BACKGROUND: The bioconversion efficiency of yellow maize β-carotene to retinol in humans is unknown. OBJECTIVE: The objective of this study was to determine the vitamin A value of yellow maize β-carotene in humans. DESIGN: 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 the study. On day 1 after a fasting blood draw, subjects consumed 300 g yellow maize porridge containing 1.2 mg β-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 β-carotene in labeled doses and serum were determined with the use of HPLC, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry. RESULTS: The area under the curve (AUC) of retinol from 1.2 mg yellow maize β-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 β-carotene to retinol by weight was 3.2 ± 1.5 to 1. CONCLUSION: In 8 healthy Zimbabwean men, 300 g cooked yellow maize containing 1.2 mg β-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.
BACKGROUND: The bioconversion efficiency of yellow maize β-carotene to retinol in humans is unknown. OBJECTIVE: The objective of this study was to determine the vitamin A value of yellow maize β-carotene in humans. DESIGN: 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 the study. On day 1 after a fasting blood draw, subjects consumed 300 g yellow maize porridge containing 1.2 mg β-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 β-carotene in labeled doses and serum were determined with the use of HPLC, gas chromatography-mass spectrometry, and liquid chromatography-mass spectrometry. RESULTS: The area under the curve (AUC) of retinol from 1.2 mg yellow maize β-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 β-carotene to retinol by weight was 3.2 ± 1.5 to 1. CONCLUSION: In 8 healthy Zimbabwean men, 300 g cooked yellow maize containing 1.2 mg β-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.
Authors: Samantha Schmaelzle; Bryan Gannon; Serra Crawford; Sara A Arscott; Shellen Goltz; Natalia Palacios-Rojas; Kevin V Pixley; Philipp W Simon; Sherry A Tanumihardjo Journal: J Agric Food Chem Date: 2013-12-23 Impact factor: 5.279
Authors: Guangwen Tang; Yuming Hu; Shi-an Yin; Yin Wang; Gerard E Dallal; Michael A Grusak; Robert M Russell Journal: Am J Clin Nutr Date: 2012-08-01 Impact factor: 7.045