From biology to behavior: a cross-disciplinary seminar series surrounding added sugar and low-calorie sweetener consumption.

INTRODUCTION: This report presents a synopsis of a three-part, cross-sector, seminar series held at the George Washington University (GWU) in Washington, DC from February-April, 2018. The overarching goal of the seminar series was to provide a neutral forum for diverse stakeholders to discuss and critically evaluate approaches to address added sugar intake, with a key focus on the role of low-calorie sweeteners (LCS). METHODS: During three seminars, twelve speakers from academic institutions, federal agencies, non-profit organizations, and the food and beverage industries participated in six interactive panel discussions to address: 1) Do Farm Bill Policies Impact Population Sugar Intake? 2) What is the Impact of Sugar-sweetened Beverage (SSB) Taxes on Health and Business? 3) Is Sugar Addictive? 4) Product Reformulation Efforts: Progress, Challenges, and Concerns? 5) Low-calorie Sweeteners: Helpful or Harmful, and 6) Are Novel Sweeteners a Plausible Solution? Discussion of each topic involved brief 15-minute presentations from the speakers, which were followed by a 25-minute panel discussion moderated by GWU faculty members and addressed questions generated by the audience. Sessions were designed to represent opposing views and stimulate meaningful debate. Given the provocative nature of the seminar series, attendee questions were gathered anonymously using Pigeonhole™, an interactive, online, question and answer platform. RESULTS: This report summarizes each presentation and recapitulates key perspectives offered by the speakers and moderators. CONCLUSIONS: The seminar series set the foundation for robust cross-sector dialogue necessary to inform meaningful future research, and ultimately, effective policies for lowering added sugar intakes.

Early rapid weight gain among formula-fed infants: Impact of formula type and maternal feeding styles.

BACKGROUND: What and how infants are fed are considered important determinants for the risk factor of early rapid gain weight. OBJECTIVES: We conducted secondary analyses on data from a randomized clinical trial, wherein infants randomized to feed cow milk formula had double the incidence of early rapid weight gain than those fed extensively hydrolyzed protein formula, to determine whether maternal feeding styles had independent effects or interactive effects with infant formula type on early rapid weight gain. METHODS: Anthropometry and feeding patterning (number of daily formula feeds) were measured monthly, and maternal feeding styles were measured at 0.5, 3.5, and 4.5 months. Longitudinal models were fitted using generalized estimating equations and separate logistic models conducted. RESULTS: The treatment groups did not differ in formula feeding patterning or in maternal feeding styles, which were stable across the first 4.5 months. Feeding styles had no significant effects on early rapid weight gain and did not interact with formula group. However, type of infant formula had a direct and independent impact on early rapid weight gain (P = 0.003). CONCLUSIONS: The type of infant formula had a differential impact on early rapid weight gain independent of maternal feeding style, highlighting the self-regulatory capabilities of infants.

Consistency in infants' behavioural signalling of satiation during bottle-feeding.

BACKGROUND: Understanding the dynamics of feeding is essential for preventing accelerated weight gain during infancy, a risk factor for obesity. OBJECTIVES: Because infants satiate on larger volumes of cow milk formula (CMF) than CMF enriched with the free amino acid glutamate (CMF + glu), we used this model system to determine whether infants displayed consistent behaviours despite satiating on lower volumes. METHODS: In this laboratory-based, within-subject experimental study of ≤4-month-old infants (n = 41) and their mothers, infants were videotaped while feeding to satiation CMF on one test day and CMF + glu on the other, in counterbalanced order. Each video-recording was analysed frame-by-frame for frequency and timing of behaviours. RESULTS: Infants' behaviours were consistent in types and frequency but were displayed sooner when feeding CMF + glu compared with CMF. The less responsive the mother's feeding style, the less consistent the infant displayed behaviours across the two formula meals (P = 0.05). Infants who spat up (a possible sign of overfeeding) consumed more formula (P = 0.01) and had less responsive mothers (P = 0.04) compared with the other infants. CONCLUSIONS: Infants are consistent in their behavioural displays during feeding at this developmental age. Regulation of intake and signalling of satiation during bottle-feeding are associated with formula composition and maternal feeding style.

The proof is in the pudding: children prefer lower fat but higher sugar than do mothers.

