A Comparison of Sodium Citrate and Sodium BicarbonateIngestion: Blood Alkalosis and Gastrointestinal Symptoms.

Abstract

This study compared the recommended dose of sodium citrate (SC, 500mg/kg body mass) and sodium bicarbonate (SB, 300mg/kg body mass) for blood alkalosis (blood [HCO3-]) and gastrointestinal symptoms (GIS; number and severity). Sixteen healthy individuals ingested the supplements in a randomized, crossover design. Gelatin capsules were ingested over 15min alongside a carbohydrate-rich meal, after which participants remained seated for forearm venous blood sample collection and completion of GIS questionnaires every 30min for 300min. Time-course and session value (i.e.,peak and time to peak) comparisons of SC and SB supplementation were performed using linear mixed models. Peak blood [HCO3-] was similar for SC (mean 34.2, 95% confidence intervals [33.4, 35.0]mmol/L) and SB (mean 33.6, 95% confidence intervals [32.8, 34.5]mmol/L, p = .308), as was delta blood [HCO3-] (SC = 7.9mmol/L; SB = 7.3mmol/L, p = .478). Blood [HCO3-] was ≥6mmol/L above baseline from 180 to 240min postingestion for SC, significantly later than for SB (120-180min; p < .001). GIS were mostly minor, and peaked 80-90min postingestion for SC, and 35-50min postingestion for SB. There were no significant differences for the number or severity of GIS reported (p > .05 for all parameters). In summary, the recommended doses of SC and SB induce similar blood alkalosis and GIS, but with a different time course.