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Yellow maize with high ?-carotene is an effective source of vitamin A in healthy Zimbabwean men.

ABSTRACT: The bioconversion efficiency of yellow maize ?-carotene to retinol in humans is unknown.The objective of this study was to determine the vitamin A value of yellow maize ?-carotene in humans.High ?-carotene-containing yellow maize was grown in a hydroponic medium with 23 atom% (2)H(2)O during grain development. Yellow maize ?-carotene showed the highest abundance of enrichment as [(2)H(9)]?-carotene. Eight healthy Zimbabwean men volunteered for the study. On day 1 after a fasting blood draw, subjects consumed 300 g yellow maize porridge containing 1.2 mg ?-carotene, 20 g butter, and a 0.5-g corn oil capsule. On day 8, fasting blood was drawn, and subjects consumed 1 mg [(13)C(10)]retinyl acetate in a 0.5-g corn oil capsule and 300 g white maize porridge with 20 g butter. Thirty-six blood samples were collected from each subject over 36 d. Concentrations and enrichments of retinol and ?-carotene in labeled doses and serum were determined with the use of HPLC, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry.The area under the curve (AUC) of retinol from 1.2 mg yellow maize ?-carotene was 72.9 nmol · d, and the AUC of retinol from 1 mg retinyl acetate (13)C(10) was 161.1 nmol · d. The conversion factor of yellow maize ?-carotene to retinol by weight was 3.2 ± 1.5 to 1.In 8 healthy Zimbabwean men, 300 g cooked yellow maize containing 1.2 mg ?-carotene that was consumed with 20.5 g fat showed the same vitamin A activity as 0.38 mg retinol and provided 40-50% of the adult vitamin A Recommended Dietary Allowance. This trial was registered at clinicaltrials.gov as NCT00636038.

SUBMITTER: Muzhingi T

PROVIDER: S-EPMC3142725 | biostudies-literature | 2011 Aug

REPOSITORIES: biostudies-literature

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Yellow maize with high β-carotene is an effective source of vitamin A in healthy Zimbabwean men.

Muzhingi Tawanda T Gadaga Tendekayi H TH Siwela Andrew H AH Grusak Michael A MA Russell Robert M RM Tang Guangwen G

The American journal of clinical nutrition 20110629 2

<h4>Background</h4>The bioconversion efficiency of yellow maize β-carotene to retinol in humans is unknown.<h4>Objective</h4>The objective of this study was to determine the vitamin A value of yellow maize β-carotene in humans.<h4>Design</h4>High β-carotene-containing yellow maize was grown in a hydroponic medium with 23 atom% (2)H(2)O during grain development. Yellow maize β-carotene showed the highest abundance of enrichment as [(2)H(9)]β-carotene. Eight healthy Zimbabwean men volunteered for ...[more]

PMID: 21715509

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Project description:Background: Asymmetric ?-carotene, a provitamin A carotenoid, is cleaved to produce retinol (vitamin A) and ?-retinol (with negligible vitamin A activity). The vitamin A activity of ?-carotene-containing foods is likely overestimated because traditional analytic methods do not separate ?-retinol derivatives from active retinol.Objective: This study aimed to accurately characterize intestinal ?-carotene cleavage and its relative contribution to postprandial vitamin A in humans after consumption of raw carrots.Design: Healthy adults (n = 12) consumed a meal containing 300 g raw carrot (providing 27.3 mg ?-carotene and 18.7 mg ?-carotene). Triglyceride-rich lipoprotein fractions of plasma were isolated and extracted, and ?-retinyl palmitate (?RP) and retinyl palmitate were measured over 12 h postprandially via high-performance liquid chromatography-tandem mass spectrometry. The complete profile of all ?-retinyl esters and retinyl esters was measured at 6 h, and total absorption of ?- and ?-carotene was calculated.Results: ?RP was identified and quantified in every subject. No difference in preference for absorption of ?- over ?-carotene was observed (adjusting for dose, 28% higher, P = 0.103). After absorption, ?-carotene trended toward preferential cleavage compared with ?-carotene (22% higher, P = 0.084). A large range of provitamin A carotenoid conversion efficiencies was observed, with ?-carotene contributing 12-35% of newly converted vitamin A (predicted contribution = 25.5%). In all subjects, a majority of ?-retinol was esterified to palmitic acid (as compared with other fatty acids).Conclusions: ?-Retinol is esterified in the enterocyte and transported in the blood analogous to retinol. The percentage of absorption of ?-carotene from raw carrots was not significantly different from ?-carotene when adjusting for dose, although a trend toward higher cleavage of ?-carotene was observed. The results demonstrate large interindividual variability in ?-carotene conversion. The contribution of newly absorbed ?-carotene to postprandial vitamin A should not be estimated but should be measured directly to accurately assess the vitamin A capacity of ?-carotene-containing foods. This trial was registered at clinicaltrials.gov as NCT01432210.

Project description:Finishing pigs (N = 224; 28.66 ± 1.90 kg bodyweight) were randomly assigned across 56 pens of either four barrows or gilts, and assigned to one of four diets: control (7,656 IU vitamin A/kg), control supplemented with vitamin A (4.36 ppm, Rovimix A 1000, DSM, Parsippany, NJ, USA), control supplemented with beta-carotene (163.28 ppm, Rovimix β-Carotene 10%, DSM, Parsippany), or control supplemented with oxidized beta-carotene (40 ppm; 10% active ingredient, Avivagen, Ottawa, ON, Canada). Pigs and feeder weights were obtained at the start of the study (d 0), and end of each phase (d 21, 42, and 63). A subset of gilts had a blood sample taken via jugular venipuncture on d 0, a blood sample and vaccinations of Lawsonia intracellularis and porcine circovirus type 2 (PCV2) on d 18, a blood sample and booster vaccination of PCV2 on d 39, a blood sample on day 60, and a final blood sample on day 63. Gilts were euthanized at the end of the study to obtain a liver (entire right lobe) and a jejunum sample (15.24 cm at 10% of length). Additionally, the second and fourth right anterior mammary were collected to assess anterior mammary tissues. Data were analyzed in SAS 9.4 (Statistical Analysis System, Cary, NC) via GLIMMIX procedure. Oxidized beta-carotene supplementation increased (P = 0.02) ADG across phases over vitamin A supplementation, although there were no differences (P = 0.18) in the body weight of pigs. There was no effect (P > 0.05) of diet on plasma or hepatic retinol, IgG or IgM levels, or immune cell presence in developing mammary tissue. Supplemented vitamin A tended (P = 0.05) to increase the mRNA abundance of retinol binding protein in the jejunum, but other mRNA abundance for genes (alcohol dehydrogenase class 1, lecithin retinol acyltransferase phosphatidylcholine-retinol O-acyltransferase, and beta-carotene oxygenase 1) were not affected (P > 0.05) by dietary treatments. A diet by time interaction (P = 0.04) was noted for the circovirus S/P ratio, where vitamin A supplementation had the best ratio compared to other diets. Analyzed titer levels for the circovirus vaccine had an interaction (P < 0.01) for diet by time, where vitamin A supplementation had the highest titer at the end of the study. Thus, pigs supplemented with oxidized beta-carotene had an improved ADG over vitamin A supplemented pigs, but pigs supplemented with vitamin A seemed to have an improved immune status.

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Yellow maize with high ?-carotene is an effective source of vitamin A in healthy Zimbabwean men.

Publications

Yellow maize with high β-carotene is an effective source of vitamin A in healthy Zimbabwean men.

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