1
|
Chinique de Armas Y, Mavridou AM, Garcell Domínguez J, Hanson K, Laffoon J. Tracking breastfeeding and weaning practices in ancient populations by combining carbon, nitrogen and oxygen stable isotopes from multiple non-adult tissues. PLoS One 2022; 17:e0262435. [PMID: 35108296 PMCID: PMC8809549 DOI: 10.1371/journal.pone.0262435] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 12/22/2021] [Indexed: 11/18/2022] Open
Abstract
This paper explores the potential of combining different isotope systems from different tissues to improve resolution when reconstructing breastfeeding and weaning practices (BWP) in archaeology. Additionally, we tested whether changes in diet can be detected in deciduous teeth. Rib collagen samples from 22 infants/children from the archaeological site of Bacuranao I (Mayabeque, Cuba) were processed for nitrogen (δ15N) and carbon (δ13Cco) stable isotopes and assessed using a Bayesian model (WARN). In addition, enamel of 48 teeth from 30 infants/children were analyzed for oxygen (δ18Oen) and carbon (δ13Cen) stable isotopes. Data revealed that the timing of weaning cannot be characterized precisely by analyzing either δ18O or δ15N. While a depletion in both δ15N and δ13Cco is only evident after one year, the WARN model suggested that the weaning process started at around 3 months and ended around 1.7 years. Most teeth were enriched in δ18Oen compared to deciduous incisors, suggesting a breastfeeding signal. However, a high variability in δ18O was found between similar teeth from the same individuals. Higher enrichment in δ18Oen, and variability, was observed in tissues formed during the first six months of life. A δ13C enrichment of 1.0‰ was observed among deciduous teeth and ribs. While most individuals enriched in δ15N showed enrichment in δ13C, the δ18O values were more variable. Our data suggests that stable isotopes of deciduous teeth, especially δ13Cen, can be used to detect changes in diet during the weaning process. It is also possible that the δ18O enrichment observed in M1 is influenced by the effects of cooking techniques on weaning foods. The combination of multiple isotope systems and tissues overcome some of the limitations posed by single tissue approaches.
Collapse
Affiliation(s)
| | | | | | - Kaitlyn Hanson
- Department of Anthropology, The University of Winnipeg, Manitoba, Canada
| | - Jason Laffoon
- Faculty of Archaeology, Leiden University, Leiden, The Netherlands
| |
Collapse
|
2
|
Schimmel P, Kleinjans L, Bongers RS, Knol J, Belzer C. Breast milk urea as a nitrogen source for urease positive Bifidobacterium infantis. FEMS Microbiol Ecol 2021; 97:fiab019. [PMID: 33538807 PMCID: PMC7947585 DOI: 10.1093/femsec/fiab019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 02/03/2021] [Indexed: 02/06/2023] Open
Abstract
Human milk stimulates a health-promoting gut microbiome in infants. However, it is unclear how the microbiota salvages and processes its required nitrogen from breast milk. Human milk nitrogen sources such as urea could contribute to the composition of this early life microbiome. Urea is abundant in human milk, representing a large part of the non-protein nitrogen (NPN). We found that B. longum subsp. infantis (ATCC17930) can use urea as a main source of nitrogen for growth in synthetic medium and enzyme activity was induced by the presence of urea in the medium. We furthermore confirmed the expression of both urease protein subunits and accessory proteins of B. longum subsp. infantis through proteomics. To the same end, metagenome data were mined for urease-related genes. It was found that the breastfed infant's microbiome possessed more urease-related genes than formula fed infants (51.4:22.1; 2.3-fold increase). Bifidobacteria provided a total of 106 of urease subunit alpha alignments, found only in breastfed infants. These experiments show how an important gut commensal that colonizes the infant intestine can metabolize urea. The results presented herein further indicate how dietary nitrogen can determine bacterial metabolism in the neonate gut and shape the overall microbiome.
