Can dietary supplementation of monosodium glutamate improve the
health of the elderly?1–4
Shigeru Yamamoto, Miki Tomoe, Kenji Toyama, Misako Kawai, and Hisayuki Uneyama
Dietary free L-glutamate has been known for a century to improve
taste and palatability. Recent evidence suggests that this effect is
mediated through specific L-glutamate receptors located on the taste
buds. However, L-glutamate receptors are also present elsewhere in
the gastrointestinal tract, such as the stomach. Here, L-glutamate
exerts physiologic actions beneficial to gut function by stimulating
L-glutamate receptors linked to the gastric vagus nerve. In addition,
dietary L-glutamate also appears to be an important energy substrate
for gut tissue. Can such L-glutamate effects on taste and gut function
be clinically useful? Elderly people often develop health problems
related to their nutritional status that can be linked to insufficient
energy and nutrient intake. A number of studies have examined the
potential usefulness of L-glutamate, added to food in the form of
monosodium glutamate (MSG), in promoting better nutrition in the
elderly and in patients with poor nutrition. Some positive effects
have been observed. This article reviews the physiologic roles of
dietary L-glutamate in relation to alimentation and examines the
evidence linking the utility of MSG supplementation to the impro-
vement of nutrition in elderly and hospitalized patients.
Clin Nutr 2009;90(suppl):844S–9S.
Taste is a primitive sensory method which governs nutrition
and food selection. Free L-glutamate imparts an intrinsic taste of
its own, termed umami, the fifth basic taste (the other 4 are
sweet, salty, sour, and bitter). The sodium salt of L-glutamate,
monosodium glutamate (MSG), has been used as a flavor en-
hancer for more than a century. MSG improves the sensory
quality of many foods (1). The taste of MSG begins on the
tongue when the amino acid interacts with one or more specific
receptors for L-glutamate (2–4). All of the known taste effects
of MSG, including its marked synergism with inosine mono-
phosphate and guanine monophosphate, can be tied to interactions
with taste L-glutamate receptors in the mouth. L-Glutamate re-
ceptors have also been identified in the stomach (5). This may
not be surprising, because neurophysiologic studies over the past
2 decades have reported that L-glutamate placed on gut tissue
activates the vagus nerve (6–8). Indeed, the receptor findings
appear to explain how this transduction process occurs. In ad-
L-glutamate-induced stimulation of the vagus nerve
modifies gut functions, such as gastric secretion and motility (9,
10). In this manner, ingested L-glutamate (either as free L-
glutamate or L-glutamate liberated when proteins are digested)
can influence digestive functions. However, dietary L-glutamate
has other important effects on gut function, the most notable
being that it is a main energy source for the gut during food
Because dietary L-glutamate has many effects on food in-
gestion and digestion, it seems reasonable to ask if L-glutamate
might be useful in promoting food intake and nutrient balance in
individuals who are in poor nutritional health. Such individuals
include patients with loss of appetite and undernourished el-
derly, particularly in institutional settings (eg, nursing homes).
This review considers studies that have examined this question.
At present, the database is not extensive, but findings thus far
suggest avenues for further investigation that may show useful
roles for MSG in improving dietary compliance and nutritional
APPETITE: MSG AS AN APPETITE ENHANCER
MSG is used extensively throughout the world as a flavor
enhancer. It improves such specific flavor characteristics of food
as continuity, mouthfulness, effect, mildness, and thickness of
food (12). It also improves the overall preference for food. In the
elderly, there is a general decrease in the sensitivity of the senses,
including taste (13, 14). Several such reports have described the
16); however, few data have evaluated changes in elderly people
in Asian countries. A recent study reported the sensitivity and
preference for L-glutamate (umami taste) in middle-aged (mean 6
SD age: 49.6 6 5.6 y; n = 40) and elderly (age: 84.3 6 6.1 y; n =
39) Japanese women. Similar to findings in Western individuals,
1From the International Nutrition, Ochanomizu University Graduate
School of Humanities & Sciences, Ochanomizu University Graduate School,
Tokyo, Japan (SY); the Department of Nutrition, Okanoki Hospital, Kita-
Kyushu, Japan (MT); the Department of Nutritional Sciences, Faculty of
Health and Welfare, Seinan Jogakuin University, Kita-Kyushu, Japan
(KT); and the Physiology & Nutrition Group, Institute of Life Sciences,
Ajinomoto Co, Inc, Tokyo, Japan (MK and HU).
