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Objective: We examined the influence of effort-reward imbalance, a stressful feature of the work environment, on cardiovascular and inflammatory responses to acute mental stress., Methods: Ninety-two healthy men (mean age, 33.1 years) in full-time employment were recruited. Effort-reward imbalance was measured using a self-administered questionnaire. Blood, for the analysis of C-reactive protein (CRP) and von Willebrand factor (vWF) antigen, was sampled at baseline and 10 minutes after two mental stress tasks, whereas cardiovascular activity was measured throughout., Results: Plasma CRP and vWF were significantly elevated following the stress period, and cardiovascular activity was increased during and after both tasks (p < .001). Multiple linear regression analysis adjusted for age, body mass index, and baseline levels revealed that men with higher effort-reward imbalance demonstrated greater CRP and vWF responses to the stress tasks but blunted cardiovascular responses. Inflammatory and cardiovascular responses to stress appeared to be unrelated., Conclusions: These findings suggest that the association between chronic work stress and cardiovascular disease risk may be mediated in part by heightened acute inflammatory responsivity. These responses appear not to result from differences in sympathoadrenal activation.

Despite considerable epidemiological evidence of the health benefits of a diet high in fruit and vegetables, consumption in pre-school children remains well below recommended levels. This study evaluated the effectiveness of an exposure-based intervention, carried out by parents in the home, in increasing children's liking for a previously disliked vegetable. 156 parents of 2-6 year old children were randomly assigned to Exposure, Information or Control groups after a pre-intervention taste test at which a 'target' vegetable was selected. Parents in the Exposure group gave their child a taste of this vegetable daily for 14 days, parents in the Information group were given nutritional advice and a leaflet, and parents in the Control group received no further intervention. All participants took part in a post-intervention taste test. Greater increases in liking, ranking and consumption of the 'target' vegetable from pre- to post-intervention occurred in the Exposure group than in either of the other two groups. Only the Exposure group showed significant increases across all three outcomes. It can be concluded that a parent-led, exposure-based intervention involving daily tasting of a vegetable holds promise for improving children's acceptance of vegetables. These findings suggest a parental advice strategy which could be disseminated directly to parents or by health professionals.

Objective: The aim of this study was to evaluate two interventions (one reward-based and one exposure-based) for increasing children's acceptance of an unfamiliar vegetable compared with a no-treatment control. It was predicted that the exposure condition would increase liking for, and consumption of, the vegetable relative to either the reward or control group., Design: Using a randomized controlled design, participants were assigned to one of two intervention groups (exposure or reward) or to a no-treatment control condition, for a 2 week period. Liking for, and consumption of, red pepper was assessed before and after the treatment period., Setting: The study was conducted in three primary schools in London., Subjects: Parental consent was obtained for 49 out of a possible 72 children., Interventions: Interventions comprised eight daily sessions during which participants in the exposure group were offered a taste of sweet red pepper and told that they could eat as much as they liked. Participants in the reward group were shown a sheet of cartoon stickers and told that they could choose one of them on condition that they ate at least one piece of the pepper., Results: The exposure-based intervention significantly increased both liking (P=0.006) and consumption (P=0.03) compared with the control group. The outcome of the reward intervention was intermediate and did not differ significantly from the exposure or control conditions., Conclusions: Repeated exposure to the taste of unfamiliar foods is a promising strategy for promoting liking of previously rejected foods in children.

Eating more fruit can reduce risk of cancer and cardiovascular disease. Understanding barriers to this behaviour is critical for strategies to encourage it. We addressed the question whether the level of hunger at which fruit is eaten would influence the development of appetite for fruit. Half the participants were asked to eat a pair of novel fruit snacks (dried fruit bar; 50 kcal each) exclusively when hungry (at least 3 hours since last eating), and half to eat them exclusively when full (20-30 minutes after a meal), twice a day for one week. Rated appetite for the bars, and ad-libitum intake, were measured when hungry and full, on 2 days prior to, and 2 days after this week. Compliance was assessed from dietary diaries. Thirty participants (22 women, 8 men) completed the study satisfactorily. For the group eating the fruit bars only when hungry (hungry-trained), intake increased after the week, but only when full at the time of testing. Other measures of appetite for this group were unaffected, with the exception of a reduced desire to eat the bars when tested hungry. Ranked preference for the trained flavour increased exclusively among hungry-trained subjects, but only for those who had reported their preferred snack food to be fruit. No change in any measure was found for the group eating the fruit bars exclusively when full. The results suggest the hungry-trained group learnt that the bars lacked strong satiation, thus allowing greater intake when full (learnt desatiation). For the same reason, however, the prospect of eating the bars when mildly hungry lost its appeal. Eating fruit between meals may not encourage snacking on fruit, unless hunger is absent at the time of consumption., (Copyright 2000 Academic Press.)

