SEARCH · Search PubMed
Results for “taste perception”
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Comparative uptake of calcium from milk and a calcium-rich mineral water in lactose intolerant adults: implications for treatment of osteoporosis.
Despite the links between low calcium (Ca) intake and age-related bone loss, hypertension, and colon cancer, the majority of Western populations have average daily Ca intakes substantially below recommended daily allowances. Although dietary products are widely known as a rich and valuable source of Ca in the diet, consumption of diary products is low and has been decreasing because of perceptions of excess calories and fat in the diet, as well as taste aversions. During the last decade, a marked increase in the consumption of bottled waters has occurred. Since some of these waters are characterized by high concentrations of Ca, we have studied Ca bioavailability from a Ca-rich water, using 15 lactose intolerant male individuals as subjects, and compared such bioavailability to that from milk. We report herein that the bioavailability of Ca from the water was generally as good as or better than that from milk, a food product well known for its very high Ca bioavailability. Indeed, in eight of 15 subjects, there was a higher level of Ca absorption from mineral water than from milk; bioavailability was equal in five of 15 subjects; in contrast, in two of 15 subjects, the bioavailability of Ca absorption from milk was greater than that from the mineral water. The potential implications of this observation for the prevention and management of age-related bone loss are important for preventive medicine and indicate a new, important source of dietary Ca for lactose intolerant individuals.
Responses of cultured rat trigeminal ganglion neurons to bitter tastants.
The initial steps in taste and olfaction result from the activation by chemical stimuli of taste receptor cells (TRCs) and olfactory receptor neurons (ORNs). In parallel with these two pathways is the chemosensitive trigeminal pathway whose neurons terminate in the oral and nasal cavities and which are activated by many of the same chemical stimuli that activate TRCs and ORNs. In a recent single unit study we investigated the responses of rat chorda tympani and glossopharnygeal neurons to a variety of bitter-tasting alkaloids, including nicotine, yohimbine, quinine, strychnine and caffeine, as well as capsaicin, the pungent ingredient in hot pepper. Here we apply many of these same compounds to cultured rat trigeminal ganglion (TG) neurons and measure changes in intracellular calcium [Ca2+]i to determine whether TG neurons will respond to these same compounds. Of the 89 neurons tested, 34% responded to 1 mM nicotine, 7% to 1 mM caffeine, 5% to 1 mM denatonium benzoate, 22% to 1 mM quinine hydrochloride, 18% to 1 mM strychnine and 55% to 1 microM capsaicin. These data suggest that neurons from the TG respond to the same bitter-tasting chemical stimuli as do TRCs and are likely to contribute information sent to the higher CNS regarding the perception of bitter/irritating chemical stimuli.
Multiple receptor sites mediate sweetness: evidence from cross adaptation.
The method of cross adaptation was implemented to determine whether only one type of receptor site mediates the perception of sweetness, or whether more than one such type exists. Fourteen stimuli, seven artificial sweeteners varying widely in chemical structure as well as seven sugars, were cross adapted with one another. When a sugar was employed as the adapting stimulus, a consistent reduction in the intensity of the test solution's sweetness was found. However, the result of the cross adaptation when the adapting stimulus was an artificial sweetener was unpredictable; it led not only to a reduction but, in some cases, to an enhancement or no change in the test solution's intensity, depending on its identity. In previous investigations, enhancements have been explained through the existence of a water taste. Since this explanation is insufficient to account for the enhancement effects found in this study, it appears that cross adaptation does not always occur between sweet-tasting compounds. For this reason, it is concluded that more than one receptor mechanism may be responsible for the perception of the sweet quality.
Eating attitudes and taste responses in young ballerinas.
The Eating Attitude Test 40 (EAT 40) was administered to 23 ballerinas (mean age 18.3 +/- 0.9 years). The scores were high, as they are in anorexic patients. The EAT 40 revealed anorexic-like attitudes in dancers: selective food restrictions, severe dieting, constant preoccupations with food. However, dancers scored low at items screening bulimia, vomiting or laxative abuse. The dancers' perceptions and preferences for sweetness and fat food content were examined and compared to those of 14 sedentary controls. Taste stimuli were 20 semiliquid mixtures of soft-white cheese (0, 3 or 7 grams of fat per 100 grams) or heavy cream (30% fat), and sweetened with 1, 5, 10, 20 or 40% sucrose. The subjects used a 9-point category scale to rate the perceived sweetness, fat content, and hedonic value of the stimuli. There were no significant differences in the perceived sweetness intensity between groups, but the perception of fat appeared to be better in dancers, in particular in very sweet stimuli. Dancers showed a clear aversion for the fattest stimuli. In young female dancers, enhanced sensitivity for alimentary fats is associated with decreased preferred levels.