Collapse
Affiliation(s)
- Patrick Schimmel
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, Helix Building, 6708 WE, Wageningen, the Netherlands
| | - Lennart Kleinjans
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, Helix Building, 6708 WE, Wageningen, the Netherlands
| | - Roger S Bongers
- Danone Nutricia Research, Uppsalalaan 12, 3584CT Utrecht, the Netherlands
| | - Jan Knol
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, Helix Building, 6708 WE, Wageningen, the Netherlands
- Danone Nutricia Research, Uppsalalaan 12, 3584CT Utrecht, the Netherlands
| | - Clara Belzer
- Laboratory of Microbiology, Wageningen University & Research, Stippeneng 4, Helix Building, 6708 WE, Wageningen, the Netherlands
| |
Collapse
|
3
|
Rengstl D, Fischer V, Kunz W. Low-melting mixtures based on choline ionic liquids. Phys Chem Chem Phys 2014; 16:22815-22. [DOI: 10.1039/c4cp02860k] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This scheme presents the melting points of the single components and the melting points of the produced mixtures.
Collapse
Affiliation(s)
- Doris Rengstl
- Institute of Physical and Theoretical Chemistry
- University of Regensburg
- D-93040 Regensburg, Germany
| | - Veronika Fischer
- Institute of Physical and Theoretical Chemistry
- University of Regensburg
- D-93040 Regensburg, Germany
| | - Werner Kunz
- Institute of Physical and Theoretical Chemistry
- University of Regensburg
- D-93040 Regensburg, Germany
| |
Collapse
|
4
|
Hajela N, Nair GB, Ramakrishna B, Ganguly N. Probiotic foods: can their increasing use in India ameliorate the burden of chronic lifestyle disorders? Indian J Med Res 2014; 139:19-26. [PMID: 24604038 PMCID: PMC3994739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Probiotics are defined as live microorganisms which, when ingested in adequate amounts, confer health benefits on the host. Chronic diseases such as diabetes, non-alcoholic fatty liver disease, coronary artery disease, a variety of chronic inflammatory disorders with an immune basis, and some forms of cancer are increasing in incidence around the world and in India, and may be attributable in part to rapid changes in our lifestyle. There is considerable public interest in India in the consumption of probiotic foods. This brief review summarizes the background of the gut microbiota, the immunological reactions induced by these, the evidence linking the microbiota to health outcomes, and the evidence linking the use of probiotics for amelioration of chronic lifestyle diseases.
Collapse
Affiliation(s)
- Neerja Hajela
- Yakult India Microbiota & Probiotic Science Foundation, New Delhi, India,Reprint requests: Dr Neerja Hajela, Secretary, Yakult India Microbiota & Probiotic Science Foundation 52, Okhla Industrial Estate, Phase III, New Delhi 110 020, India e-mail:
| | | | | | - N.K. Ganguly
- National Institute of Immunology, New Delhi, India
| |
Collapse
|
5
|
Stewart GS, Smith CP. Urea nitrogen salvage mechanisms and their relevance to ruminants, non-ruminants and man. Nutr Res Rev 2012; 18:49-62. [PMID: 19079894 DOI: 10.1079/nrr200498] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Maintaining a correct balance of N is essential for life. In mammals, the major sources of N in the diet are amino acids and peptides derived from ingested proteins. The immediate endproduct of mammalian protein catabolism is ammonia, which is toxic to cells if allowed to accumulate. Therefore, amino acids are broken down in the liver as part of the ornithine-urea cycle, which results in the formation of urea - a highly soluble, biochemically benign molecule. Mammals cannot break down urea, which is traditionally viewed as a simple waste product passed out in the urine. However, urea from the bloodstream can pass into the gastrointestinal tract, where bacteria expressing urease cleave urea into ammonia and carbon dioxide. The bacteria utilise the ammonia as an N source, producing amino acids and peptides necessary for growth. Interestingly, these microbial products can be reabsorbed back into the host mammalian circulation and used for synthetic processes. This entire process is known as 'urea nitrogen salvaging' (UNS). In this review we present evidence supporting a role for this process in mammals - including ruminants, non-ruminants and man. We also explore the possible mechanisms involved in UNS, including the role of specialised urea transporters.
