Extracellular buffer choice influences acid-base responses and gastrointestinal symptoms

Figures & data

Figure 1. Mean (±SD) A blood HCO₃⁻ concentration and B pH following the consumption of 0.3 g^.kg^–1 BM sodium bicarbonate, sodium citrate or a placebo (cornflower). *Denotes significant difference between sodium bicarbonate and sodium citrate (P < 0.05)

Table 1. Mean (±SD) bicarbonate kinetic variables following the consumption of 0.3 g^.kg^–1 BM sodium bicarbonate and sodium citrate

Variable	Sodium Bicarbonate	Sodium Citrate	P-value	Effect size [95%CI]
Tlag (min)	30 ± 8	45 ± 19	0.024*	1.0 [0.2, 1.9]
Cmax (mmol∙L^–1)	30.9 ± 1.2	29.0 ± 0.7	< 0.001**	1.9 [1.0, 2.8]
∆Cmax (mmol∙L^–1)	5.9 ± 0.7	3.8 ± 0.9	< 0.001**	2.5 [1.5, 3.6]
Tmax (min)	123 ± 17	145 ± 28	0.010*	0.9 [0.1, 1.7]
AUC (mmol∙min^–1∙L^–1)	5165 ± 168	4919 ± 109	< 0.001**	1.7 [0.8, 2.6]

Notes: T_lag, lag time; C_max, peak bicarbonate concentration; ∆C_max, change in peak bicarbonate concentration; T_max, time to peak bicarbonate concentration; AUC, area under the curve. Effect size is reported using the Hedge’s g correction.

Table 2. Overall and maximal GI symptoms experienced for each participant following the consumption of 0.3 g^.kg^–1 BM sodium bicarbonate and sodium citrate. Symptom severity scores are displayed in (). Time or time range of maximal symptom are displayed in []

	Sodium Bicarbonate		Sodium Citrate
Participant (#)	GI Symptoms Experienced	Maximal GI Symptom	GI Symptoms Experienced	Maximal GI Symptom
1		No symptom (0)		No symptom (0)
2	N/SC/SA/BU	Nausea (3) [100]	N	Nausea (3) [30]
3	B	Belching (2) [30]	F	Flatulence (3) [90]
4	BU/D	Bowel urgency (7) [90]	BU	Bowl urgency (5) [70–90]
5		No symptom (0)		No symptom (0)
6		No symptom (0)		No symptom (0)
7		No symptom (0)	N/F	Nausea/Flatulence (2) [60]
8		No symptom (0)		No symptom (0)
9	D/F	Diarrhoea (6) [70]	F	Flatulence (2) [30]
10		No symptom (0)		No symptom (0)
11	N/N/SC/B/SA/BU	Diarrhoea (9) [60–80]		No symptom (0)
12		No symptom (0)		No symptom (0)
13		No symptom (0)	F/N/SC/SB/SA	Flatulence (4) [90]

Belching = B; Bowel Urgency = BU; Diarrhoea = D; Flatulence = F; Nausea = N; Stomach Ache = SA; Stomach Bloating = SB; Stomach Cramping = SC; Vomiting = V.

Figure 2. Mean (±SD) gastrointestinal symptom scores following the consumption of 0.3 g^.kg^–1 BM sodium bicarbonate and sodium citrate. *Denotes significant difference between conditions (P < 0.05)