Dietary Acid Load Is Positively Associated with the Incidence of Hyperuricemia in Middle-Aged and Older Korean Adults: Findings from the Korean Genome and Epidemiology Study

Hyperuricemia has been associated with a number of chronic diseases, such as type 2 diabetes mellitus, hypertension, and cardiovascular diseases. Dietary acid load plays a key role in regulating uric acid levels. We hypothesized that potential renal acid load (PRAL) and net endogenous acid production (NEAP) score would be positively associated with the incidence of hyperuricemia. Data from the Health Examinees study, a part of the Korean Genome and Epidemiology Study were used. The PRAL and NEAP scores were calculated to evaluate the dietary acid load. Hyperuricemia was defined as follows: >7.0 mg/dL and >6.0 mg/dL of serum uric acid levels in men and women, respectively. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the incidence of hyperuricemia. We identified 2500 new cases of hyperuricemia during a mean follow-up of 5.0 years (223,552 person years). The participants in the highest quartiles of the PRAL and NEAP score had 21% (HR: 1.21, 95% CI: 1.07–1.35, p for trend <0.0001) and 17% (HR: 1.17, 95% CI: 1.04–1.31, p for trend <0.0001) higher risks for hyperuricemia, respectively, than those in the lowest quartiles, after adjusting for covariates. In this prospective cohort study, a higher dietary acid load was positively associated with a higher incidence of hyperuricemia in Korean adults. This suggests that an alkaline diet may be an effective strategy to reduce the future risk of elevated uric acid levels.

A Vegan Diet Is Associated with a Significant Reduction in Dietary Acid Load: Post Hoc Analysis of a Randomized Controlled Trial in Healthy Individuals

The composition of diet strongly affects acid–base homeostasis. Western diets abundant in acidogenic foods (meat and cheese) and deficient in alkalizing foods (fruits and vegetables) increase dietary acid load (DAL). A high DAL has been associated with numerous health repercussions, including cardiovascular disease and type-2-diabetes. Plant-based diets have been associated with a lower DAL; however, the number of trials exploring this association is limited. This randomized-controlled trial sought to examine whether an isocaloric vegan diet lowers DAL as compared to a meat-rich diet. Forty-five omnivorous individuals were randomly assigned to a vegan diet (n = 23) or a meat-rich diet (n = 22) for 4 weeks. DAL was determined using potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores at baseline and after 3 and 4 weeks, respectively. After 3 weeks, median PRAL (−23.57 (23.87)) and mean NEAPR (12.85 ± 19.71) scores were significantly lower in the vegan group than in the meat-rich group (PRAL: 18.78 (21.04) and NEAPR: 60.93 ± 15.51, respectively). Effects were mediated by a lower phosphorus and protein intake in the vegan group. Our study suggests that a vegan diet is a potential means to reduce DAL, whereas a meat-rich diet substantially increases the DAL burden.

Associations between Dietary Acid Load and Migraine Headache Severity and Duration among Women: A Cross-Sectional Study

Background: Migraine is considered the most common cause of long-term disability in under-50s, which can lead to unbearable pain and neurological dysfunction. Many factors, especially dietary factors, are suggested to trigger migraine headaches. The present study aimed to examine the association between diet-dependent acid load and severity and duration of headaches among migraine patients. Methods: In this cross-sectional study, a sample of 266 women (18-45 years) with history of migraine headaches was enrolled. Dietary data was collected by using a validated Food Frequency Questionnaire (FFQ). Then, diet-dependent acid load indices including Potential Renal Acid Load (PRAL) and Net Endogenous Acid Production (NEAP) were calculated for the participants. For all cases, anthropometric measurements and headache duration were assessed. Headache severity was determined by Visual Analog Scale (VAS) and Migraine Disability Assessment (MIDAS) questionnaires. Results: In this study, individuals with higher PRAL (OR=1.87, 95% CI=1.19-2.96, p=0.007) and NEAP (OR=1.58, 95% CI=1.02-2.44, p=0.03) scores were 87 and 58%, respectively, more likely to have severe headaches. Moreover, our results showed a significant direct correlation between PRAL (β=0.14, 95% CI=0.56-2.94, p=0.04) and NEAP (β=0.18, 95% CI=0.45-3.34, p=0.01) scores and headache duration of participants. Conclusion: The present study showed that higher diet-dependent acid load scores may be associated with higher headache severity and duration in migraine patients.

