AUTHOR=Williamson Ellen , Monteyne Alistair J. , Van der Heijden Ino , Abdelrahman Doaa R. , Murton Andrew J. , Hankamer Benjamin , Stephens Francis B. , Wall Benjamin T. 

TITLE=Ingestion of ‘whole cell’ or ‘split cell’ Chlorella sp., Arthrospira sp., and milk protein show divergent postprandial plasma amino acid responses with similar postprandial blood glucose control in humans

JOURNAL=Frontiers in Nutrition

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2024.1487778

DOI=10.3389/fnut.2024.1487778

ISSN=2296-861X

ABSTRACT=<sec id="sec89"><title>Introduction</title><p>Microalgae provide a sustainable basis for protein-rich food production. However, human data concerning microalgae ingestion, subsequent postprandial amino acid (AA) availability and associated metabolic responses are minimal.</p></sec><sec id="sec80"><title>Objectives</title><p>We investigated ingesting <italic>Arthrospira</italic> sp. (spirulina;SPR), and <italic>Chlorella</italic> sp. (chlorella; in ‘whole cell’ [WCC] and ‘split cell’ [SCC] forms, the latter proposed to improve digestibility), compared with a high-quality animal derived protein source (milk; MLK).</p></sec><sec id="sec81"><title>Subjects/methods</title><p>Ten participants (age; 21 ± 1y, BMI; 25 ± 1 kg·m<sup>−2</sup>) completed a randomised, crossover, double-blind study, partaking in 4 counterbalanced (for order) experimental visits. At each visit participants ingested SPR, WCC, SCC or MLK drinks containing 20 g protein and 75 g carbohydrate. Arterialised venous blood samples, indirect calorimetry and visual analogue scales were assessed postabsorptive, and throughout a 5 h postprandial period to measure AA, glucose, insulin and uric acid concentrations, whole-body energy expenditure and appetite scores, respectively.</p></sec><sec id="sec82"><title>Results</title><p>Protein ingestion increased plasma AA concentrations (<italic>p</italic> &lt; 0.001) to differing total postprandial total—and essential—AA availabilities; highest for MLK (86.6 ± 17.8 mmol·L<sup>−1</sup>) and SPR (84.9 ± 12.5 mmol·L<sup>−1</sup>), lowest for WCC (−4.1 ± 21.7 mmol·L<sup>−1</sup>; <italic>p</italic> &lt; 0.05), with SCC (55.7 ± 11.2 mmol·L<sup>−1</sup>) marginally greater than WCC (<italic>p</italic> = 0.09). No differences (<italic>p</italic> &gt; 0.05) were detected between conditions for postprandial glucose or insulin concentrations, whole-body energy expenditure or appetite scores, but serum uric acid concentrations increased (<italic>p &lt;</italic> 0.05) following microalgae ingestion only.</p></sec><sec id="sec83"><title>Conclusion</title><p>Our data imply that microalgae can present a bioavailable source of protein for human nutrition, however, challenges remain, requiring species selection and/or biomass processing to overcome.</p></sec>