Intakes and Excretions of Iron, Copper, and Zinc in the Neonatal Period

Cavell, P. A.; Widdowson, E. M.

doi:10.1136/adc.39.207.496

Cited by 127 publications

(52 citation statements)

References 10 publications

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“…It has been suggestea that a primary role for metallothionein is as a storage depot for zinc and that zinc bound to metallothionein can be reutilized in the body thus protecting the body during periods of limited access to exogenous zinc (2). Consistent with the theory that metallothionein is a storage depot for zinc is the described negative zinc balance in preterm and full-term infants during the first months of life (26,27). Thus at a time when zinc balance is negative, hepatic metallothionein/zinc levels are at their highest and are likely able to contribute zinc to maintain the high rates of tissue synthesis that occur during the newborn period.…”

Section: Discussionsupporting

confidence: 68%

Hepatic Metallothionein as a Source of Zinc and Cysteine during the First Year of Life

Zlotkin

Cherian

1988

Pediatr Res

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ABSTRACT. Metallothionein, a high cysteine-containing protein, can bind with both essential and nonessential metals and thus play an important role as a metal storage protein and also in the detoxification of toxic metals. Although in the human fetus, levels of trace minerals and metallothionein are very high, their postnatal changes are not well documented. The purpose of the present investigation, therefore, was to quantify the accumulation of metallothionein in premature and full-term infants during the first year of life and to identify factors affecting its accumulation. From 47 postmortem samples, it was determined that hepatic metallothionein levels were highest in newborn premature and full-term infants falling to levels found in older children by 4.4 months of age. Hepatic zinc levels were also highest in the youngest infants, falling with increasing postnatal age. There was a significant positive correlation between zinc and metallothionein at all ages. However, there was a negative correlation between hepatic metallothionein levels and cystathionase activity. Hepatic copper and metallothionein levels were unrelated. The renal concentration of metallothionein, zinc, and copper were significantly lower than corresponding hepatic levels. The fall in hepatic levels of zinc and metallothionein during the first months of life correspond to a period of negative zinc balance and low endogenous cysteine production in the newborn. Thus metallothionein may play an important role as a storage depot for these two essential nutrients during this critical period of active growth. (Pediatr Res 24: 326-329, 1988) During the last trimester of pregnancy the mature placenta regulates the transfer of nutrients and protects the fetus from potentially toxic substances. With premature birth, the newborn infant is at risk of both nutrient deficiencies and toxicities for at least five reasons. I) Nutrient intake requirements may be unknown thus too much or too little may be provided; 2) homeostatic mechanisms in the functionally immature preterm are poorly developed; 3) the immature blood-brain bamer is more permeable to any elements present in the plasma; 4) growth is extremely rapid, thus nutrient needs are highest at the same time that nutrient stores are very low; and 5) postnatal adaptation may be prolonged for months even in the absence of overt disease. This combination of factors demand that both environmental and nutritional factors be rigidly controlled for the newborn premature infant.It has been established that most of the minerals of the human fetus are layed down during the last trimester of pregnancy (1).

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Section: Discussionsupporting

confidence: 68%

Hepatic Metallothionein as a Source of Zinc and Cysteine during the First Year of Life

Zlotkin

Cherian

1988

Pediatr Res

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“…As the newborn babies generally have acquired adequate iron storage from their mothers at birth, the main role of lactoferrin and iron in colostrum and transitional milk may not be a source of iron nutrition; instead, it supports a role in bacteriostatic activity. Cavell and Widdowson reported that breast-fed infants excreted 10times more iron than they absorbed during the first week of life (29).…”

Section: Discussionmentioning

confidence: 99%

Concentrations of lactoferrin and iron in human milk at different stages of lactation.

