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United States Department of Agriculture

Agricultural Research Service

Research Project: DIETARY CAROTENOIDS, RETINOIDS, AND BIOACTIVATES ON HEALTHY AGING

Location: Human Nutrition Research Center on Aging

Title: Yellow maize with high (beta)-carotene is an effective source of vitamin A in healthy Zimbabwean men

Authors
item Muzhingi, Tawanda -
item Gadaga, Tendekayi H. -
item Siwela, Andrew H. -
item Grusak, Michael A. -
item Russell, Robert M. -
item Tang, Guangwen S. -

Submitted to: American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: May 24, 2011
Publication Date: August 1, 2011
Citation: Muzhingi, T., Gadaga, T., Siwela, A., Grusak, M., Russell, R., Tang, G. 2011. Yellow maize with high (beta)-carotene is an effective source of vitamin A in healthy Zimbabwean men. American Journal of Clinical Nutrition. 94(2):510-519.

Interpretive Summary: The bioconversion efficiency of yellow maize Beta-carotene to retinol in humans is unknown. The objective of this study was to determine the vitamin A value of yellow maize Beta-carotene in humans. Eight healthy Zimbabwean men volunteered for the study. On day 1 after a fasting blood draw, subjects consumed yellow maize porridge containing Beta-carotene, butter, and a corn oil capsule. On day 8, fasting blood was drawn, and subjects consumed retinyl acetate in a corn oil capsule and white maize porridge with butter. Thirty-six blood samples were collected from each subject over 36 d. Concentrations and enrichments of retinol and Beta-carotene in labeled doses and serum were determined with the use of advance instrumentational analysis. In 8 healthy Zimbabwean men, 300 g cooked yellow maize containing 1.2 mg Beta-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.

Technical Abstract: BACKGROUND: The bioconversion efficiency of yellow maize Beta-carotene to retinol in humans is unknown. OBJECTIVE: The objective of this study was to determine the vitamin A value of yellow maize Beta-carotene in humans. DESIGN: High Beta-carotene-containing yellow maize was grown in a hydroponic medium with 23 atom% (2)H(2)O during grain development. Yellow maize Beta-carotene showed the highest abundance of enrichment as [(2)H(9)]Beta-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 Beta-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 Beta-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 Beta-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 Beta-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 Beta-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.

Last Modified: 7/28/2014
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