Objective: This study investigated experimentally whether acute stress alters food choice during a meal. The study was designed to test claims of selective effects of stress on appetite for specific sensory and nutritional categories of food and interactions with eating attitudes., Methods: Sixty-eight healthy men and women volunteered for a study on "the effects of hunger on physiology, performance, and mood." Eating attitudes and food preferences were measured on entry to the study. The stressed group prepared a 4-minute speech, expecting it to be filmed and assessed after a midday meal, although in fact speeches were not performed. The ad libitum meal included sweet, salty, or bland high- and low-fat foods. The control group listened to a passage of neutral text before eating the meal. Blood pressure, heart rate, mood, and hunger were measured at baseline and after the 10-minute preparatory period, when appetite for 34 foods and food intake were recorded., Results: Increases in blood pressure and changes in mood confirmed the effectiveness of the stressor. Stress did not alter overall intake, nor intake of, or appetite for the six food categories. However, stressed emotional eaters ate more sweet high-fat foods and a more energy-dense meal than unstressed and nonemotional eaters. Dietary restraint did not significantly affect appetitive responses to stress., Conclusions: Increased eating of sweet fatty foods by emotional eaters during stress, found here in a laboratory setting, may underlie the previously reported finding that dietary restraint or female gender predicts stress-induced eating. Stress may compromise the health of susceptible individuals through deleterious stress-related changes in food choice.

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.

The importance of hunger state for the acquisition and expression of chocolate craving was investigated. Seventeen chocolate cravers and 12 non-cravers were supplied with chocolate and instructed to eat some twice a day for 14 days. Within each group, subjects were allocated to one of two conditions, hungry- or full-trained. Hungry-trained subjects were asked to eat the chocolate exclusively at least 2 h after last eating; full-trained subjects were asked only to eat the chocolate 15-30 min after eating a meal. A diary was kept to encourage and allow assessment of compliance. At the start and end of the 2 weeks, subjects rated their craving for and anticipated intake of chocolate prior to eating it; then, on initial tasting, pleasantness of the taste was rated. All subjects made these ratings on one day when hungry and on another when full, as defined above. For cravers and non-cravers who ate chocolate exclusively when hungry, chocolate craving increased post-training, but, at least for cravers, only when ratings were made while hungry. For full-trained subjects, chocolate craving decreased post-training, but this decrease did not depend on whether subjects were currently hungry or full. A similar pattern of results was found for anticipated intake and pleasantness of taste, except that pleasantness did not increase in hungry-trained subjects. The results are interpreted with reference to learned control of appetite and in particular to recent findings on incentive learning processes. Craving for chocolate or other foods may be an expression of a strong appetite elicited by hunger that has been acquired by repeated experience of eating the craved food when hungry., (Copyright 1999 Academic Press.)

Objective: This study was conducted to determine whether an increase in salivary free cortisol would be reliably elicited by a midday meal, thus providing a convenient physiological challenge to the hypothalamic-pituitary-adrenal (HPA) axis, and whether this cortisol release depended on the protein content of the meal., Method: In healthy men, free cortisol was measured in saliva samples taken before and after two identical protein-rich midday meals (39% energy as protein) and compared with a day on which no meal was eaten. Next, in healthy women in a nonclinical setting, salivary cortisol was measured before and after a protein-rich meal (32% energy as protein) on one day and a low-protein meal (5% energy as protein) on another day. Measures of mood, appetite, and psychological well-being were also taken., Results: An acute meal-dependent increase in salivary cortisol occurred, which was reliable over 2 test days. This increase in cortisol depended on the proportion of protein in the meal, increasing after the high-protein but not the low-protein meal. The extent of this increase in cortisol correlated significantly with poor psychological well-being in women. Some postmeal improvement of mood (positive affect) was associated with the high- but not the low-protein meal., Conclusions: The cortisol response to meals may have implications for the effects of meal composition on mood, cognitive function, and food choice. The measurement of free cortisol in saliva provides a psychologically stress-free and reliable technique to assess the cortisol response to a standard protein-rich meal, ie, a physiological challenge to the HPA axis in men and women that could be investigated in naturalistic settings outside the laboratory.