OBJECTIVE: Although there are established age-related differences in sweet preferences, it remains unknown whether children differ from mothers in their preference for and perception of fat (creaminess). We examined whether individual differences in sucrose and fat preferences and perception are related to age, genotype and lifestyle. SUBJECTS: Children 5-10 years-old (n=84) and their mothers (n=67) chose the concentration of sucrose and fat most preferred in pudding and sucrose most preferred in water using identical, two-alternative, forced-choice procedures, and ranked pudding samples for intensity of sweetness and creaminess. Subjects were also weighed and measured for height, as well as genotyped for a sweet-receptor gene (TAS1R3). RESULTS: Children preferred higher concentrations of sucrose in water (P=0.03) and in pudding (P=0.05) and lower concentrations of fat in pudding (P<0.01) than did mothers. Children and mothers were equally able to rank the intensity of different concentrations of fat (P=0.12) but not sucrose in pudding (P=0.01). Obese and lean children and mothers did not differ in preferences, but obese mothers were less able to correctly rank the concentration of fat in pudding than were lean mothers (P=0.03). Mothers who smoked preferred a higher concentration of sucrose than did those who never smoked (P<0.01). Individual differences in sweet preference were associated with genetic variation within the TAS1R3 gene in mothers but not children (P=0.04). CONCLUSION: Irrespective of genotype, children prefer higher concentrations of sugar but lower concentrations of fat in puddings than do their mothers. Thus, reduced-fat foods may be better accepted by children than adults.

Effects of breast pumping on the pharmacokinetics and pharmacodynamics of ethanol during lactation.

This study tested two hypotheses. First, that breast pumping contributes to the previously observed decrease in ethanol bioavailability in lactating women. Second, that the effects of breast pumping are more pronounced when ethanol is consumed after a meal. The within-subject factor was test condition (fed or fasted) and the between-subject factor was experimental group (pumped before, PB; pumped after, PA). Those randomly assigned to the PB group (N = 8) breast pumped 1 h before drinking, whereas those assigned to the PA group (N = 8) breast pumped 0.6 h after drinking. Pumping before drinking significantly decreased blood ethanol concentration (P < 0.05) and ethanol bioavailability (P = 0.05). Pumping after drinking sped up elimination (P = 0.008), attenuated ethanol-induced hypothermia (P = 0.002), and increased feelings of stimulation (P = 0.03). The effects were more pronounced when ethanol was consumed after a meal. Common neural/hormonal responses to food and suckling may contribute additive effects in altering the pharmacokinetics/pharmacodynamics of ethanol, and perhaps of other drugs, during lactation.

Prenatal and postnatal flavor learning by human infants.

BACKGROUND: Flavors from the mother's diet during pregnancy are transmitted to amniotic fluid and swallowed by the fetus. Consequently, the types of food eaten by women during pregnancy and, hence, the flavor principles of their culture may be experienced by the infants before their first exposure to solid foods. Some of these same flavors will later be experienced by infants in breast milk, a liquid that, like amniotic fluid, comprises flavors that directly reflect the foods, spices, and beverages eaten by the mother. The present study tested the hypothesis that experience with a flavor in amniotic fluid or breast milk modifies the infants' acceptance and enjoyment of similarly flavored foods at weaning. METHODS: Pregnant women who planned on breastfeeding their infants were randomly assigned to 1 of 3 groups. The women consumed either 300 mL of carrot juice or water for 4 days per week for 3 consecutive weeks during the last trimester of pregnancy and then again during the first 2 months of lactation. The mothers in 1 group drank carrot juice during pregnancy and water during lactation; mothers in a second group drank water during pregnancy and carrot juice during lactation, whereas those in the control group drank water during both pregnancy and lactation. Approximately 4 weeks after the mothers began complementing their infants' diet with cereal and before the infants had ever been fed foods or juices containing the flavor of carrots, the infants were videotaped as they fed, in counterbalanced order, cereal prepared with water during 1 test session and cereal prepared with carrot juice during another. Immediately after each session, the mothers rated their infants' enjoyment of the food on a 9-point scale. RESULTS: The results demonstrated that the infants who had exposure to the flavor of carrots in either amniotic fluid or breast milk behaved differently in response to that flavor in a food base than did nonexposed control infants. Specifically, previously exposed infants exhibited fewer negative facial expressions while feeding the carrot-flavored cereal compared with the plain cereal, whereas control infants whose mothers drank water during pregnancy and lactation exhibited no such difference. Moreover, those infants who were exposed to carrots prenatally were perceived by their mothers as enjoying the carrot-flavored cereal more compared with the plain cereal. Although these same tendencies were observed for the amount of cereal consumed and the length of the feeds, these findings were not statistically significant. CONCLUSIONS: Prenatal and early postnatal exposure to a flavor enhanced the infants' enjoyment of that flavor in solid foods during weaning. These very early flavor experiences may provide the foundation for cultural and ethnic differences in cuisine.

Regulation of milk intake after exposure to alcohol in mothers' milk.

