Dietary Acid Load and the Risk of All-Cause Mortality: A Systematic Review and Meta-Analysis of Observational Studies

Various dietary patterns have different dietary acid loads (DALs) and may affect the body's acidity, initiate compensatory mechanisms, cause chronic low-grade metabolic acidosis over time, and thereby lead to the development of metabolic alterations.

In this systematic review and meta-analysis we focused on the association between DAL, as measured by the potential renal acid load (PRAL), net endogenous acid production (NEAP), and mortality risk.

The protocol for this review was registered in the PROSPERO database under registration number CRD42024570100. PubMed, Scopus, and Web of Science were systematically searched to find relevant studies published up to March 2024.

The full texts of the obtained articles were screened by 2 researchers to identify eligible studies. Then, all necessary information was drawn independently by one author according to an arranged screening form.

Six observational studies were included in this meta-analysis. Risk estimates were pooled using a random-effects model. A positive association was observed between the PRAL score and all-cause mortality, with non-significant heterogeneity (odds ratio [OR] per 10 mEq/d increase = 1.03, 95% CI, 1.01-1.05, P = .002, I2 = 48.4%). The NEAP score had no significant association with all-cause mortality, and there was substantial heterogeneity between studies (OR per 10 mEq/d increase = 1.00, 95% CI, 0.96, 1.05, P = .834, I2 = 66.6%).

Our results support the positive association between DAL and all-cause mortality risk, such that per 10 mEq/d increment in PRAL score, the risk of mortality increased up to 3%. Well-designed interventional studies are warranted to verify this association.