{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,24]],"date-time":"2026-09-24T18:29:34Z","timestamp":1790274574120,"version":"4.1.0"},"reference-count":35,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2021,2,19]],"date-time":"2021-02-19T00:00:00Z","timestamp":1613692800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Nutr."],"abstract":"<jats:p><jats:bold>Introduction:<\/jats:bold> Sodium bicarbonate (NaHCO<jats:sub>3<\/jats:sub>) is a well-established nutritional ergogenic aid that is typically ingested as a beverage or consumed in gelatine capsules. While capsules may delay the release of NaHCO<jats:sub>3<\/jats:sub> and reduce gastrointestinal (GI) side effects compared with a beverage, it is currently unclear whether the capsule size may influence acid\u2013base responses and GI symptoms following supplementation.<\/jats:p><jats:p><jats:bold>Aim:<\/jats:bold> This study aims to determine the effects of NaHCO<jats:sub>3<\/jats:sub> supplementation, administered in capsules of different sizes, on acid\u2013base responses, GI symptoms, and palatability.<\/jats:p><jats:p><jats:bold>Methods:<\/jats:bold> Ten healthy male subjects (mean \u00b1 SD: age 20 \u00b1 2 years; height 1.80 \u00b1 0.09 m; weight 78.0 \u00b1 11.9 kg) underwent three testing sessions whereby 0.3 g NaHCO<jats:sub>3<\/jats:sub>\/kg of body mass was consumed in either small (size 3), medium (size 0), or large (size 000) capsules. Capillary blood samples were procured pre-ingestion and every 10 min post-ingestion for 180 min. Blood samples were analyzed using a radiometer (Radiometer ABL800, Denmark) to determine blood bicarbonate concentration ([<jats:inline-formula><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\" id=\"M1\"><mml:msubsup><mml:mrow><mml:mtext>HCO<\/mml:mtext><\/mml:mrow><mml:mrow><mml:mn>3<\/mml:mn><\/mml:mrow><mml:mrow><mml:mo>-<\/mml:mo><\/mml:mrow><\/mml:msubsup><\/mml:math><\/jats:inline-formula>]) and potential hydrogen (pH). GI symptoms were measured using a questionnaire at the same timepoints, whereas palatability was recorded pre-consumption.<\/jats:p><jats:p><jats:bold>Results:<\/jats:bold> Capsule size had a significant effect on lag time (the time [<jats:inline-formula><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\" id=\"M2\"><mml:msubsup><mml:mrow><mml:mtext>HCO<\/mml:mtext><\/mml:mrow><mml:mrow><mml:mn>3<\/mml:mn><\/mml:mrow><mml:mrow><mml:mo>-<\/mml:mo><\/mml:mrow><\/mml:msubsup><\/mml:math><\/jats:inline-formula>] changed, <jats:italic>T<\/jats:italic><jats:sub>lag<\/jats:sub>) and the timing of peak blood [<jats:inline-formula><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\" id=\"M3\"><mml:msubsup><mml:mrow><mml:mtext>HCO<\/mml:mtext><\/mml:mrow><mml:mrow><mml:mn>3<\/mml:mn><\/mml:mrow><mml:mrow><mml:mo>-<\/mml:mo><\/mml:mrow><\/mml:msubsup><\/mml:math><\/jats:inline-formula>] (<jats:italic>T<\/jats:italic><jats:sub>max<\/jats:sub>). Bicarbonate <jats:italic>T<\/jats:italic><jats:sub>lag<\/jats:sub> was significantly higher in the large-sized (28 \u00b1 4 min) compared with the small-sized (13 \u00b1 2 min) capsules (<jats:italic>P<\/jats:italic> = 0.009). Similarly, <jats:italic>T<\/jats:italic><jats:sub>max<\/jats:sub> was significantly lower in the small capsule (94 \u00b1 24 min) compared with both the medium-sized (141 \u00b1 27 min; <jats:italic>P<\/jats:italic> &amp;lt; 0.001) and the large-sized (121 \u00b1 29 min; <jats:italic>P<\/jats:italic> &amp;lt; 0.001) capsules. The GI symptom scores were similar for small-sized (3 \u00b1 3 AU), medium-sized (5 \u00b1 3 AU), and large-sized (3 \u00b1 3 AU) capsules, with no significant difference between symptom scores (<jats:italic>F<\/jats:italic> = 1.3, <jats:italic>P<\/jats:italic> = 0.310). Similarly, capsule size had no effect on palatability (<jats:italic>F<\/jats:italic> = 0.8, <jats:italic>P<\/jats:italic> = 0.409), with similar scores between different capsule sizes.<\/jats:p><jats:p><jats:bold>Conclusion:<\/jats:bold> Small capsule sizes led to quicker <jats:italic>T<\/jats:italic><jats:sub>lag<\/jats:sub> and <jats:italic>T<\/jats:italic><jats:sub>max<\/jats:sub> of blood [<jats:inline-formula><mml:math xmlns:mml=\"http:\/\/www.w3.org\/1998\/Math\/MathML\" id=\"M4\"><mml:msubsup><mml:mrow><mml:mtext>HCO<\/mml:mtext><\/mml:mrow><mml:mrow><mml:mn>3<\/mml:mn><\/mml:mrow><mml:mrow><mml:mo>-<\/mml:mo><\/mml:mrow><\/mml:msubsup><\/mml:math><\/jats:inline-formula>] concentration compared to medium and large capsules, suggesting that individuals could supplement NaHCO<jats:sub>3<\/jats:sub> in smaller capsules if they aim to increase extracellular buffering capacity more quickly.<\/jats:p>","DOI":"10.3389\/fnut.2021.634465","type":"journal-article","created":{"date-parts":[[2021,2,20]],"date-time":"2021-02-20T22:12:30Z","timestamp":1613859150000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":8,"title":["Capsule Size Alters the Timing of Metabolic Alkalosis Following Sodium Bicarbonate Supplementation"],"prefix":"10.3389","volume":"8","author":[{"given":"India","family":"Middlebrook","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Joe","family":"Peacock","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Daniel J.","family":"Tinnion","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nicholas K.","family":"Leach","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nathan P.","family":"Hilton","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Bryan","family":"Saunders","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"S. 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