Higher dietary acid load is associated with hyperuricemia in Chinese adults: a case-control study

Dietary Acid Load and Human Health: A Systematic Review and Meta-analysis of Observational Studies

CONTEXT

Dietary acid load (DAL) plays an important role in different aspects of human health.

OBJECTIVE

The aim of this meta-analysis was to systematically synthesize the observational evidence reporting on the associations between the DAL (represented by a potential renal acid load [PRAL] and net endogenous acid production [NEAP]) and a range of health outcomes.

DATA SOURCES

A systematic search of Medline (via PubMed), EMBASE, Scopus, and Web of Science was performed to identify eligible studies.

DATA EXTRACTION

Study screening and risk-of-bias assessment were conducted by 2 independent reviewers.

DATA ANALYSIS

The credibility of each outcome was graded based on predefined criteria: pooled effect size with corresponding 95% CI, 95% prediction interval, heterogeneity, small-study effect, and excess significance bias. In total, 118 observational studies (case-control [n = 22], cross-sectional [n = 65], and cohort [n = 31]) on 38 outcomes were included, incorporating a total population of 1 014 081 participants. Overall, 21/37 and 20/38 of the outcomes reported statistically significant effect sizes for PRAL and NEAP, respectively. The credibility of the evidence for PRAL was rated convincing (class I) for type 2 diabetes (T2D), and as highly suggestive evidence (class II) for overall cancer and systolic blood pressure. By assessing the credibility of the evidence for NEAP, T2D and overall cancer presented convincing evidence (class I) and breast cancer presented highly suggestive evidence (class II). The remaining outcomes presented class III (suggestive) or lower evidence (weak or no association).

CONCLUSION

The higher acid-forming potential of diet was associated with a higher risk of T2D and overall cancer. Since this meta-analysis included observational studies and some of the associations were graded as weak, caution should be exercised in interpreting these associations. Further cohort studies are required with consideration of other factors that can cause biases.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42022336050.

The effects of diacylglycerol edible oil intervention in patients with chronic metabolic syndrome combined with asymptomatic hyperuricemia: study protocol for a multicenter, prospective, double-blind, randomized controlled trial

BACKGROUND

The aim of this study is to evaluate the efficacy and safety of diacylglycerol (DAG) edible oil intervention in patients with chronic metabolic syndrome complicated by asymptomatic hyperuricemia through a multicenter, prospective, double-blind, randomized controlled clinical trial.

METHODS

A multicenter, double-blind, and randomized controlled trial involving 176 patients was designed. All patients with chronic metabolic syndrome complicated by asymptomatic hyperuricemia who meet inclusion and exclusion criteria will be included in the study and will be randomized to either group A or group B. Group A will receive DAG-rich oil (≥ 80%) and group B will receive conventional cooking oil (triacylglycerol (TAG)-rich oil) for 12 weeks. Serum uric acid level is the primary outcome. Fasting blood glucose, 2 h postprandial blood glucose, fasting insulin, glycated hemoglobin, lipid profile, and average carotid intima-media thickness will be evaluated as the secondary outcomes. Blood routine, urine routine, liver enzymes, and electrocardiogram will be tested to assess the safety. The sample size for each group was calculated to be 88 cases.

DISCUSSION

We will evaluate the efficacy and safety of DAG oil compared with conventional TAG oil in patients with chronic metabolic syndrome with asymptomatic hyperuricemia. The dietary oil with superior efficacy and better safety will be recommended for reference use.

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2400085336. Registered on June 5, 2024.

Higher dietary acid load is associated with the risk of hyperuricemia

PURPOSE

Dietary acid load plays a key role in regulating serum uric acid levels. We hypothesized that dietary acid load indices would be positively associated with the odds of hyperuricemia. We aimed to test this hypothesis in a representative sample of Iranian adult population.

METHODS

In this cross-sectional study, a total of 6145 participants aged 35-65 years were recruited from MASHAD cohort study. Dietary intakes were assessed using a 24-h dietary recall. Diet-based acid load was assessed as the potential renal acid load (PRAL), net endogenous acid production (NEAP), and dietary acid load (DAL). Hyperuricemia was defined as serum uric acid greater than the 75th percentile. Multivariable logistic regression models were applied to determine the association between diet-based acid load scores and hyperuricemia.

RESULTS

The mean age of participants was 48.89 ± 8.09 years. Overall, 25.7% had hyperuricemia. According to the full-adjusted model, there was a significant association between higher tertile of PRAL, and DAL and hyperuricemia (Q3 PRAL; OR (95% CI): 1.23 (1.05-1.43), Q3 DAL; OR (95% CI): 1.22 (1.05-1.42)). Regarding NEAP, there was no significant association with hyperuricemia. We also found that dietary intake of total sugars, fiber, calcium, and magnesium was associated with the odds of hyperuricemia in our population.

CONCLUSION

This study showed a significant positive association between two indicators of dietary acid load (PRAL, and DAL) and odds of hyperuricemia among Iranian adults.

Association between Dietary Acid Load and Hyperuricemia in Chinese Adults: Analysis of the China Health and Nutrition Survey (2009)

BACKGROUND

This study evaluates the association between dietary acid load (DAL) and hyperuricemia in Chinese adults.

METHODS

The China Health and Nutrition Survey (CHNS) in 2009 was used in this cross-sectional study. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) were applied to estimate DAL. A multiple logistic regression model was used to test the relationship between DAL and hyperuricemia risk.

RESULTS

A total of 7947 participants were included in this study, of whom 1172 had hyperuricemia. The PRAL score was positively related to the prevalence of hyperuricemia, even when potential covariates were taken into account. In comparison with Q1, the ORs were 1.12 (95% CI, 0.92-1.38), 1.20 (95% CI, 0.97-1.47) and 1.42 (95% CI, 1.16-1.75) in Q2, Q3 and Q4. However, there was no significant relationship between NEAP scores and hyperuricemia. Every 10 g increase in energy-adjusted fat, protein and animal protein intakes caused a 10%, 17% and 18% increase in hyperuricemia risk, respectively (OR: 1.10, 95% CI: 1.04-1.16; OR: 1.17, 95% CI: 1.11-1.25; OR: 1.18, 95% CI: 1.12-1.24, respectively). An obvious linear correlation was also suggested by the restricted cubic spline.

CONCLUSIONS

Hyperuricemia risk was associated with higher PRAL among Chinese adults. This means that a diet low in PRAL scores could be a very valuable uric acid-lowering dietary pattern.