads, and when no soup was consumed, were assessed in 3 studies. The soups supplemented with MSG were rated as more "pleasant," more "savoury" and more "satisfying" than soup with no added MSG. Compared with the no preload condition, consumption of the soups initially reduced appetitive motivational ratings and increased fullness ratings, but did not alter food intake in a test meal begun either 2 or 30 minutes later. This immediate inhibition of subjective motivation to eat was unaffected by MSG concentration. The failure of the soups to reduce subsequent food intake is presumably due to their low energy content (< 10 kcal) and indicates that sensory stimulation alone is insufficient to reduce appetite. Indeed, the most important finding concerning MSG showed that motivation to eat recovered more rapidly following a lunchtime meal in which MSG-supplemented soup was served as the first course (compared both with the effect of unsupplemented soup and no preload). It is suggested tentatively that MSG through its stimulation of orosensory receptors and/or by improving the palatability of the soup may have influenced the metabolic disposal of nutrients consumed in the previous meal. Monosodium glutamate
Hunger
Food intake
Taste
Human eating behaviour
Caloric compensation
METHOD
G L U T A M A T E has long been used to improve the taste quality of food. The taste of glutamate has been named umami which is derived from the Japanese word meaning "deliciousness," and several umami substances, including monosodium L-glutamate (MSG), sodium 5'-inosinate and 5'-guanylate, are now widely available as "flavour enhancers" (5). However, despite the importance of umami taste in many foods and much research on, for example, the physiological mechanisms of umami taste perception, there appears to be little information on the relationship between umami and appetite control (5). Umami taste substances may be expected to influence appetite in a number of ways, such as through effects on palatability, and because of their natural association with protein containing foods: to British palates umami taste may best be described as " s a v o u r y . " Some evidence indicates that protein is more satiating calorie for calorie than carbohydrate or fat [see (3)1. Three studies are reported here in which subjects consumed soup preloads of a fixed size containing various concentrations of MSG. Effects on appetite following these preloads, and when no soup was consumed, were assessed by tracking motivation to eat and by measuring the amount of food eaten in test meals.
Subjects A total of 36 undergraduate volunteers, 23 women and 13 men, took part in the 3 studies. All were of normal weight for height (mean Body Mass Index = 21.1), and all reported that they were not currently dieting to lose weight. Four subjects, however, were excluded from the fmal data analysis because they failed to complete all of their scheduled experimental sessions.
Design and Preloads An outline of the 3 studies is given below: STUDY 1 Soup preload STUDY 2 Soup preload STUDY 3 Soup preload
--, Motivational ratings for 60 minutes ---, 30-minute interval --* Test meal 2-minute ~ interval
Test----~ Postmeal meal motivational ratings for 3 hours
IRequests for reprints should be addressed to Peter J. Rogers at his current address: Department of Food Acceptability, AFRC Institute of Food Research, Shinfield, Reading, RG2 9AT, UK.
801
802
ROGERS AND BLUNDELL
TABLE 1 COMPOSITION OF THE BEEF CONSOMME* Component
Percentage by Weight
TABLE 2 MEAN (+ SE) SENSORY AND AFFECTIVE RATINGS OF TWO MSG-SUPPLEMENTED SOUP PRELOADS: COMBINED DATA FROM STUDIES 1 AND 3 Rating
Crude protein Fat Sugar Ash Water Umami compounds: MSG Disodium inosinate Disodium guanylate
0%-MSG
20%-MSG
t(20)
p
0.55 0.75 0.61 3.19 1.51 1.75 2.70 3.67
ns ns ns
