Consumer acceptance of foods lower in sodium.

OBJECTIVE: To assess the magnitude of sodium reduction that can be made without significantly changing the perception of saltiness and acceptability of a broad range of common food items. DESIGN: The investigation was carried out in two phases. Military and civilian volunteers (N = 190 in study 1; N = 380 in study 2) from the US Army Natick Research, Development and Engineering Center rated the saltiness and acceptability of foods containing differing sodium concentrations. SETTING: Consumers rated food items in the sensory testing laboratory. INTERVENTION: "Regular" and "low-sodium" entrees were rated for saltiness and acceptability in study 1. Prepared food, commercially prepared food, and beverages containing various concentrations of sodium were rated for saltiness and acceptability in study 2. STATISTICAL ANALYSES PERFORMED: Results were analyzed using Pearson correlation coefficients, Student's t test, and analysis of variance. RESULTS: The perception of saltiness increased as the concentration of sodium increased. Acceptance ratings varied considerably over a broad range of sodium concentrations, which indicates that the relationship was product specific. Results suggest that a reduction of one third or more in added sodium can be made to some foods without significantly affecting consumer acceptance. APPLICATIONS: The sodium content of food can be reduced by consumer-guided food engineering and food preparation. Alterations in food preparation and product formulation, in conjunction with alterations in diet, can be effective methods for reducing sodium consumption.

Thirst and fluid intake following graded hypohydration levels in humans.

The relationship among changes in thirst sensations, blood variables, and differential fluid intake in hypohydrated humans was examined. Seven subjects were hypohydrated by 0%, 3%, 5%, and 7% of their body weight on four separate trials which were systematically randomized between subjects. Hypohydration levels were achieved with a regimen of restricted food and fluid intake and moderate heat-exercise stress. Statistically significant linear and quadratic trends were found for the intensity of several sensations with progressive hypohydration levels. In general, plasma osmolality and renin activity increased and plasma volume decreased with increasing hypohydration levels. During a one hour period of ad lib drinking, all subjects consumed insufficient fluid to rehydrate back to baseline body weights. Using regression analyses, fluid intake was predicted by the magnitude of subjective and physiological indices of hypohydration. Results demonstrate that both hypovolemia and plasma osmolality contribute significantly to fluid intake in hypohydrated humans. The results also indicate that thirst sensations make a substantial contribution to differential fluid intake in humans.

Voluntary dehydration and alliesthesia for water.

The purpose of this experiment was to explore the complex relationship between fluid consumption and consumption factors (thirst, voluntary dehydration, water alliesthesia, palatability, work-rest cycle) during a simulated 14.5-km desert walk (treadmill, 1.34 m X s-1, 5% grade, 40 degrees C dry bulb/26 degrees C wet bulb, and wind speed of approximately 1.2 m X s-1). Twenty-nine subjects were tested (30 min X h-1, 6 h) on each of two nonconsecutive days. The subjects were randomly assigned to one of three groups: tap water (n = 8), iodine-treated tap water (n = 11), or iodine-treated flavored tap water (n = 10). The temperature of the water was 40 degrees C during one trial and 15 degrees C on the other. Mean sweat losses (6 h) varied between 1.4 kg (warm iodine-treated; 232 +/- 44 g X h-1) and 3.0 kg (cool iodine-treated flavored; 509 +/- 50 g X h-1). Warm drinks were consumed at a lower rate than cool drinks (negative and positive alliesthesia). This decreased consumption resulted in the highest percent body weight losses (2.8 and 3.2%). Cooling and flavoring effects on consumption were additive and increased the rate of intake by 120%. The apparent paradox between reduced consumption concomitant with severe dehydration and hyperthermia is attributed to negative alliesthesia for warm water rather than an apparent inadequacy of the thirst mechanism. The reluctance to drink warm iodine-treated water resulted in significant hyperthermia, dehydration, hypovolemia, and, in two cases, heat illness.

Perception of drinking water temperature and effects for humans after exercise.

Subjects rated the perceived temperature and hedonic values of four samples of drinking water (5 degrees, 16 degrees, 22 degrees, 38 degrees C) after exercise and on a control day. Ad lib drinking of any of the four samples was permitted for 20 minutes after exercise and intake was measured. Subjects completed questionnaires pertaining to their subjective states. Sensory thermal neutral water was found to be close to 22 degrees C which was also judged to be affectively neutral. Subjects rated 16 degrees C water higher on the hedonic scale after exercise than they did on a control day, despite the fact that no change in the perception of this temperature was observed. Responses to the symptoms questionnaire showed a marked effect of exercise on the perception of thirst, sweating, body warmth and dryness in the mouth. Sensations of stomach fullness could not account for the incomplete rehydration of most subjects in the time allotted. It was suggested that a rapid reduction in symptoms which initiate drinking was responsible for drinking termination. The role of water temperature in the reduction of thirst symptoms was discussed.

Effects of protein and carbohydrate meals on mood and performance: interactions with sex and age.

