Submitted to: Society of Psychophysiological Research
Publication Type: Abstract Only
Publication Acceptance Date: 6/25/2008
Publication Date: 1/15/2008
Citation: Pivik, R.T., Jing, H., Gilchrist, J.M., Badger, T.M. 2008. Resting heart rate in infants and toddlers: Variations associated with early infant diet and the omega 3 fatty acid DHA [abstract]. Psychophysiology. 45(S1):S118.
Interpretive Summary: This is a report based on our long-term Beginnings study which looks at how what healthy babies eat affects their development. We studied measures of resting heart rate from ages 3 months through 2 years in infants fed parent-selected diets in which a fatty acid (DHA) was naturally present (breast-milk), commercially added (milk- and soy-based formulas), or absent (a soy-based formula). Feeding groups were alike in length of gestation, birth weight and length, mother’s IQ, family socioeconomic status. Heart rate in infants receiving the DHA-free diet was higher than that in other diet groups. These findings suggest that early dietary DHA may affect heart rate control during and beyond infancy. The influence of this effect on later health and development warrants further study. In view of concerns about the safety of soy-formula on development, the absence of study effects specific to this formula is notable.
Technical Abstract: Although early postnatal nutrition can have long-term effects on developmental processes, the influence of infant diet on the maturation of cardiac development has not been documented. To study this relationship we recorded resting heart-rate (HR) in awake, healthy infants and toddlers exclusively breast fed (BF), or fed milk (MF) or soy formula with (SF+) or without (SF-) commercial DHA (decosahexaenoic acid) during infancy. Groups were recorded at 3 mo (n = 10), 6 mo (n = 11), 9 mo (n =9), 12 mo (n = 9), and 24 mo (n = 10). Artifact-free recordings were digitized and RR intervals determined and subjected to power spectral analyses. Data were analyzed using ANOVA procedures with post-hoc t-tests. Significant (p < .05) decreases in HR, and increases in HRV, LF (0.04-0.15 Hz) and HF (0.15-0.5 Hz) activity were observed for all groups across the study period. SF- infants showed higher HR, lower HRV, and lower LF and HF relative to comparison groups. Statistical differences were most prevalent between 6 and 12 months, but although significant differences were not present at 2 yrs, HR remained higher (5-7 %), and LF and HF measures lower (3-8% and 10-25%, respectively) in SF- compared to other feeding groups. Indications of decreased parasympathetic influence in SF- infants beyond weaning and reports of DHA-associated HR decreasing effects may suggest a role for DHA in programming cardiovascular development and regulation. It remains to be determined whether these diet-related early developmental differences in cardiac control have long–term behavioral effects.