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S Fairweather-Tait

Publications and source records attributed to S Fairweather-Tait.

18 recordsLinked to original sources
PubMed2003

Detection of caseinophosphopeptides in the distal ileostomy fluid of human subjects.

Caseinophosphopeptides (CPP) were detected for the first time in ileostomy fluid, collected at 2 h intervals for 10 h post milk and CPP ingestion, from human volunteers with an ileostomy. The level of CPP present in ileostomy fluid obtained from milk-fed volunteers was markedly higher than that from volunteers fed with selected CPP preparations. The findings are based on HPLC analysis in combination with peptide-bound P determination, thin-layer electrophoresis and amino acid analysis, together with ELISA studies using polyclonal antibodies raised against a set of CPP to detect immunoreactive CPP in ileostomy fluid. These procedures allowed the detection of nm concentrations of CPP. CPP, which can be released during intestinal digestion, may function as bioactive constituents and carriers for different minerals, especially Ca, and may be used as ingredients in functional foods or pharmaceutical preparations.

Adult↗
PubMed2000

Clinical safety of iron-fortified formulas.

BACKGROUND: Iron-fortified formulas are recommended throughout infancy and are frequently used beyond, yet safety aspects have been inadequately studied. Iron could theoretically increase pro-oxidant stress, with potential adverse effects, including infection risk, and some clinicians suspect that iron-fortified formulas induce gastrointestinal disturbance. OBJECTIVE: A planned component of a large intervention trial has been to test the hypothesis that infants receiving iron-fortified formula do not have a higher incidence of infections (primary outcome) or gastrointestinal problems (secondary outcome) than infants on low iron-formulas or cow's milk. Methods. Children (n = 493) 9 months old receiving cow's milk were recruited in 3 UK centers and randomized to: 1) cow's milk as before, 2) formula containing.9 mg/L of iron, or 3) an otherwise identical formula but containing 12 mg/L of iron. Children were followed at 3 monthly intervals and the episodes of infections, diarrhea and constipation, and general morbidity to 18 months old were recorded. Hematologic indices of iron status were determined at 18 months old. RESULTS: Serum ferritin concentrations were increased in infants receiving iron-fortified formula but there were no intergroup differences in incidence of infection, gastrointestinal problems, or in general morbidity or weight gain. CONCLUSIONS: We were unable to identify adverse health effects in older infants and toddlers consuming a high iron-containing formula (12 mg/L) even when used in populations with a low incidence of iron deficiency.

Animals↗
PubMed1999

Effect of dietary copper intakes on biochemical markers of bone metabolism in healthy adult males.

OBJECTIVE: To investigate the effects of changing from a medium (1.6 mg Cu/d) to a low (0.7 mg Cu/d) or a high (6.0 mg/d) Cu intake on biochemical indices of bone turnover in healthy adult males. DESIGN: A longitudinal intervention trial. SETTING: The study was conducted at the Institute of Food Research, Norwich, UK. SUBJECTS: Eleven healthy adult males aged 20-59 y were recruited from Norwich Research Park. INTERVENTION: Subjects were given medium (1.6 mg/d), low (0.7 mg/d) and high (6.0 mg/d) intakes of Cu, in that order, over consecutive 8 week periods with a minimum of 4 week washout periods. On the last d of each dietary period fasting first void urine and blood were collected. RESULTS: Serum caeruloplasmin or Cu (indices of Cu status), serum osteocalcin (biomarker of bone formation), urinary creatinine (Cr) were unaffected by dietary Cu intake. Urinary Pyr/Cr and Dpyr/Cr (biomarkers of bone resorption) were significantly increased (P < 0.05) (by 30% and 25%, respectively), when subjects were switched from the medium to the low Cu diet and were significantly decreased (P < 0.05) (by 30%) and 22% respectively), when subjects were switched from the low to the high Cu diet. CONCLUSION: The findings of the present study could have implications for bone health in individuals with marginal Cu intakes. Thus, further studies are warranted to better define the relationship of marginal Cu intakes to bone health.

