The claimEvidence A · guideline-tier
Alkaline water / diet neutralises body acid
The evidence
Blood pH is locked at 7.35-7.45 by lungs and kidneys, and gastric acid neutralises the water first; Fenton 2016 (BMJ Open) systematic review rules out an acid-base/cancer link.
The mechanism, in brief
Human blood pH is held in an extremely narrow band of 7.35-7.45. This is not a recommended range but a survival limit. Once blood pH drifts below about 7.0 or above 7.7, proteins and enzymes denature — a life-threatening emergency. So the body evolved three powerful defenses that lock blood pH down:
Sources (2)
- Fenton, T. R., & Huang, T. (2016). Systematic review of the association between dietary acid load, alkaline water and cancer. BMJ Open, 6(6), e010438. Found no evidence supporting a causal link between dietary acid load or alkaline water and cancer.
- Hall, J. E., & Hall, M. E. (2020). Guyton and Hall Textbook of Medical Physiology (14th ed.): Acid-Base Regulation. Blood pH is held at 7.35-7.45 by the bicarbonate buffer, respiratory CO2 control, and renal handling of hydrogen and bicarbonate ions.