An interventional study of β-cryptoxanthin in Vitamin A Deficiency, sponsored by Newcastle University. Status unknown at 1 site in United Kingdom. Open to participants aged 18 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2020-11-04.
Sponsored by Newcastle University · Not applicable, Interventional, and Basic science
Since no quantitative information currently exists on how effectively the pro-vitamin A carotenoid (pVAC) β-cryptoxanthin (βCX) is converted to vitamin A (VA) in humans, this proof of principle study aims to compare the efficacy of both βCX and β-carotene (βC) to yield VA from biofortified maize. This data is critical before the breeding strategy for biofortified maize is directed towards high βCX-containing varieties in order to reduce VA deficiency in low-income countries.
Despite advances in reducing vitamin A (VA) deficiency worldwide, the prevalence remains highest and unchanged in sub-Saharan Africa and South Asia. Efficacy studies have demonstrated that increasing provitamin A carotenoid (pVAC) intake through consuming pVAC biofortified crops results in increased circulating β-carotene (βC) and VA body stores. It has also been shown that consumption of biofortified maize improved VA total body stores (TBS) as effectively as preformed VA supplementation, and significantly improved visual function in marginally VA deficient children. Despite the fact that βC is the primary focus of breeding programs for pVAC biofortified maize, there is convincing evidence that comparable dietary intakes of βC and β-cryptoxanthin (βCX) would result in 7-fold greater concentrations of βCX in blood.
The study is designed to determine for the first time the bioefficacy of βCX in comparison to βC in humans using state of the art isotope dilution techniques in combination with compartmental modelling. The project is conducted in two phases: Phase 1) the determination of best time points for assessment of βCX bioconversion, intestinal and postintestinal bioefficacy as well as quantifying TBS of VA in healthy volunteers; Phase 2) to test the bioefficacy of βCX and βC in maize by comparing a high βCX and low βC maize variety to a high βC and low βCX maize variety.
Phase 1 of the study involves 1 long study day (D0), where 10 ml of blood will be taken every 2 hours, via cannulation, for a total of 12 hours (70 ml of blood total). Subsequently, there are 13 followup visits on the mornings of Days 1, 2, 4, 7, 11, 14, 21, 28, 35, 49, 63, 77, and 91 where one 10 ml blood sample is taken.
Phase 2 of the study involves 2 whole days (D0 and D21) where approximately 10 ml of blood will be taken every 30-60 minutes, via cannulation, for a total of 8 hours (110 ml of blood total). Subsequently, there are 3 follow-up visits on the mornings of Days 1, 7, and 22 where one 10 ml blood sample is taken on each occasion.
In the mornings of the long/whole study days at either D0 or D21, participants will receive the muffin test meal before stable isotopes, dissolved in sunflower oil, are administered via oral pipette. At D0 or D21, the total dose of pVACs (labelled and unlabelled carotenoids) consumed in the muffin and oil is 3 mg alongside 0.4 mg of pre-formed VA.
67 studies on the registry are indexed under Vitamin A Deficiency; 7 are open to participants now.
This study's planned enrollment of 50 is below the median of 200 across 49 interventional studies indexed under Vitamin A Deficiency.
Browse Vitamin A Deficiency studies →Newcastle University is the lead sponsor of 60 studies on the registry; 15 are open to participants now.
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Exclusion Criteria:
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Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Determination absorption and bioconversion kinetics of \[13C14\]β-cryptoxanthin and provide external validation for single-sample prediction methods.
Dietary Supplement: β-cryptoxanthin
Test the bioefficacy of provitamin A carotenoids (pVACs) in maize by comparing a high β-cryptoxanthin:β-carotene (βCX:βC) variety to a low βCX:βC variety in combination with external \[13C\]-labelled pVACs.
Dietary Supplement: β-cryptoxanthin
Phase 1: 2.0mg of \[13C14\]β-cryptoxanthin, 1.0mg of \[13C10\]β-carotene and 0.4mg \[2H6\]retinyl acetate are given in sunflower oil at Time 0. Phase 2: 1.5mg of \[13C14\]β-cryptoxanthin, 0.75mg of \[13C10\]β-carotene, 0.4mg \[2H6\]retinyl acetate are given in sunflower oil along with 0.25mg β-carotene and 0.5mg β-cryptoxanthin from maize are given at Time 0. Then, 0.75mg of \[13C14\]β-cryptoxanthin, 1.5mg of \[13C10\]β-carotene, and 0.4mg \[2H6\]retinyl acetate are given in sunflower oil along with 0.5mg β-carotene and 0.25mg β-cryptoxanthin from maize are given on day 21.
Also known as: β-carotene; retinyl acetate
Bioefficacy of β-cryptoxanthin
Plasma concentrations of \[13C14\]-β-cryptoxanthin, \[13C7\]-retinyl esters, and \[13C7\]-retinol.
Time frame: Phase 1 = 91 days. Phase 2 = 22 days.
Plan to share: No
No publications or documents are linked to this record.
Started Apr 2019 (actual). Primary completion is estimated for Dec 2020, 20 months after the start.
Of 19 interventional studies with no phase under Vitamin A Deficiency, half reached primary completion within 15 months of starting (the median), counting those still running; a quarter within 7 and three quarters within 26. This study's planned 20 months is above that.
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This study is status unknown, as verified in Nov 2020. You cannot join it, but the record below documents what was studied.
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Newcastle University