2Presented at the “100th Anniversary Symposium of Umami Discovery:
The Roles of Glutamate in Taste, Gastrointestinal Function, Metabolism, and
Physiology,” held in Tokyo, Japan, September 10–13, 2008.
3Supported in part by the Ajinomoto Company, a manufacturer of food
and amino acids, including glutamate.
4Address correspondence to S Yamamoto, International Nutrition, Ocha-
nomizu University Graduate School of Humanities & Sciences, 2-1-1 Oht-
suka, Bunkyo-ku, Tokyo 112-8610, Japan. E-mail: yamamoto.shigeru@
First published online July 1, 2009; doi: 10.3945/ajcn.2009.27462X.
Am J Clin Nutr 2009;90(suppl):844S–9S. Printed in USA. ? 2009 American Society for Nutrition
the threshold and preferred concentrations of L-glutamate were
significantly higher in elderly Japanese women than in middle-
aged Japanese women (17) (Figure 1).
L-Glutamate (umami taste) preference varies under different
physiologic conditions. The preference for umami is affected by
nutritional status. For example, poorly nourished subjects prefer
foods with a higher MSG concentration than do well-nourished
subjects (18). It was reported that umami taste sensitivity is
correlated with the protein preference score, suggesting that the
taste threshold for umami predicts one’s liking as well as pref-
erence for high-protein foods.
Patients with head and neck cancer treated with radiation
therapy have gustatory dysfunctions, including loss of umami
umami sensitivity showed the strongest correlation with human
MSG is very important to nutrient intake and quality of life
(QOL). During the past 25 y, the effects of MSG supplementation
of the foods for the elderly who have lost their appetite have been
studied in several countries. MSG supplementation of food
caused an increase in the intake of certain foods by the elderly
(20). For example, the intakes of energy and nutrients were
measured in hospitalized elderly subjects (n = 65; average age:
65 y) given foods with or without added MSG (0.6%) for 6 mo.
Although total energy intake did not change, higher intakes of
the foods containing added MSG (soups, meats, vegetables)
were observed, and the intake of foods without added MSG (eg,
desserts) was low. A similar result was reported in 62 middle-
aged patients with diabetes mellitus (21). The combination of
MSG and food flavors also increased food intake and improved
nutritional status in 43 hospitalized elderly patients whose body
weights were reduced from disease (22). A similar result has
been reported with the addition of MSG and food flavors to
foods administered to elderly subjects in a nursing home for 4
mo (23). Favorable effects of MSG on palatability and appetite
are clearer in patients subject to strict restrictions of sodium
intake, such as elderly individuals with high blood pressure or
children with kidney disease (24, 25). Thus, human sensory and
appetite evaluation studies indicate that adequate MSG fortifi-
cation to the diet in the elderly might have potential to improve
their nutritional status by increasing palatability and appetite for
Oral care: improvement of oral functions with MSG
Eating is one of the great pleasures in life. Optimal nutrition,
appetite satisfaction, and QOL are of paramount importance in
the elderly. When food is ingested, saliva acts not only as
a solvent that allows tastants to be extracted from foods but also
as a glue and lubricant for masticated foods that permits safe
swallowing. Furthermore, salivais important forthe dental health
(lubrication and mineralization), immune function, and pre-
vention of microbial growth. Dry mouth because of diminished
to poor oral hygiene (26, 27).
Salivary secretion is provoked by mechanical (mastication and
speech) and gustatory stimuli, as well as the autonomic nerves
that umami taste stimuli increase salivary flow in healthy adult
subjects. According to one study, next to sour taste, umami taste
is the most potent taste stimulus of saliva secretion from the
parotid gland (31). In addition, of the 5 basic tastes, the increase
in salivary secretion produced by umami is the most long
Schiffman and Miletic (33) have measured the influence of
umami taste on the amount of immunoglobulin A in the saliva
(sIgA) secreted by elderly subjects ingesting food. The ingestion
of a food containing added MSG was observed to produce sig-
nificantly more saliva secretion than occurred after ingesting the
same food with no added MSG (Figure 2). Salivary sIgA con-
centration was not different; hence, the oral cavity experienced
a greater total exposure to secreted sIgAwhen MSG was present
in the food (33). The ability of umami to increase salivary flow
may therefore have clinical potential in the elderly, who fre-
quently experience dry mouth and its complications.
