. 2017 Aug 22;9(8):914. doi: 10.3390/nu9080914

Table 5.

Randomized controlled trials (RCTs) comparing low mineralized water with bicarbonate-rich water with magnesium-rich water.

Author/y	Study Type	Population	Intervention	Comparison	Outcome	Results	Risk of Bias
Gutenbrunner, 1993 [16]	RCT parallel 2 groups single-blind	23 healthy men, 19–31 y, Germany	1.4 L per day of the test waters for 28 days Bicarbonate and magnesium-rich carbonated water: HCO³⁻ 2946 mg/L Cl⁻ 128 mg/L Na⁺ 967 mg/L Mg²⁺ 102 mg/L	Uncarbonated water: HCO³⁻ 150 mg/L Na⁺ 19.8 mg/L Mg not mentioned	FPG Fasting insulin GTT Fructosamin (all PO)	Bicarbonate and magnesium-rich water sign. decreased glucose tolerance and fructosamin compared to control water, but not FPG and fasting insulin.	No ITT, 1/24 drop-outs, single blind, randomization and allocation not reported
Murakami et al., 2015 [30]	RCT parallel 2 groups	19 healthy (7 men, 12 women), 47 y (26–59 y), Japan	500 mL per day premeal, mineral or control water for one week in two cycles. The intervention lasted 4 weeks Bicarbonate and magnesium-rich uncarbonated water: HCO³⁻ 2485 mg/L Cl⁻ 182 mg/L Na⁺ 412 mg/L Mg²⁺ 291 mg/L	Uncarbonated water: HCO³⁻ 28 mg/L Cl⁻ 11 mg/L Na⁺ 10 mg/L Mg²⁺ 1.9 mg/L	FPG Glycoalbumin, Fasting insulin HOMA-IR (all PO) Microbiome	Bicarbonate and magnesium-rich water sign. decreased glycoalbumin compared to control water. No sign. differences for FPG and fasting insulin. Lean-inducible bacteria was increased	No ITT, 7/26 drop-outs, no blinding

CG: control group; PO: primary outcome; SO: secondary outcome; sign.: p < 0.05; RCT: randomized controlled trial; FPG: fasting plasma glucose; GTT: glucose tolerance test; CVRF: cardiovascular risk factors; y: years.