Search

Refeeding syndrome is a life-threatening complication that may occur after initiation of nutritional therapy in malnourished patients, as well as after periods of fasting and hunger. Refeeding syndrome can be effectively prevented and treated if its risk factors and pathophysiology are known. The initial measurement of thiamine level and serum electrolytes, including phosphate and magnesium, their supplementation if necessary, and a slow increase in nutritional intake along with close monitoring of serum electrolytes play an important role. Since refeeding syndrome is not well known and the symptoms can be extremely heterogeneous, this complication is poorly recognized, especially against the background of severe disease and multimorbidity. This overview aims to summarize the current knowledge and increase awareness about refeeding syndrome.

The phenomenon of the so-called "obesity pandemic" having arisen over the last decades has to be, in large part, attributed to changes of lifestyle and the associated changes in dietary habits and physical activity observed world-wide. The resulting interference in energy homeostasis plays a central role in the development of obesity in a large proportion of the population worldwide. In this article, current knowledge about central biological mechanisms of energy intake, energy storage, and energy expenditure is summarized. This includes, for example, the feeling of hunger/satiety, lipid turnover with the two components of lipolysis and lipogenesis, adipogenesis, as well as energy-consuming processes like (adaptive) thermogenesis, resting metabolic rate, and physical activity energy expenditure. Based on examples, the possible influence of genetic polymorphisms contributing to the development of adiposity are illustrated.

The controlled study examined the distortion of hunger und satiation in 12 patients with restrictive AN (BMI = 14.0; SD: 1.78; age 27.4 years; SD = 10.5) and 13 healthy and not eating-disordered normalweight controls (BMI = 21.3; age 25.3 years; SD = 3.4) by visual confrontation with food stimuli in different states of nutrition. During fasting patients with AN describe less hunger-feelings. In contrast to healthy women pictures of food and the anticipation of the consumption of hot chocolate are not experienced enjoyable, but aversive. Visual confrontation of food has a satiable effect on anorexic patients. Healthy women, however, indicate a moderate decrease in hunger feelings. After eating ad libitum satiety of healthy women reach a plateau instead of further eating. Anorexic patients initially feel hungry, a stable level of satiety, however, cannot be obtained. The visual confrontation with food is experienced aversively and satiably. These results leads us to assume a cognitive allocation of satiation ratings. The dysfunctional cognitive allocation of satiation ratings may represent a mean to maintain a food-avoidance.

Background: In order to improve perioperative subjective quality of care it seems desirable to shorten preoperative fasting times as much as possible within acceptable safety limits. These efforts should result in a measurable reduction of preoperative thirst and hunger as well as in improvements of patient well-being. It is unknown to what extent preoperative patient comfort is limited by thirst and hunger from a patient point of view. The purpose of this study was to determine the impact of a traditional fasting regimen on preoperative patient discomfort., Patients and Methods: We conducted a survey on preoperative thirst and hunger in 412 adult American Society of Anesthesiologists ASA I and II patients scheduled for minor elective surgery., Results: Of the patients 33% complained of moderate to strong thirst, whereas 19% had moderate to strong hunger, 47% of the participants would have liked to have been able to drink and 72% would have appreciated a light breakfast before surgery. Mean preoperative fasting times were 12.8+/-3.4 h for fluids and 15.5+/-4.4 h for solids. "Thirst" was named by 3.3% and "hunger" by 0.8% of patients as the most important factor for preoperative discomfort but "long wait" (8.5%), "tenseness" (6.5%) and "anxiety" (4.8%) were the most frequently named factors. Answers were independent of the duration of preoperative fasting., Conclusion: Patient comfort is compromised by traditional fasting rules and liberalization of these policies is desired by patients. However, efforts to reduce preoperative anxiety and tenseness might have an additional, important potential to improve perioperative quality of care from a patient's perspective.

Obesity is a chronic condition associated with a reduction in the quality of life and a high risk for disease and death and requiring long-term care. In Germany, 51.4% of the population is overweight, with 9 million suffering from obesity and its consequences, such as hypertension, diabetes and sleep apnea. In addition, the number of patients undergoing treatment for painful chronic-degenerative disease of the joints is on the increase. After first exhausting all conservative therapeutic options, effective surgical measures can bring about a lasting overweight reduction of up to 50%. By this means, both pain and adverse consequences of obesity can be improved.