Collapse
Affiliation(s)
- Gavin S Stewart
- School of Biological Sciences, Stopford Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
| | | |
Collapse
|
6
|
Abdela W, Graham M, Tsegaye H, Temesgen S, Yehualaeshet T. Effects of orange juice pH on survival, urease activity and DNA profiles of Yersinia enterocolitica and Yersinia pseudotuberculosis stored at 4 degree C. J Food Saf 2011; 31:487-496. [PMID: 22081735 PMCID: PMC3212038 DOI: 10.1111/j.1745-4565.2011.00325.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The objective of this study was to determine the survival, growth rate and possible cellular adaptation mechanisms of Y. pseudotuberculosis and Y. enterocolitica in orange juice under different pH conditions. Yersinia was inoculated in orange juice with adjusted pH levels of 3.9, 4.0, and 7.0 and stored at 4 C for 3, 24, 72 and 168 hours (h). The inter-and intra-species variation is significant to the pH and time of incubation variables (p<0.05). At 3.9 pH the CFU (colony forming units) count decreased significantly.At pH 3.9 and 4.0, Y. enterocolitica and Y. pseudotuberculosis survived for at least 30 days and 15 days, respectively. Yersinia that survived under low pH in orange juice revealed enhanced urease activity within 12 h of incubation. The attachment gene (ail) could not be detected by PCR in Y. enterocolitica from undiluted sample incubated for 24 h or longer. Moreover, the FesI-restriction profile was altered when Y. pseudotuberculosis was stored at pH 4.0 orange juice for 7 days. These results indicate that Yersinia could survive and grow at low pH and the survival mechanisms could also enable the bacteria to survive the stomach pH barrier to cause enteric infection.
Collapse
Affiliation(s)
- Woubit Abdela
- Department of Pathobiology, College of Veterinary Medicine, Nursing and Allied Health, Tuskegee University, AL 36088
| | | | | | | | | |
Collapse
|
7
|
Dwarkanath P, Kurpad AV, Muthayya S, Thomas T, Mhaskar A, Mhaskar R, Thomas A, Vaz M, Jahoor F. Glucose kinetics and pregnancy outcome in Indian women with low and normal body mass indices. Eur J Clin Nutr 2009; 63:1327-34. [PMID: 19471289 DOI: 10.1038/ejcn.2009.33] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND/OBJECTIVES Fetal energy demands are met from the oxidation of maternally supplied glucose and amino acids. During the fasted state, the glucose supply is thought to be met by gluconeogenesis. Underweight women with low body mass index (BMI) might be unable to adequately supply amino acids to satisfy the demands of gluconeogenesis. SUBJECTS/METHODS Glucose kinetics were measured during the first and second trimesters of pregnancy in 10 low-BMI and 10 normal-BMI pregnant women at the 12th hour of an overnight fast using a primed 6 h U-(13)C glucose infusion and was correlated to maternal dietary and anthropometric variables and birth weight. RESULTS Low-BMI mothers consumed more energy, carbohydrates and protein, had faster glucose production (R (a)) and oxidation rates in the first trimester. In the same trimester, dietary energy and carbohydrate correlated with glucose production, glycogenolysis and glucose oxidation in all women. Both groups had similar rates of gluconeogenesis in the first and second trimesters. Glucose R (a) in the second trimester was weakly correlated with the birth weight (r=0.4, P=0.07). CONCLUSIONS Maternal energy and carbohydrate intakes, not BMI, appear to influence glucose R (a) and oxidation in early and mid pregnancy.
Collapse
Affiliation(s)
- P Dwarkanath
- St John's Research Institute, St John's National Academy of Health Sciences, Bangalore, Karnataka, India
| | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Prosser CG, Mclaren RD, Frost D, Agnew M, Lowry DJ. Composition of the non-protein nitrogen fraction of goat whole milk powder and goat milk-based infant and follow-on formulae. Int J Food Sci Nutr 2008; 59:123-33. [PMID: 17852511 DOI: 10.1080/09637480701425585] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The non-protein nitrogen fraction of goat whole milk powder and of infant and follow-on formulae made from goat milk was characterized and compared with cow milk powder and formulae. Goat milk infant formula contained 10% non-protein nitrogen, expressed as a proportion of total nitrogen, compared with 7.1% for cow milk formula. Goat follow-on formula contained 9.3% and cow 7.4% non-protein nitrogen. Urea, at 30%, was quantitatively the most abundant component of the non-protein nitrogen fraction of goat milk and formulae, followed by free amino acids at 7%. Taurine, glycine and glutamic acid were the most abundant free amino acids in goat milk powders. Goat milk infant formula contained 4 mg/100 ml total nucleotide monophosphates, all derived from the goat milk itself. Goat milk has a very different profile of the non-protein nitrogen fraction to cow milk, with several constituents such as nucleotides at concentrations approaching those in human breast milk.
