Combination of flavor enhancement and chemosensory education improves nutritional status in older cancer patients.

BACKGROUND: Abnormalities in taste and smell functioning occur with elevated frequency in both older adults and patients with cancer. With the predicted increase in both of these populations in the coming decades, it is imperative to evaluate potential interventions that are designed to help older cancer patients compensate for the additive burden of this disease and its treatment on age-related taste and smell losses. OBJECTIVE: The purpose of the current study was to determine if providing instruction and products for flavor enhancement of foods to elderly cancer patients in addition to nutritional information would improve their nutritional status, and, by extension, functional and immune status as well as quality of life. DESIGN: One hundred and seven subjects enrolled in the study. Fifty-four subjects were in the experimental group that received flavor enhancement plus nutritional information; fifty-three control subjects received only nutritional information. Subjects were evaluated 1 month, 3 months, and 8 months after beginning chemotherapy. At every session, subjects completed taste and smell assessments as well as questionnaires related to nutritional status, activities of daily living, and quality of life. Blood samples were also obtained to determine immune parameters. RESULTS: At the eight-month time point, experimental subjects had better scores on the mini nutritional assessment (MNA) and the physical function assessment of the quality of life questionnaire. Also at eight months, self-reported taste and smell perception for experimental subjects was better than that of controls as well as better than at earlier time points. Tests that assessed quantity and quality of food intake, as well as a number of immune parameters declined over time and did not differ significantly between groups. CONCLUSION: The combination of flavor enhancement, chemosensory education, and nutritional information for elderly cancer patients improved their nutritional assessment on the MNA and physical function over time. On the whole, experimental subjects perceived themselves to be better functioning at eight months than did their control counterparts.

Taste, smell and neuropsychological performance of individuals at familial risk for Alzheimer's disease.

The purpose of the study was to determine whether there are chemosensory and neuropsychological changes that predate the onset of Alzheimer's disease in individuals at enhanced risk of developing the condition. To study this question, a unique sample of individuals (n = 33) was studied who were genetically at-risk for AD by virtue of documented multigenerational evidence of the disease (so-called multiplex families). The performance of at-risk individuals was evaluated on various smell, taste, and neuropsychological measures at baseline and 18 months later. Their performance was compared to a control group (n = 32) that was matched in age, gender, education, and race. At baseline the at-risk group performed worse than the control group on the chemosensory measures of phenethyl alcohol smell detection, smell memory, and taste memory, and on a memory measure involving recall of narrative information (Logical Memory I from the Wechsler Memory Scale- Revised). Across both sessions, the at-risk group had lower smell memory scores than the control group. At-risk status was not significantly associated with APOE status. The results of this and other studies suggest that individuals who are genetically at risk for developing AD may perform more poorly on memory and smell measures compared to those not at risk. This effect may be separate from one known genetic risk factor of AD, APOE, and supports that multiple genes are likely responsible for the disease and its associated memory and other neurocognitive symptoms.

Taste and smell perception affect appetite and immunity in the elderly.

The losses in taste and smell that occur with advancing age can lead to poor appetite, inappropriate food choices, as well as decreased energy consumption. Decreased energy consumption can be associated with impaired protein and micronutrient status and may induce subclinical deficiencies that directly impact function. Most nutritional interventions in the elderly do not compensate for taste and smell losses and complaints. For example, cancer is a medical condition in which conventional nutritional interventions (that do not compensate for taste and smell losses) are ineffective. Evidence is now emerging that suggests compensation for taste and smell losses with flavor-enhanced food can improve palatability and/or intake, increase salivary flow and immunity, reduce chemosensory complaints in both healthy and sick elderly, and lessen the need for table salt.

Elevated and sustained desire for sweet taste in african-americans: a potential factor in the development of obesity.