Hirai

Satoh

et al. 1990

Journal of Nutritional Science and Vitaminology, J Nutr Sci Vit

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“…A total value of about 16 mg in the placenta and fetus was reported (Cavell and Widdowson, 1964). The Panel considers that the accretion rate is not linear, with most of the accumulation occurring in the last trimester of pregnancy.…”

Section: Indicators Of Copper Requirement In Pregnancy and Lactationmentioning

confidence: 99%

“…The Netherlands Food and Nutrition Council (1992) noted a copper deposition in the fetus and placenta of 16 mg (Cavell and Widdowson, 1964) and considered that this amount is deposited mainly in the last trimester, equivalent to a requirement for absorbed copper of 0.2 mg/day. When taking into account an absorption efficiency of 40 %, an increment in intake of 0.5 mg/day was proposed for pregnant women during the last trimester of pregnancy.…”

Section: Pregnancy and Lactationmentioning

confidence: 99%

“…For infants aged 0 to 12 months, the Netherlands Food and Nutrition Council (1992) set an adequate range of intake of 0.3-0.5 mg/day based on a copper concentration of breast milk of about 0.3-0.5 mg/L (Cavell and Widdowson, 1964;Vuori, 1979) and assumed absorption efficiencies of 50 % from breast milk and 40 % from infant formula. For children, adequate ranges of intake were extrapolated from that of adults on the basis of body weight.…”

Section: Infants and Childrenmentioning

confidence: 99%

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Scientific Opinion on Dietary Reference Values for copper

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2015

EFSA Journal

143

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Following a request from the European Commission, the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) derived Dietary Reference Values (DRVs) for copper. Owing to the absence of appropriate biomarkers of copper status and the limitations of available balance studies, the Panel was unable to derive Average Requirements (ARs) and Population Reference Intakes (PRIs). Hence, Adequate Intakes (AIs) were defined based on mean observed intakes in several European Union (EU) countries, given that there is no evidence of overt copper deficiency in the European population. Data from balance studies were used as supportive evidence. For adults, AIs of 1.6 mg/day for men and 1.3 mg/day for women are proposed. For children, AIs are 0.7 mg/day for children aged 1 to < 3 years, 1 mg/day for children aged 3 to < 10 years, and 1.3 and 1.1 mg/day for boys and girls aged 10 to < 18 years, respectively. For infants aged 7-11 months, based on mean observed intakes in four EU countries, an AI of 0.4 mg/day is proposed, which is supported by upwards extrapolation of estimated copper intake in exclusively breast-fed infants. For pregnant women, an increment of 0.2 mg/day is estimated to cover the amount of copper deposited in the fetus and the placenta over the course of pregnancy and in anticipation of the needs for lactation, and for lactating women the same increment is estimated to cover the amount of copper secreted with breast milk. Thus, for pregnant and lactating women, the Panel derived an AI of 1.5 mg/day. Copper is an essential micronutrient required for electron transfer processes. It is a central component of many enzymes, including those involved in neurotransmitter synthesis, in energy metabolism and in collagen and elastin cross-linking.The main food group contributing to the copper intake of all population groups except infants is grains and grain-based products. Another important contributor to copper intake is the food group meat and meat products.Based on balance studies and other studies, the Panel considered that copper absorption from the diet is around 50 % for all age and life-stage groups.The primary site of copper absorption is the upper small intestine. Uptake is through a carrier protein, Ctr1, and once in the cell, the copper is directed towards its target via one of a series of chaperone proteins that ensure the metal is present in a non-toxic form. In the gut, the major pathway of transport into the portal circulation is via a Cu-ATPase, ATP7A. In the portal circulation, copper is bound to histidine, albumin or possibly transcuprein and transported to the liver, where it is incorporated into ceruloplasmin, which is then secreted into the systemic circulation. It is taken up into the liver through Ctr1 and, if it is not incorporated into ceruloplasmin, it is stored as metallothionein. Excess copper is excreted in bile after transport across the apical membrane of the hepatocytes via another ATPase, ATP7B. This copper is not reabsorbed. In humans, between 80 and 95 % of the copper in...

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Intakes and Excretions of Iron, Copper, and Zinc in the Neonatal Period

Cited by 127 publications

References 10 publications

Hepatic Metallothionein as a Source of Zinc and Cysteine during the First Year of Life

Hepatic Metallothionein as a Source of Zinc and Cysteine during the First Year of Life

Concentrations of lactoferrin and iron in human milk at different stages of lactation.

Scientific Opinion on Dietary Reference Values for copper

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