William C. Heird, M.D.
Professor of Pediatrics, Baylor College of Medicine
Fatty acid and Amino Acid Requirements of Infants
Previous research related to the needs for specific fatty acids during infancy has helped establish that both term and preterm infants can convert the 18-carbon precursors of n-6 and n-3 fatty acids to longer chain, more unsaturated fatty acids and has helped clarify the metabolic steps involved. This research also showed that a higher intake of alpha-linolenic acid (3.2 vs. 0.4% of total fatty acids), the 18-carbon precursor of the n-3 fatty acids, resulted, as expected, in higher plasma lipid levels of docosahexaenoic acid (DHA) and other long chain, polyunsaturated n-3 fatty acids but plasma lipid levels of DHA remained below those of breastfed infants and infants fed DHA-supplemented formulas suggesting that DHA is an essential nutrient for the infant. Current clinical studies focus on the role of this fatty acid in infant development, including long-term effects. Current animal studies focus on the relationship between plasma lipid and brain DHA as well as transport of this fatty acid from plasma to brain.
Research concerning amino acid needs of infants focuses on the effect of protein intake on catch-up growth and neurodevelopment of preterm infants. A specific hypothesis is that there is a finite period during which these infants can utilize protein for growth. Another interest concerns the need for tyrosine by infants who are dependent on parenterally delivered nutrients. Although both term and preterm infants can convert phenylalanine to tyrosine, the extent of this conversion appears to be inadequate to meet the requirement for both parenteral phenylalanine and tyrosine. A specific hypothesis is that available tyrosine is used preferentially by stressed infants and older children for synthesis of acute phase proteins and that failure to provide sufficient tyrosine necessitates breakdown of endogenous proteins and also inhibits whole body protein synthesis. This research is being pursued in collaboration with Dr. Farook Jahoor (see description of his research interests).
Both areas of research utilize state-of-the-art stable isotope and mass spectroscopy techniques, standard anthropometry and nutrient balance techniques as well as collaboration with development psychologists at the Meyer Center for Developmental Pediatrics.
Heird, WC. Progress in promoting breast-feeding, combating malnutrition, and composition and use of infant formula, 1981-2006. J Nutr.137:499S-502S, 2007.
Reuter SD, O’Donovan DJ, Hegemier SE, Smith EO, Heird WC, Fernandes CJ. Urinary F2-isoprostanes are poor prognostic indicators for the development of bronchopulmonary dysplasia. J Perinatol. 27:303-306, 2007.
Voigt RG, Llorente A, Jensen, CL, Fraley JK, Barbaresi WJ, Heird WC. Comparison of the validity of direct pediatric developmental evaluation versus developmental screening by parent report. Clin Pediatr. 46:523-529, 2007.
Llorente AM, Voigt RG, Jensen CL, Berretta MC, Fraley J, Heird WC. Performance on a visual sustained attention and discrimination task is associated with urinary excretion of norepinephrine metabolite in children with attention-deficit/hyperactivity disorder (AD/HD). Clin Neuropsychol. 20:133-44, 2006.
Heird WC, Ziegler P, Reidy K, Briefel R. Current electrolyte intakes of infants and toddlers. J Am Diet Assoc.106(Suppl):S43-S51, 2006.
Chang BH, Li L, Taniguchi PA, Nannegari V, Heird WC, Chan L. Protection against fatty liver but normal adipogenesis in mice lacking adipose differentiation-related protein. Mol Cell Biol. 26:1063-76, 2006.
Heird WC. The role of essential fatty acids in development. In: Hay WW Jr., Thureen PJ (eds). Neonatal Nutrition and Metabolism, 2nd ed. New York. Cambridge University Press, 2006;13:147-60.
Heird WC. Intravenous feeding. In: Hay WW Jr., Thureen PJ (eds). Neonatal Nutrition and Metabolism, 2nd ed. New York. Cambridge University Press, 2006;20:312-331.
Heird WC. Infant Nutrition. In: Bowman BA, Russell RM (eds). Present Knowledge in Nutrition, 9th ed., Vol II. Washington, DC, International Life Sciences Institute (ILSI) Press, 2006; pp 544-556.
Heird WC. Nutrient requirements of term and preterm infants. In: Burg FD, Ingelfinger JR, Polin RA, Gershon AA (eds). Current Pediatric Therapy 18th ed.. Philadelphia, Elsevier Inc., 2006; 66-71.
Heird WC, Voigt RG. Nutritional influences on infant development. In: Bhatia J (ed). From Preconception to Infancy. New York. Marcel Dekker, Inc., 2005; pp153-164.
Heird WC. Infancy and childhood. In: Shils ME, Ross AC, Shike M, Caballero B,
Weinsler RL & Cousins RJ (eds). Modern Nutrition in Health and Disease, 10th ed.
Baltimore Lippincott Williams & Wilkins, 2005; pp797-817.
Cooper A, Heird WC. Nutritional management of infants and children with specific diseases and other conditions. In: Shils ME, Ross AC, Shike M, Caballero B, Weinsler RL & Cousins RJ (eds). Modern Nutrition in Health and Disease, 10th ed. Baltimore Lippincott Williams & Wilkins, 2005; 991-1003.