Medical and social pressures have led to increased emphasis on dieting. However, there has been a concurrent world wide increase of obesity. Therefore, much attention has been paid to the development of drugs which decrease appetite. The most extensively used drug of this type over the past three decades has been the serotonergic compound fenfluramine. Recent findings have cast doubt on the previously accepted view that its action requires the release of central 5-HT. Instead, it seems likely that action on specific 5-HT receptors independently of 5-HT stores is involved. It is ironic that these new developments in understanding its mechanism of action have coincided with the recognition of its cardiovascular side-effect apparent especially in patients treated with d-fenfluramine combined with phentermine. This has forced the withdrawal of fenfluramine (both as racemate and d-isomer) from clinical use. The implications of these developments are commented upon.

Increasing fruit and vegetable consumption is an important health behaviour. Parental and other psychosocial influences on children's fruit and vegetable consumption are poorly understood. The contribution of a variety of psychosocial and environmental factors to consumption of fruit and vegetables by children aged 9-11 years was explored. Ninety-two mothers and children (48 girls and 44 boys) were recruited via urban primary health-care practices. Socio-economic and educational level, nutritional knowledge and health- and diet-related beliefs and attitudes were assessed in mothers and children by questionnaires and semistructured interviews. Mothers>> diets were measured by a food frequency questionnaire, while children's diets were assessed by 3-day diaries (N=80). The pattern of influence of the various measures on fruit and vegetable consumption was compared with that on children's confectionery intake. The children's intakes of macronutrients were typical for the U.K. (37% fat, 50% carbohydrate and 13% protein by energy; 12 g/day fibre), while median fruit, fruit juice and vegetable intake amounted to about 2.5 servings/day. Univariate correlations and subsequent multiple regression analyses revealed quite different influences on the three food types. Independent predictors of children's fruit intake included mothers>> nutritional knowledge (beta=0.37), mothers>> frequency of fruit consumption (beta=0.30) and mothers>> attitudinal conviction that increasing fruit and vegetable consumption by their children could reduce their risk of developing cancer (beta=0.27; multiple r2=0.37,p<0.0001). Children's vegetable consumption was independently explained by the child's liking for commonly eaten vegetables (beta=0.36) and the mother's belief in the importance of disease prevention when choosing her child's food (beta=-0.27 r2=0.20,p<0.001). Children's confectionery consumption was predicted by the mother's liking for confectionery (beta=0.32) and the children's concern for health in choosing what to eat (beta=-0.26 r2=0.16, p<0.005). Children's consumption of fruit and vegetables are related to different psychosocial and environmental factors. Promotion of this behaviour may require attention to nutritional education and child feeding strategies of parents., (Copyright 1998 Academic Press)

The widely prescribed appetite suppressants D-fenfluramine and fluoxetine not only decrease feeding and body weight but also increase extracellular brain 5-HT. As central injection of 5-HT also decreases feeding, the drugs are often thought to require an increase of 5-HT at receptors in order to exert their hypophagic effect. However, much evidence now suggests that D-fenfluramine and its metabolite D-norfenfluramine can cause hypophagia by acting directly at unspecified 5-HT receptors and at 5-HT2C receptors, respectively, while fluoxetine may act independently of 5-HT receptors. These hypophagias may involve interference with the hyperphagic action of neuropeptide Y.

Acute (10mg/kg, i.p.) and chronic (10mg/kg/day, i.p. for 10 days) diazepam treatments decreased hippocampal dialysate 5-HT (but not 5-HIAA) concentrations in freely moving rats, suggesting decreased availability of 5-HT to receptors. Twenty-four hours after the last chronic diazepam injection, hippocampal dialysate 5-HT did not differ from that in vehicle-treated rats. However, although reduced 5-HT availability often increases postsynaptic 5-HT receptor-mediated responses, the anxiogenic effect of m-chlorophenylpiperazine (mCPP), which is mediated by the activation of postsynaptic 5-HT(2C) receptors, was not increased (as indicated by the elevated plus-maze test) when given 2 days after 10 days of chronic diazepam, in intact rats. Nevertheless, concurrently in that test, significantly increased anxiety occurred after withdrawal from chronic diazepam (10mg/kg/day x 10 days). The results suggest that benzodiazepine withdrawal-induced anxiety is not mediated by changes in 5-HT(2C) receptor sensitivity, and may be independent of the benzodiazepine-induced reduction of 5-HT release in the rat hippocampus.

