Bioefficacy of Beta-cryptoxanthin From Biofortified Maize — BIOCRYPT  

Vitamin A Deficiency Clinical Trial

Official title: Determination of Relative Bioavailability, Bioconversion and Bioefficacy of β-cryptoxanthin in Comparison to β-carotene From Biofortified Maize and External Stable Isotopes Using Compartmental Modelling

Status Recruiting

Clinical Trial Summary

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.

Clinical Trial Description

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. ;

Related Conditions & MeSH terms

• Night Blindness
• Vitamin A Deficiency

• NCT number: NCT04153968
• Study type: Interventional
• Source: Newcastle University
• Contact: Anthony Oxley, PhD
• Phone: 0191 208 1403
• Email: anthony.oxley@ncl.ac.uk
• Status: Recruiting
• Phase: N/A
• Start date: April 1, 2019
• Completion date: December 31, 2020