Gastrointestinal disfunction in the elderly: can dietary
The elderly are at higher risk of developing malnutrition;
unfortunately, its diagnosis is often missed on examination. Good
FIGURE 1. Monosodium glutamate (MSG) threshold of Japanese
subjects. Two-alternative forced-choice test was performed with rice
porridge containing 0.2% NaCl as a medium. Threshold concentration of
each subject was assumed the lowest MSG concentration of successive
correct answers. The threshold for the aged was significantly higher than
for the middle-aged (Mann-Whitney U test). Reproduced with permission
from reference 17.
FIGURE 2. Mean (6SD) effects of monosodium glutamate (MSG) on the
secretion of salivary immunoglobulin A (sIgA). Secretion rate of sIgA by
stimulation of chicken soup (left), and carrots (right) with (black bar) and
without (white bar) MSG. In the experiments, 10 elderly subjects (aged 69.5 6
1.9 y) held one of the test foods in the mouth for 10 s before swallowing. The
saliva secreted during 120 s after swallowing was collected, and the weight
and sIgAwere measured. The same procedure was repeated 3 times with 30-
min interval for the same test food. The sIgA secretion rates between the
MSG and no MSG tests were reported to be different at the 30- and 60-min
samplings for both foods. Adapted from reference 33.
GLUTAMATE AND NUTRITION IN THE ELDERLY
a key determinant of morbidity and mortality in the elderly (34).
Because poor nutritional status is preventable and reversible,
nutritional strategies should be developed to optimize nutritional
status in the elderly. Many factors contribute to the development
of malnutrition in the elderly, including 1) reduced food intake,
because of appetite loss or difficulty in mastication and swal-
lowing or both; 2) poor mental state, including depression; 3)
social isolation; 4) diminished senses of taste and smell and di-
minished gastric secretions and motility; and 5) pathologic fac-
tors, including indigestion, diarrhea, and constipation (35, 36).
A more serious pathologic condition that can compromise
good nutrition is chronic atrophic gastritis, which has a high
prevalence in the elderly, and can cause malabsorption of nutrients
and appetite loss (37). Atrophy of gastric acid-secreting parietal
cells and pepsinogen-secreting chief cells occurs in this disease,
and patients often complain of appetite loss. Can adding MSG to
the diet improve gastric function and nutritional state in such
patients? In one clinical trial, MSG supplementation of meals
(2–3 g/d for 1 mo) was reported to increase basal and maximal
acid output to near normal amounts and also improved appetite
(Figure 3) (38).
elderly that can contribute to poor nutritional status. Delayed
gastric emptying after a meal causes prolonged stomach dis-
tension, which can reduce hunger, increase satiety, and, in some
cases, produce stomach discomfort (35, 36). Further, the increase
in abdominal pressure caused by delayed gastric emptying can
lead to gastroesophageal reflux and oropharyngeal aspiration,
leading to pneumonia in elderly patients (39). Some evidence
suggests that dietary MSG supplementation might be useful in
moderating this condition, particularly when consuming protein.
For example, Zai et al (10) reported in healthy adults (aged ?40
y) that supplementing a protein-rich liquid diet with 0.5% MSG
increased the gastric emptying rate (Table 1). Of interest, this
action of MSG occurred only in a protein-rich liquid diet and not
when it was added to an equicaloric carbohydrate (no-protein)
liquid diet. In another study, Tanaka et al (40) also reported that
0.5% MSG supplementation of a similar protein-rich liquid diet
reduced postingestive abdominal discomforts, such as stomach
fullness and heaviness in healthy adult volunteers .45 y of age
(Figure 4). Such findings suggest that dietary MSG supple-
mentation in elderly subjects experiencing clinically significant
gastric disorders might improve stomach function and overall
Poor nutrition in the hospitalized elderly: a role for MSG?