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.

d-Fenfluramine (2.5 mg/kg i.p.) caused marked hypophagia in food-deprived rats and significantly increased medial hypothalamic extracellular 5-hydroxytryptamine (5-HT) as indicated by in vivo microdialysis. When the drug was given after the 5-HT synthesis inhibitor p-chlorophenylalanine (150 mg/kg per day x 3) the hypophagic response was unimpaired but dialysate 5-HT concentration no longer rose. The d-fenfluramine metabolite d-norfenfluramine (1.5 mg/kg i.p.) caused slightly greater hypophagia than the parent drug and completely blocked feeding in animals pretreated with p-chlorophenylalanine, but dialysate 5-HT was increased in neither circumstance. The results provide evidence against mediation of the hypophagic effects of d-fenfluramine and d-norfenfluramine by increased availability of 5-HT to receptors.

1-(3-Chlorophenyl)piperazine (mCPP) (0.125-1.0 mg/kg i.p.), previously shown to inhibit social interaction, dose-dependently reduced exploration of the open arms of an elevated plus-maze. These findings suggest anxiogenic properties. The effect of mCPP was more potently inhibited by 1-(1-naphthyl)piperazine than by ketanserin, indicative of its mediation via activation of 5-HT2C rather than 5-HT2A receptors. The 5-HT1B receptor agonist CGS 12066B did not antagonise the anxiety-like response to mCPP, and further reduced exploration at the highest dose tested (10 mg/kg i.p.). Depletion of serotonin (5-HT) by p-chlorophenylalanine (PCPA, 150 mg/kg/day x 3) did not prevent the response, although PCPA itself increased open arm exploration. The 5-HT1A/B and beta-adrenoceptor antagonist 1-propanolol (5 mg/kg i.p.) and the peripheral beta 1-receptor antagonist atenolol (20 mg/kg i.p.) showed no significant activity on the plus-maze either alone or against the anxiogenic effect of mCPP. These results indicate that mCPP induces anxiety in the rat in the elevated plus-maze primarily by stimulation of postsynaptic 5-HT2C receptors, and suggest that sympathomimetic effects of mCPP are not involved.

Severe depletion of 5-hydroxytryptamine (5-HT) by para-chlorophenylalanine (pCPA, 150 mg/kg per day x3) did not alter the hypophagic effect of d-fenfluramine (1-3 mg/kg i.p.) 1 h after food presentation in 24-h food-deprived rats, and moderately and comparably increased the hypophagic effects of its metabolite, d-norfenfluramine (0.35-1.0 mg/kg i.p.), and of the 5-HT1C receptor agonist, 1-(3-chlorophenyl)piperazine (mCPP; 1.5, 2.0 mg/kg i.p.). Chronic treatment with mCPP (2.5 mg/kg i.p. x 14) attenuated the hypophagia induced by d-norfenfluramine (1, 1.5 mg/kg) but not d-fenfluramine (1, 3 mg/kg). 1-(1-Naphthyl)piperazine (3, 8 mumol/kg s.c.), which has greater affinity for 5-HT1C than for 5-HT2 receptors, had no effect on the hypophagia induced by d-fenfluramine (1.25, 2.0 mg/kg), but 1.3 and 3 mumol/kg 1-(1-naphthyl)piperazine largely and comparably attenuated the substantial hypophagic effect of d-norfenfluramine (0.75 mg/kg). The essentially complete hypophagic action of d-norfenfluramine (1.25 mg/kg) was inhibited by 1-(1-naphthyl)piperazine with ID50 = 2.13 mumol/kg. Ketanserin, which binds more weakly than 1-(1-naphthyl)piperazine to 5-HT1C receptors and more strongly to 5-HT2 receptors, attenuated weaker but not stronger hypophagic effects of d-fenfluramine (1.25, 2.0 mg/kg) when given at high dosage (8, 16 mumol/kg s.c.). Ketanserin (16 mumol/kg) also weakly attenuated the hypophagia due to d-norfenfluramine (0.75 mg/kg), but not the essentially complete hypophagia due to d-norfenfluramine (1.25 mg/kg).(ABSTRACT TRUNCATED AT 250 WORDS)

The effects of pretreatments on behavioural responses to activation of 5-HT1C receptors by m-chlorophenylpiperazine (mCPP) were investigated. The hypo locomotor and anxiogenic effects of mCPP (social interaction test) were influenced neither by previous housing (single versus grouped) nor by restraint (2 h, 24 h previously). In the absence of mCPP, 24 h group housing led to decreased social interaction and the restraint procedure led to significant decreases of feeding and locomotion. The hypophagic effect of mCPP was unaffected by previous restraint. However, chronic pretreatment with mCPP (2.5 mg/kg per day IP x 14) or with the antidepressant 5-HT reuptake inhibitor sertraline (5 mg/kg per day SC x 14) attenuated all three behaviours. The above findings are discussed with respect to published data on effects of pretreatments on responses to the activation of 5-HT1C receptors.

