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Biomedical subjects

D A Booth

Publications and source records attributed to D A Booth.

At least 19 recordsLinked to original sources
PubMed2003

Perceptual channels for the texture of a food.

The present study makes a start on characterising the cognitive processes by which physical effects of eating on the senses are transformed into quantitative judgments about perceived characteristics of a food. It was hypothesised that there is a discrete perceptual channel for an aspect of texture sensed during each of the three initial movements of eating a piece of a cookie. The results showed that the force required for initial compression of the surface of the biscuit related to how 'crisp' it was. Scores on 'hard' were sensitive to higher forces being required to bite off a piece. Ratings of crunchiness responded to both amplitude and frequency of the cracks opened up in this heterogeneously structured material during the first crushing of the bitten piece. These findings are being pursued to identify the stimulation patterns more precisely and to measure how the percepts are integrated into judgments of overall texture.

Bite Force↗
PubMed2001

Sensory, digestive and metabolic influences on preference and intake.

In the 1960s. scientific work on the mechanisms of appetite began to shift from the effects of deprivation on reinforcement, motivation and sensation (hunger and thirst) to the influences of ingestion itself on what and how much was chosen at a bout of eating and drinking (the sating of appetite). This personal overview starts with John D. Davis's involvement in this trend to studying sensory, digestive and metabolic controls of meal volume, as he and the author each joined the field. The main topic is the diverse series of innovative experiments that Davis carried out in the author's research group in 1970 1971. This work exemplified Davis's technical inventiveness and theoretical precision. It generated influential findings on behavioural roles of dietary flavours, gastric distension and hepatic metabolism.

Animals↗
PubMed2001

No unique role for nausea attributed to eating a food in the recalled acquisition of sensory aversion for that food.

Currently in the U.K., as in the U.S.A. 20 years ago, when students were asked to name a food that they did not like, more dislike for the food was attributed to nausea or vomiting after eating than to other gastrointestinal symptoms or to illness in other parts of the body. However, when members of the public first identified adverse symptoms and then attributed them to foods, and dislike for the food was first enquired about on a later occasion, there was no evidence for a unique role for a causal association with nausea in the human acquisition of food aversions. Furthermore, fear of the symptom was more prevalent than acquired sensory aversion when there was more precise recall of memories of the food being followed by nausea or vomiting and greater likelihood of there having been causal contingency rather than mere coincidence. Therefore, the more frequent invocation of nausea than of some other symptoms as the cause of a sensory aversion to a food may result from personal theory of the body, rather than from a veridically recalled occasion when nausea was contingent on eating the food---an event that must occur for aversion to arise from associative conditioning.

Adolescent↗
PubMed2001

Acquisition of texture-cued fasting-anticipatory meal-size change in rats with adequate energy intake.

To determine if an increase in intake at a meal before a long fast can be conditioned to food texture cues, male Sprague-Dawley rats were given a high- or low-fat diet in one texture (powder or pellet) for 1 h prior to a 12.5-h fast and in the other texture before a 3-h fast. Each group (N = 9) went through a pseudorandom sequence of four duplicates of each texture-fast pairing over 4 experimental days in each of three training trials, followed by one 4-day trial under extinction, i.e. without the difference in fast lengths between textures. Neither the high-fat group nor the low-fat group as a whole gave a clear indication of a learnt texture-cued increase in meal size before the longer fast relative to the shorter fast. However, the rats trained on the high-fat diet that had the highest intakes on the first 4 days of training showed a relative increase in the amount eaten of the texture predicting the longer fast during the third training trial, and this effect also approached statistical significance in the extinction test. These results provide some support for the conclusion that anticipatory hunger/satiety can be differentially conditioned to dietary texture cues, but only if sufficient food is eaten before a short fast to prevent the rise in hunger during longer fasts that reinforces the discriminative increase in meal size.

Animals↗
PubMed2000

Food-conditioned odour rejection in the late stages of the meal, mediating learnt control of meal volume by aftereffects of food consumption.

In a two-bottle choice test, rats drank more of the fluid having a novel odour than that having an odour which had previously been presented in the later part of meals on concentrated maltodextrin solution. Rats are normally more averse to a novel odour than to a familiar odour; therefore, the conditioned reaction to the odour acquired in these circumstances is likely to be an ingestive aversion, rather than merely a lack of preference. Furthermore, this learnt odour rejection was seen only in the second half of the meal, indicating that it is dependent on an ingestion-induced state of repletion. Together then, these observations are evidence that the volume of meals rich in carbohydrate can be controlled by learnt rejection of particular food flavours in the presence of visceral cues specific to repletion (previously dubbed "conditioned satiety"), the only known mechanism by which aftereffects of ingested energy could reduce meal volume.

