These findings are the first experimental evidence to indicate that exposure to a variety of flavors enhances acceptance of novel foods in human infants.

ABSTRACT.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 ϳ15 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. Pediatrics 1998;101(5). URL: http://www.pediatrics.org/cgi/content/full/101/5/e2; alcohol, lactation, sleep, activity, development, infant behavior. ABBREVIATION. NS, not significant. T he notion that infants can be influenced by components in their mothers' breast milk has a rich, long history.1 Physicians in the 18th century often would treat the infants' ailments by prescribing certain diets to the mother or wet nurse. 2 That such practices continue in more modern times is evident in the medical lore that recommends that nursing mothers drink an occasional alcoholic beverage, preferably before the evening feeding, to alleviate and sedate their fussy infants. 3,4 No experimental evidence supports this recommendation, although a previous study on the effects of maternal alcohol consumption on the feeding behaviors of breastfed infants reported that the infants' patterning of sleeping, as determined from logs completed by mothers, indeed was altered in the short term. 5Despite this lore, the question of whether occasional exposure to alcohol in breast milk can affect the infant continues to generate much speculation in the medical community.6,7 Because alcohol is excreted to a limited extent in breast milk, 5,8,9 occasional exposure often is considered insignificant, 8,10 except in such rare cases of intoxication when the mothers of breastfeeding infants drank quite heavily 11,12 or when infants were inadvertently fed large amounts of alcohol in a bottle. 13 Moreover, an epidemiologic study 14 found no significant difference in the ...

Individual dams and their litters were observed from Days 14-22 in a seminatural environment consisting of a nestbox attached to a larger, open field in which powdered chow was available. Ambient temperature in the field was either warm (30"C), moderate (21"C), or cold (10°C); nest temperature was always moderate. Behavior was monitored 12 hr/day by time-lapse video recording. The pups' egressions into the field and onset of independent feeding were temperature-related: Weaning was earliest in the warmth and increasingly late with decreasing ambient temperature. Among subjects in the cold condition, there was a positive correlation between duration in the field and duration feeding. Pup growth was unaffected by the temperature regimes. Environmental temperature has emerged as a determinant for early nest egressions and weaning onset.

Twenty-day-old litters and their dams were observed in seminatural habitats consisting of a nest compartment and adjacent open field that contained powdered rat chow. It was found that pups displayed marked bursts of activity after suckling. Independent feeding reliably followed nursing bout termination (Experiment 1). Nipple withdrawal, with or without milk transfer, induced behavioral arousal whereas withdrawal of thermotactile and conspecific odor cues did not (Experiments 2-3). Increased thermogenesis was observed following milk transfer (Experiment 4). Finally, preweanling pups (10- to 12-day-olds) also displayed postsuckling arousal within the confines of the nest; full locomotor expression of this arousal was not evident until weaning age (Experiment 5). It was concluded that postsuckling arousal in weanlings functions to stimulate activities performed away from the nest and suckling, propelling pups into the field where feeding begins.

Weanling Sprague Dawley rat pups (Rattus norvegicus) selected between 2 safe palatable diets in concordance with the preferences of either an adult or a juvenile conspecific model (Experiment 1). Nevertheless, weanlings chose to feed more in the vicinity of an adult than in the vicinity of a juvenile, thus fulfilling the prediction of an adaptive feeding strategy (Experiment 2). The weanlings' bias for feeding in the vicinity of an adult was eliminated by increasing the magnitude of pup stimulus to 3 pups (Experiment 3). Thus, weanlings do not possess a specialization rendering them more sensitive to adults than to pups as models for diet selection. By responding to stimulus magnitude, weanlings are more likely to feed with adult conspecifics, choose foods used by them, and derive the benefits correlated with the adults' successful feeding habits.