OBJECTIVE: Contrary to the folklore which claims that drinking alcohol during lactation benefits both mother and infant, previous research in our laboratory revealed that breastfed infants consumed significantly less milk during the immediate hours after their mothers' consumption of an alcoholic beverage. Because breastfed infants are clearly capable of regulating milk intake, the present study tested the hypothesis that infants would compensate for the diminished milk intake if their mothers then refrained from drinking alcohol. METHODS: A within-subjects design that controlled for time of day was implemented because of the great individual and daily variation in both milk composition and intake. To this end, 12 exclusively breastfed infants and their mothers were tested on 2 days separated by 1 week. Each woman drank a 0.3 g/kg dose of alcohol in orange juice on one testing day and orange juice alone on the other; the order was counterbalanced. The infants' behaviors were monitored for the next 16 hr, the first 4 hr of monitoring on each test day occurred at the Monell Center. The infants fed on demand and immediately before and after each feeding, infants were weighed without a change in clothing. RESULTS: Consistent with previous findings, infants consumed significantly less milk during the 4 hr immediately after exposure to alcohol in mothers' milk compared with the control condition. Compensatory increases in intake were then observed during the 8 to 16 hr after exposure when mothers refrained from drinking alcohol. CONCLUSIONS: These findings demonstrate that short-term exposure to small amounts of alcohol in mothers' milk produces distinctive changes in the infants' patterns of feeding.

Flavor variety enhances food acceptance in formula-fed infants.

BACKGROUND: Research in humans and animal models suggests that acceptance of solid foods by infants during weaning is enhanced by early experiences with flavor variety. OBJECTIVE: We tested the hypotheses that the acceptance of novel foods by formula-fed infants could be facilitated by providing the infants with a variety of flavors at the time when beikost is first introduced and that, contrary to medical lore, infants who had previously consumed fruit would be less likely to reject vegetables when first introduced than would infants without such an experience. DESIGN: The infants' acceptance of a novel vegetable (puréed carrot) and a novel meat (puréed chicken) was evaluated after a 9-d exposure period in 3 groups of infants, some of whom had previously consumed fruit. During the home-exposure period, one group was fed only carrots, the target vegetable; a second group was fed only potatoes, a vegetable that differed in flavor from carrots; and a third group was fed a variety of vegetables that did not include carrots. RESULTS: Infants fed either carrots or a variety of vegetables, but not those fed potatoes, ate significantly more of the carrots after the exposure period. Exposure to a variety of vegetables also facilitated the acceptance of the novel food, puréed chicken, and daily experience with fruit enhanced the infants' initial acceptance of carrots. CONCLUSION: These findings are the first experimental evidence to indicate that exposure to a variety of flavors enhances acceptance of novel foods in human infants.

Sleep disturbances after acute exposure to alcohol in mothers' milk.

The results of previous research in our laboratory revealed that breast-fed infants experience significantly less active sleep after exposure to alcohol in their mothers' milk than do breast-fed infants not exposed to alcohol. The present study tested the hypothesis that infants would compensate for such reductions if their mothers then refrained from drinking alcohol. To this end, 23 breast-fed infants from 3 to 5 months of age and their mothers were tested on 2 days separated by 1 week. A small, computerized movement detector, an actigraph, was placed on the infants' left ankles to monitor sleep and activity patterning after which they were bottle fed mother's milk alone (control condition) on 1 test day and mother's milk containing 32 mg of ethanol per 100 ml--the average concentration detected in human milk after lactating women drank an acute dose (0.3 g/kg) of alcohol--on the other. The infants' behaviors were monitored for the next 24 h; the first 3.5 h of monitoring on each test day took place at the Monell Center. Consistent with previous findings, infants exhibited significantly less active sleep during the 3.5 h immediately after exposure to alcohol in mothers' milk compared with the control condition; the decrease in active sleep was observed in all but 4 of the infants tested. Compensatory increases in active sleep were then observed in the next 20.5 h, when mothers refrained from drinking alcohol. Although the mechanisms underlying the reduction in sleep remain to be elucidated, these findings demonstrate that short-term exposure to small amounts of alcohol in mothers' milk produces distinctive changes in the infants' sleep-wake patterning.

Children's hedonic response to the smell of alcohol: effects of parental drinking habits.

