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Biomedical subjects

Julie A Mennella

Publications and source records attributed to Julie A Mennella.

At least 19 recordsLinked to original sources
PubMed2006

Vegetable acceptance by infants: effects of formula flavors.

Individual differences in acceptance patterns are evident as early as the child's first experiences with a particular food. To test hypothesis that the flavor of formula fed to infants modifies their acceptance of some foods, we conducted a within- and between-subjects design study in which two groups of 6- to 11-month-old infants were tested on two separate days. One group was currently feeding a milk-based formula whereas the other was feeding a protein hydrolysate formula, a particularly unpleasant tasting formula to adults that contains similar flavor notes (e.g., sulfur volatiles) with Brassica vegetables such as broccoli. In counterbalanced order, acceptance of pureed broccoli/cauliflower was determined during one test session and pureed carrots on the other. Although there were no group differences in the amount of carrots consumed, hydrolysate infants consumed significantly less broccoli/cauliflower relative to carrots when compared to those who were currently fed milk based formulas (F(1,72 df)=4.43; p=0.04). The mothers of hydrolysate infants were significantly more likely to report that their infants did not enjoy feeding the broccoli/cauliflower (54.2%) when compared to mothers of infants being fed milk-based formulas (28.0%; Chi-Square (1 df)=4.79; p=0.03). Such findings are consistent with prior research that demonstrated a sensory specific satiety following repeated exposure to a particular flavor in milk. We hypothesize that when infants are experiencing a flavor in milk or formula, in the short term, the preference that develops is specific to the context it is experienced in (e.g., milk). Over the longer term, the preference may generalize to other contexts such as solid foods. Hydrolysate infants were also significantly more likely to be judged by their mothers as being more active (F(1,69 df)=3.95; p=0.05) and hesitant (F(1,69 df)=6.55; p=0.01) when compared to those infants who were feeding milk-based formulas, a finding that further supports the hypothesis that mother-child dynamics surrounding early feeding impacts upon mothers' perception of their children's temperament.

Adult↗
PubMed2006

Short-term effects of alcohol consumption on the hormonal milieu and mood states in nulliparous women.

The present study was designed to determine the short-term effects of alcohol consumption on hormonal responses and mood states in nulliparous women who have regular menstrual cycles. To this aim, we conducted a within-subjects design study in which eight women consumed a 0.4-g/kg dose of alcohol in orange juice during one test session (alcohol condition) and an equal volume of orange juice (control condition) during the other. Changes in plasma prolactin, oxytocin and cortisol levels, blood alcohol concentrations (BACs), and mood states were compared. BAC peaked at approximately 36.7+5.4 min after the consumption of the alcoholic beverage and decreased thereafter. Alcohol consumption significantly increased the area under the concentration-time curve (AUC) of prolactin (P<.01) and decreased the oxytocin AUC (P=.04) when compared to the control condition. Cortisol AUCs were not different across the two experimental conditions. Similar to that previously observed in lactating women, changes in prolactin and oxytocin paralleled changes in feelings of drunkenness. The magnitude and persistence of the alcohol-induced hormonal changes in nulliparous women were significantly less pronounced than those observed in lactating women, further highlighting the dynamics of the system under study during lactation.

Adult↗
PubMed2006

Feeding Infants and Toddlers Study: the types of foods fed to Hispanic infants and toddlers.

OBJECTIVE: To assess the prevalence of breastfeeding and formula feeding, the age of introduction to specific foods, and the types of foods and beverages consumed by Hispanic infants and toddlers compared with similarly aged non-Hispanic infants and toddlers living in the United States. DESIGN: Descriptive and comparative analysis of dietary recall data and responses to specific interview questions, which were collected in the 2002 Feeding Infants and Toddlers Study. Breastfeeding status, timing of introduction of complementary foods, percentage consuming foods from specific food groups, and the most frequently consumed fruits and vegetables by Hispanic and non-Hispanic children by age group (4-5 months, 6-11 months, 12-24 months). SUBJECTS: A national random sample of 371 Hispanic and 2,637 non-Hispanic infants and toddlers between the ages of 4 and 24 months. STATISTICAL ANALYSIS: To test for differences between Hispanic and non-Hispanic children in the percentage who consumed a particular food item, we calculated percentages and standard errors in SUDAAN and 95% and 99% confidence intervals. The most frequently consumed fruits and vegetables were determined by tallying the percentage of infants and toddlers who consumed each specific fruit or vegetable on a given day. RESULTS: Although there were some similarities, the early flavor and food experiences of Hispanic infants were different from similarly aged non-Hispanic infants in several ways. Hispanic infants younger than 1 year of age were more likely to have ever been breastfed and those who were 4 to 5 months were more likely than non-Hispanics to be eating pureed baby foods on a daily basis. Although less likely to be eating non-infant cereals and baby food vegetables, 6- to 11-month-old Hispanics were more likely to be eating fresh fruits, fruit-flavored drinks, baby cookies, and foods such as soups, rice, and beans that are common in many Hispanic cultures. When fruits were introduced into the Hispanic child's diet, they were most commonly consumed fresh. This higher prevalence of being fed soups, rice, beans, and sweetened fruit-flavored drinks as well as tortillas was also observed among the 12- to 24-month-old toddlers. CONCLUSIONS: Dietetics professionals should be aware of the cultural differences in the foods fed to infants and toddlers that may contribute to the development of long-term food preferences and impact on nutrition. Understanding the factors that underlie food preferences is important if we are to develop evidence-based strategies to improve children's eating habits and lower their risks factors associated with obesity and other chronic diseases.

