Mammary Amylase: a Possible Alternate Pathway of Carbohydrate Digestion in Infancy

Heitlinger, Leo A.; Lee, Ping C.; Dillon, William P.; Lebenthal, Emanuel

doi:10.1203/00006450-198301000-00003

Cited by 52 publications

(27 citation statements)

References 14 publications

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“…The third group includes two compensatory digestive enzymes present in human milk, a-amylase (EC 3.2.1.1) and bile-salt-stimulated lipase (BSSL). Full-term neonates have only about 0.5% of the amylase activity of the adult, and provision of a-amylase in milk assists the breakdown of oligosaccharides, about 15% of milk carbohydrates (Heitlinger et al 1983). Similarly, fat digestion requires adequate lipase (EC 3.1.1.3) activity and concentration of bile salts.…”

Section: Mode Of Deliverymentioning

confidence: 99%

The nutritive and metabolic advantages of homologous milk

Casey

1989

Proc. Nutr. Soc.

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Section: Mode Of Deliverymentioning

confidence: 99%

The nutritive and metabolic advantages of homologous milk

Casey

1989

Proc. Nutr. Soc.

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Section: Calculated Estimations Of Breast-milk Amylase Intake In Gambmentioning

confidence: 99%

“…In the sma ll inte stin e, glucose polymers and starch are hydrolyzed by amylase fro m saliva and pan creatic j uice, by bru sh-b ord er glucoa mylase, and, in th e breast-fed in fant , by breast-m ilk am ylase (10,(13)(14)(15). Breast-milk am ylase, which is of salivary type, is resistant to gastric digestion ( 10,(13)(14)(15). In a 10-m o-old infant, 50% of total amylase activity in du odenal j uice afte r a human mil k feed was acco unted for by salivary-type amylase ( 10) and, in vitro, breast-milk amylase reta ined a significant prop ortion of its activity after simulated gastric digestion, especially in the presence of breast-milk proteins, starch , or oligosac charides .…”

Section: Calculated Estimations Of Breast-milk Amylase Intake In Gambmentioning

confidence: 99%

“…Th e secretion of both salivary and pancreatic amylases is reduced in infant s with malnutrition (5,7,8). Breast milk is kno wn to contain an amylase (9-1 2) that has been shown to sur vive gastric digestion and remain active in the small intestine ( 10,(13)(14)(15). It has been suggested that, together with pancreatic and salivary am ylases and brush-border glucoamylase, breast-milk amylase may take part in the digestio n of carbohydra tes in breast-fed infants during com plementary feeding (16).…”

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Breast-Milk Amylase Activity in English and Gambian Mothers: Effects of Prolonged Lactation, Maternal Parity, and Individual Variations

1990

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SUBJECTS AN D METHODSevaluate the potenti al role of breast-milk amylase in digestion of food carbo hydrate given in complement of breast-feedin g.The object of our study was to measure breast-milk am ylase activity in two different groups of women practicing prolonged lactati on: mothers living in an affiuent city of England, and less privileged mothers living in a rural village of Th e Gambia, West Africa, whose children are at a high risk for malnutrition . Th e results demonstrated that am ylase is secreted into breast milk th rou ghout 2 y of lactation in quantities of potentially valuable digestive capacity and that the activity of this enzyme is rema rkably similar in the breast milk of English and Gambian women. T he results brought out the great differences in breast-milk amylase activity amo ng mothers living in the same community.Within-subj ect variations. Before the main studies, a detailed investigation of within-subject variations in amylase activity was cond ucted on English and Gambian subjects, to develop a sampling protoco\' Within-feed and diurn al variations, and consistency within indi viduals were examined in five English and five Gambian mothers. The English mothers provided a small sample of milk from both breasts by manual expression, just before and after each feed duri ng a single 24 h period. Th e mothers were 27-to 32-y-old, parity 1-3, and were at vario us stages oflactatio n ranging from 4 to 13 wk of lactation . Th e feed frequency per day was 6-7. The Ga mbian moth ers provided a small sample of mil k from both breasts by ma nual expression at 0800 , 1200, 1500, 1800, and 2100 h on 3 con secuti ve days. The moth ers were 27-to 33-y-old, parity 6-8, an d were at 5-6 wk of lactati on . In addition , to stud y within-subject variations du ring exclusive breast-feedi ng, a longitudinal stud y was conducted in a group of seven mot hers who were recru ited in the lactation clinic of the Helena Venizelos Maternity Hospital, Athens, Gree ce, where it is clinic policy to recommend exclusive breast-feeding for 6 mo. The mot hers were 20-to 37-y-old, parity 1-4, and were exclusively breast-feeding throughout the study . The moth ers provided small sam ples of transiti onal milk (3-1 1 d postpartum) and sequential sampl es of mature milk at approxima tely monthl y inte rvals for 6 mo from both breasts.Milk collection. On the strength of the results of these studies (detailed later) a sim ple samp ling procedu re was adopted for the further studies: amylase was measured in a small sample « 1 mL) of milk obta ined from both breasts on one occasion, irrespective of the suckling pattern, and milk samp les from left and right breast were pooled before analysis.Stu dy comm unities. Breast-milk am ylase was measured in two cross-sectional groups of English and Gambian mothe rs. Th e English subjects lived in the Cambridge area and were recruited th rough local lactation support groups. Fifty-eight mothers par-502 ABSTRACT. Breast milk contains an amyla se that may contribute to carboh ydrate diges...

