scholarly journals THE VITAMIN C REQUIREMENT OF MAN. ESTIMATED AFTER PROLONGED STUDIES OF THE PLASMA CONCENTRATION AND DAILY EXCRETION OF VITAMIN C IN 3 ADULTS ON CONTROLLED DIETS1

1939 ◽  
Vol 18 (6) ◽  
pp. 705-714 ◽  
Author(s):  
Elaine P. Ralli ◽  
Gerald J. Friedman ◽  
Sol Sherry
Keyword(s):  
Plasma Concentration ◽  
Vitamin C ◽  
Daily Excretion

Vitamin C Concentrations in Plasma as a Function of Intake: a Meta-analysis

2000 ◽  
Vol 70 (5) ◽  
pp. 226-237 ◽  
Author(s):  
Dorothee Brubacher ◽  
Ulrich Moser ◽  
Paul Jordan
Keyword(s):  
Plasma Concentration ◽  
Plasma Level ◽  
Vitamin C ◽  
Meta Analysis ◽  
Target Population ◽  
Consensus Conference ◽  
Inclusion Criteria ◽  
Data Set ◽  
Medline Search ◽  
Data Points

The purpose of this study was to estimate the intake – plasma relationship for vitamin C by means of a meta-analysis. A MEDLINE search revealed 30 publications matching our inclusion criteria. We completed the set with 5 older papers and with one monograph. The proposed statistical model corrects for inconsistencies with regard to methodological differences between the various studies. Therefore, the contribution of a particular study to the estimation is independent of the number of data points. The estimations were performed for the complete data set as well as for different subgroups: “adult” aged 15–65 years, “elderly” aged 60–96 years, “nonsmokers” and “smokers”. The 50th percentile of the plasma concentration for a daily vitamin C intake of 60 mg was 42.4 mumol/L. The corresponding values for the different subgroups were: “adult” 44,1 mumol/L, “elderly” 31.0 mumol/L, “nonsmokers” 42,4 mumol/L, and “smokers” 33.6 mumol/L. Thus, this meta-analysis confirms earlier results that the requirements of vitamin C is higher in “elderly” and “smokers” compared to “adult” and “nonsmokers” and it can be used for the estimation of the vitamin C intake in order to achieve a desired plasma level within a target population. In the general population the assumed optimal plasma concentration of 50 mumol/L, as proposed by a consensus conference, can be achieved by the intake of 100 mg per day, which is the new recommendation of the Austrian, German, and Swiss Nutrition Societies.

scholarly journals The ‘anomalous’ absorption of labelled and unlabelled vitamin C in man

2005 ◽  
Vol 93 (5) ◽  
pp. 627-632 ◽  
Author(s):  
Leslie J. C. Bluck ◽  
Kerry S. Jones ◽  
W. Andy Coward ◽  
Christopher J. Bates
Keyword(s):  
Plasma Concentration ◽  
Stable Isotope ◽  
Vitamin C ◽  
Experimental Results ◽  
Concentration Profiles ◽  
Model Structure ◽  
Limited Information ◽  
Anomalous Absorption ◽  
Plasma Model ◽  
Isotope Measurement

Previous studies of vitamin C absorption in man using stable isotope probes have given results which cannot easily be reconciled with those obtained using non-isotope measurement. In order to investigate some of the apparent paradoxes we have conducted a study using two consecutive doses of vitamin C, one labelled and one unlabelled, given 90 min apart. Compatibility of the experimental results with two feasible models was investigated. In Model 1, ingested vitamin C enters a pre-existing pool before absorption, which occurs only when a threshold is exceeded; in Model 2, ingested vitamin C is exchanged with a pre-existing flux before absorption. The key difference between these two models lies in the predicted profile of labelled material in plasma. Model 1 predicts that the second unlabelled dose will produce a secondary release of labelled vitamin C which will not be observed on the basis of Model 2. In all subjects Model 1 failed to predict the observed plasma concentration profiles for labelled and unlabelled vitamin C, but Model 2 fitted the experimental observations. We speculate on possible physiological explanations for this behaviour, but from the limited information available cannot unequivocally confirm the model structure by identifying the source of the supposed flux.

scholarly journals Relation between intake and plasma concentration of vitamin C in elderly women.