Adaptation, Physiological↗
PubMed1999

Evidence-based reduction of obesity: identification of a subculture's least fattening eating patterns.

Public health nutritional interventions, like clinical treatments in medicine or psychology, should be based on direct evidence of their efficacy relative to prior existing modalities. Yet the contribution of applied human nutrition and the psychology of eating to research into ways of slowing the rise of obesity has been limited to the intake of energy nutrients and investigator-prejudged questions about appetite and food choices. In contrast, it is feasible to get members of the public to describe their patterns of eating in their own words. Self-assessed current frequency of each common potentially less or more fattening eating pattern can then be used to associate weight change with changes in habit frequency. This design has been used to identify the long-term least fattening eating patterns retrospectively and prospectively in several studies in England and Germany. Without using assessments of usual nutrient intake, these studies demonstrate that the least fattening patterns over 1-2 or more years are drinks between meals with no energy intake, cutting back on fat in all foods and replacing as much sitting and riding as feasible each day with walking or cycling. An hypothesis to be tested by this method is that the only known automatic mechanism for eating less dessert is the learnt effect of boosting the readily digested carbohydrate content of high-energy main courses. Such evidence-based advice as well as self-therapy for emotional eating and body-shape distress should be the front line of defence against unhealthy weight gain and re-gain.

Behavior Therapy↗
PubMed1999

Psychological characteristics of people with perceived food intolerance in a community sample.

In most adults who believe themselves to be food intolerant there is no objective supporting evidence. It has therefore been proposed that the misperception of intolerance to food is linked to psychiatric illness or personality disorder. This hypothesis was tested in a community-derived sample of individuals who attributed an adverse symptom to a type of food. A random mailing recruited 955 participants aged > or =18 years, of whom 232 perceived themselves to be food intolerant (PFI). All recruits were sent two questionnaires, the General Health Questionnaire-28 (GHQ-28) and the shortened version of the Eysenck Personality Questionnaire (EPQ-R). A total of 535 GHQ-28 and 518 EPQ-R forms were returned that were correctly completed, an overall response rate of 55%. For the subscales of the EPQ-R, neuroticism was greater in those with a PFI than those without. Women with a PFI were more extroverted than control women. For the GHQ-28 subscales, women with a PFI had significantly higher scores than control women on somatic symptoms, anxiety, insomnia, and severe depression. There was a greater percentage of psychiatric caseness among women with a PFI than among men with a PFI or control women. Nevertheless, this percentage was no greater than that reported among a reference sample derived from NHS and university staff. It is concluded that perceived food intolerance is associated with psychological distress in women with a PFI, and neurotic symptoms in both men and women with a PFI, but there is no greater prevalence of psychiatric disorder among women or men with a PFI than there is in some professional groups.

Adult↗
PubMed1999

Macronutrient-specific dietary selection in rodents and its neural bases.

The only evidence for nutrient selection comes from baseline or treatment effects on nutrient intakes that are qualitatively similar when sensorily contrasting forms of each macronutrient are investigated and/or dietary compositions and strains of rat or mouse are different within or between laboratories. By that criterion the only potential case of a treatment reliably altering macronutrient selection identified in the present review of the literature is d-norfenfluramine, fluoxetine and paraventricular serotonin (5-HT) reducing the intake of dextrin-containing diets at early dark. The only clear example of reverse effects of an agonist and an antagonist on dietary intake was found with serotonergic agents. Claims for catecholaminergic or opioid involvement in protein intake and peptidergic involvement in carbohydrate intake were not substantiated. There remain the issues of which learnt macronutrient-specific postgastric actions and sensory cues from the affected diet rely on the neural pathway(s) on which the drug is acting to alter dietary selection. Until experiments address these questions, the neural bases of nutrient-specific appetites will remain unknown. Drug effects must be consistent across differently textured and flavoured versions of each macronutrient tested.

Animals↗
PubMed1996

Influences on meat avoidance among British students.