Collapse
|
9
|
Abstract
The mechanisms by which amino acids are transferred across the human placenta are fundamental to our understanding of foetal nutrition. Amino acid transfer across the human placenta is dependent on transport across both the microvillous and basal plasma membranes of the placental syncytiotrophoblast, and on metabolism within the syncytiotrophoblast. Although the principles underlying uptake of amino acids across the microvillous plasma membrane are well understood, the extent to which amino acids are metabolised within human placenta and the mechanisms by which amino acids are transported out of the placenta across the basal plasma membrane are not well understood. Understanding the mechanisms and regulation of amino acid transport is necessary to understand the causes of intrauterine growth restriction in human pregnancy.
Collapse
Affiliation(s)
- J K Cleal
- The Institute of Developmental Sciences, University of Southampton, Southampton, UK.
| | | |
Collapse
|
10
|
Kalhan SC, Parimi PS. Transamination of leucine and nitrogen accretion in human pregnancy and the newborn infant. J Nutr 2006; 136:281S-7S. [PMID: 16365099 DOI: 10.1093/jn/136.1.281s] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Kinetics of leucine and its oxidation were determined in human pregnancy and in the newborn infant, using stable isotopic tracers, to quantify the dynamic aspects of protein metabolism. These data show that in human pregnancy there is a decrease in whole-body rate of leucine turnover compared with nonpregnant women. In addition, data in newborn infants show that leucine turnover expressed as per kg body weight is higher compared with adults. The administering of nutrients resulted in a suppression of the whole-body rate of proteolysis. Because nonessential amino nitrogen is an important component of nutritional nitrogen and can be limiting for growth under certain circumstances, and because BCAA are an important source of nonessential amino nitrogen, we have examined the relations among the transamination of leucine, leucine N kinetics, and urea synthesis and glutamine kinetics in human pregnancy and newborn infants. In human pregnancy, early in gestation, there is a significant decrease in urea synthesis in association with a decrease in the rate of transamination of leucine. A linear correlation was evident between the rate of leucine reamination and urea synthesis during fasting in pregnant and nonpregnant women. In healthy-term newborn and growing infants, although the reamination of leucine was positively related to glutamine flux, leucine reamination was negatively related to urea synthesis, suggesting a redirection of amino N toward protein accretion. The regulatory mechanism involved in this redirection of nitrogen from irreversible loss to accretion remains under investigation.
Collapse
Affiliation(s)
- Satish C Kalhan
- Schwartz Center for Metabolism and Nutrition, Department of Pediatrics, Case Western Reserve University at MetroHealth Medical Center, Cleveland, OH, USA.