Oral habituation is a relatively long-lasting decrease in oral responsiveness that results from the repeated presentation of a single stimulus. The purpose of this study was to evaluate the degree of habituation to sweet-tasting foods and to determine whether there are differences in the rate of habituation between African Americans and European Americans. These two groups were compared because the prevalence of obesity and obesity-related disorders such as diabetes and hypertension is significantly higher among African Americans than among European Americans. Nine different commercial foods and beverages that differed in sweetness intensity and caloric density served as stimuli. Subjects tasted and rated each food once per minute for a 30-min period on scales related to desire for another taste of the same sample and desire for a different taste. The stimuli and portion size for each of the 30 samples were two candy bars (Ultra Slim-Fast Cocoa Almond Crunch Bar, 1/16 of a bar; Natural Nectar Peanut Butter Granola Bar, 1/16 of a bar), three beverages (Nestea Lemon Flavored Instant Tea with NutraSweet, 5 mL; Welch's Grape Juice, 5 mL; Pink Swimmingo Kool-Aid, 5 mL), two gelatin desserts (Cherry Flavored Jell-O Gelatin, 5 g; Cherry Flavored Jell-O Gelatin with NutraSweet, 5 g), one enteral nutrition drink (Vanilla Ensure Plus, 5 mL), and one pudding (Ultra Slim-Fast Chocolate Pudding, 5 g). Subjects consumed the entire portion of each sample. Habituation occurred for seven of the nine foods as judged by a decrease in the desire for another taste of the same food. The degree of habituation for European Americans and African Americans was similar except for the sweetest food (Cherry Flavored Jell-O Gelatin with NutraSweet), for which African Americans showed no habituation. The degree of habituation in both groups was unrelated to caloric density. Overall, young African Americans had a significantly greater desire for another taste of the same food than did young European Americans for seven of the nine foods, and this desire was strongly correlated with the sweetness intensity for young African Americans but not for young European Americans. Furthermore, young African Americans had a greater desire than young European Americans for a different taste for seven of nine foods. The greater desire for intense sweet tastes may be a factor in the elevated incidence of obesity and diabetes in African Americans. In addition, young African Americans had greater perceived stress in this study than did young European Americans. If African Americans use sweet taste to compensate for feelings of stress, this compensation may also contribute to weight gain.

Effect of antimicrobial and anti-inflammatory medications on the sense of taste.

Elderly individuals and HIV-infected patients have a disproportionate number of taste complaints relative to the general population, and these taste alterations are correlated with the use of medications. Clinical reports of taste disorders have been associated with many drugs, including antimicrobial and anti-inflammatory medications. The purpose of this study was to quantify the taste effects of 6 nonsteroidal anti-inflammatory drugs (NSAIDS) and 13 antimicrobial drugs. The six NSAIDS were: diclofenac sodium salt, fenoprofen calcium salt, ibuprofen, ketoprofen, nabumetone, and sulindac. The 13 antimicrobials were: acyclovir, ampicillin, atovaquone, dapsone, enoxacin, ethambutol, lomefloxacin HCl, ofloxacin, pentamidine isethionate, pyrimethamine, sulfamethoxazole, tetracycline HCl, and trimethoprim. These 19 medications were applied topically to the tongues of unmedicated young and elderly volunteers as well as unmedicated HIV-infected patients to measure the direct effect of the drug on taste receptors. Topical application of drugs to the apical tongue surface was used to mimic the situation in which the drug is secreted into the saliva. The main finding was that the taste qualities of these drugs were perceived as predominantly bitter, metallic, and/or sour, although several did not have a taste. Elderly subjects had higher thresholds than young subjects for one-third of the drugs that were tested. Thresholds for HIV-infected patients were statistically equivalent to young controls; however, HIV-infected patients rated the drugs as more intense at four times above the detection threshold than young subjects. Most of these drugs when applied directly to the tongue also modified the taste intensity of other tastants (e.g., NaCl, citric acid).

Taste quality and neural coding: implications from psychophysics and neurophysiology.