The percentage of elderly in the population is increasing
worldwide. Protein energy malnutrition is a problem in many
elderly individuals (41). In Japan, .35% of hospitalized elderly
patients are estimated to have protein-calorie malnutrition and to
have a plasma albumin value ,3.5 g/100 mL (42). The addition
Effect of monosodium glutamate (MSG) on gastric emptying1
Protein-rich meal (n = 10)Carbohydrate meal (n = 9) Water (n = 9)
Cumulative percentage dose at 1.5 h4
153.0 6 34.63
212.7 6 102.6
197.6 6 92.8
172.6 6 38.2
90.8 6 9.0
97.4 6 10.2
28.6 6 2.43
24.7 6 3.4
36.4 6 2.6
38.6 6 3.2
45.6 6 1.7
42.7 6 4.8
1Data are modified from reference 10. All values are means 6 SDs. Gastric emptying was studied with 3 types of
liquid test meals (400 mL volume in water; protein-rich meal: 12.5% casein calcium + 12.5% dextrin; carbohydrate meal:
25.0% dextrin; and water) labeled with 100 mg13C sodium acetate, for continuous monitoring of13CO2excretion in breath.
MSG (0.5% wt:vol) in 400 mL water was used to prepare the liquid meals for the “adding MSG” trials. The data obtained
by breath test are expressed as percentage of recovery per hour of the initial administered13C dose (percentage dose/h);
these data correspond to the velocity of the gastric emptying. The value of percentage dose/h is determined by calculating
a ratio of13CO2administered to13CO2in the breath samples. Three-factor repeated-measures ANOVA (time, treatment,
and meal) with interaction and Bonferroni test were used for statistical analysis. Significant differences between meals were
detected in the cumulative percentage dose/h (P , 0.001). Note that only after intake of protein-rich meal does MSG
significantly reduce the half excretion time (t1/2ex) and increase cumulative percentage dose/h at 3 h. These effects indicate
that MSG accelerates digestive function after intake of protein meal.
2Time during which half of total cumulative13CO2excretion has occurred.
3Significantly different from without MSG, P , 0.05 (Bonferroni test).
4Area under the cumulative percentage dose/h curve from time 0 to 1.5 h.
FIGURE 3. Mean (6SD) effects of monosodium glutamate (MSG)
supplementation on gastric acid secretion in patients with chronic gastritis.
All patients receiving medical treatments (enzyme preparations and vitamins)
were given MSG in amounts of 2–3 g/d as a food additive for 24–25 d. In all
patients, gastric secretion was evaluated before (basal acid output; BAO) and
after (maximum acid output; MAO) treatment with pentagastrin. White
bars represent gastric secretion before MSG intervention, and black bars
represent those after MSG intervention. mequ/h, the amount of NaOH
(mmol) required for neutralization of 1 h gastric fluid. Reproduced with
permission from reference 38.
YAMAMOTO ET AL
of MSG to foods may help to increase food intake in the elderly
by enhancing the taste of foods and by stimulating gastric
functions through gastric L-glutamate receptors. A small, long-
term intervention study in hospitalized, elderly Japanese patients
has recently assessed this prospect (42). A dietary survey has
shown that the amount of free L-glutamate in hospital food in
Japan is less than half the daily intake by healthy people .65 y
of age (42). The amount of MSG intake in this latter group is
estimated to be 1640 mg/d (43) (Figure 5A). Hence, to exceed
the intake of healthy elderly individuals, 0.5% MSG supple-
ments were added to the staple diet of elderly patients (age: 85.5 6
8.2 y; n = 11) for 2 mo, and the effect on nutritional status,
general health, and QOL were examined. No change in food or
protein intake resulted, but a significant increase in peripheral
FIGURE 4. Mean (6SEM) effects of monosodium glutamate (MSG)
supplementation on self-reported postingestion abdominal feelings. In 66
healthy volunteers (aged 22–59 y), postingestion abdominal feelings were
monitored by questionnaire with a 100-mm visual analog scale after taking
a protein-rich liquid diet (400 kcal/400 mL; a mixture of 50% calcium
caseinate and 50% dextrin). In subjects ,45 y old, no difference was
observed between the postprandial sensation curves with and without
MSG enrichment of the meal. However, in subjects aged .45 y, MSG
supplementation showed a tendency to lower postprandial feelings of
fullness. Data were adapted from reference 40.