BMJ ◽  
1983 ◽  
Vol 287 (6403) ◽  
pp. 1429-1429 ◽  
Author(s):  
H M Newton ◽  
D B Morgan ◽  
C J Schorah ◽  
R P Hullin
Keyword(s):  
Plasma Concentration ◽  
Vitamin C ◽  
Elderly Women

scholarly journals Plasma concentrations of carotenoids and vitamin C are better correlated with dietary intake in normal weight than overweight and obese elderly subjects

2007 ◽  
Vol 97 (5) ◽  
pp. 977-986 ◽  
Author(s):  
Jesús Vioque ◽  
Tanja Weinbrenner ◽  
Laura Asensio ◽  
Adela Castelló ◽  
Ian S. Young ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Vitamin C ◽  
Dietary Intake ◽  
Plasma Concentrations ◽  
Normal Weight ◽  
Elderly Subjects ◽  
Plasma Vitamin ◽  
Dietary Intakes ◽  
Cross Sectional ◽  
Β Carotene

Carotenoid and vitamin C intakes, assessed by FFQ, have been positively associated with plasma concentrations in different populations. However, the influence of BMI on these associations has not been explored in detail. We explored in a cross-sectional study the relation between dietary carotenoid and vitamin C intakes, using a 135-item FFQ, with their plasma concentrations by BMI categories in 252 men and 293 women, 65 years and older. For men and women combined, significant (P < 0·05) Pearson correlations were observed between energy-adjusted dietary intakes and plasma concentrations (carotenoids adjusted for cholesterol) for: α-carotene 0·21, β-carotene 0·19, lycopene 0·18, β-cryptoxanthin 0·20 and vitamin C 0·36. Multiple linear regression analyses showed that the intake of carotenoids and vitamin C were significant predictors of their respective plasma concentration (P < 0·01), and that BMI was inversely associated with plasma concentration of carotenoids (P ≤ 0·01) but not with plasma vitamin C. In addition, we observed significant interactions between BMI and the intakes of α-carotene and lutein + zeaxanthin, and to a lower extent β-carotene, suggesting that these intakes in subjects with high BMI were not good predictors of their plasma concentration. The present data suggest that plasma carotenoids and vitamin C may be good markers of dietary intake in elderly subjects, but not so for α-carotene, β-carotene and lutein + zeaxanthin in obese subjects.

The effect of vitamin C supplementation on plasma concentration and urinary excretion of vitamin C in cattle

2007 ◽  
Vol 85 (12) ◽  
pp. 3367-3370 ◽  
Author(s):  
L. Padilla ◽  
T. Matsui ◽  
S. Ikeda ◽  
M. Kitagawa ◽  
H. Yano
Keyword(s):  
Plasma Concentration ◽  
Vitamin C ◽  
Urinary Excretion ◽  
Vitamin C Supplementation

scholarly journals Effect of H2Blockade and Food on Single-Dose Pharmacokinetics of GSK1322322, a Peptide Deformylase Inhibitor Antibacterial

2013 ◽  
Vol 57 (6) ◽  
pp. 2556-2561 ◽  
Author(s):  
Odin J. Naderer ◽  
Etienne Dumont ◽  
John Zhu ◽  
Milena Kurtinecz ◽  
Lori S. Jones
Keyword(s):  
Single Dose ◽  
Plasma Concentration ◽  
Vitamin C ◽  
Relative Bioavailability ◽  
Peptide Deformylase ◽  
Maximum Plasma ◽  
High Fat ◽  
Tablet Formulations ◽  
Fast Release ◽  
Fat Meal

ABSTRACTGSK1322322 is first in a new class of antibiotics, peptide deformylase inhibitors, and is active against multidrug-resistant respiratory and skin pathogens. Part 1 of this phase 1, randomized, single-dose (1,000 mg) study in 20 healthy volunteers compared the relative bioavailability of three different tablet formulations of GSK1322322 (fast release, intermediate release, and slow release) to that of the previously studied powder-in-bottle formulation to assess the optimal formulation for progression into clinical trials. Part 2 assessed the effect of a high-fat meal and drug interaction with an H2blocker and an H2blocker plus vitamin C on the pharmacokinetic profile of GSK1322322. Of the three tablet formulations, fast-release GSK1322322 provided pharmacokinetic profiles similar to those of the powder-in-bottle reference formulation (∼93% relative bioavailability) and was selected for progression in part 2. When GSK1322322 was administered with a high-fat meal, the maximum observed plasma concentration (Cmax) was reduced by 20%, and the time to maximum plasma concentration (Tmax) was delayed by 1.9 h. The exposure (area under the concentration-time curve [AUC]) increased by ∼20% compared to that in volunteers in the fasted state. Coadministration of GSK1322322 with an H2blocker resulted in a slight delay in absorption (Tmax∼0.75 h later) and 58 and 38% decreases in theCmaxand AUC0–∞values, respectively, compared to GSK1322322 alone. This effect was reversed with vitamin C intake (i.e., no delay inTmaxand theCmaxand AUC0–∞values decreased by only 21 and 12%, respectively). GSK1322322 was generally well tolerated, and most adverse events were mild in intensity during both parts of the study.

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