Butte NF, Heird WC. Knowing what’s best for baby to eat. Agriculture Research Magazine. 53:7, 2005.
Heird WC. Biochemical homeostasis and body growth are reliable end points in clinical nutrition trials. Proc Nutr Soc. 64:297-303, 2005.
Heird WC. Biochemical homeostasis and body growth are reliable end points in clinical nutrition trials. Proc Nutr Soc. 64(3):297-303, 2005.
Jensen CL, Voigt RG, Prager TC, Zou YL, Fraley JK, Rozelle JC, Turcich MR, Llorente AM, Anderson RE, Heird WC. Effects of maternal docosahexaenoic acid intake on visual function and neurodevelopment in breastfed term infants. Am J Clin Nutr. 82(1):125-132, 2005.
Thureen P, Heird WC. Protein and energy requirements of the preterm/low birthweight (LBW) infant. Pediatr Res. 57(5 Pt 2):95R-98R, 2005.
Heird WC, Lapillonne A. The role of essential fatty acids in development. Annu Rev Nutr. 25:549-571, 2005.
Heird WC. Taurine in neonatal nutrition--revisited. Arch Dis Child Fetal Neonatal Ed. 89(6):F473-F474, 2004.
Heird WC, Kashyap S. Protein and Amino Acid Metabolism and Requirements. In: Polin RA, Fox WW, Abman SH (eds). Fetal and Neonatal Physiology. 3rd ed. Philadelphia. W.B. Saunders, 2004; pp 527-539.
Reid M, Forrester T, Badaloo A, Heird WC, Jahoor F. Supplementation with aromatic amino acids improves leucine kinetics but not aromatic amino acid kinetics in infants with infection, severe malnutrition, and edema. J Nutr.134(11):3004-3010, 2004.
Nicklas TA, Hampl JS, Taylor CA, Thompson VJ, Heird WC. Monounsaturated fatty acid intake by children and adults: temporal trends and demographic differences. Nutr Rev. 62(4):132-141, 2004.
Lapillonne A, Clarke SD, Heird WC. Polyunsaturated fatty acids and gene expression. Curr Opin Clin Nutr Metab Care. 7(2):151-156, 2004.
Butte N, Cobb K, Dwyer J, Graney L, Heird W, Rickard K; American Dietetic Association; Gerber Products Company. The Start Healthy Feeding Guidelines for Infants and Toddlers. J Am Diet Assoc. 104(3):442-454, 2004.
Agostoni C, Heird W. Long chain polyunsaturated fatty acids in chronic childhood disorders: panacea, promising, or placebo. J Pediatr Gastroenterol Nutr. 38(1):2-3, 2004.
Heird WC and Kashyap S. Protein and amino acid metabolism requirements. In: Polin RA, Fox WW, Abman SH (eds). Fetal & Neonatal Physiology, 3rd ed. Philadelphia , W.B. Saunders. 2003, pp 527-539.
Lapillonne A, Clarke SD, Heird WC. Plausible mechanisms for effects of long-chain polyunsaturated fatty acids on growth. J Pediatr. 143(4 Suppl):S9-S16, 2003.
Jahoor F, Abramson S, Heird WC. The protein metabolic response to HIV infection in young children. Am J Clin Nutr. 78(1):182-189, 2003.
Voigt RG, Brown FR 3rd, Fraley JK, Llorente AM, Rozelle J, Turcich M, Jensen CL, Heird WC. Concurrent and predictive validity of the cognitive adaptive test/clinical linguistic and auditory milestone scale (CAT/CLAMS) and the Mental Developmental Index of the Bayley Scales of Infant Development. Clin Pediatr. 42(5):427-432, 2003.
Llorente AM, Jensen CL, Voigt RG, Fraley JK, Berretta MC, Heird WC. Effect of maternal docosahexaenoic acid supplementation on postpartum depression and information processing. Am J Obstet Gynecol. 188(5):1348-1353, 2003.
Ding ST, Lapillonne A, Heird WC, Mersmann HJ. Dietary fat has minimal effects on fatty acid metabolism transcript concentrations in pigs. J Anim Sci. 81(2):423-431, 2003
Heird WC. The role of polyunsaturated fatty acids in term and preterm infants and breastfeeding mothers. In: Schanler RJ (ed). Pediatric Clinics of North America. Breastfeeding 2001, Part I, The Evidence for Breastfeeding. Philadelphia , WB Saunders, 48:173-88, 2001;.
Heird WC. Early use of parenteral amino acids. In: Nutrition of the Very Low Birthweight Infant. EE Ziegler (ed). Nestlé Nutrition Workshop Series, vol 43, Lippincott Williams & Wilkins, New York, 53-68, 1999.
Jahoor F, Gazzard B, Phillips G, Heird, W, Sharpstone D, Delrosario M, Frazer ME, Smith R, and Jackson A. The acute-phase protein response to human immunodeficiency virus infection in human subjects. Am J Physiol, 276 (Endocrinol Metab 39): E1092-E1098, 1999.