| | | |
Collapse
|
11
|
Parimi PS, Devapatla S, Gruca LL, Amini SB, Hanson RW, Kalhan SC. Effect of enteral glutamine or glycine on whole-body nitrogen kinetics in very-low-birth-weight infants. Am J Clin Nutr 2004; 79:402-9. [PMID: 14985214 DOI: 10.1093/ajcn/79.3.402] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Glutamine is a critical amino acid for the metabolism of enterocytes, lymphocytes, and other proliferating cells. Although supplementation with glutamine has been suggested for growing infants, its effect on protein metabolism has not been examined. OBJECTIVE The objective was to examine the effect of enteral glutamine or glycine on whole-body kinetics of glutamine, phenylalanine, leucine, and urea in preterm infants. DESIGN Infants at <32 wk of gestation were given formula supplemented with either glutamine (0.6 g. kg(-1). d(-1); n = 9) or isonitrogenous amounts of glycine (n = 9) for 5 d. Eight infants fed unsupplemented formula served as control subjects. Glutamine, phenylalanine, leucine nitrogen flux, leucine carbon flux, and urea kinetics were quantified during a basal fasting period and in response to nutrient intake. RESULTS Growing preterm infants had a high weight-specific rate of appearance of glutamine, phenylalanine, and leucine nitrogen flux. When compared with the control treatment, enteral glutamine resulted in a high rate of urea synthesis, no change in the plasma glutamine concentration, and no change in the rate of appearance of glutamine. Glycine supplementation resulted in similar changes in nitrogen metabolism, but the magnitude of change was less than that in the glutamine group. In the nonsupplemented infants, the rate of appearance of leucine nitrogen flux was negatively correlated (rho = -0.72) with urea synthesis. In contrast, the correlation (rho = 0.75) was positive in the glutamine group. CONCLUSION Enterally administered glutamine in growing preterm infants is entirely metabolized in the gut and does not have a discernable effect on whole-body protein and nitrogen kinetics.
Collapse
Affiliation(s)
- Prabhu S Parimi
- Schwartz Center for Metabolism & Nutrition, MetroHealth Medical Center, Cleveland, OH 44109-1998, USA.
| | | | | | | | | | | |
Collapse
|
12
|
Faber P, Johnstone AM, Gibney ER, Elia M, Stubbs RJ, Roger PL, Milne E, Buchan W, Lobley GE. The effect of rate and extent of weight loss on urea salvage in obese male subjects. Br J Nutr 2003; 90:221-31. [PMID: 12844395 DOI: 10.1079/bjn2003859] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
It is well established that in human subjects a proportion of urea production undergoes hydrolysis in the gastrointestinal tract with release of N potentially available for amino acid synthesis. Previous studies have suggested adaptive changes in urea kinetics, with more urea-N retained within the metabolic pool during reduced dietary intakes of energy and protein. We therefore investigated the effect of rate and extent of weight loss on adaptive changes in urea kinetics in two groups (each n 6) of obese men (mean age 43 (sd 12) years, BMI 34.8 (sd 2.9) kg/m(2)) during either total starvation for 6 d or a very-low-energy diet (2.55 MJ/d) for 21 d. Subjects were resident in the Human Nutrition Unit of the Rowett Research Institute (Aberdeen, Scotland, UK) and lost 6 and 9 % initial body weight within the starvation and dieting groups respectively. Changes in urea-N metabolism were assessed by stable isotope tracer kinetics using [(15)N(15)N]urea infused intravenously for 36 h before, during and after weight loss. In response to weight loss, urea production decreased (P<0.01) by 25 % from 278 to 206 micromol urea-N/h per kg within the dieting group only. However, no changes were observed in the proportion of urea being hydrolysed in the gastrointestinal tract (range 20-25 %) or in the proportion of N retained for anabolic purposes (80-85 % urea-N from gastrointestinal hydrolysis) within either group. It was concluded that no adaptive changes in urea kinetics occurred in response to either the different rate or extent of weight loss.
Collapse
Affiliation(s)
- Peter Faber
- Rowett Research Institute, Greenburn Road, Bucksburn, Aberdeen AB21 9SB, Scotland, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Parimi PS, Devapatla S, Gruca L, O'Brien AM, Hanson RW, Kalhan SC. Glutamine and leucine nitrogen kinetics and their relation to urea nitrogen in newborn infants. Am J Physiol Endocrinol Metab 2002; 282:E618-25. [PMID: 11832365 DOI: 10.1152/ajpendo.00403.2001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glutamine kinetics and its relation to transamination of leucine and urea synthesis were quantified in 16 appropriate-for-gestational-age infants, four small-for-gestational-age infants, and seven infants of diabetic mothers. Kinetics were measured between 4 and 5 h after the last feed (fasting) and in response to formula feeding using [5-(15)N]glutamine, [1-(13)C,(15)N]leucine, [(2)H(5)]phenylalanine, and [(15)N(2)]urea tracers. Leucine nitrogen and glutamine kinetics during fasting were significantly higher than those reported in adults. De novo synthesis accounted for approximately 85% of glutamine turnover. In response to formula feeding, a significant increase (P = 0.04) in leucine nitrogen turnover was observed, whereas a significant decrease (P = 0.002) in glutamine and urea rate of appearance was seen. The rate of appearance of leucine nitrogen was positively correlated (r(2) = 0.59, P = 0.001) with glutamine turnover. Glutamine flux was negatively correlated (r(2) = 0.39, P = 0.02) with the rate of urea synthesis. These data suggest that, in the human newborn, glutamine turnover is related to a high anaplerotic flux into the tricarboxylic acid cycle as a consequence of a high rate of protein turnover. The negative relationship between glutamine turnover and the irreversible oxidation of protein (urea synthesis) suggests an important role of glutamine as a nitrogen source for other synthetic processes and accretion of body proteins.
