The effect of diet, usual (44 +/- 4% energy as fat), high-fat (49 +/- 4% energy as fat), and moderate-fat (33 +/- 2% energy as fat), on gastric function (lipase and pepsin activities, pH, emptying rate) and intragastric digestion of fat were assessed in six children with cystic fibrosis. Fasting and postprandial activity of digestive enzymes, gastric pH, and gastric volume measured before, during, and after 120 min of feeding did not differ significantly as a function of fat intake. Postprandial gastric lipase output (units per kilogram of body weight) during usual, moderate-fat, and high-fat diets was close to or higher than (38.
View Article and Find Full Text PDFIn the human stomach, gastric lipase hydrolyzes only 10 to 30% of ingested triacylglycerols because of an inhibition process induced by the long chain free fatty acids generated, which are mostly protonated at gastric pH. The aim of this work was to elucidate the mechanisms by which free fatty acids inhibit further hydrolysis. In vitro experiments examined gastric lipolysis of differently sized phospholipid-triolein emulsions by human gastric juice or purified human gastric lipase, under close to physiological conditions.
View Article and Find Full Text PDFGastric proteolysis is assumed to be low in the newborn (Britton & Koldovsky 1989). Postprandial pepsin output is significantly lower in preterm infants than adults, 589 vs. 3352U/kg, respectively (Armand et al.
View Article and Find Full Text PDFLong-chain polyunsaturated fatty acids (LC-PUFA) accretion (essential for growth and neural development) was studied from late fetal throughout weaning age in the ferret, a species with maternal LC-PUFA sufficiency during pregnancy and lactation. The data show that a) accretion rate of LC-PUFA is rapid during early postnatal development, b) milk LC-PUFA decrease during lactation, c) adipose tissue LC-PUFA level is directly related to milk LC-PUFA level, while accretion in brain and liver exceeds dietary intake, d) accretion of arachidonic acid occurs earlier than docosahexaenoic acid, suggesting earlier development of n6-fatty acid endogenous synthesis.
View Article and Find Full Text PDFThe MUC1 mucin, lactadherin, and butyrophilin are 3 major components of the human milk fat globule membrane. The mucin inhibits binding of S-fimbriated Escherichia coli to buccal epithelial cells, and lactadherin prevents symptomatic rotavirus infection in breast-fed infants. Butyrophilin has been suggested to be a structural component of the human milk fat globule (HMFG) membrane and to have receptor functions, but has no known anti-infective activity.
View Article and Find Full Text PDFThis article reviews the bioactive components of human milk. Special emphasis is given to immune and nonimmune protective function of major and minor nutrients in human milk. Immune modulating components, such as cytokines, nucleotides, hormones, and growth factors, are discussed.
View Article and Find Full Text PDFHuman milk contains many components that protect the newborn against infection at a time when the infant's own defense mechanisms are poorly developed. Fat is one of the major nutrients in human milk. The fat is contained within milk fat globules composed of a core of triglyceride and a membrane consisting of phospholipids, cholesterol, proteins, and glycoproteins.
View Article and Find Full Text PDFHuman milk fat globule (HMFG) glycoproteins can prevent infections by microorganisms in breast-fed infants; the MUC-1 mucin inhibits binding of S-fimbriated Escherichia coli to buccal mucosa, and lactadherin may prevent symptomatic rotavirus infections. In this study, the survival of these HMFG glycoproteins in the stomach of human milk-fed preterm infants (gestational age = 27.5 +/- 0.
View Article and Find Full Text PDFFerret lactating mammary gland bile salt-dependent lipase (BSDL, EC 3.1.1.
View Article and Find Full Text PDFBiol Neonate
October 1998
Breast-feeding protects the newborn against infectious diseases in developing as well as in industrialized countries. Protection is conferred against gastrointestinal and respiratory tract diseases as well as against otitis media. This protection provided by specific (antibody dependent) and broad, nonspecific protective factors in human milk (proteins, glycoproteins, and lipids) is associated with lower global morbidity and mortality of breast-fed infants as compared with formula-fed infants.