FIGURE 5. Free-glutamate supplementation changes the concentration of
plasma lymphocytes in elderly inpatients. A: Mean (6SD) daily free-
glutamate contents in hospital meals for elderly inpatients (42). Population
daily free-glutamate intake by age, estimated by the Ministry of Health and
Welfare (43), was presented for comparison. B: Mean (6SD) changes in
plasma lymphocyte concentrations (n = 11) during a 1-mo lead-in period (0)
and intervention months 1 and 2. **P , 0.01 (Scheffe test). Modified from
Change in mealtime behavior scores by monosodium glutamate (MSG) supplementation1
MSG group Control
Mean 6 SDP valueMean 6 SDP value
Motion of arm and hand
0.31 6 0.28
0.87 6 0.41
0.0280.31 6 0.28
0.83 6 0.72
0.37 6 0.17
0.71 6 0.21
0.017 0.56 6 0.64
0.79 6 0.65
0.32 6 0.18
0.78 6 0.19
0.0030.40 6 0.43
0.85 6 0.52
0.45 6 0.27
0.67 6 0.35
0.2740.41 6 0.41
0.85 6 0.56
0.28 6 0.24
0.94 6 0.41
0.0080.49 6 0.62
1.04 6 0.82
0.36 6 0.24
0.88 6 0.28
0.009 0.47 6 0.55
1.08 6 0.64
0.31 6 0.24
0.93 6 0.40
0.012 0.44 6 0.48
1.05 6 0.74
0.28 6 0.21
0.94 6 0.30
0.0020.52 6 0.65
1.04 6 0.81
1Data are from a double-blind, placebo-controlled trial of dietary MSG supplementation (45). Mealtime behaviors of
those who did not have total care were video-recorded for 5 min from the initiation of lunch during the last week of both the
lead-in period (LI) and the 3-mo intervention period (3M). Thirteen university students who watched the 2 videos of each
subject were forced to choose the better and the degree of the difference for each evaluation item. The results were
transformed to numerical values: eg, 2 for the better, 1 for the slightly better, and 0 for the same and the worse one.
Statistical analyses were performed within each group by the paired t test.
GLUTAMATE AND NUTRITION IN THE ELDERLY
lymphocyte concentrations was noted, suggesting improved
immune status (Figure 5B). In addition, improvements were
observed in routine functions such as speech, facial expression,
and eye opening (42). Schiffman (22) and Schiffman and
Warwick (44) reported previously an improvement in immune
function in the elderly after the enhancement of the flavors of
typical institutional diets. In a recent, double-blind, placebo-
controlled trial in hospitalized elderly, MSG supplementation of
a standard institutional diet also improved daily performance
(mealtime behavior) (Table 2) (45).
Overall, work on the usefulness of MSG supplementation of
institutionalized diets in improving nutritional status and well-
being in elderly individuals is still fairly preliminary. Some
suggestive benefits seem apparent, but study duration and sample
size havegenerally been toosmall in published studies to identify
clear effects. Effects on salivaryvolumeand IgAsecretion and on
stomach functions seem promising. Given the multiplicity of
effects of L-glutamate now evident in the gastrointestinal tract,
future studies of appropriate statistical power will hopefully
provide clarity on the possible digestive and nutritional benefits
of supplemental dietary MSG for the elderly. (Other articles in
this supplement to the Journal include references 46–74.)
We thank Hrudananda Mallick (All India Institute of Medical Sciences,
New Delhi, India) for helpful advice and proofreading the manuscript.
The authors’ responsibilities were as follows—SY, MK, and HU: contrib-
uted equally to the preparation of the manuscript; and MTand KT: assisted in
the preparation of the manuscript. The presenting author’s (SY) travel
expenses associated with participation in the symposium and an honorarium
were paid by the conference sponsor, the International Glutamate Technical
Committee, a nongovernmental organization funded by industrial producers
and users of glutamate in food. Two of the authors (MK and HU) are employ-
ees of Ajinomoto Company, a manufacturer of food and amino acids, includ-
ing glutamate. The remaining authors had no conflicts of interest.
1. Kurihara K, Kashiwayanagi M. Physiological studies on umami taste.
J Nutr 2000;130(suppl):931S–4S.
2. Chaudhari N, Landin A, Roper SD. A metabolic glutamate receptor
variant functions as a taste receptor. Nat Neurosci 2000;3:113–9.
3. Li X, Staszewski L, Xu H, Durick K, Zoller M, Adler E. Human re-
ceptors for sweet and umami taste. Proc Natl Acad Sci USA 2002;99:
4. Nelson G, Chandrashekar J, Hoon MA, et al. An amino-acid taste re-
ceptor. Nature 2002;416:199–202.