Bottle Feeding↗
PubMed2005

Sucrose-induced analgesia is related to sweet preferences in children but not adults.

The present study tested the hypothesis that the efficacy of sucrose in reducing pain during the Cold Pressor Test (CPT) was related to its hedonic value. To this aim, we determined the most preferred level of sucrose and the analgesic properties of 24% w/v sucrose during the CPT in 242, 5- to 10-year-old children and their mothers. Outcome measures included pain thresholds (the time at which discomfort was first indicated) and pain tolerance (the length of time the hand was kept in the cold water bath). Although children, as a group, preferred significantly higher sucrose concentrations than adults, there were individual differences that allowed us to group them on the basis of those who preferred sucrose concentrations below that used in the CPT (24% w/v) and those who preferred levels >or=24% w/v sucrose. Regardless of such groupings, sucrose was not an effective analgesic in adult women. Unlike adults, the more children liked sucrose, the better its efficacy as an analgesic. That is, children who preferred >or=24%w/v sucrose exhibited an increased latency to report pain and tolerated pain for significantly longer periods of time when sucrose was held in their mouths relative to water. This effect was more pronounced among normal weight when compared to overweight/at risk for overweight children. The role that dietary habits and individual differences contribute to the preferences for sweet taste and its physiological consequences in children is an important area for future research.

Administration, Oral↗
PubMed2005

Infant feeding practices and early flavor experiences in Mexican infants: an intra-cultural study.

OBJECTIVES: The study explored the maternal beliefs and practices related to pregnancy, breastfeeding, and infant feeding among women living in several regions in Mexico. We hypothesized that, despite the culinary diversity within Mexico, there would be similar patterns in the types of flavors and foods eaten by mothers and fed to infants. DESIGN: A structured interview was conducted through personal interviews with mothers during routine visits to their local family medical units. The units were located in four regions in Mexico that represent the diversity of culinary practices characteristic of the country. SUBJECTS: A random sample of 101 women whose infants ranged in age from 6 days to 9 months. RESULTS: Although the vast majority of mothers knew of its benefits and nursed their infants, breastfeeding during the first week of life was not exclusive; approximately one third of the infants were also fed teas, water, and/or formula. The feeding of teas continued throughout infancy in three of the regions, but the flavor of the tea differed. There were also regional similarities in the foods chosen and avoided during pregnancy and lactation and the type of first foods offered to the infants. CONCLUSIONS: The similarities in the types of foods fed to infants and eaten more of by mothers during pregnancy suggest that these cultural and regional practices contribute to the development of strong preferences for regional cuisines. The foods eaten by the mother during pregnancy and lactation form the basis of the child's weaning patterns.

Adult↗
PubMed2005

Children's hedonic judgments of cigarette smoke odor: effects of parental smoking and maternal mood.

Age-appropriate tasks were used to assess 3- to 8-year-old children's liking, identification, and preference for a variety of odors, including that of exhaled cigarette smoke. Children whose parents smoke took longer to decide whether they liked the cigarette odor and were significantly more likely to prefer the odor of cigarette to the neutral and unfamiliar odor of green tea compared with children of nonsmokers. Among children of smokers, relative preferences for the cigarette odor were related to maternal mood disturbance and depression scores. These findings suggest that some early learning about cigarette smoke odor is based on sensory experiences at home and anchors it to the emotional context in which their mothers smoke.

Affect↗
PubMed2005

Genetic and environmental determinants of bitter perception and sweet preferences.