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“…Milk enzymes may act in the milk itself, in the intestine, or may be absorbed by intestinal epithelial cells and transported to target tissues. At least two human milk enzymes, bile salt-stimulated lipase and mammary amylase, have been shown to play a physiologic role in the digestion of milk nutrients (15,18,19,22,23,28). It is unlikely, considering the strict control of secretory processes (29), that a significant number of enzymes occur in milk simply because of "spillage" from the blood or acinar cells.…”

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Sulfhydryl Oxidase in Human Milk: Stability of Milk Enzymes in the Gastrointestinal Tract

et al. 1984

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SummarySulfhydryl oxidase (SOX) is present in human milk and in milk from all species that have been studied. The pH optimum of human milk SOX is in the neutral range between 7.0 and 7.5. Human milk SOX is stable in an acid environment: 50% of its activity remains after 1 h at pH 2.5. Acid stability is also characteristic of 7-glutamyltranspeptidase, another membranebound enzyme in skim milk. SOX is resistant to pepsin (4000 U/ ml), trypsin (50 pg/ml), chymotrypsin (200 pg/ml), and to trypsin plus chymotrypsin (25 pg eachlml). Milk SOX activity has been detected in the stomach and proximal small intestine contents of suckling rats. Human and bovine SOX are relatively heat stable: 75% of the latter remains after treatment at 62.S°C for 30 min and 65% of the former remains after treatment at 60°C for 10 min. Neither remains after 62.5"C for 30 min. AbbreviationsDTT, dithiothreitol GGT, 7-glutamyltranspeptidase GI, gastrointestinal GSH, reduced glutathione GSSG, oxidized glutathione SIgA, secretory IgA SOX, sulfhydryl oxidase Some 60-70 enzymes have been reported to be present in milk (4, 35) but little is known about their function. Milk enzymes may act in the milk itself, in the intestine, or may be absorbed by intestinal epithelial cells and transported to target tissues. At least two human milk enzymes, bile salt-stimulated lipase and mammary amylase, have been shown to play a physiologic role in the digestion of milk nutrients (15,18,19,22,23,28). It is unlikely, considering the strict control of secretory processes (29), that a significant number of enzymes occur in milk simply because of "spillage" from the blood or acinar cells.Sulfhydryl oxidases are a class of enzymes that catalyze the net synthesis of disulfide bonds (21). These enzymes use molecular oxygen and both low molecular weight sulfhydryl compounds and protein sulfhydryls as substrates in vitro (3, 3 1, 34); they produce H202 plus a disulfide. Sulfhydryl oxidases were originally described in bovine milk (24) but have subsequently been found in skin (38), seminal vesicle (31), epididymis (6), and in mouse plasmacytomas producing IgM (34). The in vivo substrates for SOX in mouse plasmacytomas were shown to be IgM monomers and the associated J chain (34). But in vivo substrates for the sulfhydryl oxidases found in mammalian secretions and tissues have not been established. Milk SOX might play a role in altering the structure of milk or intestinal proteins that are dependent upon the redox state of their sulfhydryls for function.The present experiments were designed to determine whether or not SOX and other milk enzymes had stability characteristics similar to those of milk proteins, such as secretory immunoglobulins (13, 25), which have been shown to be active in the gastrointestinal tract of the suckling neonate. Studies, both in vitro and in vivo, were done in order to measure the stability of SOX to acid and to gut protease. MATERIALS AND METHODSHuman milk samples were obtained through the La Leche League of Staten Island. The milk was frozen im...

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Mammary Amylase: a Possible Alternate Pathway of Carbohydrate Digestion in Infancy

Cited by 52 publications

References 14 publications

The nutritive and metabolic advantages of homologous milk

The nutritive and metabolic advantages of homologous milk

Breast-Milk Amylase Activity in English and Gambian Mothers: Effects of Prolonged Lactation, Maternal Parity, and Individual Variations

Sulfhydryl Oxidase in Human Milk: Stability of Milk Enzymes in the Gastrointestinal Tract

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