The dietary acid load is higher in subjects with prediabetes who are at greater risk of diabetes: a case–control study

BACKGROUND: We aimed to examine the association of dietary acid load and prediabetes in a case–control study. METHODS: This study recruited 297 subjects including 147 prediabetic subjects and 150 controls referred to diabetes screening center in Shahreza, Iran. Participants were frequency-matched by sex and age. Blood pressure, anthropometric measures and blood glucose levels were measured. Dietary intake was assessed using a validated 168-items food frequency questionnaire (FFQ). The dietary acid load scores including the potential renal acid load (PRAL) and net endogenous acid production (NEAP) were calculated based on nutrients intake. NEAP and PRAL scores were categorized by quartiles based on the distribution of controls. Logistic regression models were used to estimate multivariable odds ratio (OR) of prediabetes across the energy-adjusted and sex-specific quartiles of NEAP and PRAL scores. RESULTS: Participants of control group in the higher quartiles of NEAP and PRAL tended to have higher body weight compared to the lower quartiles (P-trend < 0.04). After adjustment for multiple confounding variables, participants in the highest quartiles of NEAP and PRAL had increased OR for prediabetes (OR = 14.48 95% CI 5.64–37.19), and (OR = 25.61 95% CI 9.63–68.08) (P-trend < 0.001), respectively. CONCLUSION: Our data indicated subjects with prediabetes had diets with more acid-forming potential than control group. Our findings suggest that higher dietary acid load was associated with increased prediabetes morbidity. Interventional studies are warranted to elucidate the role of acidogenic diets in the development of prediabetes. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1186/s13098-019-0447-5) contains supplementary material, which is available to authorized users.