Adult↗
PubMed1999

Iron fortified follow on formula from 9 to 18 months improves iron status but not development or growth: a randomised trial.

AIMS: Iron deficiency anaemia is associated, in observational studies, with developmental disadvantage. This study tested the hypothesis that feeding iron supplemented formula from 9 to 18 months of age would improve developmental performance. SUBJECTS AND METHODS: 493 healthy children aged 9 months being fed pasteurised cows' milk were recruited from three UK centres. They were randomised to: cows' milk as before, formula containing 0.9 mg/litre iron, or formula containing 1.2 mg/litre iron, until 18 months of age. Bayley mental and psychomotor developmental indices were measured at 18 months, as were growth and haematological indices. RESULTS: Children fed iron fortified formula had higher plasma ferritin concentrations, but there were no significant intergroup differences in development or growth. CONCLUSIONS: There are no developmental or growth advantages in children given iron supplemented formula, but a benefit for a minority who were anaemic, or the possibility that a benefit may emerge at a later age, cannot be excluded.

Anemia, Iron-Deficiency↗
PubMed1998

Adaptation to high and low copper intakes: its relevance to estimated safe and adequate daily dietary intakes.

Different approaches are used to determine ideal ranges of intakes and threshold levels of safe intakes for nutrients. A consequence of this is that, for inorganic nutrients particularly, a safe level set by traditional toxicologic procedures might be compromised because it is inconsistent with physiologic observations and customary intakes and because the levels set may allow an inordinately narrow range of safe intakes above the upper limit of recommended intakes. This article used data from studies in animal models and in human volunteers to construct a provisional continuum of adaptive processes and pathophysiologic phenomena associated with a range of copper intakes extending from toxic to deficient to suggest an approach to establishing an acceptable range of intakes for copper that would address simultaneously the advisory and regulatory needs of nutritionists and toxicologists.

Adaptation, Physiological↗
PubMed1998

Evaluation of iron bioavailability in infant weaning foods fortified with haem concentrate.

BACKGROUND: Nutritional iron deficiency in infants over 4 months of age is one of the most common deficiency disorders. Dietary iron is comprised of non-haem and haem iron, the latter being absorbed by a separate pathway and more efficiently than non-haem iron. Fortification of infant weaning foods is one of the strategies adopted for preventing iron deficiency and the aim of this project was to examine the potential use of haem iron concentrate as a fortificant. METHODS: Sixteen non-anaemic 6-month old infants were recruited and allocated to two groups of 8. Each infant consumed 2 meals/day of a commercial weaning food (100 g) for 7 consecutive days containing 40 mg ascorbic acid and 2.5 mg haem iron/100 g (Group 1) or the same quantity of iron as ferrous sulphate plus 40 mg ascorbic acid (Group 2). Bioavailability was assessed by chemical balance using carmine to mark the beginning and end of the faecal collection. The effect of haem iron concentrate (as a candidate for the factor in meat that enhances iron absorption) was examined by measuring its effect on 57Fe-labelled non-haem iron absorption. RESULTS: There was no difference in iron balance between the two groups. Mean iron retention was 3.5 (SD 2.1) mg/day in Group 1 (haem iron) and 3.0 (SD 2.4) mg/day in Group 2 (ferrous sulphate). Haem concentrate did not enhance the absorption of 57Fe-labelled non-haem iron, Group 1: 1710 (SD 11.1)%, Group 2: 28.4 (SD 17.7)%. CONCLUSIONS: Haem iron concentrate appears to be a highly bioavailable form of iron when added to infant weaning foods. This protein is not, however, responsible for the enhancing effect of animal protein on non-haem iron absorption.

Absorption↗
PubMed1998

Biochemical markers of calcium and bone metabolism during 18 months of lactation in Gambian women accustomed to a low calcium intake and in those consuming a calcium supplement.

