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PubMed1987

Taste preference thresholds for Polycose, maltose, and sucrose in rats.

The taste preference thresholds of adult female rats for polysaccharide (Polycose), maltose, and sucrose were compared. The nondeprived animals were given 24-hr two-bottle preference tests (saccharide solution vs. water) and, starting at 0.008%, the saccharide concentration was increased daily. The rats first preferred the Polycose solution to water at 0.01% (0.0001 M), the maltose solution to water at 0.09% (0.0025 M), and the sucrose solution to water at 0.09% (0.0026 M). Thus, on a molar basis the rats' Polycose threshold was 25 to 26 times lower than their maltose and sucrose threshold. It was postulated that the low taste threshold for polysaccharides allows the rat to detect starch which, unlike sugar, is very low in solubility.

Animals↗
PubMed1989

Taste. Robust across the age span?

The prevalence of taste loss over a discrete area of the tongue or palate is unknown; however, we have identified discrete losses in three etiological groups: head trauma, upper respiratory infection, and bulimia. We have now identified discrete losses in elderly subjects. To summarize, elderly subjects show elevated taste thresholds for some taste stimuli. Mild dysgeusia may act as a masking stimulus that makes taste thresholds appear to be elevated, and this may be more common in the elderly than the young. Discrete taste losses occur more often among the elderly than the young but usually go unnoticed (although these losses may contribute to elevated thresholds when the test procedure stimulates an area of loss). When the samples are at high concentrations, when the subject judges total intensity rather than typical quality, and when the whole mouth is used to do the tasting, the taste responses of elderly subjects look much like those of the young. Two factors contribute to the failure of people to notice localized taste loss. First, there appear to be mutually inhibitory connections between various taste loci such that if taste input from one area is blocked, the inhibition from that area is also blocked. This results in increases in perceived taste from the other areas. Second, a blank spot for taste can go unnoticed because taste is poorly localized. We can demonstrate this with an illusion. If a taste solution is painted from an area with receptors into an area that does not have receptors, the taste sensation seems to invade the area with no receptors. We suggest that a similar phenomenon may occur with areas from which receptors are lost. This localization illusion could then prevent a subject from noticing that an area has lost taste function. The discovery of discrete taste losses in a population of elderly subjects suggests that earlier failures to find substantial taste losses with age may reflect the redundancy of the taste system. This possibility raises the question of what functions taste subserves that require this kind of redundancy. The taste system appears to be "hard wired" to maintain the constancy of perceived intensity even if substantial taste areas are damaged. This constancy suggests that taste is serving important biological functions.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMedDate not supplied

Late taste disorders in bone marrow transplantation: clinical evaluation with taste solutions in autologous and allogeneic bone marrow recipients.

The aim of this work was to determine the type and the significance of taste disorders in allogeneic bone marrow transplanted patients. In a retrospective study the taste threshold of a cohort of 15 allogeneic bone marrow transplanted patients, 4-51 months after transplantation (mean: 30.6 +/- 15.8), was compared to the taste threshold of 8 autologous bone marrow recipients, 4-48 months after transplantation (mean: 24.12 +/- 12.18), and to the taste threshold of a group of 20 consecutive normal subjects. Allogeneic bone marrow transplanted patients showed a significant hypogeusia for salt (Pearson's chi square p = 0.0002; Yates' correction p = 0.0007) and sour (Pearson's chi square p = 0.001; Yates' correction p = 0.008). No significant variations were observed for sweet and bitter. Autologous bone marrow recipients did not show any significant variation of taste acuity for sweet, salt or sour; a constant reduction of the taste threshold for bitter was observed, but the values were not significantly different from normal (Pearson's chi square p = 0.47; Yates' correction p = 0.83). So, late and selective taste disorders are observed in allogeneic bone marrow transplanted patients. Since the severity of the disorders is not strictly related to the severity of chronic oral G.V.H.D., taste analysis could discover the slightest, clinically undetectable cases of chronic oral G.V.H.D. The mechanism of immune aggression on the sensorial taste cells is poorly understood. Further trials are needed to define variations of taste acuity not only after allogeneic bone marrow transplantation, but also in systemic immune diseases.

Adolescent↗
PubMed1991

Basic properties of umami and effects on humans.

This is a review of the taste of umami substances, and some related findings. The data demonstrate that, though the taste of the common umami substances such as MSG and IMP is mainly caused by their anions, the effects of their cations, such as Na, should not be ignored. The effects of cations approach the taste thresholds of umami substances. Although the taste threshold of MSG was slightly lower than that of Na, the threshold of IMP was found to be controlled by Na. However, the degree of saltiness was less than 10% above the threshold of the equivalent weight of NaCl. It was also found that the taste of IMP was probably caused by glutamic acid in saliva, since IMP itself has no umami taste. That is, IMP enhances the umami taste of MSG. Finally, comparison of umami sensitivity of Japanese and Americans revealed no difference.

Cross-Cultural Comparison↗
PubMed1989

[Variability of serum zinc concentration and taste acuity in denture wearers].