BACKGROUND: Previous research in our laboratory revealed that during the first year of life, infants who had more exposure to alcohol, as inferred from questionnaires about parental alcoholism and alcohol intake, mouthed an ethanol-scented toy more compared with less exposed infants. The present study focused on older children (3.8-6.0 years) to determine whether their hedonic response to the odor of alcohol was related to the drinking habits of their parents. METHODS: Age-appropriate, game-like tasks that were fun for children and minimized the impact of language development were used to examine their preferences and identification of a variety of odors, one of which was beer. RESULTS: The children's preference for the odor of beer varied as a function of the escape drinking of their mothers alone or both parents. That is, children who lived in a household in which one or both parents drank alcohol to escape were significantly more likely to dislike the odor bottle that contained alcohol when compared with children whose parents did not drink to escape. This difference between the groups was odor specific. Additional analyses also revealed that the fathers of children who rejected the beer odor reported drinking significantly more than the fathers of those who liked the odor. CONCLUSIONS: These findings suggest that some early learning about alcohol is based on sensory experiences and anchor it to children's experiences at home and the emotional context in which their parents experience alcohol.

Short-term influence of breastfeeding on the infants' interaction with the environment.

The present study tested the hypothesis that around the age of weaning, human infants are more interactive with their environment immediately after breastfeeding. To this aim, we assessed 4- to 6-month-old infants' responsiveness to a rotating, musical mobile before breastfeeding on one test day, and after breastfeeding on another. Thirteen infants, fitted with miniature movement detectors on both their left leg and wrist, were videotaped for 4 consecutive min during which the mobile was alternately switched on and off in 1-min intervals. Although the infants showed no significant differences in limb activity as a function of the timing of a breastfeed, they looked at the mobile significantly longer when tested after breastfeeding. This finding suggests that breastfeeding has a substantial effect on 4- to 6-month-old infants' attentiveness to and interaction with their environment.

Experience with a flavor in mother's milk modifies the infant's acceptance of flavored cereal.

The present series of studies aimed to investigate whether experience with a flavor in mothers' milk modifies the infants' acceptance of similarly flavored foods at weaning. First, we established, using methods developed in our laboratory, that the ingestion of carrot juice by lactating women produced a sensory change in their milk approximately 2 to 3 hr after the ingestion of the beverage. Second, we randomly formed two groups of breast-fed infants who had been fed cereal for a few weeks but had only experienced cereal prepared with water. Their mothers were asked to consume one of two types of beverages (i.e., carrot juice, water) during the exposure period. Each mother was observed feeding her infant cereal during four test sessions. The first two sessions occurred during the 2 days before the exposure period; in counterbalanced order, infants were fed cereal prepared with water on 1 testing day and cereal prepared with carrot juice on the other. These two test sessions were then repeated following the exposure period. The results demonstrated that the infants who had exposure to the flavor of carrots in their mothers' milk during the exposure period consumed less of the carrot-flavored cereal and spent less time feeding when compared to the control infants whose mothers consumed the water. This may be a form of sensory-specific satiety such that the infants become less responsive to a flavor that they have been extensively exposed to in the very recent past.

Short-term effects of maternal alcohol consumption on lactational performance.

Previous research demonstrated that breast-feeding infants consumed significantly less milk during the immediate hours after their mothers consumed an acute dose of alcohol when compared with a nonalcoholic beverage. The present study tested the hypothesis that maternal alcohol consumption decreases the amount of milk available to the infant and alters milk composition in the short term. To this aim, 22 lactating women were tested on 2 days separated by 1 week; the women reported that they drank very little during pregnancy, but significantly increased alcohol intake during lactation. Each woman drank a 0.3 g/kg dose of alcohol in orange juice on one testing day and orange juice alone on the other; the order was counterbalanced. Immediately before drinking the beverage (baseline) and 2 hr after (postconsumption), women expressed their milk by using an electric breast pump until no milk had been secreted from either breast for 5 min. Although there was no difference in the energy content of the milk, maternal alcohol consumption slightly, but significantly, reduced the amount of milk produced by the lactating mother. These findings underscore the importance of determining whether and when infants compensate for the reductions in intake experienced at the breast following maternal alcohol consumption and how such changes impact on mother-infant interaction.

Early flavor experiences: research update.

Anyone who has observed infants for any period of time can testify to the intense activity occurring in and around their mouths--the primary site for learning in the first few months of life. Before they are even able to crawl, infants have learned much about their new sensory world. Though recent research we have begun to explore the impact of these early experiences on infants' acceptance of solid foods and how they explore objects in their environment. We have also begun to focus on the sensory experiences of the formula-fed infant, in particular, how their responses to particular formulas, which are extremely unpalatable to older children and adults, change during infancy. This is a relatively new and exciting area of study, with much research yet to be done. It is clear, however, that infants are not passive receptacles for flavored foods. Parents who offer a variety of foods will provide both a nutritious, well-balanced diet, as well as an opportunity for their children's own personal preferences to develop.