Male and female undergraduates (18-23 years old; 68% in their first year; N = 158) who had just chosen a vegetarian dish in a campus dining hall or restaurant reported a diversity of meat avoidance habits before arrival at University a few weeks previously. More women than men had avoided meat and other flesh foods, with the exception of fish. Consistently with the distinction between "red" and "white" meats, chicken and turkey were the least often avoided flesh foods among men and women. The only clear gradation from flesh-eating to vegetarianism was eating poultry and either beef/lamb or pork, eating only poultry and eating neither; fish was not on this Guttman scale, contrary to previous assumptions. Reasons for avoiding meat and perceived influences on preferences for food in their chosen vegetarian dish were elicited by open-ended interviews in 41 women from the meat-avoidance survey. Rationales spontaneously offered were as diverse as reported in previous studies, but always included at least two of the following: ethics of raising/killing animals, concern for health, sensory factors, disgust and influence of friends. In contrast, choices among described variants of the familiar dish were largely controlled by its sensory and nutritional features, presumably because other attributes had been factored out.

Adolescent↗
PubMed1995

Disguised protein in lunch after low-protein breakfast conditions food-flavor preferences dependent on recent lack of protein intake.

As in the conditioning of appetite for protein in the rat, human preference for and intake of a food at lunch was increased when the flavor of that food was paired with an adequate supply of protein, following a breakfast lacking in protein. Men and women rated their preferences for two flavors in tasted foods (soup and cornflour dessert) on test days before and after a day when one flavor was eaten in very low protein food and another day with a different flavor eaten in food containing protein, but with minimal sensory differences between these foods. Subjects given a low-protein drink preload preferred the protein-paired flavor, while those receiving a high-protein drink did not. In a second experiment, preferences were measured by intake as well as ratings, and the difference in amount of protein between high- and low-protein lunches was increased. By both measures, relative preference for high-protein-paired dessert flavors increased from before to after pairing. The increase in intake preference ratio for the protein-paired flavor was abolished by a high-protein preload. Thus, people have a learning mechanism whereby a lack in protein intake comes to cue the selection of protein-rich foods that are not known to be such, and/or loading with protein might trigger avoidance specifically of a high-protein diet.

Adolescent↗
PubMed1995

Cognitive processes in odorant mixture assessment.

'Comparison of models of odor interaction' by Cain and his colleagues (1995) is a turning point in assessment of the strengths of smell of mixtures of odorants. Their paper provides the best empirical comparison to date of models of (olfactory) binary mixture intensities and combines this analysis with a cogent critique of the whole tradition of mixture psychophysics. This commentary on their paper argues that their critique is not radical enough.

Cognition↗
PubMed1993

Discriminative feature integration by individuals.

A tactile pattern on the skin generally comes to be recognised from its function within action. What is perceived tactually and may generate a textural or geometrical sensation is therefore a set of dynamic characteristics that can be extracted by mechanoreceptors and central neural processing from the physics of the interactions of hands, mouth or other parts of the body with common objects and materials. The recognised dynamic (as is true of any sensory modality) may be diagnosable as distinct features that are integrated by the whole system's operation. If so, this transmission of feature information over a channel or in a dimension can be measured as the strength of the influence of that aspect of the stimulating pattern on the observed output, in units of the acuity of response differences for deviations of the pattern from its familiar configuration of features. When applied at the individual level, such multidimensional discrimination analysis provides powerful diagnoses of pattern-recognition processes.

Attention↗
PubMed1993

Multiple physical patterns in judgements of the creamy texture of milks and creams.

The textural sensation generated by dairy creams and milks in the mouth was hypothesized to arise from mechanoreceptor stimulation by the viscosity of these oil-in-water emulsions and features arising from characteristics of the globules of fat. The viscosity, range of sizes of the fat globules and the average distance between globules were varied independently in dairy emulsions and samples rated for creaminess by six assessors. In this brief report, each assessor's performance is tested for multidimensional combinations of discriminations among viscosities, globule-size ranges and interglobule distances. Those individuals whose judgements of creaminess were sensitive to these physical variables appeared to differ greatly in the factors on which they based their judgements. This also depended on whether a high-fat milk or a light cream was used as the standard for comparison. Subject to confirmation of the stability of the discrimination space for an individual using a standard, it is preliminarily concluded that recognition of the physical properties of fat in dairy emulsions is highly idiosyncratic, perhaps indicating that it has to be learned.

Adult↗