Perception, preference, and selection are all objectively measurable performances that discriminate between different levels of entities such as the sugar, thickener, or protein in a food. A rating or an intake may not be controlled by the word that the experimenter or the subject uses to describe it: "protein"-oriented food selection, "thickness" preference, or "sweetness" perception is proved only when the named objective influence, isolated from any other influence, accounts for the observed variations in choice response. Difference-measuring designs can be extended from merely two levels of an influence to a continuum over the natural range of levels, thus evoking linear psychophysical (dose-response) performance from which the strength of that influence can be estimated. Usually, at least a few influences are operative at once on a choice. Because the interactions may vary among people, the only valid causal analysis is at the individual level. Examples are given of food taste tolerance in the elderly, integration of sensory and attitudinal influences, and dietary choices misattributed to carbohydrate craving.

Paraventricular (PVN) hypothalamic norepinephrine (NE) injections which facilitated feeding were nonetheless found to reduce both the unconditioned preference for saccharin and starch-conditioned preferences for almond odor and lemon taste, as well as enhancing aversion to quinine. These results add to the evidence that PVN NE elicits eating by attenuating a satiety signal.

Rats are shown to acquire a preference for protein-predictive olfactory cues which depends on a state of mild deficit in protein intake--i.e. a learned protein-specific appetite.

Serial eosinophil counts were determined in 38 hospitalized, appropriately grown premature infants whose gestational ages ranged from 27 to 35 weeks. Absolute eosinophilia (greater than 700/mm3) was documented in 76% (29/38). Eosinophilia was mild (700 to 999/mm3) in 9, moderate (1,000 to 2,999/mm3) in 17, and marked (greater than or equal to 3,000/mm3) in 3 patients. The average time of onset was day 19. Peak eosinophilia was usually seen within one week of onset and lasted an average of 16 days. A consistent relationship (r = 0.86) was found between the day of peak eosinophilia (mean = day 27) and the day on which birthweight was regained (mean = day 22). No association was apparent between the occurrence or degree of eosinophilia and gestational age, birth stress, presence of umbilical catheter, parenteral alimentation solution, and time of beginning or type or oral feeds. The data suggest that eosinophilia is strongly associated with the establishment of an anabolic state.

A gastric slowing effect of fenfluramine accounts for most of the drug's suppressant effect on food intake in freely feeding rats. It is conceivable on the evidence to date that this gastromotor action of fenfluramine explains all its effects on appetite and metabolism, but additional peripheral and central effects--such as motor inhibition--are likely. Rate of gastric emptying is quantitatively the dominant physiological control of appetite: it determines the duration for which absorption of a meal sustains metabolic satiety; it also influences gastric distension, which can be a source of innate satiation and of learned carbohydrate-specific satiation. Since most of the neurotransmitter serotonin (5HT) resides in the gastrointestinal wall, not the brain, gastromotor suppression of appetite should be the first working hypothesis for a serotoninergic drug such as fenfluramine. The largest effect on food intake that arises from gastric slowing by fenfluramine and active metabolites is a lengthening of the period of satiety after a meal of a given size. The residue of this extended satiety could reduce appetite at a subsequent fixed mealtime and hence the size of such a meal. Fenfluramine appears not to intensify satiation processes generated by a meal. Rather, it affects eating processes from the start. Also, fenfluramine disrupts learned carbohydrate-specific satiation operative within a meal. This negates the claim that fenfluramine reduces carbohydrate-specific appetite--which in any case (like other claims that drugs modulate nutrient selection) is not based on adequately designed dietary selection tests.

The effects of pharmacological modulation of monoamine transmitter activity on genuine nutrient selection were assessed: that is, drug-induced changes in nutrient-specific dietary choice behaviour were measured, using rats that had learned to select an odour cueing protein content or carbohydrate content of the diet. Anorexigenic doses of DL-fenfluramine-HCl (1.25 or 2.5 mg/kg) and D-amphetamine2 SO4 (0.5 or 1.0 mg/kg) did not affect the selection of protein-paired or carbohydrate-paired odours by trained rats. This weighs against the claim that 5-hydroxytryptamine or catecholamine transmitters are involved in the selection of macronutrients, as distinct from selection between diets in response to sensory differences functionally unrelated to nutrient composition.