The effect of 18 months of lactation on indexes of calcium and bone metabolism was studied in 60 Gambian women accustomed to a very low calcium intake. Half the women consumed a calcium supplement from 10 days postpartum for 52 weeks (supplement, 714 mg Ca/day; total Ca intake, 992 +/- 114 mg/day), and half consumed placebo (total Ca intake, 288 +/- 128 mg/day). Fasting blood and 24-h urine samples were collected at 1.5, 13, 52, and 78 weeks of lactation and analyzed for calciotropic hormones (intact PTH, 1,25-dihydroxyvitamin D, and calcitonin), bone turnover markers (osteocalcin, bone alkaline phosphatase, and urinary deoxypyridinoline), and plasma minerals (calcium and phosphate). The first months of lactation were associated with increased bone turnover and plasma phosphate, and decreased PTH and 1,25-dihydroxyvitamin D. These effects diminished by 52 weeks, although breast milk volumes remained high. The Gambians had higher PTH, 1,25-dihydroxyvitamin D, and bone formation than British women with a greater customary calcium intake. None of the biochemical indexes was affected by calcium supplementation, with the possible exception of bone alkaline phosphatase (-29% at 52 weeks; P = 0.015). These data demonstrate that lactation-associated changes in calcium and bone metabolism are physiological and are independent of dietary calcium supply in women with very low calcium intakes.

Adolescent↗
PubMed1997

Can a double isotope method be used to measure fractional zinc absorption from urinary samples?

OBJECTIVE: This study was designed to test whether fractional absorption calculated from urinary enrichment of stable isotopes of zinc accurately reflects true absorption measured by faecal monitoring. DESIGN: The two techniques were directly compared in volunteers, whereby each subject acted as his/her own control. SETTING: Volunteers were healthy adults, living at home, who were taking part in a larger study on zinc. They attended the local hospital for isotope administration. SUBJECTS: Fifteen volunteers were recruited, seven of whom had non-insulin dependent diabetes mellitus. All completed the study, but five did not carry out a complete faecal collection. INTERVENTIONS: Each subject received an oral and i.v. dose of different stable isotopes of zinc with breakfast. Faecal and urinary enrichment with the isotopes was measured. RESULTS: There was no significant correlation between the two measures of absorption. CONCLUSIONS: The double label stable isotope technique for determining zinc absorption from measurements of urinary enrichment does not reliably predict true zinc absorption (measured by faecal and urinary monitoring) in a heterogenous group of adults given relatively low doses of stable isotopes of zinc.

Absorption↗
PubMed1997

Vitamin D status does not influence the breast-milk calcium concentration of lactating mothers accustomed to a low calcium intake.

Plasma 25-hydroxy-vitamin D and breast-milk calcium concentration were measured at 3 months of lactation in 60 Gambian mothers accustomed to a low calcium diet, of whom 30 were consuming a calcium supplement and 30 were receiving a placebo, and in 48 British mothers. The plasma 25-hydroxy-vitamin D concentration of the Gambian women was not affected by either calcium supplementation (supplemented, 64.4 +/- 2.5 nmol l(-1); placebo, 64.9 +/- 3.5 nmol l(-1); mean +/- SE) or season. The British average was lower (53.9 +/- 3.0 nmol l(-1), p = 0.004), owing to marked seasonal effects. The breast-milk calcium concentration was lower in The Gambia (supplemented, 5.38 +/- 0.13 mmol l(-1); placebo, 5.10 +/- 0.13 mmol l(-1); British, 6.93 +/- 0.15 mmol l(-1), p < 0.0001). There was no relationship between plasma 25-hydroxy-vitamin D and breast-milk calcium concentration in any group. There was no trend towards lower breast-milk calcium concentration in women with vitamin D status towards the bottom of the normal range or in British women during the winter. This study provides no support for the hypothesis that breast-milk calcium concentration is influenced by vitamin D status or that lactating women with a low calcium intake are at particular risk of vitamin D deficiency.