Epidemiologic Evidence for Association between a High Dietary Acid Load and the Breast Cancer Risk

Background and Purpose: Dietary acid load contributes to metabolic acidosis, leading to inflammation and cell transformation, potentially implicated in cancer development. Albeit an increased risk of recurrence among BC survivors was reported for a high acid load, the epidemiologic evidence associating diet-dependent acid load and cancer risk, particularly for breast cancer (BC), is still very limited. Therefore, we have explored in the present study its role in BC risk. Methods: A case-control study was performed on 1461 patients (572 BC cases and 889 age-frequency matched controls), through a multi-topic questionnaire, which included a food frequency questionnaire. Food-derived nutrients were calculated from available databases. The dietary acid load was calculated based on existing measures as potential renal acid load (PRAL) score and net endogenous acid production (NEAP) score. Odds Ratios (ORs) and their 95% confidence intervals were estimated by logistic regression, adjusting for potential confounders. Results: We found direct associations between dietary acid load and BC risk. Both scores were significantly associated (OR=2.46 and OR=1.78 for highest PRAL and NEAP, respectively). A positive BC family history involved higher risks (OR=6.14 and OR=3.38 for highest PRAL and NEAP, respectively). Linear trends were found in all overall and stratified analyses. Conclusions: Results suggest that a low acid load dietary style may reduce BC risk since both PRAL and NEAP scores were directly associated with meat intake and inversely associated with plant-based foods intake. The findings agree with studies focused on food groups and dietary patterns. Further studies are needed to confirm these findings. Doi: 10.28991/SciMedJ-2021-0302-8 Full Text: PDF

Dietary Acid Load and the Risk of Cardiovascular Disease: A Prospective Population-based Study

Background: Considering the established association between the dietary acid load and cardiovascular outcomes, as well as the existing inconstancies in the previous studies, we aimed to assess the association between the dietary acid load and the risk of cardiovascular diseases in the framework of the Tehran Lipid and Glucose Study. Methods: Eligible participants (n= 2369, 19- 70 years old, 43.5% men) with no cardiovascular diseases at baseline (2006-2008) were recruited and followed up for a mean period of 6.7 ± 1.4 years. Potential Renal Acid Load and Net Endogenous Acid Production, as the two indexes of dietary acid load, were calculated based on the macronutrient and micronutrient constitutions. The Cox proportional hazard regression model was used to report the association between tertiles of Potential Renal Acid Load and Net Endogenous Acid Production, and 6-years incident risk of cardiovascular diseases.Results: The mean age and body mass index of the participants were 38.5 ± 13.3 years and 26.6 ± 4.8 kg/m2 at baseline, respectively. The incident rate of cardiovascular diseases was reported as 3.3% (79 cases). No significant associations were detected between the Potential Renal Acid Load and the cardiovascular diseases incidence in the crude or the adjusted models (HRs= 0.63; CI: 0.36-1.17; P trend= 0.10). Meanwhile, the Net Endogenous Acid Production index was marginally significantly associated with the crude model (HR= 0.57; CI: 0.33-0.99, P trend= 0.048). Conclusions: Data from the current study were not in favor of an independent association between the dietary acid load and the incidence of cardiovascular diseases within the Iranian population.

Acid-Producing Diet and Depressive Symptoms among Breast Cancer Survivors: A Longitudinal Study

The incidence of depression is two-to-three times higher in cancer survivors than the general population. Acid-producing diets may play important roles in the development of depression. Cancer survivors are more susceptible to acid-producing diets, yet few prospective studies have investigated the association of acid-producing diets with depression among breast cancer survivors. We leveraged a large cohort of 2975 early stage breast cancer survivors, which collected detailed dietary data via 24-h recalls. Potential renal acid load (PRAL) and net endogenous acid production (NEAP), two commonly used dietary acid load scores, were used to estimate acid-producing diets. Intakes of PRAL and NEAP were assessed at baseline and years one and four. Increased PRAL and NEAP were each independently associated with increased depression in the longitudinal analyses, after adjusting for covariates. The magnitude of the associations was stronger for PRAL than NEAP. Women with the highest quartile intakes of PRAL had 1.34 (95% CI 1.11–1.62) times the risk of depression compared to women with the lowest quartile. Furthermore, we also observed a joint impact of PRAL and younger age on depression, as well as a joint impact of PRAL and physical activity on depression. Decreasing the consumption of acid-producing diets may be a novel and practical strategy for reducing depressive symptoms among breast cancer survivors, especially those who are younger and have a sedentary lifestyle.