Physical entropy and the senses.
With reference to two specific modalities of sensation, the taste of saltiness of chloride salts, and the loudness of steady tones, it is shown that the laws of sensation (logarithmic and power laws) are expressions of the entropy per mole of the stimulus. That is, the laws of sensation are linear functions of molar entropy. In partial verification of this hypothesis, we are able to derive an approximate value for the gas constant, a fundamental physical constant, directly from psychophysical measurements. The significance of our observation lies in the linking of the phenomenon of "sensation" directly to a physical measure. It suggests that if the laws of physics are universal, the laws of sensation and perception are similarly universal. It also connects the sensation of a simple, steady physical signal with the molecular structure of the signal: the greater the number of microstates or complexions of the stimulus signal, the greater the magnitude of the sensation (saltiness or loudness). The hypothesis is currently tested on two sensory modalities.
[Arterial hypertension in the adolescent: its possible relation to the salt taste threshold].
The purpose of the study was to define the relationship between the salt intake and the levels of arterial blood pressure in adolescent people. Seventy-eight youngs between 12 and 18 years old with diastolic/systolic blood pressure above 95 percentile formed the hypertensive group; a similar population with the same characteristic (age, sex, race, weight and height) with normal blood pressure were selected as a control group. The salt taste threshold was carried out through tasting a saline solution in different concentrations, till it could be distinguished as salted. Moreover, 45 hypertensive adolescent were follow-up for 12 weeks under a hiposodic diet and consequently a new salt taste threshold was done. The results showed that the control group had a salt perception under 80 mg %, instead the hypertensive group showed a higher threshold (above 160 mg %). Those hypertensive adolescent which were followed for 12 weeks changed its pattern in this way: in 24, a lesser perception was observed with a reduction in their blood pressure in 11 of them. These findings suggest that hypertensive adolescent had an elevated threshold for salt, usually above 160 mg % and the test should be helpful for the identification of a subgroup "salt-sensible".
[Taste impairment in Alzheimer's disease].
We conducted a study of Alzheimer's disease focusing on taste impairment to determine at which step of gustatory information processing (discriminative or perceptive, gnosic or associative, gustatory-verbal) possible perturbations might be located. We used various foods found in a normal diet. Twenty patients and a matched control group participated in this study. The patients were divided into two subgroups according to disease severity (mild, moderate or severe). The study showed that patients with Alzheimer's disease exhibited an impairment at all three levels of gustatory information processing. Impairment of discriminative and gustatory-verbal stages was more obvious in the group of patients with severe Alzheimer's disease. Our study also showed that the gustatory deficiency can be described as an associative agnosia in the mild stage of Alzheimer's disease. This concept is in line with the notion of a dissociation between preservation of olfactory and gustatory thresholds and an alteration in odor identification in patients with mild stage Alzheimer's disease, suggesting that the alteration is central rather than peripheral. Our findings suggest that an alteration of the associative level of gustatory information processing can be found in Alzheimer's disease early stage.
Natural selection and molecular evolution in PTC, a bitter-taste receptor gene.
The ability to taste phenylthiocarbamide (PTC) is a classic phenotype that has long been known to vary in human populations. This phenotype is of genetic, epidemiologic, and evolutionary interest because the ability to taste PTC is correlated with the ability to taste other bitter substances, many of which are toxic. Thus, variation in PTC perception may reflect variation in dietary preferences throughout human history and could correlate with susceptibility to diet-related diseases in modern populations. To test R. A. Fisher's long-standing hypothesis that variability in PTC perception has been maintained by balancing natural selection, we examined patterns of DNA sequence variation in the recently identified PTC gene, which accounts for up to 85% of phenotypic variance in the trait. We analyzed the entire coding region of PTC (1,002 bp) in a sample of 330 chromosomes collected from African (n=62), Asian (n=138), European (n=110), and North American (n=20) populations by use of new statistical tests for natural selection that take into account the potentially confounding effects of human population growth. Two intermediate-frequency haplotypes corresponding to "taster" and "nontaster" phenotypes were found. These haplotypes had similar frequencies across Africa, Asia, and Europe. Genetic differentiation between the continental population samples was low (FST=0.056) in comparison with estimates based on other genes. In addition, Tajima's D and Fu and Li's D and F statistics demonstrated a significant deviation from neutrality because of an excess of intermediate-frequency variants when human population growth was taken into account (P<.01). These results combine to suggest that balancing natural selection has acted to maintain "taster" and "nontaster" alleles at the PTC locus in humans.