5. San Gabriel AM, Maekawa T, Uneyama H, Yoshie S, Torii K. mGluR1
in the fundic glands of rat stomach. FEBS Lett 2007;581:1119–23.
6. Niijima A. Effects of oral and intestinal stimulation with umami sub-
stance on gastric vagus activity. Physiol Behav 1991;49:1025–8.
7. Niijima A. Reflex effect of oral, gastrointestinal and hepatoportal glu-
tamate sensors on vagal nerve activity. J Nutr 2000;130(suppl):971S–3S.
8. Uneyama H, Niijima A, San Gabriel A, Torii K. Luminal amino acid
sensing in the rat gastric mucosa. Am J Physiol Gastrointest Liver
9. Zolotarev V, Khropycheva R, Uneyama H, et al. Effect of free dietary
glutamate on gastric secretion in dogs. Ann N Y Acad Sci (in press).
10. Zai H, Kusano M, Hosaka H, et al. Glutamate added to a high-energy
high-protein liquid diet promotes gastric emptying. Am J Clin Nutr
11. Janeczko MJ, Stoll B, Chang X, Guan X, Burrin DG. Extensive gut
metabolism limits the intestinal absorption of excessive supplemental
dietary glutamate loads in infant pigs. J Nutr 2007;137:2384–90.
12. Yamaguchi S, Kimizuka A. Psychometric studies on the taste of mono-
sodium glutamate. In: Filer LJ Jr, Garattini S, Kare MR, Reynolds WA,
Wurtman RJ, eds. Glutamic acid: advances in biochemistry and physiol-
ogy. New York, NY: Raven Press, 1979:35–54.
13. Stevens JC, Bartoshuk LM, Cain WS. Chemical senses and aging: Taste
versus smell. Chem Senses 1984;9:167–79.
14. Schiffman SS. Taste and smell losses in normal aging and disease.
15. Schiffman SS, Sattely-Miller EA, Zimmerman IA, Graham BG,
Erickson RP. Taste perception of monosodium glutamate (MSG) in
foods in young and elderly subjects. Physiol Behav 1994;56:265–75.
16. Mojet J, Christ-Hazelhof E, Heidema J. Taste perception with age: ge-
neric or specific losses in threshold sensitivity to the five basic tastes?
Chem Senses 2001;26:845–60.
17. Hayakawa Y, Kawai M, Sakai R, et al. Koureisha no umami kanjusei
sokutei -sounen tono hikaku- [Umami sensitivity of the elderly
females-Comparison with middle-aged females]. Jpn J Taste Smell Res
2007;14:443–6 (in Japanese).
18. Murphy C. Flavor preference for monosodium glutamate and casein
hydrolysate in young and elderly persons. In: Kawamura Y, Kare MR,
eds. Umami: a basic taste. New York, NY: Marcel Dekker, 1987:139–51.
19. Shi H-B, Masuda M, Umezaki T, et al. Irradiation impairment of umami
taste in patients with head and neck cancer. Auris Nasus Larynx 2004;
20. Bellisle F, Monneuse MO, Chabert M, Larue-Achagiotis C, Lanteaume
MT, Louis-Syrvestre J. Monosodium glutamate as a palatability en-
hancer in the European diet. Physiol Behav 1991;49:869–73.
21. Bellisle F, Dalixa M, Chapppuis AS, et al. Monosodium glutamate af-
fects mealtime food selection in diabetic patients. Appetite 1996;26:
22. Schiffman SS. Sensory enhancement of foods for the elderly with
monosodium glutamate and flavors. Food Rev Int 1998;14:321–33.
23. Mathey MF, Siebelink E, de Graaf C, Van Staveren WA. Flavor en-
hancement of food improves dietary intake and nutritional status of el-
derly nursing home residents. J Gerontol A Biol Sci Med Sci 2001;56:
24. Roininen K, Lahteenmaki L, Tuorila H. Effect of umami taste on
pleasantness of low-salt soups during repeated testing. Physiol Behav
25. Ball P, Woodward D, Beard T, et al. Calcium diglutamate improves taste
characteristics of lower-salt soup. Eur J Clin Nutr 2002;56:519–23.
26. Gupta A, Epstein JB, Sroussi H. Hyposalivation in elderly patients.
J Can Dent Assoc 2006;72:841–6.