Effects of exposure to alcohol in mother's milk on infant sleep.

OBJECTIVE: To test the hypothesis that exposure to alcohol in breast milk affects infants' sleep and activity levels in the short term. METHODS: Thirteen lactating women and their infants were tested on 2 days, separated by an interval of 1 week. On each testing day, the mother expressed 100 mL of milk, while a small, computerized movement detector called an actigraph was placed on the infant's left leg to monitor sleep and activity patterning. After the actigraph had been in place for approximately 15 minutes, the infants ingested their mother's breast milk flavored with alcohol (32 mg) on one testing day and breast milk alone on the other. The infants' behaviors were monitored for the next 3.5 hours. RESULTS: The infants spent significantly less time sleeping during the 3.5 hours after consuming the alcohol-flavored milk (78.2 minutes compared with 56.8 minutes after feeding alcohol in breast milk). This reduction was apparently attributable to a shortening in the longest sleeping bout (34.5 compared with 56.7 minutes for sleeping after breast milk alone) and the amount of time spent in active sleep (25.8 minutes compared with 44.2 minutes after breast milk alone); the decrease in active sleep was observed in all but 2 of the 13 infants tested. CONCLUSIONS: Although the mechanisms underlying the reduction in sleep remain to be elucidated, this study shows that short-term exposure to small amounts of alcohol in breast milk produces distinctive changes in the infant's sleep-wake patterning.

Infants' exploration of scented toys: effects of prior experiences.

To evaluate breastfed infants' responses to scented objects, we videotaped the facial and bodily reactions of sixty-three infants as they explored, in succession, three toys that were identical in appearance but different in their characteristic odor. Two of the toys were scented with odorants previously shown to be transmitted to human milk, one with ethanol and the other with vanilla, whereas the third toy was unscented. Each videotape was subjected to frame-by-frame analysis to measure a variety of behaviors that are considered either to be exploratory in nature in that they lead to perceptual information about the object or to reflect the infants' hedonic reaction. Analyses of these behaviors revealed that the infants looked more and vocalized less in the presence of the vanilla-scented toy and spent less time manipulating the ethanol-scented toy when compared with the unscented toy. Moreover, differential exposure to the odors of ethanol and vanilla, as indicated by differential consumption of alcohol by a parent or use of vanilla-scented product by the mother, was related to differential responses to these odors. These findings suggest that human infants are able to detect and retain information about the chemical features of their environment.

Infants' suckling responses to the flavor of alcohol in mothers' milk.

Contrary to medical folklore, previous research has demonstrated that alcohol consumption by lactating women diminished milk intake by their infants during breast feeding. To determine whether this decrease in milk consumption was due to the infants responding to the altered flavor of the milk that also resulted, we evaluated the infants' intake and sucking responses to alcohol-flavored human milk outside of the context of breast feeding, thereby separating the changes due to the infants response to the flavor from any other changes that could also result from acute maternal alcohol consumption such as alterations in milk ejection or the composition of milk. The testing procedure consisted of a two-bottle preference test that was composed of four, 60-sec trials in which the mother's milk flavored with alcohol was alternated with the mother's milk alone in an ABBA or BAAB design. Attached to the nipple of each bottle was a transducer that responded to pressure changes produced by the infants' suckling. There was no suppression of sucking or intake in response to the ethanol-flavored milk. Rather, the infants consumed significantly more and sucked more frequently when drinking the alcohol-flavored milk compared with the unaltered milk. That experience with the flavor of alcohol in mothers' milk modified the infants' responses to alcohol flavor is suggested by the relationship between the reported frequency of mothers' drinking during lactation and the infants' rhythm and frequency of sucking when feeding the alcohol-flavored milk. These findings indicate that infants can readily detect the flavor of alcohol in mother's milk but that the decrease in consumption at the breast after maternal alcohol consumption is apparently not due to the infants rejecting the flavor of alcohol in their mothers' milk.

Mothers' milk enhances the acceptance of cereal during weaning.

Although baby food manufacturers and child care manuals often advise parents to prepare their infant's cereal with water or either mother's milk or formula, depending on the feeding regimen of the infant, little is known about the infant's acceptance of differently flavored cereals. The present study demonstrates that breast-fed infants, who had been fed cereal for approximately 2 wk but had experienced cereal prepared only with water, consumed more of the cereal-mother's milk mixture compared with cereal water mixture and displayed a series of behaviors signaling their preferences for the former. Moreover, the infants' willingness to accept the flavored cereal is correlated with their mothers' reported willingness to try novel foods and flavors.