Collapse
Affiliation(s)
- Prabhu S Parimi
- Department of Pediatrics, Robert Schwartz M.D. Center for Metabolism and Nutrition, MetroHealth Medical Center, Case Western Reserve University School of Medicine, Cleveland, Ohio 44109-1998, USA
| | | | | | | | | | | |
Collapse
|
14
|
Affiliation(s)
- Alan A. Jackson
- Institute of Human Nutrition, University of Southampton, Southampton General Hospital, Southampton, UK
| |
Collapse
|
15
|
Abstract
Although extensive data are available on the impact of nutrient and protein administration on growth, plasma amino acids, and nitrogen balance in the newborn and growing infants, relatively few studies have carefully examined the dynamic aspects of protein metabolism in vivo and particularly in the micropremie or ELBW infant. These studies show that the very preterm infants, either because of immaturity or because of the intercurrent illness, have high rates of protein turnover and protein breakdown. This high rate of proteolysis is not as responsive to nutrient administration. Intervention strategies aimed at promoting nitrogen accretion, such as insulin, human growth hormone, or glutamine, have not thus far resulted in enhanced protein accretion and growth. This may be, in part, due to limitations in delivery of adequate calorie and nitrogen.
Collapse
Affiliation(s)
- S C Kalhan
- Robert Schwartz, MD, Center for Metabolism & Nutrition, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA.
| | | |
Collapse
|
16
|
Rudloff S, Kunz C. Protein and nonprotein nitrogen components in human milk, bovine milk, and infant formula: quantitative and qualitative aspects in infant nutrition. J Pediatr Gastroenterol Nutr 1997; 24:328-44. [PMID: 9138181 DOI: 10.1097/00005176-199703000-00017] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- S Rudloff
- Research Institute of Child Nutrition, Dortmund, Germany
| | | |
Collapse
|
17
|
Abstract
Urea kinetics were measured in normal women aged 22-34 years at weeks 16, 24 and 32 on either their habitual protein intake (HABIT) or a controlled intake of 60 g protein/d (CONTROL), using primed-intermittent oral doses of [15N15N]urea and measurement of plateau enrichment in urinary urea over 18 h (ID) or a single oral dose of [15N15N]urea and measurement of enrichment of urea in urine over the following 48 h (SD). The intake of protein during HABIT-ID (80 g/d) was greater than that on HABIT-SD (71 g/d); urea production as a percentage of intake was significantly greater at week 16 for HABIT-ID than HABIT-SD, whereas urea hydrolysis at week 16 was greater for HABIT-SD than HABIT-ID and urea excretion at week 32 was greater for HABIT-ID than HABIT-SD. The combined results for HABIT-ID and HABIT-SD showed a significant reduction in urea production at week 32 compared with week 24. Urea excretion decreased significantly from week 16 to week 24 with no further decrease to week 32 and urea hydrolysis was significantly greater at week 24 than either week 16 or week 32. Compared with HABIT, on CONTROL there was a decrease in urea production at week 16, and urea excretion was significantly reduced at week 16. For all time periods urea production was closely related to the sum of intake plus hydrolysis. Hydrolysis was greatest at week 24 and closely related to urea production. There was a significant inverse linear relationship overall for hydrolysis as a proportion of production and excretion as a proportion of intake. The results show that on HABIT N is more effectively conserved in mid-pregnancy through an increase in urea hydrolysis and salvage, and during late pregnancy through a reduction in urea formation. Lowering protein intake at any stage of pregnancy increased the hydrolysis and salvage of urea. The staging of these changes was later than that in pregnancy in Jamaica.