OBJECTIVE: Flavor is the primary dimension by which young children determine food acceptance. However, children are not merely miniature adults because sensory systems mature postnatally and their responses to certain tastes differ markedly from adults. Among these differences are heightened preferences for sweet-tasting and greater rejection of bitter-tasting foods. The present study tests the hypothesis that genetic variations in the newly discovered TAS2R38 taste gene as well as cultural differences are associated with differences in sensitivity to the bitter taste of propylthiouracil (PROP) and preferences for sucrose and sweet-tasting foods and beverages in children and adults. DESIGN: Genomic DNA was extracted from cheek cells of a racially and ethnically diverse sample of 143 children and their mothers. Alleles of the gene TAS2R38 were genotyped. Participants were grouped by the first variant site, denoted A49P, because the allele predicts a change from the amino acid alanine (A) to proline (P) at position 49. Henceforth, individuals who were homozygous for the bitter-insensitive allele are referred to as AA, those who were heterozygous for the bitter-insensitive allele are referred to as AP, and those who were homozygous for the bitter-sensitive allele are referred to as PP. Using identical procedures for children and mothers, PROP sensitivity and sucrose preferences were assessed by using forced-choice procedures that were embedded in the context of games that minimized the impact of language development and were sensitive to the cognitive limitations of pediatric populations. Participants were also asked about their preferences in cereals and beverages, and mothers completed a standardized questionnaire that measured various dimensions of their children's temperament. RESULTS: Genetic variation of the A49P allele influenced bitter perception in children and adults. However, the phenotype-genotype relationship was modified by age such that 64% of heterozygous children, but only 43% of the heterozygous mothers, were sensitive to the lowest concentration (56 micromoles/liter) of PROP. Genotypes at the TAS2R38 locus were significantly related to preferences for sucrose and for sweet-tasting beverages and foods such as cereals in children. AP and PP children preferred significantly higher concentrations of sucrose solutions than did AA children. They were also significantly less likely to include milk or water as 1 of their 2 favorite beverages (18.6% vs 40%) and were more likely to include carbonated beverages as 1 of their most preferred beverages (46.4% vs 28.9%). PP children liked cereals and beverages with a significantly higher sugar content. There were also significant main effects of race/ethnicity on preferences and food habits. As a group, black children liked cereals with a significantly higher sugar content than did white children, and they were also significantly more likely to report that they added sugar to their cereals. Unlike children, there was no correspondence between TAS2R38 genotypes and sweet preference in adults. Here, the effects of race/ethnicity were the strongest determinants, thus suggesting that cultural forces and experience may override this genotype effect on sweet preferences. Differences in taste experiences also affected mother-child interaction, especially when the 2 resided in different sensory worlds. That is, children who had 1 or 2 bitter-sensitive alleles, but whose mothers had none, were perceived by their mothers as being more emotional than children who had no bitter-sensitive alleles. CONCLUSION: Variations in a taste receptor gene accounted for a major portion of individual differences in PROP bitterness perception in both children and adults, as well as a portion of individual differences in preferences for sweet flavors in children but not in adults. These findings underscore the advantages of studying genotype effects on behavioral outcomes in children, especially as they relate to taste preferences because cultural forces may sometimes override the A49P genotypic effects in adults. New knowledge about the molecular basis of food likes and dislikes in children, a generation that will struggle with obesity and diabetes, may suggest strategies to overcome diet-induced diseases.

Adult↗
PubMed2004

Acute alcohol consumption disrupts the hormonal milieu of lactating women.

Despite the lack of scientific evidence to support the claim that alcohol is a galactagogue, lactating women have been advised to drink alcohol as an aid to lactation for centuries. To test the hypothesis that alcohol consumption affects the hormonal response in lactating women, we conducted a within-subjects design study in which 17 women consumed a 0.4 g/kg dose of alcohol in orange juice during one test session and an equal volume of orange juice during the other. Changes in plasma prolactin, oxytocin, and cortisol levels during and after breast stimulation, lactational performance, and mood states were compared under the two experimental conditions. Oxytocin levels significantly decreased, whereas prolactin levels and measures of sedation, dysphoria, and drunkenness significantly increased, during the immediate hours after alcohol consumption. Changes in oxytocin were related to measures of lactational performance such as milk yield and ejection latencies, whereas changes in prolactin were related to self-reported measures of drunkenness. Although alcohol consumption resulted in significantly higher cortisol when compared with the control condition, cortisol levels were not significantly correlated with any of the indices of lactational performance or self-reported drug effects. Moreover, cortisol levels steadily decreased on the control day, indicating that the procedures were not stressful to the subjects. In conclusion, recommending alcohol as an aid to lactation may be counterproductive. In the short term, mothers may be more relaxed, but the hormonal milieu underlying lactational performance is disrupted, and, in turn, the infant's milk supply is diminished.