27. Navazesh M. Dry mouth: aging and oral health. Compend Contin Educ
28. Proctor GB, Carpenter GH. Regulation of salivary gland function by
autonomic nerves. Auton Neurosci 2007;133:3–18.
29. Kawamura Y, Yamamoto T, Fujiwara T, Matsuo R, Takahashi T. Ka-
kushu teimi zoukyou busshitsu ni yoru mikaku-daeki bunpi hansha ni
kansuru kenkyu [Studies on the gustatory-salivary reflex elicited by
chemical taste enhancers]. Osaka Daigaku Shigaku Zasshi 1980;25:179–
85 (in Japanese).
30. Horio T, Kawamura Y. Salivary secretion induced by umami taste. Shika
Kiso Igakkai Zasshi 1989;31:107–11.
31. Hodson NA, Linden RW. The effect of monosodium glutamate on pa-
rotid salivary flow in comparison to the response to representatives of
the other four basic tastes. Physiol Behav 2006;89:711–7.
32. Hayakawa Y, Kawai M, Torii K, Uneyama H. Umami shigeki ni yoru
daeki bunpi sokushin kouka sokutei [The effect of umami taste on saliva
secretion]. Jpn J Taste Smell Res 2008;15:367–70 (in Japanese).
33. Schiffman SS, Miletic ID. Effect of taste and smell on secretion rate of
salivary IgA in elderly and young persons. J Nutr Health Aging 1999;3:
34. Katona P, Katona-Apte J. The interaction between nutrition and in-
fection. Clin Infect Dis 2008;46:1582–8.
35. Hays NP, Roberts SB. The anorexia of aging in humans. Physiol Behav
36. Morley JE, Thomas DR. Anorexia and aging: pathophysiology. Nutri-
37. Halter F, Hurlimann S, Inauen W. Pathophysiology and clinical rele-
vance of Helicobacter pyroli. Yale J Biol Med 1992;65:625–38.
38. Kochetkov AM, Shlygin GK, Loranskaia TI, Vasilevskaia LS, Kondrashev
SI. The use of monosodium glutamate in the combined therapy of patients
with atrophic gastritis. Vopr Pitan 1992;5-6:19–22 (in Russian).
YAMAMOTO ET AL
39. Marik PE, Kaplan D. Aspiration pneumonia and dysphagia in the el-
derly. Chest 2003;124:328–36.
40. Tanaka T, Fujita S, Kawai M, et al. Koutanpakushitsu ryuudoushoku
sesshugo no shokugo kankaku ni taisuru gurutaminsan natoriumu no
kouka. [Effect of dietary free glutamate on the postprandial sensation
for protein-rich liquid diet]. Jpn J Taste Smell Res 2006;13:415–6 (in
41. Price DM. Protein-energy malnutrition among the elderly: implications
for nursing care. Holist Nurs Pract 2008;22:355–60.
42. Toyama K, Tomoe M, Inoue Y, et al. A possible application of mono-
sodium glutamate to nutritional care for elderly people. Biol Pharm Bull
43. The Japan Food Chemical Research Foundation. Daily intake study of
food additives by age cohort based on the market basket method. Na-
tional Institute of Health Science. Available from: http://www.ffcr.or.
jp/zaidan/FFCRHOME.nsf/pages/DI-study (cited 20 October 2008).
44. Schiffman SS, Warwick ZS. Effect of flavor enhancement of foods for
the elderly on nutritional status: food intake, biochemical indices, and
anthropometric measures. Physiol Behav 1993;53:395–402.
45. Tomoe M, Inoue Y, Sanbe A, et al. Clinical trial of glutamate for the
improvement of nutrition and health in the elderly. Ann N Y Acad Sci
46. Fernstrom JD. Introduction to the symposium. Am J Clin Nutr 2009;90
47. Krebs JR. The gourmet ape: evolution and human food preferences. Am
J Clin Nutr 2009;90(suppl):707S–11S.
48. Curtis RI. Umami and the foods of classical antiquity. Am J Clin Nutr
49. Kurihara K. Glutamate: from discovery as a food flavor to role as a basic
taste (umami). Am J Clin Nutr 2009;90(suppl):719S–22S.
50. Beauchamp GK. Sensory and receptor responses to umami: an overview
of pioneering work. Am J Clin Nutr 2009;90(suppl):723S–7S.
