Submitted to: Federation of American Societies for Experimental Biology Conference
Publication Type: Abstract Only
Publication Acceptance Date: 11/15/2007
Publication Date: 4/28/2007
Citation: Pivik, R.T., Jing, H., Gilchrist, J.M., Badger, T.M. 2007. Infant diet and cardiovascular reactivity during the first year of life [abstract]. The FASEB Journal. 21(5):A322.
Interpretive Summary: The maturation of heart rate control is important for later behavioral self-regulation and learning. The influence of infant diet on this development has not been studied. We recorded heart rate reactions during the first year of life to sounds that were either brief and loud or longer and less intense in infants who were breast fed or fed milk- or soy-based formula. This is a frequently used test of the central nervous system function and development. At 3 months, breast-fed infants were more reactive than bottle-fed infants. After 3 months, all groups showed a similar slowing of heart rate to both kinds of sounds, with greater slowing to loud sounds. These responses reflect the development of processes related to attention in infants. Whether the early differences that were seen have long-term behavioral effects will be determined as this longitudinal study progresses.
Technical Abstract: The postnatal maturation of cardiac control and reactivity has implications for later behavioral self regulation and information processing. The influence of infant diet on heart-rate (HR) responses to acoustic stimuli were evaluated in awake healthy full-term infants exclusively breast fed (BF; n = 87), or fed milk (MF; n = 87) or soy formula (SF; n = 69). At ages 3, 6, 9 and 12 months startle stimuli [1000 Hz, 105dB, 50 ms] were presented with and without a preceding tone (1000 Hz, 75 dB, 2 sec; 4 trials each, inter-trial intervals less then/equal to 25 sec). Artifact-free recordings were digitized (1000 Hz), inter-beat intervals determined, interpolated and downsampled at 5 Hz. Data (2 sec pre-, 4 sec post-startle stimulus) were analyzed using ANOVAs with post-hoc t-tests. There was marked within- and between-group response variability across this developmental period. For all groups after 3 months HR deceleration was present to both stimuli (p < .01) and was greatest to pre-conditioned startle stimuli (p < .01). BF infants were more reactive than bottle-fed infants at 3 months (p<.05), but group effects at later ages were non-significant. These are preliminary data from a longitudinal prospective study of the effects of infant feeding on cardiovascular activity related to child behavior and the long-term behavioral significance of these early diet-related differences is unknown.