1998 — 2002 |
Swithers, Susan E |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Ontogeny of Metabolic Controls of Ingestive Behavior @ Purdue University West Lafayette
DESCRIPTION: The transition from suckling to adult ingestion is a challenge facing all young mammals. In rats, this transition is made within weeks of birth and understanding the mechanisms by which rat pups normally develop from complete dependence on the dam to completely independent intake regulation may provide valuable insight for intervention in failures to accomplish the suckling to weaning transition in mammals in general. Early in a rat pup's life, the physiological signals which modulate ingestion appear to be few, but prior to weaning pups begin to modulate their intake in response to a signal related to changes in energy metabolism. The experiments in this proposal test questions about the development of intake regulation in rat pups using this emergent metabolic responsiveness. First, the role of changes in utilization of a specific metabolic fuel (fat) is tested using several pharmacological agents known to inhibit oxidation of fatty acids at several different biochemical steps. The behavioral effects of these agents are compared to their biochemical effects to test changes in the utilization of fats affect intake in young rats. Second, because physiological signals can affect ingestion at a number of behavioral levels, the ingestive behavioral components on which metabolic signals exert their effects during development is examined to test the mechanisms by which changes in the utilization of energy are translated into changes in ingestive behavior. Further, if a signal related to changes in the utilization of energy normally modulates ingestion, then feeding induced by metabolic blockers should be similar to feeding induced by energy restriction (i.e. food deprivation). Thus, similar pre- and post-absorptive physiological signals should suppress intake stimulated by food deprivation and pharmacological blockade of metabolism. This hypothesis is tested by examining the physiological signals suppressing intake stimulated by metabolic blockers. Finally, the neural mechanisms involved in translating physiological changes related to energy utilization into increases in ingestive behavior are tested.
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2007 — 2011 |
Swithers, Susan E |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Food Cues, Calories and Energy Regulation in Rats @ Purdue University West Lafayette
DESCRIPTION (provided by applicant): Despite recent advances in our knowledge of the neural, metabolic and genetic controls of food intake and body weight regulation, the causes of obesity remain elusive and compelling explanations about how changes in body physiology or genetics might produce the current obesity epidemic have not been forthcoming. The present application approaches the problem from a novel theoretical formulation that links the efficiency of the regulatory control of intake and body weight to a relatively simple form of Pavlovian conditioning. Within this framework, consuming sweet-tasting substances (such as artificial sweeteners) which contain few or no calories has the effect of degrading the normal ability of sweet orosensory cues to predict calories. As a consequence of weakening this predictive relationship, sweet-tasting foods that contain calories become less able to evoke the compensatory physiological responses that underlie tight regulation. Preliminary results suggest that one mechanism by which exposure to such nonpredictive relationships may impair energy regulation is through a disruption of cephalic phase physiological responses. Studies are proposed to determine the relationship between cephalic phase responses and energy dysregulation produced by nonpredictive experience with sweet tastes and calories. In addition, we determine how the magnitude and impact of this experiential variable interacts with other environmental variables, including the composition of the maintenance diet and the duration of exposure to the nonpredictive diets. Finally, we test whether exposure to other dietary experiences, such as consumption of products manufactured with fat substitutes, which degrade the ability of tastes to predict calories produce similar effects on body weight regulation. Changes in the food environment in the U.S. over the past 25 - 30 years may have increased exposure to diets in which the sensory properties of a food are not predictive of its caloric consequences. The work described in the present proposal examines specific mechanisms by which this type of disruption predictive relationships could contribute to energy dysregulation;and the experiments may not only identify circumstances under which energy dysregulation occurs, but may also to identify potential approaches to reversing such impairment. Given the rapidity with which overweight and obesity continue to increase, identifying such novel approaches is becoming increasingly critical
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2007 — 2011 |
Swithers, Susan E |
