Effect of Tofu (bean curd) ingestion and on uric acid metabolism in healthy and gouty subjects

Association between dietary approaches to stop hypertension (DASH) diet and hyperuricemia among Chinese adults: findings from a nationwide representative study

Background

Certain foods and food groups could positively or negatively impact serum uric acid (SUA) levels. However, evidence on the holistic dietary strategy to prevent and control hyperuricemia (HUA) development remains limited.

Objective

The aim of this research work was to explore the association of dietary approaches to stop hypertension (DASH) diet with SUA levels and odds of HUA among Chinese adults.

Methods

This research premise included 66,427 Chinese adults aged 18 and above who were part of the China Adult Chronic Disease and Nutrition Surveillance in 2015. Dietary consumptions were assessed via the household condiment weighing approach and a three-day, 24-hour dietary recall. Total fat, saturated fat, calcium, protein, potassium, cholesterol, magnesium, fiber, and sodium were all adopted to calculate the DASH score (score range, 0–9). The associations of DASH score with SUA levels and odds of HUA were evaluated using multiple linear and logistic regression models, respectively.

Results

We established that a higher DASH score was linked with a lower SUA levels (β = − 0.11; 95% CI: − 0.12, − 0.1; p < 0.001) and odds of HUA (OR = 0.85; 95% CI: 0.83, 0.87; p < 0.001) after adjustment for age, sex, ethnicity, education status, marital status, health behaviours and health factors. The association of the DASH diet with odds of HUA was stronger among men (p-interaction = 0.009), non-Han Chinese (p-interaction< 0.001) as well as rural residents (p-interaction< 0.001).

Conclusions

Our results illustrate that the DASH diet was remarkably negatively with SUA levels and odds of HUA in the Chinese adult population.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12937-023-00845-w.

Soy consumption and serum uric acid levels: A systematic review and meta-analysis

Background

Soy consumption has health benefits, but the relationship between soy and uric acid remains uncertain. This meta-analysis and systematic review evaluated the effects of soy intake on plasma uric acid.

Methods

PubMed, Embase, CNKI, and the Cochrane Library were searched for studies evaluating the effects of soy, soy products, soy protein, and soy isoflavones on uric acid levels. The primary outcome was serum or plasma uric acid concentration. Study quality was evaluated by the Cochrane Collaboration and SYRCLE risk-of-bias tools.

Results

A total of 17 studies were included. Qualitative analysis of three human clinical studies of acute effects revealed that soy consumption increased serum uric acid concentration; however, soy-derived products, including tofu, bean curd cake, and dried bean curd sticks, had no significant effect on serum uric acid. A meta-analysis of five long-term human studies (10 data sets) revealed that soy protein and soy isoflavones had no significant effects on uric acid levels [weighted mean difference (WMD) = -2.11; 95% confidence interval (CI): -8.78, 4.55; p = 0.53]. However, most epidemiological data revealed that soy intake is inversely associated with uric acid levels. Meta-analysis of nine animal trials (29 data sets) revealed that soy protein and soy isoflavones significantly reduced serum uric acid concentrations (vs. controls; MD = -38.02; 95% CI: -50.60, -25.44; p < 0.001).

Conclusion

Soy and its products have different effects on serum uric acid. Soy products like tofu, bean curd cake, and dried bean curd sticks could be high-quality protein sources for individuals with hyperuricemia or gout. It can be beneficial to nutritionists and healthcare decision-makers reconsider their conceptions about the relationship between soy and uric acid levels according to the latest and further scientific study results.

Systematic review registration

[www.crd.york.ac.uk/PROSPERO], identifier [CRD42022331855].

The health effects of soy: A reference guide for health professionals

Soy is a hotly debated and widely discussed topic in the field of nutrition. However, health practitioners may be ill-equipped to counsel clients and patients about the use of soyfoods because of the enormous, and often contradictory, amount of research that has been published over the past 30 years. As interest in plant-based diets increases, there will be increased pressure for practitioners to gain a working knowledge of this area. The purpose of this review is to provide concise literature summaries (400-500 words) along with a short perspective on the current state of knowledge of a wide range of topics related to soy, from the cholesterol-lowering effects of soy protein to the impact of isoflavones on breast cancer risk. In addition to the literature summaries, general background information on soyfoods, soy protein, and isoflavones is provided. This analysis can serve as a tool for health professionals to be used when discussing soyfoods with their clients and patients.

Influence of d-Amino Acids in Beer on Formation of Uric Acid

Excessive intake of beer could increase serum uric acid levels, leading to high risk of gout, which was previously attributed to high purine content in beer. Recent reports that purine-rich vegetables and bean products do not cause higher uric acid levels do not support this theory. Why excessive intake of beer could increase a high risk of gout has been unclear. Other factors affecting the accumulation of uric acid in the blood have been explored. Beer contains relatively high levels of d-amino acids due to the racemization of l-amino acids induced by food processing. d-amino acid was catalyzed by d-amino acid oxidase to produce H₂O₂, which is further oxidized in the presence of Fe²⁺ to produce hydroxyl radicals, resulting in DNA damage and formation of a large amount of purine bases, which are oxidized to uric acid by a series of enzymes. Some food ingredients, such as vitamins and I^-, prompt d-amino acids to form uric acid. d-amino acids in beer are one of the key factors responsible for the increase in uric acid levels. The biological response of d-amino acids could explain gout occurrence in beer drinkers.