Adolescent↗
PubMed1997

A case of hyperzincemia with functional zinc depletion: a new disorder?

We report the case of an 1l-y-old boy with a plasma Zn concentration greater than 200 micromol/L, but with symptoms consistent with Zn deficiency. He has had hepatosplenomegaly, rashes, stunted growth (<3rd centile), anemia, and impaired immune function since infancy. He also has vasculitis and osteoporosis. A plasma Zn-binding protein has been separated and characterized by a combination of size exclusion and ion exchange chromatography and electrophoretic studies and by immunologic methods. Antibodies to the partially purified protein have been raised in rabbits. Size exclusion chromatography shows that Zn is bound to a protein with a mass 110000-300000 kD. Electrophoretic and mass spectrometry studies suggest that the protein may be composed of several subunits. One component of the isolated protein reacts with antiserum to alpha2-macroglobulin; immunoprecipitation studies confirm that the protein is not alpha2-macroglobulin or a histidine-rich glycoprotein. Kinetic studies of zinc metabolism in the patient and his mother with stable Zn isotopes show the presence of increased exchangeable Zn, with a rapid flux from plasma to a stable pool. Liver and muscle Zn and Cu concentrations are raised, but with no abnormal liver histology. Immunoreactive metallothionein in the liver is increased. We suggest that this boy may suffer from a previously unrecognized inborn error of Zn metabolism causing symptomatic zinc deficiency.

Biopsy↗
PubMed1996

The effect of long-term calcium supplementation on indices of iron, zinc and magnesium status in lactating Gambian women.

The effect of long-term supplementation with CaCO3 on indices of Fe, Zn and Mg status was investigated in a randomized, double-blind intervention study of sixty lactating Gambian women. The supplement contained 1000 mg Ca and was consumed between meals 5 d/week, for 1 year starting 1.5 weeks postpartum. Compliance was 100%. Plasma ferritin concentration, plasma Zn concentration and urinary Mg output were measured before, during and after supplementation at 1.5, 13, 52 and 78 weeks postpartum. No significant differences in mineral status were observed at any time between women in the supplement and placebo groups. Analysis of the longitudinal data series showed that plasma ferritin and Mg excretion were characteristic of the individual (P < 0.001). Within individuals, ferritin concentration was higher at 1.5 weeks postpartum than later in lactation (P = 0.002). Plasma Zn concentration was lower at 1.5 weeks postpartum than at other times (P < 0.001), an effect which disappeared after albumin correction. Low plasma concentrations of ferritin and Zn indicated that the Gambian women were at high risk of Fe and Zn deficiency. Measurements of alpha 1-antichymotrypsin suggested that the results were not confounded by acute-phase responses. The results of the present study indicate that 1000 mg Ca as CaCO3 given between meals does not deleteriously affect plasma ferritin and Zn concentrations or urinary Mg excretion in women who are at risk of Fe and Zn deficiency.

Adolescent↗
PubMed1995

Calcium requirements of lactating Gambian mothers: effects of a calcium supplement on breast-milk calcium concentration, maternal bone mineral content, and urinary calcium excretion.

The calcium requirement for prolonged lactation was investigated in a randomized supplementation study of Gambian mothers consuming a low-calcium diet (7.1 mmol/d, or 283 mg/d). Sixty women were studied from 10 d to 78 wk of lactation, receiving calcium or placebo for the first 12 mo. The supplement increased average calcium intake by 17.9 mmol/d (714 mg/d). Supplementation had no effect on breast-milk calcium concentration or on maternal bone mineral content. Urinary calcium output was higher in supplemented than in unsupplemented mothers by 1.18 mmol/d (47 mg/d), P < or = 0.005. Longitudinal changes in urinary calcium output and bone mineral content made a substantial contribution to calcium requirements for lactation. This study suggests that, in women with low calcium intakes, there is no direct benefit from increasing calcium intake during lactation, and that physiological mechanisms operate to furnish calcium for breast-milk production.