Occupational exposure to chemicals and sensory organs: a neglected research field.
The effect of industrial chemicals on the sensory perception of exposed workers has received scant attention from the medical community to date, and the scientific literature is mainly limited to some case-reports or isolated studies. Possible explanations for this include the complexity of sensory perception, and the lack of agreement among researchers on methods for testing large groups of subjects. Nevertheless, some published studies showed that vision, hearing and olfactory function can be affected by various industrial metals and solvents, and some data exist also for touch and taste. This review discusses the main industrial chemicals involved. The pathogenesis of the toxicity of chemicals to sensory perception may be related to an action on receptors, nerve fibers, and/or the brain; probably, different pathogenetic mechanisms are involved. One of the main problems in this research field is that most of the studies to date evaluated the effect of a single industrial chemical on a single sense: as an example, we know that styrene exposure can impair smell and also hearing and vision but we have little idea whether different senses are impaired in the same worker, or whether each impairment is independent. In addition, workers are frequently exposed to different chemicals: co-exposure may have no effect, or result in both an increase or a decrease of the effect, as was observed for hearing loss, but studies on this aspect are largely insufficient. Research shows that both occupational and environmental exposure to industrial chemicals can affect sense organs, and suggests that the decline of perception with age may be, at least partly, related to this exposure. Nevertheless, available evidence is incomplete, and is largely inadequate for an estimation of a "safe" threshold of exposure. Good quality further research in this field is needed. This is certainly complex and demands adequate resources, but is justified by the ultimate result: the possibility to prevent an avoidable part of the decline in sensory function with age.
[History-taking in neurology (author's transl)].
History-taking in neurology is particularly favored by the fact that the disease processes occur at or in structures which underlie direct sensation and perception. No-one can so exactly report on disturbances of seeing, hearing, feeling, smelling, tasting, and equilibrium as the patient himself. But the personality of the observer is particularly involved: Is he minimizing, dramatizing, or are there changes in the cerebral cortex? For this reason the statements of relatives have special importance, particularly in convulsions and in the matter of personality changes.
Impact of beverage acceptability on fluid intake during exercise.
These two studies investigated the impact of beverage acceptability on voluntary fluid intake during exercise and the subsequent impact of exercise on the perception and liking of beverages. In Experiment 1, 49 triathletes and runners first tasted an array of 10 commercially available flavors of a 6% carbohydrate-electrolyte drink (CE) and water (W) to determine the most-acceptable flavor (M) and least-acceptable flavor (L) for each subject. Subjects were subsequently given M, L, or W ad libitum during 180 min of exercise. Drink acceptability was again measured after 90 and 180 min of exercise. Drink intake was measured at 15-min intervals. Intake of M was significantly greater than L and W throughout the first 75 min and significantly greater than W throughout the entire exercise period. In Experiment 2, subjects were given M+W, or L+W, in a two-bottle procedure. Voluntary intake of M and L exceeded W by 318% and 233%, respectively. An unexpected finding was a strong interaction between drink acceptability and exercise state. The acceptability of L increased substantially from sedentary to exercise conditions. These data demonstrated that the flavored, sweetened beverages used in this study, substantially increased voluntary fluid intake over W.
Complexity of olfactory lateralization processes revealed by functional imaging: a review.
Currently available techniques used in neurosciences and particularly cerebral imaging are contributing to a better understanding of human perception and the treatment of sensorial information. In this field, the chemical senses (taste and smell) have received little attention when compared with the auditory, visual and tactile senses. Nevertheless, recent research has been trying to overcome this. Brain regions involved in the processing of olfactory information have been investigated in several studies including a large number dealing with the question of lateralization. However, functional asymmetry in olfaction has still not been resolved and the resulting data have not been homogeneous. In this field, the contribution of cerebral imaging studies is very important insofar as it shows that the processes of functional lateralization in olfaction depend on many factors (nature of stimulus, nature of task, characteristics of subjects ...) that future research will have to consider.