Historically, taste research has often been guided by the concept that there are only four (or possibly five) basic taste qualities (sweet, sour, salty, and bitter, and possibly "umami"). All other tastes have been presumed to be combinations of these basic tastes. This psychophysical concept has been extended to electrophysiological data. That is, the neural code for each basic taste is hypothesized to be coded by a dedicated channel of neurons (the "Labeled-Line" theory); i.e., one group of neurons signals "salty" and another separate group signals "sweet." Numerous psychophysical and electrophysiological findings, however, cannot be accomodated by this quadripartite theory, which limits taste to four basic qualities and four basic neuron types. Rather, the data described in this article suggest that the range of taste is more extensive than four or five basic tastes, and that this breadth of taste quality results initially from the activation of a broad array of ion channels, receptors, and second messengers associated with taste cell membranes. These findings have implications for neural organization and provide support for the "Across-Fiber Pattern" theory in which the neural code for taste is represented by the pattern of activity across all of the neurons, i.e., neurons are not exclusively labeled for a particular sensation but cooperate with the others in the ensemble to encode taste quality.

High dietary copper improves odor characteristics of swine waste.

We conducted two experiments to determine the effects of dietary copper concentration and source on odor characteristics of swine waste. In both experiments, 192 weanling gilts and barrows were allotted to 24 pens. Pens were randomly assigned to one of six dietary treatments, consisting of control (10 ppm Cu as cupric sulfate, CuSO4), 66 or 225 ppm Cu as CuSO4, or 33, 66, or 100 ppm Cu as cupric citrate (Cucitrate). An antibiotic was included in the diets for Exp. 1, but not Exp. 2. On d 28, fecal samples were randomly obtained from one pig per pen and stored at -20 degrees C until preparation and evaluation by an odor panel. The odor panel consisted of 10 individuals, and each panelist evaluated the odor intensity, irritation intensity, and odor quality of the samples. In Exp. 1, the odor and irritation intensity of the feces were lower (P < .05) from animals consuming diets containing 225 ppm Cu as CuSO4 and 66 or 100 ppm Cu as Cu-citrate compared to the control. The odor quality of the waste from animals consuming diets containing 225 ppm Cu as CuSO4 and 66 or 100 ppm Cu as Cu-citrate was improved (P < .05) compared to the 33 ppm Cu treatment. In Exp. 2, the odor intensity of the feces of pigs receiving diets supplemented with all concentrations of Cu-citrate was lower (P < .05) than that of feces from the control animals. Irritation intensity of the feces was not affected by treatment. Odor quality of waste of pigs supplemented with 225 ppm Cu from CuSO4 and all concentrations of Cu-citrate was improved (P < .05) compared to that of waste of the control pigs. Two gilts and two barrows from each nursery pen in Exp. 1 were continued through the growing-finishing phase on their respective experimental diets. The growing-finishing phase lasted 103 d, and fecal samples were randomly obtained from one pig per pen at the completion of the phase. During the growing-finishing phase, the odor intensity and the irritation intensity of the feces were lower (P < .05) from pigs supplemented with 66 and 225 ppm Cu as CuSO4 and 66 and 100 ppm Cu from Cu-citrate than from the control pigs. The odor quality of the waste was improved (P < .05) in all animals receiving supplemental Cu. These data indicate an improvement in odor characteristics of swine waste with the supplementation of Cu. In addition, lower concentrations of an organic nonsulfate Cu source resulted in similar odor characteristics of swine waste as 225 ppm CuSO4.

Effect of tricyclic antidepressants on taste responses in humans and gerbils.