The zinc appears to play a significant roles in enzymatic activities as well as taste qualities, and it has been given considerable attention to the decreased serum zinc concentration patients who has been suffering from changes in taste acuity. There is, however, no report regarding the influence of the zinc concentration related to the denture wearers taste qualities. This study was undertaken to elucidate the correlation between serum zinc concentration and taste acuity in denture wearers. Total of 66 subjects were selected on 35 male and 31 female, aged 22 to 81 years. Within 66 subjects, 16 male and 18 female were denture wearers on aged 35 to 81 years. Serum zinc levels were made using atomic-absorption flame spectrophotometry, and taste thresholds were tested using electrogustometer on the anterior and posterior part of the tongue and on the soft palate. The results were as follows: 1. Significant decrease in serum zinc concentration with advancing age were obtained in both male and female subjects (Male: Y = 123.1-0.4 X, R = -0.67, p less than 0.01, Female: Y = 103.5-0.2 X, R = -0.37, p less than 0.05, where Y is serum zinc concentration in micrograms/dl and X is age in years). 2. Significant increase in taste-thresholds in every area with advancing age were obtained in both male and female subjects. 3. Denture wearers showed low value of serum zinc concentration (Male: 90.7 micrograms/dl, Female: 91.7 micrograms/dl) compared to young subjects (Male: 110.8 micrograms/dl, Female: 102.6 micrograms/dl). 4. Denture wearers showed high value of taste thresholds (Anterior part of the tongue: 18.8 dB, Posterior part of the tongue: 15.8 dB, Soft palate: 18.9 dB) compared to young subjects (Anterior part of the tongue: 6.6 dB, Posterior part of the tongue: 7.6 dB, Soft palate: 8.8 dB).

Adult↗
PubMed1975

Abnormalities of taste sensation in cancer patients.

In fifty patients with cancer, subjective and objective correlates of anorexia of malignancy were studied. Decreased taste was reported by 25 patients, and an aversion for meat was reported by 16 patients. The decreased taste symptom correlated with an elevated taste threshold for sweet (sucrose), and the symptom of meat aversion correlated with a lowered taste threshold for bitter (urea). The likelihood of having a taste abnormality increased with increasing extent of disease, but not with histologic type of neoplasm. Patients with an abnormality of taste had an increased incidence of weight loss compared with patients with normal taste, even though many in the latter group had other causes of weight loss. These observations suggest that an abnormality of taste may be one determinant of the anorexia of malignancy. Better understanding of the anorexia in the cancer patient may contribute to the care of the patient.

Adult↗
PubMed1977

[Investigation about the taste of di, tri- and tetrahydroxy fatty acid].

Two diastereomeric 9, 10-dihydroxystearic acids, four diasteromeric 9,10,12-trishydroxystearic acids, a mixture of diastereomeric 9,10,12,13-tetrahydroxystearic acids, a mixture of 9.12,13,-trihydroxy-10 trans- and 9,10,13-trihydroxy-11-trans-octadecenoic acids (tri-OH-mixture from lipoxygenase catalysis) and the hydrogenated tri-OH mixture were tested for bitter taste. Only the tri - and tetrahydroxy acids are bitter. The taste thresholds of the saturated tri- and tetrahydroxy acids are in the range from 1.0--4.3 micron ol/ml. There are no significant differences in the taste thresholds between the four diastereomeric 9,- 10,12-trihydroxy acids. The double bond in the trihydroxy acids from the lipoxygenase catalysis enhances the bitter taste 3-fold.

Humans↗
PubMed1975

[Bitter peptides isolated from corn protein zein by hydrolysis with pepsin (author's transl)].

Eight peptides with bitter taste were isolated from a hydrolyzate of the corn protein zein using several chromatographic procedures. The peptides have the following amino acid sequences and taste thresholds (muM/ml): Ala-Ile-Ala (50-100), Ala-Ala-Leu (50-100), Gly-Ala-Leu (50-100), Leu-Glu-Leu (2.5-3.5), Leu-Glu-Leu (8-12), Leu-Val-Leu (1.5-2.5), Leu-Pro-Phe-Asn-Gln-Leu (0.1-0.2), Leu-Pro-Phe-Ser-Gln-Leu (0.1-0.2). The threshold for bitter taste decreases with increasing number of hydrophobic side chains (greater than or equal to C3) in the peptide. It increases in the presence of hydrophilic side chains to their polarity.

Amino Acid Sequence↗
PubMed1986

Role of zinc supplementation in type II diabetes mellitus.

