Co-ingestion of black tea reduces the indispensable amino acid digestibility of hens’ egg in Indian adults

Kashyap, S., Shivakumar, N., Varkey, A., Preston, T. , Devi, S. and Kurpad, A. V. (2019) Co-ingestion of black tea reduces the indispensable amino acid digestibility of hens’ egg in Indian adults. Journal of Nutrition, 149(8), pp. 1363-1368. (doi: 10.1093/jn/nxz091) (PMID:31127832) (PMCID:PMC6682489)

Abstract

Background: Tea, a commonly consumed beverage, contains high amounts of polyphenols that can impair protein digestibility, as demonstrated in vitro. There are no human studies examining the inhibitory influence of tea polyphenols (TPP) on high-quality protein digestibility. Objective: The aim of this study was to determine the effect of black tea on the true indispensable amino acid (IAA) digestibility of whole boiled egg protein, in healthy adult humans, through use of a dual isotope tracer approach. Methods: The effect of black TPP (4.6 mg/mL, ingested as a beverage with the meal) on 2H-labeled whole boiled egg protein, administered with ghee rice and tomato curry, was measured with reference to 13C-spirulina protein in healthy Indian adults aged 20–27 y of both sexes with BMI of 22.0 ± 2.8 kg/m2. The results were then compared to previously determined whole egg mean IAA digestibility measured by the same method, without black tea, in the same subjects (n = 5). To correct for any independent effect of TPP on spirulina protein (used as a standard protein), the true IAA digestibility of 13C-spirulina protein was independently measured with reference to a 2H-amino acid mixture, with and without co-ingestion of black tea, in 3 of the same subjects. Results: The true IAA digestibility of whole boiled egg protein significantly decreased by 17% when co-ingested with black tea. However, there was no significant reduction in the true IAA digestibility of spirulina protein when co-ingested with black tea. Conclusions: TPP protein interactions reduced whole egg digestibility in healthy Indian adults but had minimal effect on spirulina protein digestibility. In populations who are at risk of dietary quality protein inadequacy, the consumption of tea during or after a meal can further increase the risk of inadequacy. This trial was registered at Clinical Trials Registry of India (http://ctri.nic.in) as CTRI/2018/03/012265.

• Item Type: Articles
• Additional Information: Supported by The Wellcome Trust/DBT India Alliance through the Margdarshi fellowship to AVK.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Preston, Professor Tom
• Authors: Kashyap, S., Shivakumar, N., Varkey, A., Preston, T., Devi, S., and Kurpad, A. V.
• College/School: College of Science and Engineering > Scottish Universities Environmental Research Centre
• Journal Name: Journal of Nutrition
• Publisher: Oxford University Press
• ISSN: 0022-3166
• ISSN (Online): 1541-6100
• Published Online: 25 May 2019
• Copyright Holders: Copyright © 2019 American Society of Nutrition
• First Published: First published in Journal of Nutrition 149(8): 1363-1369
• Publisher Policy: Reproduced under a Creative Commons License