One of the side effects of antidepressant pharmacotherapy reported clinically is impairment of the sense of taste. In this study, the taste effects of four tricyclic antidepressant compounds (clomipramine HCl, desipramine HCl, doxepin HCl, and imipramine HCl) were evaluated experimentally by topical application of the drugs to the tongue. Taste detection threshold concentrations for all four medications ranged from 0.1 mM to 0.2 mM in young persons but were elevated by as much as 7.71 times that in elderly individuals who were taking no concurrent medications. Each compound had a predominantly bitter taste with other qualities including metallic, sour, and sharp-pungent. In addition, each tricyclic antidepressant at concentrations from 1 mM to 5 mM blocked responses to a wide range of taste stimuli in both humans and gerbils. The differential suppression of other tastes by tricyclic antidepressants at the level of the taste receptors may contribute to the clinical reports of dysgeusia and hypogeusia.

Synergism among ternary mixtures of fourteen sweeteners.

The purpose of the present study was to determine the degree of synergism of sweet taste among ternary mixtures of 14 sweeteners. A trained panel evaluated ternary mixtures of 14 sweeteners varying in chemical structure and type. The ternary mixtures that were tested were limited to those in which the compounds comprising the mixture were synergistic in binary combinations, according to an earlier study. All sweeteners in the ternary mixtures were isointense with 2% sucrose, according to a previously developed formulae. Each self-mixture was also tested (e.g. 2% sucrose + 2% sucrose + 2% sucrose). The triad with the highest mean sweetness intensity rating was alitame-neohesperidin dihydrochalcone-rebaudioside-A (10.8). This represents an increase of 99.4% when compared with the average of the self-mixtures. While this is greater than the maximum of 74% increase found for binary mixtures, more dyadic combinations of sweeteners tested previously exhibited synergism than ternary combinations tested here. However, most ternary mixtures were synergistic (significantly greater than the average of the three self-mixtures) to some degree.

Intensification of sensory properties of foods for the elderly.

Taste and smell losses in the elderly can reduce appetite and lead to inadequate dietary intake. Although these chemosensory deficits are generally not reversible, sensory interventions including intensification of taste and odor can compensate for perceptual losses. One method for "treatment" of chemosensory losses involves sensory enhancement of foods with flavors and monosodium glutamate (MSG). Amplification of flavor and taste can improve food palatability and acceptance, increase salivary flow and immunity, and reduce oral complaints in both sick and healthy elderly.

Effect of temperature, pH, and ions on sweet taste.

The purpose of this experiment was to determine the effects of temperature (50 degrees C and 6 degrees C), pH (pH 3.0, 4.0, 5.0, 6. 0, and 7.0) and the addition of monovalent and divalent cations (5 mM Na(+), 5 mM K(+), and 5 mM Ca(2)+ ) on the sweetness intensity ratings of sweeteners ranging widely in chemical structure. A trained panel provided intensity evaluations for prototypical tastes (sweet, bitter, sour, and salty) as well as aromatic and mouth-feel attributes. The following sweeteners were included in this experiment: three sugars (fructose, glucose, sucrose), three terpenoid glycosides (monoammonium glycyrrhizinate, rebaudioside-A, stevioside), two polyhydric alcohols (mannitol, sorbitol), two dipeptide derivatives (alitame, aspartame), two N-sulfonylamides (acesulfame-K, sodium saccharin), one sulfamate (sodium cyclamate), one protein (thaumatin), one dihydrochalcone (neohesperidin dihydrochalcone), and one chlorodeoxysugar (sucralose). Two to five levels of each sweetener reflecting a range of sweetness intensities were tested, using formulae developed by DuBois et al. The main finding from this three-part study was that temperature, pH, and ions had little effect on perceived sweetness intensity. Even when significant differences were found in the temperature study, the effects were very small.

Taste effects of lingual application of cardiovascular medications.

