The importance of timing potassium bicarbonate supplementation to affect acid-base balance

In dealing with the negative consequences of a low-grade-metabolic acidosis, induced partially by the western industrialized world’s nutrient composition, alkaline salts such as potassium bicarbonate (KHCO3) have shown to serve as an effective countermeasure. We have recently shown that high sodium chloride (NaCl) intake also induces a low-grade metabolic acidosis. However, timing of the alkaline salt’s application relative to a meal might lead to different responses. Therefore, the main aim of the present study was to determine the ideal time for the intake of KHCO3 relative to a sodium chloride abundant meal. 10 subjects (6 male, 4 female) completed 4 identically scheduled days of the experiment, with 1 day for the control experiment (no supplementation) and 3 days for the different interventions (supplementation of 45mmol KHCO3 before, with or after lunch, respectively). Meals and bloodgas analyses (measured parameters: pH, HCO3-, base excess (BE)) were appointed at definite times. Additionally, a questionnaire monitored any side effects of the supplementation, possibly gastrointestinal disturbances (e.g. flatulence, nausea, diarrhea). Supplementing KHCO3 results in a more alkaline status within the normal range compared to the control (control/different times of supplementation: HCO3- 24mmol/L/ 26mmol/L (p=0.02); BE 0mmol/L/ 1mmol/L (p=0.002)) (before meal: HCO3- /BE: p=0.02/p=0.002; with the meal: p=0.02/p=0.002; after meal: p=0.003/p<=0.001). In this context pH showed significant effects in only two different times of supplementation (during meal (p=0.007), after lunch (p<=0.001)). Except for pH (p=0.01, originating from the supplementation after lunch) timing of the supplements did not lead to different results (HCO3-: p=0.24; BE (p=0.24). Regarding the side effects, subjects were most comfortable in the supplementation with the meal. With the present study, the positive effects of a KHCO3´s administration on the acid-base balance in combination to a sodium chloride abundant meal were confirmed. In aiming to advise an ideal time of KHCO3`s- intake with the focus on all three main descriptive parameters the results make no allowance for setting an advisable time of intake. When taking into account the side effects supplementation of KHCO3 with the meal is highly appreciated