The influence of flavor and color on drink identification by children and adults.
This study investigated how color and flavor influences drink identification by children and adults. The children ranged in age from 2 to 18 years of age. Each subject tasted four drinks that differed in color and flavor. Each drink had an atypical color-flavor pairing (e.g., brown-pineapple) or a typical pairing (e.g., brown-chocolate). After tasting each drink, the subject chose which of four flavor names identified the drink. For the atypical drinks, the selection of color-associated names (e.g., chocolate for a brown drink) decreased, and the selection of flavor-associated names increased with age from the preschoolers to the adults. For the typical drinks, the selection of the correct name was greater than 80% for all ages. These results suggest that drink identification becomes more influenced by flavor as children get older because of an increase in the ability of children to focus on flavor as their perceptual-attentional skills mature.
Sensory experience induced by nitrous oxide analgesia.
Preliminary findings on a group of 15 dental patients, treated with nitrous oxide indicated frequent occurrence of several, well-defined sensory experiences related to various modalities. A subsequent controlled experiment carried out on 44 volunteers, inhaling a 35% N2O + 65% O2 sedative gas-mixture as well as O2 alone in two different sessions confirmed a large variety of sensations not related to external stimuli. Taste and/or odor and thermal sensations were often reported as well as changes in auditory or visual perception of the environment in addition to reports of general heaviness, relaxation or tingling.
Hedonic and sensory characteristics of odors conditioned by pairing with tastants in humans.
Animals readily acquire positive odor-taste hedonic associations, but evidence for this in humans remains weak and was explored further. Retronasal pairing of odors with sucrose or salty stimuli (Experiment 1) increased the rated sweetness of sucrose-paired odors without altering liking, although changes in odor pleasantness correlated with sucrose liking. Experience of odors with sucrose or quinine by sweet likers (Experiment 2) found increased pleasantness and sweetness for sucrose-paired odors, whereas quinine-paired odors became less liked and more bitter. Odor-sucrose pairings in sweet likers and dislikers (Experiment 3) found increased sweetness in both groups but increased odor liking only in likers. These data suggest that evaluative and sensory learning are dissociable and that evaluative changes are sensitive to individual differences in sweet liking.
Detection of novelty by perinatal rats.
This study investigated the development of fetal/neonatal rats' ability to distinguish between a novel and familiar taste. Here, we report that neonatal rats alter their orofacial movements (e.g., mouth movements and licks) upon tasting saccharin (SAC) if it was experienced previously. We also sought to determine the origins and duration of this response. Fetuses of embryonic ages E17, E18, or E19 received an oral injection of 10 microL 0.3% SAC while in utero. These animals were then reexposed to SAC on postnatal day 3, (P3) and observations of orofacial motor responses were recorded. Only neonates that first experienced SAC on E19 exhibited a SAC-induced stimulation of mouthing and licking on P3. These data suggested that a taste-recognition memory (TRM) is maintained for up to 5 days (i.e., E19 to P3). However, in this paradigm, the youngest fetuses also have the longest retention interval. Could these data also reflect the limitations of the E17 and E18 fetuses in retaining the TRM? In a second study, we shortened the taste exposure-reexposure interval to 2 days in an attempt to detect the TRM in younger fetuses. As expected, E19 rats exhibited a TRM when tested on E21. However, neither the E17 nor E18 fetuses showed SAC-induced increases in mouthing and licking when tested 2 days after their initial exposure (E19 or E20). Finally, in order to determine whether a TRM could be detected in fetuses as well as neonates (see above), we conducted an additional study wherein E21 fetuses were tested before parturition. Like E21 neonates, E21 rat fetuses that had received SAC on E19 showed a differential response to SAC depending on whether it was novel or familiar. Thus, although E21 fetal orofacial movements were less frequent than those of the E21 neonate, the fetal-testing procedures were not sufficient to obscure the detection of a TRM. In summary, the data indicate that E19 rat fetuses can acquire a TRM and retain it for at least 2-5 days, whereas E17 and E18 fetuses cannot.
The Habbanite isolate. 3. Anthropometrics, taste sensitivity and color vision.
Explore the source record for details and available documents.