Medications used to treat cardiovascular diseases such as congestive heart failure, high blood pressure, and arrhythmia, are prescribed extensively in Western countries. However, taste complaints are common side effects of many of these cardiovascular medications. Although clinical observations are helpful in determining potential taste problems from a medication, experimental studies are necessary to obtain quantitative data on taste. In the studies performed here, nine cardiovascular medications (labetalol HCl, captopril, diltiazem HCl, enalapril maleate, hydrochlorothiazide, propranolol HCl, mexiletine HCl, procainamide HCl, and propafenone HCl) were applied to the tongue in human volunteers to measure the direct effect of these drugs on taste receptors. The medications were applied topically to the tongue surface of both young and elderly subjects to mimic the situation in which the drug is secreted into the saliva. Detection thresholds ranged from 0.048 mM (propafenone) to 0.438 mM (procainamide). The detection thresholds of healthy elderly subjects did not significantly differ from young controls. The compounds tested had a predominantly bitter taste with other qualities as well. In addition, topical application of the medications to the tongue affected the taste of one or more taste stimuli, with medications differing in the pattern of taste effects exhibited. The mechanism of taste effects is not fully known, but the results of this study suggest one route may be due to medications' effect on peripheral taste receptors.

Effect of the nucleoside analogs zidovudine, didanosine, stavudine, and lamivudine on the sense of taste.

The purpose of this study was to investigate the taste properties of nucleoside analogs, which are among the current medications used to treat human immunodeficiency virus (HIV) infection. Eighteen unmedicated HIV-positive subjects and 41 healthy control subjects participated in threshold and suprathreshold experiments. All of the nucleoside medications tested were perceived as predominantly bitter (along with other qualities such as metallic, medicinal, sour, astringent, and cooling). The nucleoside analog with the lowest detection thresholds was zidovudine; the detection threshold was 1.47 mM for HIV-infected patients and 2.15 mM for control subjects. Detection thresholds for lamivudine were 4.41 mM for HIV-infected patients and 4.36 mM for control subjects. Detection thresholds for stavudine were 6.39 mM for HIV-infected patients and 5.99 mM for control subjects. Detection thresholds for didanosine were 14.29 mM for HIV-infected patients and 24.0 mM for control subjects. The nucleoside analogs also modified the taste perception of KCl and CaCl2. There were no significant differences between HIV-infected subjects and control subjects for detection threshold values for any of the drugs. However, HIV-infected subjects rated lamivudine, zidovudine, and stavudine as significantly more bitter than did the control subjects at concentrations four times higher than their detection thresholds. This result was not due to use of medications by HIV-infected subjects because none of the subjects (neither HIV-infected nor control) were taking medications.

Effect of protease inhibitors on the sense of taste.

The purpose of this study was to investigate the taste properties of protease inhibitors which are essential components of drug regimes used to treat human immunodeficiency virus (HIV) infection. In this study, the taste properties of four protease inhibitors (indinavir, ritonavir, saquinavir, and nelfinavir) were investigated in unmedicated HIV-infected patients and healthy controls. Three of the four protease inhibitors (indinavir, ritonavir, and saquinavir) were found to be predominantly bitter (with additional qualities of medicinal, metallic, astringent, sour, and burning). Nelfinavir was found to be relatively tasteless. HIV-infected and uninfected control subjects detected protease inhibitors at similar concentrations, but HIV-infected subjects perceived suprathreshold concentrations as more bitter than controls. Detection thresholds ranged from 0.0061 mM for saquinavir in HIV-infected patients to 0.0702 mM for ritonavir in uninfected control subjects. Suprathreshold studies indicated that protease inhibitors modified the taste perception of a variety of other taste compounds. These results are consistent with clinical findings that protease inhibitors produce taste complaints that can impact patient compliance.

Selective inhibition of sweetness by the sodium salt of +/-2-(4-methoxyphenoxy)propanoic acid.