Collapse
Affiliation(s)
- I S McClelland
- Department of Human Nutrition, University of Southampton
| | | | | |
Collapse
|
18
|
Steinbrecher HA, Griffiths DM, Jackson AA. Urea production in normal breast-fed infants measured with primed/intermittent oral doses of [15N, 15N]urea. Acta Paediatr 1996; 85:656-62. [PMID: 8816198 DOI: 10.1111/j.1651-2227.1996.tb14118.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Urea kinetics were measured on 11 occasions in six normal, breast-fed infants aged 29-88 days. Prime and intermittent oral doses of [15N, 15N]urea with measurement of enrichment of urea in urine were used. The rate at which urea appeared in the urea pool was 265 mgN/kg per hour, 85% of which derived from endogenous production and 15% from the diet. Urinary excretion of urea was 87 mgN/kg per hour. Therefore, 60% of the urea entering the pool each day was hydrolysed by the metabolic activity of the colonic microflora and the nitrogen was made available for further metabolic interaction. The rate of urea appearance and the extent to which urea nitrogen was salvaged were greater in infants under 6 weeks than in those over 6 weeks, indicating that urea kinetics is a more active process at an early age, and slows with time. With respect to factors influencing urea kinetics, the apparently conflicting results which have appeared in the literature may be explained. The results may help explain the growth of breast-fed infants on low protein intakes.
Collapse
Affiliation(s)
- H A Steinbrecher
- Wessex Regional Paediatric Surgical Unit, Southampton General Hospital, UK
| | | | | |
Collapse
|
19
|
|
20
|
Bickerton AS, Birch R, Jackson AA, Uauy R, Persaud C, Gattas V, Barrera G. Protein quality and urea kinetics in prepubertal Chilean schoolboys. Int J Food Sci Nutr 1996; 47:61-70. [PMID: 8616675 DOI: 10.3109/09637489609028562] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Urea kinetics were measured non-invasively in 12 Chilean schoolboys aged 8-10 years who were receiving one of two diets, either predominantly animal protein or predominantly vegetable protein. Both the diets provided an equivalent level of gross protein, 1.2 g/kg/day. The study diets were given for 10 days to enable adaptation to take place. On the eighth day a single oral dose of 15N15N-urea, 100 mg, was given and the amount of label excreted as 15N15-urea in urine over the subsequent 48 hours was measured. There was little difference in any aspect of urea kinetics between the two diets with urea production (animal, 173 +/- 50 mgN/kg/day; vegetable 179 +/- 53 mgN/kg/day), urea excretion (animal, 86 +/- 19 mgN/kg/day; vegetable, 105 +/- 13 mgN/kg/day), urea nitrogen hydrolysis (animal, 87 +/- 49 mgN/kg/day; vegetable, 74 +/- 42 mgN/kg/day), and the salvaged urea-nitrogen derived from hydrolysis which returned to urea formation (animal, 12 +/- 5 mgN/kg/day; vegetable, 17 +/- 9 mgN/kg/day) all being similar. A very high proportion of the salvage nitrogen derived from urea hydrolysis was maintained within the metabolic pool, about 80%, which was equivalent to 0.4 g protein/kg/day. This is the first time urea kinetics have been measured in children of this age and shows that 57% of the ura produced is excreted in urine on average with about 43% of the urea-nitrogen being salvaged for further metabolic interaction. It is concluded that the vegetable based protein diet taken habitually by Chilean children is metabolically equivalent in terms of urea kinetics to a diet based upon animal protein at this level of intake, but that high rates of salvage of urea nitrogen are found on both diets.
Collapse
Affiliation(s)
- A S Bickerton
- Department of Human Nutrition, University of Southampton, UK
| | | | | | | | | | | | | |
Collapse
|
21
|
Affiliation(s)
- A A Jackson
- Institute of Human Nutrition, University of Southampton
| |
Collapse
|
22
|
|