Zinc is required for normal immune function and taste acuity and enhances the in vitro effectiveness of insulin. Impaired immune function and taste have been reported in diabetic subjects, and decreased serum zinc levels and hyperzincuria occur in some diabetic subjects and animals. Subjects with type II diabetes were examined to determine whether the similar effects of zinc depletion and diabetes are causally related. Low serum zinc levels were found in 16 of 180 subjects (9 percent). There was no correlation between serum zinc and glycosylated hemoglobin levels. Natural killer cell activity did not differ between diabetic subjects (n = 28) and control subjects (n = 38) and did not correlate with serum zinc levels. T lymphocyte response to phytohemagglutinin was lower in diabetic subjects than in control subjects (70 +/- 10 versus 103 +/- 7 X 10(3) counts per minute) but was not lowest in those with the lowest zinc levels. Taste thresholds for hydrochloric acid, sucrose, sodium chloride, and urea were elevated in diabetic subjects (n = 28) versus control subjects (n = 10), but thresholds did not correlate with glycosylated hemoglobin or serum zinc levels. Zinc supplementation in nine diabetic subjects had no effect on the glycosylated hemoglobin level, natural killer cell activity, or taste thresholds, but it did increase mitogen activity in those with the lowest initial phytohemagglutinin responses. It is concluded that zinc deficiency occurs in a subset of subjects with type II diabetes but is not related to diabetes control and does not explain decreased taste acuity. Zinc deficiency may play a role in abnormal immune function in type II diabetes mellitus.

Adult↗
PubMed1990

Incidence of P.T.C. taste sensitivity and threshold in Kashmiri population.

Taste sensitivity and threshold of Phenylthiourea (PTC) was determined in 800 individuals of Kashmir who form a distinct ethnic group. Correlation, if any, with age, sex, blood group, pH of Saliva, or smoking habits was investigated. The taste sensitivity of P.T.C. increased with advancing age. The percentage of non-tasters was more in blood group 'B' & 'O'. However, no correlation was observed as far as sex, pH of saliva and smoking habits were concerned.

Adolescent↗
PubMed1976

[Relations between structure and bitter taste of amino acids and peptides. II. Peptides and their derivatives (author's transl)].

About 80 peptides and their derivatives were tested for bitter taste. The taste thresholds are in the range of 70-80 muMol/ml (Gly-Val) to 0.01-0.02 muMol/ml (Bacitracin). They are dependent on nature and number of the side chains and on the hydrophobicity of the whole molecule. An estimation of the taste thresholds of all di-and tripeptides with known amino acid composition is possible on the basis of their hydrophobicity. As could be shown recently for bitter amino acids, a polar (electrophilic) and a hydrophobic group are essential requirements for bitter peptides also. This model corresponds to all sensory results, e.g. to the bitter taste of all hydrophobic peptides independent on their sequence and configuration and to the sweet taste of L-aspartyl dipeptide esters.

Amino Acids↗
PubMedDate not supplied

The effects of diabetes and autonomic neuropathy on parotid salivary flow in man.

Stimulated parotid salivary flow studies were performed on 20 non-diabetic subjects and on 30 patients with insulin-dependent diabetes mellitus who had been screened for autonomic neuropathy using tests of cardiovascular reflexes. Electrical gustometry was performed to detect the taste threshold. The stimulated parotid salivary flow rates of diabetics with no autonomic neuropathy or early parasympathetic autonomic dysfunction alone were similar to those of non-diabetic subjects. Diabetic patients with established parasympathetic autonomic neuropathy had significantly higher salivary flow rates as did those with combined sympathetic and parasympathetic neuropathies. Taste thresholds did not correlate either with the duration of the diabetes or with the presence of autonomic neuropathy. The cause of the increased salivary flow associated with diabetic autonomic neuropathy is unclear. It may represent the removal of a neural inhibitory mechanism which modulates salivary flow, or the effects of long-standing diabetes on salivary secretion.

Adult↗
PubMed1977

Phenylthiocarbamide (PTC) taste sensitivity in selected populations of the Isle of Man and Cumbria.

PTC taste thresholds were determined using a modification of the Harris and Kalmus sorting technique for 854 Cumbrian schoolchildren and 699 individuals from the Isle of Man. A non-taster frequency of 19.7 percent was observed in the Cumbrian sample compared with a frequency of 27.8 per cent in that from the Isle of Man. Analysis of taste threshold distributions revealed significant variability, both within and between these two samples. Evidence of significant regional heterogeneity was detected in Cumbria but not in the Isle of Man. Finally, these two series were compared with data from neighbouring regions of the British Isles and Scandinavian populations.

Adolescent↗
PubMed1990

[Taste disorders in chromium exposed workers].

Taste thresholds were investigated by means of chemical and electric stimulation in order to prove the induction of taste disturbances by chrome dust. There were examined 46 persons with exposition by potassium bichromate, chromic acid and zinc chromate, 19 of them working under conditions of a lower chrome exposition level but 27 of them working under conditions of a higher chrome exposition level. We could find a increasing threshold in taste qualities "sweet", "poor", "salty" and "bitter" corresponding to an increase of chrome exposition on the one hand and likewise of electric stimuli on the other hand. The quantity of chrome exposition must be regarded more important than its quality and its duration. Finally we want to recommend the appliance of always as electrogustometry as chemogustometry for occupational taste investigations because both the methods seem to differ somewhat.

Ageusia↗