Normal adult subjects (n = 184) consumed a high-protein or high-carbohydrate meal. Two hours later their mood and performance were tested. The effects of meal composition on mood were different for men and women, and for older and younger subjects. Females, but not males, reported greater sleepiness after a carbohydrate as opposed to a protein meal. Male subjects, but not females, reported greater calmness after a carbohydrate as opposed to a protein meal. Older subjects responded differently to meals depending upon the time of day when these were consumed. When meals were eaten for breakfast (but not for lunch) individuals 40 yr of age or older felt more tense and less calm after a protein than after a carbohydrate meal. Although older subjects reported subjective discomfort after a morning protein meal, they displayed objective performance impairments after a carbohydrate lunch. Subjects 40 yr of age or older were impaired on a test of sustained selective attention (dichotic shadowing) after consuming a high-carbohydrate lunch. The shadowing impairment after carbohydrate consumption was as pronounced without distraction as with distraction and resulted mostly from increased omission errors. Our findings suggest negative effects on concentration when older subjects consume a high-carbohydrate, low-protein lunch. These negative effects of carbohydrate consumption appear to arise predominantly from lapses of attention rather than from intrusion of distractors.

Facts and fictions about infantile obesity.

This review assesses the present state of knowledge on the etiology of infantile obesity. Current controversies such as bottle vs. breast feeding, the importance of differences in early feeding and activity patterns, and the role of early adipose cell development are discussed. There is continuing debate on the relationship of early obesity to later body weight. The major limitation of current research is the lack of adequate consideration of social and environmental factors particularly how eating and activity behaviors develop and are maintained. The emphasis of this paper is on highlighting the opportunities for different learning experiences inherent in different feeding environments during early life. Implications for research particularly the need for longitudinal studies on the establishment of characteristic eating and activity patterns are discussed.

Health care providers' attitudes toward nutrition.

A survey questionnaire, assessing general attitudes toward the importance of nutrition in the prevention of disease and the maintenance of good health, was administered to physicians, nurses, dentists, and technicians at five U.S. Army medical centers. The various groups of health care specialists differed significantly on many items concerning the importance of good nutrition and eating habits for maintenance of good health and for recovery from illness, as well as on items concerning the importance of nutrition knowledge and training in their health care professions. More agreement was found among the groups on items concerned with the relationship between disease states and dietary factors and the effectiveness of health education programs in the prevention of various diseases. Self-reports of personal health habits did not correlate with scores on survey items concerned with the importance of good nutrition, suggesting that personal attitudes toward nutrition may be unrelated to other health practices.

Amotivational syndrome in chronic schizophrenics. A biophysiological model of schizophrenic impairment.

An attempt is made ot provide a description and a biological foundation of the amotivational syndrome as a part of the schizophrenic impairment. The role of a reward system, brain stem arousal, and cortical facilitation is discussed as a neurophysiological support for self and species preservation functions, goal directed behavior and performances. Damage caused to the NA-ergic neurons by toxic metabolites of DA results in a flattening of basic motivations and an incapacity to achieve higher cortical motivations and to perform high cortical activities. As the source of the syndrome a pathological gene might be involved; as its end the superimposed institutionalization has to be removed, in order to uncover the schizophrenic defect itself.

Preferences for sweet and salty in 9- to 15-year-old and adult humans.

Preferences for the tastes of sucrose, lactose, and sodium chloride were measured in 618 subjects between 9 and 15 years of age and in 140 adults. The younger subjects preferred greater sweetness and saltiness that did the adults. In the younger groups, there were race and sex differences in preferences, none of which appeared among the adults.

Ingestive responses of human newborns to salty, sour, and bitter stimuli.

Human newborns (1-4 days old) were offered two fluids differing in taste for 3 min each. The volumes ingested were measured. Infants offered water and bitter or sour solutions did not ingest them differentially, which corroborated earlier observations with weaker solutions. A sucrose solution was used to raise baseline ingestion above that of water. Infants offered the sucrose solution with and without urea, citric acid, or sodium chloride consumed less of it when citric acid was added. They were indiffferent to the addition of urea or sodium chloride. The failure to observe intakes lower than that of water suggests that newborns maximally inhibit their ingestion of water. The effects of sex, age, birth weight, and individual consistency on intake were assessed.

Heredity and experience: their relative importance in the development of taste preference in man.

Heritability estimates for sucrose, lactose, and sodium chloride taste preferences were uniformly low in a sample of 311 monozygotic and like-sex dizygotic twin pairs between 9 and 15 years of age. Black children preferred more concentrated solutions of all three tastants than did Caucasian children. This effect was independent of socioeconomic status in the total sample. Males preferred more concentrated solutions of sucrose and lactose than did females- but there were no sex differences in sodium chloride preference. The possibility that early intake experiences may play a role in the determination of enduring taste preferences in Homo sapiens is discussed.

A motivation evaluating rating scale for chronic impaired schizophrenics (MERS).

The attempt is made to structure a rating scale intended to evaluate the motivational level of chronic impaired schizophrenics (defect-schizophrenia). The need for such a measuring tool is stressed, considering mainly the relatively poor symptomatology of these patients, the difficulties to discern changes in the patients' condition and the fact that lack of motivation basically features the schizophrenic impairment. The scale strives to be as comprehensive as possible, extending from the lowest biological level to the highest social and cultural aspects of motivation.