P01Activity Code Description: For the support of a broadly based, multidisciplinary, often long-term research program which has a specific major objective or a basic theme. A program project generally involves the organized efforts of relatively large groups, members of which are conducting research projects designed to elucidate the various aspects or components of this objective. Each research project is usually under the leadership of an established investigator. The grant can provide support for certain basic resources used by these groups in the program, including clinical components, the sharing of which facilitates the total research effort. A program project is directed toward a range of problems having a central research focus, in contrast to the usually narrower thrust of the traditional research project. Each project supported through this mechanism should contribute or be directly related to the common theme of the total research effort. These scientifically meritorious projects should demonstrate an essential element of unity and interdependence, i.e., a system of research activities and projects directed toward a well-defined research program goal. |
Taste-Calorie Consistency and Body Weight Regulation @ Purdue University West Lafayette
Homeostasis refers to the ability of humans and other animals to maintain physiological parameters at relatively constant levels in the face of environmental flux. For example, even small departures from homeostatic levels of body temperature, hydration, osmolality, blood pressure, or oxygenation can have serious adverse effects on physiological and behavioral functioning. Fortunately, tight regulation of these and many other parameters is typically carried out automatically, often without conscious awareness of the bodily adjustments that serve to that preserve equilibrium. Walter B. Cannon (1932) referred to this type of automatic regulatory control as the "wisdom of the body (13)." The term energy homeostasis refers to the ability to regulate energy use and body weight at relatively constant levels despite local environmental variations in food availability or intake. For example, it is not unusual for people to indulge in large, energy-rich meals that provide calories well in excess of their short-term needs, eat smaller more "calorie conscious" meals on other occasions, and skip meals altogether at other times. The fact that many people maintain normal body weight over the long-term, despite such wide meal-tomeal fluctuations in energy intake, points to the existence of regulatory control mechanisms that enable people to compensate precisely for shorter term excesses (or deficits) with periods of decreased (or increased) caloric consumption. Unfortunately, it appears that this compensatory system is becoming increasingly ineffective, as data from several sources indicate that the proportion of the population classified as overweight or obese has climbed steadily since the mid-1980s. This increase has been documented across the lifecycle in both genders and among all ethnic groups (32, 67, 96). Moreover, a problem often overlooked is that for many normal weight people the ability to maintain body weight at constant level is no longer automatic. Rather, it often depends on careful adherence to self-imposed regimens of dietary restriction and exercise. Given the clear and serious implications of overweight and obesity for public health, it is critically important to identify factors that not only cause this type of dysregulation but are also capable of producing dysregulation on the massive scale that we are witnessing now. Much previous research has been directed at discovering the neural, hormonal, metabolic, and genetic controls of intake and body weight regulation. Although this work has provided much new information, the causes of obesity remain elusive, and compelling explanations about how changes in body physiology or genetics might produce the current obesity epidemic have not been forthcoming. The research proposed in this application approaches the problem from a different perspective. We suggest that the "wisdom of the body" involves the ability to use food cues (e.g., taste, texture, aroma, external cues that are associated with food) to anticipate the nutritive and caloric consequences of eating. By predicting the arrival of nutrients in the gastrointestinal tract, these cues evoke physiological responses that optimize utilization of these nutrients and also minimize their ability to perturb homeostasis (102). Over the last 25 years, increased incidence of overweight and obesity in the United States appears to be directly correlated with the intake of artificial sweeteners. The focus of our proposed research program will be to study the possibility that consumption of artificially-flavored, low- or no-calorie foods and beverages might function to "outwit" the wisdom of the body. This possibility is derived from what we think is a novel theoretical formulation that links the efficiency of the regulatory control of intake and body weight to a relatively simple form of Pavlovian conditioning. Within this framework, consuming sweet- or fatty-tasting substances which contain few or no calories has the effect of degrading the normal ability of sweet or fat orosensory cues to predict calories. As a consequence of weakening this predictive relationship, sweet- or fatty-tasting foods that contain calories become less able to evoke the compensatory physiological responses that underlie tight regulation. This model supplied the impetus for several preliminary studies. These studies provided initial evidence that the ability to regulate caloric intake and body weight is disturbed in rats that have a brief history of consuming artificially-sweetened or fat-substituted foods. Specific Aims 1-4 will attempt to further characterize this type of regulatory disturbance and the conditions under which it occurs. The final specific aim is to assess directly the hypothesis that consuming sweet-tasting but noncaloric substances interferes with the normal ability of sweet tastes to evoke anticipatory physiological responses that may contribute to energy homeostasis.
