One positive quality RCT assessed blood pressure response to sodium bicarbonate (NaHCO3) intake in normotensive and hypertensive middle-aged men and women. Blood pressure was not affected by supplements of NaHCO3 (0.15 to 151mmol Na) in normotensive subjects, but in hypertensives (Luft et al, 1990) bicarbonate supplementation in mineral water (78.6mmol of sodium, 99.09mmol of bicarbonate) caused a significant decrease in SBP (by about 5mm Hg) compared to baseline. Additional studies were considered but did not meet the criteria for sample size or retention rate.
Luft et al, 1990 in a positive quality RCT assessed the effects of sodium bicarbonate (NaHCO3) on blood pressure in both normal (N=10) and hypertensive (N=10, BP greater than 140/90mm Hg) men and women ages 20-56 years. After a four-day lead-in period to achieve sodium balance and in addition to a controlled diet containing 60mmol Na per day, subjects were randomly assigned to consume one of two drinks with identical sodium concentrations:
- Three liters daily of a mineral water mix (78.6mmol of sodium, 99.09mmol of bicarbonate, along with potassium, magnesium, calcium, and chloride); or
- A control solution without bicarbonate with equimolar amounts of cations as the chloride salt was administered for seven days. Both regimens increased total sodium to 138mmol per day. After the seven days, subjects were given a lithium carbonate tablet and 30 days later, subjects followed the opposite regimen. Neither nor NaHCO3 had an effect on blood pressure in normotensive subjects, though NaHCO3 caused a significant decrease in SBP in hypertensives (by about 5mm Hg, P<0.05).