Association of High Dietary Acid Load With the Risk of Cancer: A Systematic Review and Meta-Analysis of Observational Studies

Abstract

ObjectiveThis study aimed to determine the relationship between the high dietary acid load (DAL) and the risk of cancer.MethodsFive databases of PubMed, Web of Sciences, Scopus, Cochrane Library, and Google Scholar was searched to elicit original studies on humans, up to June 2021. Quality of the articles, risk of bias, and heterogeneity were assessed. A random-effects meta-analysis model was applied to estimate pooled effect size with a 95% confidence interval. Sensitivity analysis was performed using a fixed-effects model. Subgroup analyses were carried out based on gender, age, type of cancer, and type of DAL assessment indicator.ResultsSeventeen effect sizes from 10 articles were included in the analysis. Overall, individuals with the highest DAL were associated with a 66% increased risk of cancer compared to those with the lowest DAL (p < 0.001]. The risk of cancer increased 41% (p < 0.001) and 53% (p = 0.03) by high PRAL and NEAP, respectively. High DAL was associated with 32% (p < 0.001) and 79% (p < 0.001) increased risk of breast and colorectal cancers, respectively. High DAL was associated with 32% (p = 0.001) and 76% (p = 0.007) increased risk of cancer incident in women and men, respectively. The risk of cancer incident increased 35% (p < 0.001) and 49% (p < 0.001) at age ≤ and > of 50, respectively.ConclusionHigh DAL may be associated with a higher risk of cancer incidence not only in the whole studied population but also across cancer types, both genders, both DAL assessment indicators, and also among both high- and low-risk age groups for cancer.

Dietary acid load and esophageal cancer risk: A case‐control study

“…To the best of our knowledge, this is the first case‐control study to examine such an association in the English‐speaking scientific literature. Our findings are in line with two previous meta‐analyses that observed a significant association between higher DAL scores and the risk of cancer 30,31 …”

“…Our findings are in line with two previous meta-analyses that observed a significant association between higher DAL scores and the risk of cancer. 30,31 T A B L E 4 Crude and adjusted odds ratios (OR) of esophageal cancer for acid load scores (PRAL and NEAP). p-values for their linear trends Several plausible pathophysiological mechanisms may explain the observed associations.…”

“…30 Two recently published independent meta-analyses revealed positive associations of a high DAL and a higher risk of cancer incidence. 30,31 A high DAL has been associated with the following malignancies in large epidemiological studies on cancer: prostate, 32 bladder, 33 breast, 34,35 lung, 36 colorectum, 37 head and neck, 38 and pancreatic cancer. 39 The reservation must be made that investigations in this particular field are still scarce, and whether a high DAL may increase the risk for EC has not yet been examined in particular.…”

“…Chronic tissue inflammation may thus stimulate carcinogenesis or tumor progression; 28,29 and adherence to an acidogenic diet has been associated with an increased risk for some types of cancers 30 . Two recently published independent meta‐analyses revealed positive associations of a high DAL and a higher risk of cancer incidence 30,31 …”

“… 30 Two recently published independent meta‐analyses revealed positive associations of a high DAL and a higher risk of cancer incidence. 30 , 31 …”