View Article and Find Full Text PDFHuman milk provides the infant with protection against infectious diseases. This protection is conferred through several mechanisms: specific antibody targeted protection against pathogens in the infant's environment (through milk IgA, IgG, and IgM) and broad-spectrum, nonspecific protection provided through several distinct mechanisms. These are: bactericidal effects (lactoferrin), bacteriostatic action (lactoferrin, lysozyme), lysis of microorganisms (lysozyme), antiviral effects (lactoferrin, products of milk fat digestion), antiprotozoan activity (free fatty acids produced during gastric and intestinal digestion of milk fat), and ligand action (inhibition of Helicobacter pylori adhesion to gastric mucosa by kappa-casein).
View Article and Find Full Text PDFNonimmunological components in human milk can protect breast-fed infants against infection by microorganisms. The structural and functional characteristics of four such components are discussed. The mucin inhibits binding of S-fimbriated Escherichia coli to bucal epithelial cells; lactadherin prevents symptomatic rotavirus-induced infection; glycoaminoglycans inhibit binding of human immunodeficiency virus gp120 to its host cell CD4 receptor, and oligosaccharides provide protection against several pathogens and their toxins.
View Article and Find Full Text PDFLong-chain polyunsaturated fatty acids (LC-PUFA) are essential for normal development. Fetal accretion of LC-PUFA occurs during the last trimester of gestation; therefore, premature infants are born with minimal LC-PUFA reserves. Recent studies indicate that the newborn can synthesize LC-PUFA from essential fatty acid precursors; however, the extent of de novo synthesis remains to be established.
View Article and Find Full Text PDFMilk fatty acids, including the polyunsaturated long chain fatty acids essential for retinal function and brain development, are not affected by pasteurization (62.5 degrees C for 30 min). Milk lipases are completely destroyed by pasteurization, whereas amylase lost only 15% of initial activity.
View Article and Find Full Text PDFJ Pediatr Gastroenterol Nutr
February 1998
Background: Gastric lipase has an important compensatory function in neonatal fat digestion. The activity level of pepsin and its role in protein digestion is less well understood. We have, therefore, studied the ontogeny of lipase and pepsin in the ferret, a species with a neonatal fat digestion pattern similar to that of humans.
View Article and Find Full Text PDFJ Pediatr Gastroenterol Nutr
January 1997
Background: Women who return to work outside of the home while still breastfeeding must often store the expressed milk at less than optimal temperatures. Human milk provides digestive enzymes (amylase and lipase) that compensate in the newborn for immature pancreatic function.
Methods: We have assessed the stability of amylase and bile salt-dependent lipase after storage for 1-24 h at 15, 25, and 38 degrees C.
Most of the major progress in understanding the unique and complex features of human breast milk has emerged in just the past 2 decades. Since the late 1970s, key research has examined such aspects as the composition of breast milk, effects of maternal and environmental factors on human milk, and the effect of human milk on the infant, including the protection against disease that breast milk can confer on the newborn. The composition of human breast milk includes growth factors, hormones, enzymes, and other substances that are immune-protective and foster proper growth and nutrition in the newborn.
View Article and Find Full Text PDFThe effect of diet, human milk or formula, on gastric function (lipase and pepsin activity, pH, and volume) and intragastric digestion of fat was assessed in 28 appropriate for gestational age preterm infants (gestational age, 28.9 +/- 1.4, 29.
View Article and Find Full Text PDFThe amount of mRNA hybridizing to bile salt-dependent lipase and to colipase-dependent lipase probes as well as their translation into active proteins were quantified in the adult and newborn pancreas and lactating mammary gland from the ferret, a species whose milk, similar to that of the human, has bile salt-dependent lipase. The concentration of colipase-dependent lipase mRNA correlated with the amount of activity found in the adult and newborn pancreas, whereas neither mRNA nor activity of this enzyme was detected in the kit pancreas or in the lactating mammary gland. These data indicate that colipase-dependent lipase is actually expressed in adult pancreas and might represent the main lipolytic system in the adult.
View Article and Find Full Text PDFAlthough the various aspects of digestion in the newborn have been studied for decades, we still lack quantitative information about the contribution of individual enzymes to the overall process. The information to date indicates that in spite of immaturity of many of the classical digestive mechanisms of the adult, the infant uses a number of compensatory systems to achieve adequate digestion of nutrients (Fig. 1).
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