Although François Magendie's studies on the functional differentiation of the spinal nerves, on the maintenance of blood pressure, and on the circulation of the cerebrospinal fluid have been sufficiently considered in medical historiography, his physiological research on nutrition, carried out between 1831-1841, has hardly attracted attention. With several series of animal experiments, Magendie tried to answer the question whether a gelatine-based fare would be suitable for feeding the indigent people of Paris. Taking these experimental series as a specific historical example, an approach from sociological systems theory is proposed in order to analyse the relations between Magendie's hunger laboratory, the French Académie des Sciences, food industrialists, and health and military administrators. The historiographical relevance of this approach as well as its methodological limitations are discussed in this article.

Heat production (indirect calorimetry) and motor activity were measured continuously with 4 repetitions at 8 male albino rats (24 h fasting) over 21 h (4 minute cycle of measured value registration). The average difference between maximum and minimum heat production in a 4-minute measuring period amounted to 82 +/- 14% (68 to 139%). There was a significant connection between heat production and activity. 7.9 +/- 1.2% of the heat production of the hungry rat could be ascribed to activity. In the course of the day of fasting (24 h) an average metabolism reduction of 15 kJ/kg LW0.75 could be observed.

An account is given of the fundamental mechanisms concerned with the regulation of hunger and thirst, and of the physiological processes involved in the uptake of nutrients, water and electrolytes. Several reflex chains ensure that the organism does not take up too much water and also protect it from excessive loss of water and salt.

Food intake in man and animals occurs as meals. Because changes in daily food intake in laboratory animals are often associated with corresponding changes in meal size, while meal frequency is less affected, food intake appears to be regulated mainly by the satiety mechanism. Meal size is controlled by feedback or satiety signals originating from the stomach, the small intestine, the liver and the fat depots. Both neural and hormonal (Bombesin?, Cholecystokinin?) feedback signals are elicited in the stomach and intestine. The feedback signals of the liver apparently originate from hepatic chemoreceptors, whose activity is modulated by certain metabolites, in particular glucose. The satiety effect of pancreatic glucagon, whose plasma concentration in the portal vein increases during a meal, also appears to be mediated by the hepatic chemoreceptors. Unmyelated nerve endings are probably the morphological substrate of the hepatic chemoreceptors. There is some evidence that circulating fat metabolites (fatty acids, ketone bodies, glycerol), whose plasma levels are related to the size of the fat depots, function as lipostatic feedback signals. The signal transfer from the gastrointestinal chemo- and mechanoreceptors and from the hepatic chemoreceptors to the central nervous system occurs mainly through vagal afferents. The first relay for this afferents is the nucleus tractus solitarii in the medulla oblongata. The next relay is at the pons, from where neurons project to the hypothalamus and other forebrain areas. The hypothalamus has important integrative functions in the control of food intake.

Increase in energy and release of energy are essentially regulated instinctively. The afferences from the exterior and interior milieu, the central impulse zones and the efferences form a system which may be affected by disturbances at different sites. In persons with an obesity of high degree in the majority of cases also other nervous and hormonal disturbances can be proved. The wide-spread obesity as a popular disease is based on unnatural impulses and inhibitions of the regulatory mechanisms. In this milieu the success of the treatment depends on the fact that the patient experiences greater promptings than pleasure in eating and comfort.

In 20 patients, undergoing a fasting period of 14 days, electrolyt balances were studied. Ten patients received 80 mval potassium per day. Sodium, potassium, calcium and phosphate in blood did not change; bicarbonate and chloride levels diminished. Balance studies showed a significant loss of potassium in both groups. Product of sodium and potassium was constant; calcium balance was positive, whereas that of phosphate was negative. During addition of 80 mval potassium per day significant change of sodium balance occurred.

The decisions of an individual about his food intake depend upon a variety of internal and external signals. The present contribution describes the physiological mechanisms controlling food intake to preserve body composition and performance. Centers within the hypothalamus including their connections to higher and lower structures within the central nervous system, especially to the limbic system, are involved in the control a food intake. Neuropeptides and neurotransmitters usually initiate more complex actions including the search for food and satiety phenomena. Their production and release are influenced by food consumption as well as intake of specific nutrients, sensorial perceptions, and a variety of other factors. Vagal reflexes and gastro-intestinal hormones, fat cell size, physical activity, and thermogenesis also influence perceptions of hunger and satiety. A model satisfactorily describing the interactions between all known factors that control food intake is still missing. The path from hunger to satiety could be described as sequences of cascades similar to the various steps in blood clotting. Control of food intake during early life dependably relies on energy requirement, and can be utilized for ad-libitum feeding. Obesity and anorexia nervosa are manifestations of disturbed control over food intake. Neuropharmacology offers several therapeutic approaches to specific conditions. However, by and large abnormalities of food intake control have to be treated by behavioral modification.