The association between dietary acid load and muscle strength among Iranian adults

Objective There is limited evidence regarding the association between dietary acid load and muscle strength. Thus, in this study, we investigated the association between dietary acid–base load indices and muscle strength among Iranian adults. Results This cross-sectional study was conducted on 270 Iranian adults, aged 18–70 year. Dietary acid load indexes, were calculated by using a validated 168-item semi-quantitative food frequency questionnaire (FFQ). Muscle strength was measured by a digital handgrip dynamometer. There was a significant increase in mean muscle strength of left-hand (MSL), muscle strength of right-hand (MSR) and the mean of the MSL and MSR (MMS) across tertiles of Potential Renal Acid Load (PRAL), Net Endogenous Acid Production (NEAP), and Dietary Acid Load (DAL). Significant linear relationships between PRAL and; MSL (β = 0.24, p < 0.001), MSR (β = 0.23, p < 0.001) and MMS (β = 0.24, p < 0.001), between NEAP and MSL (β = 0.21, p < 0.001), MSR (β = 0.19, p = 0.002), and MMS (β = 0.20, p = 0.001) and between DAL and MSL (β = 0.25, p < 0.001), MSR (β = 0.23, p < 0.001) and MMS (β = 0.24, p < 0.001), were attenuated after controlling for potential confounders. However, the nonlinear relationship between dietary acid load indicators and muscle strength were significant (p < 0.001 for all).

The association between dietary acid load and the migraine odds

Background: According to previous evidence, it has been shown that high acidic load in human body could affect inflammatory factors and the nitric oxide pathway. On the other hand, these factors are thought to play a role in initiation of migraine attacks. Therefore, we aimed to explore the association between dietary acid load and the odds of migraine in a case-control study.Methods: The migraine group (n=514, diagnosed according to the ICHDIII criteria) was recruited from a tertiary headache clinic. The controls consisted of 582 sex-matched healthy volunteers who were randomly selected from the general population. For dietary intake assessments, we used a validated 168-item semiquantitative food frequency questionnaire (FFQ). Using three different measures, such as potential renal acid load (PRAL), net endogenous acid production (NEAP), and protein /potassium ratio for estimation of the dietary acid load.Results: According to multivariable logistic regression analysis, in comparison with the lowest tertile, highest tertile of dietary acid load measures including PRAL (OR=7.208, 95% CI 3.33– 15.55), NEAP (OR=4.108, 95% CI 1.924– 8.774), protein/potassium ratio (OR=4.127, 95% CI 1.933– 8.814) were shown to significantly increase odds of migraine (P for trend= <0.001).Conclusions: In this study, it was found that high dietary acid load may be associated with higher odds of migraine. Consequently, restricting dietary acid load could be beneficial in reducing the odds of developing migraine in susceptible subjects.

High dietary acid load score is not associated with the risk of metabolic syndrome in Iranian adults

Background and objective: The association between dietary acid load and metabolic syndrome (MetS) risk is not well-known. Therefore, we aimed to investigate the relationship between dietary acid load and the risk of MetS among Iranian adults. Methods: This cross-sectional study was carried out on 1430 Iranian adults. Dietary intakes were assessed using a validated food frequency questionnaire. Dietary acid load was estimated using potential renal acid load (PRAL) and net endogenous acid production (NEAP). MetS was defined according to the ATP-III criteria. The risk of MetS and its components was explored using logistic regression test. Results: Totally, 205 individuals were identified to have MetS. No significant association for MetS was found across the quartiles of PRAL and NEAP either in the crude model [Q4 PRAL: OR (95% CI): 0.94 (0.67–1.32), and NEAP: OR (95% CI): 0.88 (0.63–1.25)] or fully-adjusted model [Q4 PRAL: OR (95% CI): 0.90 (0.61–1.33), and NEAP: OR (95% CI): 1.05 (0.70–1.57)]. Amongst the components of MetS, higher scores of NEAP was associated with an increased risk of impaired blood sugar after adjustment for potential confounders [OR (95% CI): 1.35 (0.93–1.96)]. No significant association was found for other components either with PRAL or with NEAP. Conclusion: Our findings suggest no association between dietary acid load and MetS risk in Iranian adults. However, higher dietary acid load, measured by NEAP, but not PRAL, was associated with increased risk of impaired fasting blood sugar. Longitudinal studies are warranted to explore whether a diet low in potential acid load could reduce MetS risk.