Adult↗
PubMed2004

Social chemosignals from breastfeeding women increase sexual motivation.

Human pheromones, a type of social chemosignal, modulate endocrine function by regulating the timing of ovulation. In animals, pheromones not only regulate ovulation but also female reproductive motivation and behavior. There is no extant evidence that humans produce social chemosignals that affect human sexual motivation or reproductive behavior as occurs in other mammals. Here, we demonstrate that natural compounds collected from lactating women and their breastfeeding infants increased the sexual motivation of other women, measured as sexual desire and fantasies. Moreover, the manifestation of increased sexual motivation was different in women with a regular sexual partner. Those with a partner experienced enhanced sexual desire, whereas those without one had more sexual fantasies. These results are consistent with previous pheromonal effects on endocrine function, and warrant further study of these social chemosignals as candidates for pheromonal processes, including their effects on other aspects of motivation and behavior.

Adolescent↗
PubMed2004

Women's sexual experience during the menstrual cycle: identification of the sexual phase by noninvasive measurement of luteinizing hormone.

Imprecise measures of ovulation obscure the relationship between women's sexuality and the menstrual cycle, as does studying women with different contraceptive goals in different social contexts. Here we present a novel noninvasive method to precisely pinpoint the preovulatory surge of Luteinizing Hormone (LH), demarcating hormonally distinct cycle phases with greater than 95% reliability. Women were more sexually active on days prior to and including the preovulatory (LH) surge. This pattern was evident only when women initiated sexual activity and not when their partners did, indicating an increase in women's sexual motivation rather than attractiveness. A second study replicated the 6-day increase in sexual activity beginning 3 days before the LH surge, accompanied by stronger sexual desire and more sexual fantasies. We propose the term 'sexual phase' of the cycle, since follicular phase is over inclusive and ovulatory phase is not sufficient. These findings are striking because the women were avoiding pregnancy and were kept blind to the hypotheses, preventing expectation bias. The sexual phase was more robust in women with regular sexual partners, although the increase in sexual desire was just as great in nonpartnered women, who also reported feeling less lonely at this time. We use these results to evaluate potential neuroendocrine mechanisms underlying women's sexual motivation and activity.

Adult↗
PubMed2004

Effects of breastfeeding chemosignals on the human menstrual cycle.

BACKGROUND: To date, there has not been an investigation to determine whether lactating women and their infants influence the ovarian function of other women with whom they interact. METHODS: In a randomized, double-blind, placebo-controlled study of 47 nulliparous women, we utilized both within- and between-subjects controls to assess the effects of sustained exposure to breastfeeding compounds on menstrual cycle length, as well as characteristics of each phase of the ovarian cycle. RESULTS: Breastfeeding compounds modulated ovarian cycle length in comparison with the carrier control (0.01 < or = all P values < or = 0.05), disrupting the normal homeostatic regulation of cycle length and tripling its variance. Hence, women with long cycles stayed long and did not regress to the mode of 29 days and women with short cycles maintained short cycles. This effect was driven by changes in both the follicular and luteal phases of the cycle (0.01 < or = all P values < or = 0.04) and changed the timing of the pre-ovulatory surge of LH. CONCLUSIONS: Because compounds from lactating women and their infants modulated the ovarian cycles of women, as is seen in other mammals, they have the potential to function as pheromones, regulating fertility within groups of women.

Adult↗
PubMed2004

Flavor programming during infancy.

OBJECTIVE: Although individuals differ substantially in their flavor and food preferences, the source of such differences remains a mystery. The present experimental study was motivated by clinical observations that early experience with formulas establishes subsequent preferences. DESIGN: Infants whose parents had chosen to formula-feed them were randomized into 1 of 4 groups by the second week of life. One group was assigned to be fed a milk-based formula (Enfamil), whereas another was assigned to be fed (Nutramigen), a particularly unpleasant-tasting protein hydrolysate formula. The remaining groups were assigned to be fed Nutramigen for 3 months and Enfamil for 4 months; the timing of exposure differed between the groups. After 7 months of exposure, infants were videotaped on 3 separate days while feeding, in counterbalanced order, Enfamil, Nutramigen, and Alimentum, a novel hydrolysate formula. RESULTS: For each of the 4 interrelated measures of behavior (intake, duration of formula feeding, facial expressions, and mothers' judgments of infant acceptance), previous exposure to Nutramigen significantly enhanced subsequent acceptance of both Nutramigen and Alimentum. Seven months of exposure led to greater acceptance than did 3 months. CONCLUSIONS: The bases for clinical difficulties in introducing hydrolysate formulas during older infancy are clarified in this study. More broadly, variation in formula flavor provided a useful model for demonstrating experimentally the effects of long-term exposure differences on later acceptance. Such early variation, under more species-typical circumstances (eg, via exposure to different flavors in amniotic fluid and mothers' milk), may underlie individual differences in food acceptability throughout the life span.