Adolescent↗
PubMed1995

Effect of calcium supplements and stage of lactation on the calcium absorption efficiency of lactating women accustomed to low calcium intakes.

The effect of calcium intake on the calcium absorption efficiency from 100 mL cow milk was measured in lactating Gambian mothers habituated to a low-calcium diet [mean intake 7.08 mmol (283 mg)/d], and compared with UK lactating mothers consuming high-calcium diets [mean intake 29.2 mmol (1168 mg)/d] by using a double stable-isotope technique (oral 44Ca and intravenous 42Ca). In a double-blind trial starting 9 d postpartum, Gambian mothers were given a calcium supplement [17.85 mmol (714 mg)/d] or placebo for 12 mo. At 3 and 12 mo postpartum, mean (+/- SEM) calcium absorption from isotopically enriched milk was 52.3 +/- 3.1% (n = 25) and 47.2 +/- 4.8% (n = 24) in the unsupplemented Gambian mothers and 48.8 +/- 2.8% (n = 28) and 42.9 +/- 3.7% (n = 24) in the supplemented mothers, respectively. There was no effect of supplementation or stage of lactation on the efficiency of calcium absorption. At 3 mo postpartum the UK mothers absorbed 32.2 +/- 3.8% of the isotopically enriched calcium added to milk, which was significantly less than that of the Gambian mothers (P < 0.01).

Absorption↗
PubMed1995

The bioavailability of iron in different weaning foods and the enhancing effect of a fruit drink containing ascorbic acid.

There is limited information on the bioavailability of Fe in infant weaning foods, mainly because of the difficulties of measuring Fe utilization directly in infants. The aim of this study was to develop a safe and relatively noninvasive method for studying Fe bioavailability (measured as percent Fe incorporation into red blood cells) in infants using 54Fe, 57Fe, and 58Fe stable isotopes. Four commonly used weaning foods were selected for study, labeled extrinsically with 57Fe- or 58Fe-enriched ferrous sulfate, and fed to five female and five male 9-mo-old fasting infants, using a multiple-dosing technique. Each food was given three times, labeled with one isotope, with a fruit juice drink containing 50 mg of ascorbic acid, and three times, labeled with a different isotope, with an ascorbic acid-free drink. Fourteen days after the last test meal, a blood sample was obtained from a heel-prick, spiked with a known amount of 54Fe, digested, and purified by ion exchange; isotopic enrichment and total Fe content were measured by quadrupole thermal ionization mass spectrometry. The proportion of administered dose of isotope circulating in the blood was calculated from an estimate of blood volume. The geometric mean bioavailability (range) was 3.0% (1.2-9.5%) in a proprietary dehydrated vegetable product, 3.0% (1.1-21.2%) in Weetabix whole-wheat breakfast cereal, 3.1% (1.2-15.4%) in wholemeal bread, and 4.3% (1.7-10.3%) in baked beans. When taken with the drink containing ascorbic acid, there was a 2-fold increase in bioavailability in all foods except the vegetable meal, presumably because this was already fortified with ascorbic acid.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1994

Orange juice enhances aluminium absorption from antacid preparation.

Aluminium absorption from four doses of the antacid preparation 'Aludrox' when taken alone, with orange juice or with milk was compared by measuring the change in urinary aluminium following Aludrox dosage in 15 normal adults. There was an approximately 10-fold increase in 24 h urinary aluminium excretion following the Aludrox plus orange juice (232 micrograms) which was significantly higher than that following Aludrox alone (62 micrograms) (P < 0.001), but milk had no effect on aluminium absorption. The results showed that orange juice greatly enhanced aluminium absorption and should not therefore be taken in conjunction with aluminium-containing antacid preparations.

Absorption↗
PubMed1993

Iron.

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Diet↗