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2009 |
Swithers, Susan E |
R13Activity Code Description: To support recipient sponsored and directed international, national or regional meetings, conferences and workshops. |
Beverages in a Healthful Diet Symposium @ Purdue University West Lafayette
DESCRIPTION (provided by applicant): Overweight and obesity are among the most daunting public health and clinical problems nationally and globally. Their etiology is complex, but ultimately stems from positive energy balance. Thus, energy intake is of fundamental concern. Myriad aspects of the diet have been implicated in the problem, but one of particular importance and controversy is the role of beverages. Among the reasons they have been singled out is they now contribute over 20 percent of daily energy and reportedly hold weak satiety properties. Thus, the energy they contribute may be uncompensated resulting in positive energy balance. However, this perspective fails to recognize the multidimensional role that beverages play. We consume a wide array of beverages, many of which contribute important nutrients (e.g., milk and calcium fruit juices and vitamin C). It is misleading to consider only aspects of a food when determining its health implications. The multidisciplinary symposium proposed in this application has the goal of advancing understanding of the role of beverages in energy balance and health and identifying promising directions for future research. The symposium will uniquely attempt to provide a balanced consideration of the role of beverages in a healthy diet. Participating speakers will consider a variety of analytic levels, from in vitro work to human clinical and epidemiological perspectives to enhance the possibility of stimulating ideas that cross traditional disciplinary boundaries. The Ingestive Behavior Research Center proposes to hold a 3-day, multidisciplinary symposium in Indianapolis, IN on September 17 - 19, 2009. Twenty-one invited speakers and discussants will meet to discuss current understanding of the role of beverages in energy balance and a healthful diet and to identify promising directions for future research.
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2015 — 2016 |
Swithers, Susan E |
R21Activity Code Description: To encourage the development of new research activities in categorical program areas. (Support generally is restricted in level of support and in time.) |
Sweetened Beverages and Cardiovascular Disease in Rats
DESCRIPTION (provided by applicant): Consumption of sugar-sweetened beverages (SSB) has increasingly been associated with negative health outcomes including overweight, obesity, type 2 diabetes, heart disease and stroke. As a result, one strategy that has been suggested is to substitute artificially-sweetened beverages (ASB) for SSB under the premise that this will result in improved health outcomes. Unfortunately, not only are there few data to support that health is improved by ASB, but recent prospective cohort studies suggest that those who consume ASB are also at increased risk for the same negative consequences. This counterintuitive effect may occur because ASB interfere with basic learning processes that normally contribute to the regulation of food intake, body weight maintenance, and blood glucose homeostasis. In fact, short-term studies using a rat model have demonstrated that animals given ASB show increased weight gain and adiposity along with hyperglycemia. The goal of the proposed work is to determine whether long-term exposure to either SSB or ASB is causally linked to changes in metabolic or cardiovascular function using novel 4D ultrasound technology which permits repeated, longitudinal analysis of cardiovascular dynamics in vivo in a rat model to identify the temporal characteristics and mechanisms by which beverage consumption contributes to overweight, obesity, diabetes, and cardiovascular disease.
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2016 — 2020 |
Swithers, Susan E |
R13Activity Code Description: To support recipient sponsored and directed international, national or regional meetings, conferences and workshops. |
Annual Meeting of the International Society For Developmental Psychobiology
? DESCRIPTION (provided by applicant): This competing continuation application aims to address a critical need to provide the highest-caliber training to the next generation of scientist by supporting travel expenses of pre- and post-doctoral students to attend the annual meeting of the International Society for Developmental Psychobiology (ISDP). Active participation of trainees at the ISDP meeting will achieve the following specific aims: 1) Expose pre-and post-doctoral trainees to a broad range of scientific paradigms; 2) Promote thinking across levels of analysis to foster increased translational relevance; 3) Increase retention of trainees in science-related fields, especially trainees from under-represented categories (e.g. racial/ethnic, gender, disability, gender-identity, sexual orientation); 4) Attract junior scientists from within and outsde the U.S. to the meetings to promote global collaborations; and 5) Facilitate broad, inclusive scientific interactions among junior trainee scientists and between trainees and senior scientists. Annual meetings of ISDP feature invited speakers, symposia, oral talks and posters that span developmental questions across species including humans, with special attention to the effects of biological factors operating at any level of organization. Funds from the previous versions of the grant have provided partial travel support for students and postdoctoral fellows to present research at the meetings and to benefit from the research-career promoting opportunities the meetings afford. The present proposal requests 5 years continuation of support from NIH to bring the brightest students and post-doctoral fellows to the meeting where they will be able to interact with senior, mid-career, and other junior scientists examining critical questions related o typical and atypical development. The society and its meetings are truly international in scope, attracting scholars from across the globe; the 2015 meeting was held in San Sebastian, Spain and 71 pre- and post-doctoral trainees from 9 countries attended. Students and postdoctoral fellows are the lifeblood and future of our science and scholarly society; their professional development is key to advancing the science at the heart of ISDP. For many of the senior members, beginning when they were students, ISDP has played an important and sustaining role in advancing their scientific and academic or research careers. Multiple year support facilitates a culture of active and continued participation at the ISDP meetings among graduate students and postdoctoral trainees, prolonging the impact of ISDP well beyond the period of support.
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