Age Factors↗
PubMed2004

Advice given to women in Argentina about breast-feeding and the use of alcohol.

OBJECTIVE: To explore the types of advice that women in Argentina received from health professionals, family members, and friends about drinking alcoholic beverages and about alcohol usage during pregnancy and lactation. METHODS: In December 2001 and December 2002, structured interviews were conducted with a total of 167 women who were then breast-feeding or who had recently breast-fed their infant. Mothers were asked about the type of advice, if any, that they had received about the use of alcohol from health professionals and from family members and friends. Also included were questions related to the usage of the traditional Argentine beverage "mate" (an infusion widely consumed in South America that is prepared from the leaves of the Ilex paraguayensis plant) and the types of advice the women had received about breast-feeding and neonatal care in general. RESULTS: Of the 167 women studied, 96.4% of them reported that their physician had advised them to breast-feed their infant. In addition, 93.4% of the women said they had treated their infant's umbilical cord stump with alcohol. Fewer than half of the women (46.7%) reported that their physician had advised them about drinking alcoholic beverages during pregnancy, and even fewer (25.7%) received such advice during lactation. Family and friends were about equally likely to give advice about the consumption of alcoholic beverages during pregnancy (42.6%) and during lactation (47.9%). However, the type of advice changed, with the family and friends being significantly more likely to encourage drinking when the women were lactating than when they were pregnant (P < 0.001). Family members and friends also encouraged the drinking of mate to increase milk production. CONCLUSIONS: As in other cultures, in Argentina the belief exists that alcohol enhances lactation. However, the majority of women whom we interviewed had not been counseled by their health professional about the consumption of alcoholic beverages during pregnancy and lactation. There is a need for professional development strategies that will address women's awareness of the risks of alcohol consumption and alcohol usage.

Adult↗
PubMed2003

Modification of bitter taste in children.

The palatability of oral medications, many of which are quite bitter, plays an important role in achieving compliance in pediatric patients. We tested the hypothesis that the addition of a sodium salt to some, but not all, bitter tasting liquids enhances acceptance and reduces the perceived bitterness in 7- to 10-year-old children and their mothers. For both children and adults, sodium gluconate significantly suppressed the perceived bitterness and enhanced the acceptance of urea and caffeine whereas the reverse was true for another bitter stimulus, Tetralone. Because children preferred salted solutions more than did adults, these data suggest that the use of sodium salts may be an especially effective strategy for reducing the bitterness of some medicines and facilitating compliance among pediatric populations. However, based on sodium's differential ability to inhibit bitterness, as has been shown here with children and adults, clearly each drug of interest must be evaluated separately.

Administration, Oral↗
PubMed2003

Heightened sour preferences during childhood.

Basic research has revealed that the chemical sensory world of children is different from that of adults, as evidenced by their heightened preferences for sweet and salty tastes. However, little is known about the ontogeny of sour taste preferences, despite the growing market of extreme sour candies. The present study investigated whether the level of sourness most preferred in a food matrix and the ability to discriminate differences in sour intensity differed between 5- to 9-year-old children and their mothers, by using a rank-by-elimination procedure embedded in the context of a game. Mothers also completed a variety of questionnaires and children were asked several questions to assess whether children's temperament and food preferences and habits related to sour preferences. The results indicated that, although every mother and all but two of the children (92%) were able to rank the gelatins from most to least sour, more than one-third (35%) of the children, but virtually none of the adults, preferred the high levels of sour taste (0.25 M citric acid) in gelatin. Those children who preferred the extreme sour tastes were significantly less food neophobic (P < 0.05) and tended to experience a greater variety of fruits when compared with the remaining children (P = 0.11). Moreover, the children's preference for sour tastes generalized to other foods, such as candies and lemons, as reported by both children and mothers. These findings are the first experimental evidence to demonstrate that sour taste preferences are heightened during childhood and that such preferences are related to children's food habits and preferences. Further research is needed to unfold the relationship between the level of sour taste preferred and the actual consumption of sour-tasting foods and flavors in children.

Adult↗