Journal of Nutrition and Metabolism

Research Article

Acid-Base Balance in Healthy Adults: Beneficial Effects of Bicarbonate and Sodium-Rich Mineral Water in a Randomized Controlled Trial: The BicarboWater Study

Table 4

Urine analysis and fluid consumption (main fluids) at the beginning of the study (), at the interim examination (), and at the end of the intervention () as well as absolute changes (∆).


Parameter	Group	Time			value (time × group)	value (time)	Change
Parameter	Group				value (time × group)	value (time)	∆ 3-0	∆ 28-0

Fluid consumption (mL)	HBS	2300 (1065)^c	—	2704 (1100)^c	0.255	<0.001	—	520 (810)
Fluid consumption (mL)	LBS	2260 (920)^c	—	2605 (822)^c	0.255	0.010	—	175 (1175)

Urine volume (mL)	HBS	2341 (1221)^a,c	2742 (879)^a	2687 (1081)^c	0.176	<0.001	395 (815)	365 (962)
Urine volume (mL)	LBS	2193 (1098)^a,c	2685 (951)^a	2704 (1021)^c	0.176	<0.001	402 (943)	363 (1214)

pH (24-hour urine)	HBS	6.17 (0.66)^a,c	7.28 (0.22)^a	7.23 (0.32)^c	<0.001^†	<0.001^†	1.15 (0.77)	1.15 (0.65)
pH (24-hour urine)	LBS	5.98 (0.88)	6.00 (0.66)	5.92 (0.68)	<0.001^†	0.710	0.07 (0.96)	−0.02 (0.53)

pH (spontaneous urine)	HBS	5.66 (0.58)^a,c	7.07 (0.53)^a	6.90 (0.71)^c	<0.001	<0.001	1.36 (0.88)	0.97 (0.78)
pH (spontaneous urine)	LBS	5.68 (0.99)	5.65 (0.86)	5.53 (0.91)	<0.001	0.922	−0.05 (0.74)	−0.04 (0.92)

TA (mmol/L)	HBS	7.78 (13.85)^a,c	0.00 (0.00)^a	0.00 (0.00)^c	<0.001^†	<0.001^†	−7.78 (13.85)	−7.78 (13.10)
TA (mmol/L)	LBS	9.20 (11.75)^a	6.95 (5.35)^a	8.33 (6.75)	<0.001^†	0.152	−2.43 (10.35)	−0.68 (10.70)

HCO₃⁻ (mmol/L)	HBS	8.25 (4.00)^a,c	24.73 (9.00)^a	24.50 (12.53)^c	<0.001^†	<0.001	16.48 (10.33)	13.68 (16.90)
HCO₃⁻ (mmol/L)	LBS	6.83 (6.15)^a	6.18 (2.65)^a	6.18 (2.25)	<0.001^†	0.004	−1.43 (2.50)	−0.74 (3.37)

NH₄⁺ (mmol/L)	HBS	22.15 (12.85)^a,c	10.70 (5.00)^a	11.50 (5.60)^c	<0.001	<0.001	−9.68 (12.95)	−9.81 (12.73)
NH₄⁺ (mmol/L)	LBS	20.45 (11.48)^a,c	17.25 (6.70)^a	17.05 (8.57)^c	<0.001	<0.001	−3.94 (8.55)	−2.68 (11.80)

NAE (mEq/d)	HBS	22.44 (23.80)^a,c	−15.40 (11.40)^a	−14.25 (15.00)^c	<0.001^†	<0.001^†	−37.29 (23.25)	−36.72 (20.57)
NAE (mEq/d)	LBS	22.28 (19.00)^a	17.80 (9.65)^a	18.53 (13.20)	<0.001^†	0.011^†	−5.68 (17.00)	−3.81 (18.15)

Data are shown as median (IQR). HBS = high bicarbonate and sodium, LBS = low bicarbonate and sodium. TA = titratable acids, HCO₃⁻ = bicarbonate in urine, NH₄⁺ = ammonium, NAE = net acid excretion. Time × group interactions were analyzed using two-way repeated measures ANOVA. Differences over the intervention time within each group were assessed using repeated measures ANOVA. ^†Greenhouse–Geisser or Huynh–Feldt adjustment was used to correct for violations of sphericity. ^a = sign. Differences between and (short term), ^b = sign. Differences between and (follow-up), ^c = sign. Differences between and (long-term). The bold values are significant at p <0.05.