The purpose of this study was to determine the degree to which the sodium salt of +/-2-(4-methoxyphenoxy)propanoic acid (Na-PMP) reduced sweet intensity ratings of 15 sweeteners in mixtures. Na-PMP has been approved for use in confectionary/frostings, soft candy and snack products in the USA at concentrations up to 150 p.p.m. A trained panel evaluated the effect of Na-PMP on the intensity of the following 15 sweeteners: three sugars (fructose, glucose, sucrose), three terpenoid glycosides (monoammonium glycyrrhizinate, rebaudioside-A, stevioside), two dipeptide derivatives (alitame, aspartame), two N-sulfonylamides (acesulfame-K, sodium saccharin), two polyhydric alcohols (mannitol, sorbitol), 1 dihydrochalcone (neohesperidin dihydrochalcone), one protein (thaumatin) and one sulfamate (sodium cyclamate). Sweeteners were tested at concentrations isosweet with 2.5, 5, 7.5 and 10% sucrose in mixtures with two levels of Na-PMP: 250 and 500 p.p.m. In addition, the 15 sweeteners were tested either immediately or 30 s after a pre-rinse with 500 p.p.m. Na-PMP. In mixtures, Na-PMP at both the 250 and 500 p.p.m. levels significantly blocked sweetness intensity for 12 of the 15 sweeteners. However, when Na-PMP was mixed with three of the 15 sweeteners (monoammonium glycyrrhizinate, neohesperidin dihydrochalcone and thaumatin), there was little reduction in sweetness intensity. Pre-rinsing with Na-PMP both inhibited and enhanced sweetness with the greatest enhancements found for monoammonium glycyrrhizinate, neohesperidin dihydrochalcone and thaumatin, which were not suppressed by Na-PMP in mixtures. The mixture data suggest that Na-PMP is a selective competitive inhibitor of sweet taste. The finding that pre-treatment can produce enhancement may be due to sensitization of sweetener receptors by Na-PMP.

Workshop on taste and smell in the elderly: an overview.

The purpose of the workshop entitled Taste and Smell in the Elderly: Behavioral and Nutritional Consequences was 1) to review the current state of knowledge in the area of taste and smell, with emphasis on age-related changes, 2) to identify existing gaps in our knowledge, and 3) to develop future research strategies. There was general agreement that the majority of scientific studies have found impairments in taste and smell acuity in the elderly. These losses may result from normal aging, certain disease states especially Alzheimer's disease, medications, surgical interventions, and environmental exposure. However, there are gaps in our knowledge of the basic mechanisms by which aging and environmental factors may impair the chemical senses in the elderly. Further research is also required in a variety of areas including chemosensory test procedures, food intake, and nutrition to understand fully the impact of chemosensory dysfunction on older individuals.

Effect of medications on taste: example of amitriptyline HCl.

Use of medications is a major factor that contributes to taste losses in the elderly. Epidemiological studies suggest that community-dwelling elderly over the age of 65 use an average of 2.9 to 3.7 medications, and this number increases significantly for elderly living in retirement and nursing homes. The tricyclic antidepressant amitriptyline HCl is used by at least half a million people aged 65 years or more. In human studies performed here, amitriptyline HCl was found to have a bitter, unpleasant taste of its own. In addition, it blocked responses to other taste stimuli in both humans and gerbils. This blockage in humans was greater when amitriptyline HCl was applied continuously to the tongue than when it was applied intermittently. Continuous application of the drug affected all of the taste qualities to varying degrees, while intermittent application led to taste decrements only for salts. Electrophysiological studies in gerbils also revealed taste decrements after a short adaptation to amitriptyline HCl.

Alterations of chemosensory function in end-stage liver disease.

Taste and smell dysfunction has been documented in patients with both acute and chronic liver disease. The purpose of this study was to determine if chemosensory function is improved after restoration of hepatic function with liver transplantation. Nine subjects (seven women and two men) with end-stage liver disease participated in the study. Taste and smell detection and recognition thresholds were determined before and after transplantation. A significant improvement in detection of the taste of sodium chloride and the odor of phenethyl alcohol was found after transplantation. These findings may have clinical significance in food choices and nutritional status of these patients.