51. Sano C. History of glutamate production. Am J Clin Nutr 2009;
52. Li X. T1R receptors mediate mammalian sweet and umami taste. Am J
Clin Nutr 2009;90(suppl):733S–7S.
53. Chaudhari N, Pereira E, Roper SD. Taste receptors for umami: the case
for multiple receptors. Am J Clin Nutr 2009;90(suppl):738S–42S.
54. San Gabriel A, Maekawa T, Uneyama H, Torii K. Metabotropic gluta-
mate receptor type 1 in taste tissue. Am J Clin Nutr 2009;90(suppl):
55. Yasumatsu K, Horio N, Murata Y, et al. Multiple receptors underlie
glutamate taste responses in mice. Am J Clin Nutr 2009;90(suppl):
56. Kinnamon SC. Umami taste transduction mechanisms. Am J Clin Nutr
57. Bachmanov AA, Inoue M, Ji H, Murata Y, Tordoff MG, Beauchamp
GK. Glutamate taste and appetite in laboratory mice: physiologic and
genetic analyses. Am J Clin Nutr 2009;90(suppl):756S–63S.
58. Shigemura N, Shirosaki S, Ohkuri T, et al. Variation in umami per-
ception and in candidate genes for the umami receptor in mice and
humans. Am J Clin Nutr 2009;90(suppl):764S–9S.
59. Chen Q-Y, Alarcon S, Tharp A, et al. Perceptual variation in umami
taste and polymorphisms in TAS1R taste receptor genes. Am J Clin Nutr
60. Mennella JA, Forestell CA, Morgan LK, Beauchamp GK. Early milk
feeding influences taste acceptance and liking during infancy. Am J Clin
61. Raliou M, Wiencis A, Pillias A-M, et al. Nonsynonymous single nu-
cleotide polymorphisms in human tas1r1, tas1r3, and mGluR1 and in-
dividual taste sensitivity to glutamate. Am J Clin Nutr 2009;90(suppl):
62. Donaldson LF, Bennett L, Baic S, Melichar JK. Taste and weight: is
there a link? Am J Clin Nutr 2009;90(suppl):800S–3S.
63. Rolls ET. Functional neuroimaging of umami taste: what makes umami
pleasant? Am J Clin Nutr 2009;90(suppl):804S–13S.
64. Blachier F, Boutry C, Bos C, Tome ´ D. Metabolism and functions of
L-glutamate in the epithelial cells of the small and large intestines. Am J
Clin Nutr 2009;90(suppl):814S–21S.
65. Kokrashvili Z, Mosinger B, Margolskee RF. Taste signaling elements
expressed in gut enteroendocrine cells regulate nutrient-responsive se-
cretion of gut hormones. Am J Clin Nutr 2009;90(suppl):822S–5S.
66. Akiba Y, Kaunitz JD. Luminal chemosensing and upper gastrointestinal
mucosal defenses. Am J Clin Nutr 2009;90(suppl):826S–31S.
67. Kondoh T, Mallick HN, Torii K. Activation of the gut-brain axis by
dietary glutamate and physiologic significance in energy homeostasis.
Am J Clin Nutr 2009;90(suppl):832S–7S.
68. Tome ´ D, Schwarz J, Darcel N, Fromentin G. Protein, amino acids, vagus
nerve signaling, and the brain. Am J Clin Nutr 2009;90(suppl):838S–43S.
69. Burrin DG, Stoll B. Metabolic fate and function of dietary glutamate in
the gut. Am J Clin Nutr 2009;90(suppl):850S–6S.
70. Brosnan ME, Brosnan JT. Hepatic glutamate metabolism: a tale of 2
hepatocytes. Am J Clin Nutr 2009;90(suppl):857S–61S.
71. Stanley CA. Regulation of glutamate metabolism and insulin secretion
by glutamate dehydrogenase in hypoglycemic children. Am J Clin Nutr
72. Hawkins RA. The blood-brain barrier and glutamate. Am J Clin Nutr
73. Magistretti PJ. Role of glutamate in neuron-glia metabolic coupling. Am
J Clin Nutr 2009;90(suppl):875S–80S.
74. Fernstrom JD. Symposium summary. Am J Clin Nutr 2009;90(suppl):
GLUTAMATE AND NUTRITION IN THE ELDERLY