Food Sources of Protein and Risk of Incident Gout in the Singapore Chinese Health Study

OBJECTIVE

Prospective studies evaluating diet in relation to the risk of gout in Asian populations are lacking. The purpose of this study was to examine the relationship between the consumption of dietary protein from each of its major sources and the risk of gout in a Chinese population.

METHODS

We used data from the Singapore Chinese Health Study, a prospective cohort of 63,257 Chinese adults who were 45-74 years old at recruitment during the years 1993-1998. Habitual diet information was collected via a validated semiquantitative food frequency questionnaire, and physician-diagnosed gout was self-reported during 2 followup interviews up to the year 2010. Cox proportional hazards models were used to calculate the hazard ratios (HRs) and 95% confidence intervals (95% CIs), with adjustment for potential confounders, among 51,114 eligible study participants who were free of gout at baseline and responded to our followup interviews.

RESULTS

A total of 2,167 participants reported physician-diagnosed gout during the followup period. The multivariate-adjusted HRs (with 95% CIs) of gout, comparing the first quartile with the fourth quartile, were as follows: 1.27 (1.12-1.44; P for trend < 0.001) for total protein, 1.27 (1.11-1.45; P for trend < 0.001) for poultry, 1.16 (1.02-1.32; P for trend = 0.006) for fish and shellfish, 0.86 (0.75-0.98; P for trend = 0.018) for soy food, and 0.83 (0.73-0.95; P for trend = 0.012) for nonsoy legumes. No statistically significant associations were found with protein intake from other sources (red meat, eggs, dairy products, grains, or nuts and seeds).

CONCLUSION

In this Chinese population living in Singapore, higher total dietary protein intake from mainly poultry and fish/shellfish was associated with an increased risk of gout, while dietary intake of soy and nonsoy legumes was associated with a reduced risk of gout.

Determination of gouty arthritis' biomarkers in human urine using reversed-phase high-performance liquid chromatography

Creatinine, uric acid, hypoxanthine and xanthine are important diagnostic biomarkers in human urine for gouty arthritis or renal disease diacrisis. A simple method for simultaneous determination of these biomarkers in urine based on reversed-phase high-performance liquid chromatography (RP-HPLC) with ultraviolet (UV) detector was proposed. After pretreatment by dilution, centrifugation and filtration, the biomarkers in urine samples were separated by ODS-BP column by elution with methanol/50 mM NaH₂PO₄ buffer solution at pH 5.26 (5:95). Good linearity between peak areas and concentrations of standards was obtained for the biomarkers with correlation coefficients in the range of 0.9957–0.9993. The proposed analytical method has satisfactory repeatability (the recovery of data in a range of creatinine, uric acid, hypoxanthine and xanthine was 93.49–97.90%, 95.38–96.45%, 112.46–115.78% and 90.82–97.13% with standard deviation of <5%, respectively) and the limits of detection (LODs, S/N≥3) for creatinine, uric acid, hypoxanthine, and xanthine were 0.010, 0.025, 0.050 and 0.025 mg/L, respectively. The established method was proved to be simple, accurate, sensitive and reliable for the quantitation of gouty arthritis' biomarkers in human urine samples. The ratio of creatinine to uric acid was found to be a possible factor for assessment of gouty arthritis.

The association of dietary intake of purine-rich vegetables, sugar-sweetened beverages and dairy with plasma urate, in a cross-sectional study

Introduction

Hyperuricemia is a strong risk factor for gout. The incidence of gout and hyperuricemia has increased recently, which is thought to be, in part, due to changes in diet and lifestyle. Objective of this study was to investigate the association between plasma urate concentration and: a) food items: dairy, sugar-sweetened beverages (SSB) and purine-rich vegetables; b) related nutrients: lactose, calcium and fructose.

Methods

A total of 2,076 healthy participants (44% female) from a population-based case-control study in Scotland (1999–2006) were included in this study. Dietary data was collected using a semi-quantitative food frequency questionnaire (FFQ). Nutrient intake was calculated using FFQ and composition of foods information. Urate concentration was measured in plasma.

Results

Mean urate concentration was 283.8±72.1 mmol/dL (females: 260.1±68.9 mmol/dL and males: 302.3±69.2 mmol/dL). Using multivariate regression analysis we found that dairy, calcium and lactose intakes were inversely associated with urate (p = 0.008, p = 0.003, p = 0.0007, respectively). Overall SSB consumption was positively associated with urate (p = 0.008), however, energy-adjusted fructose intake was not associated with urate (p = 0.66). The intake of purine-rich vegetables was not associated to plasma urate (p = 0.38).

Conclusions

Our results suggest that limiting purine-rich vegetables intake for lowering plasma urate may be ineffectual, despite current recommendations. Although a positive association between plasma urate and SSB consumption was found, there was no association with fructose intake, suggesting that fructose is not the causal agent underlying the SSB-urate association. The abundant evidence supporting the inverse association between plasma urate concentration and dairy consumption should be reflected in dietary guidelines for hyperuricemic individuals and gout patients. Further research is needed to establish which nutrients and food products influence plasma urate concentration, to inform the development of evidence-based dietary guidelines.

Purine-rich foods, protein intake, and the prevalence of hyperuricemia: the Shanghai Men's Health Study

BACKGROUND AND AIMS

Diet may play an important role in the development of hyperuricemia and gout. However, the association between dietary factors and hyperuricemia remains unclear, and few studies have investigated direct links between food intake and hyperuricemia. The aim of this study was to investigate associations between high purine-content foods and protein intake with the prevalence of hyperuricemia by using data from a cross-sectional study of 3978 men aged 40-74 yrs living in Shanghai, China.

METHODS AND RESULTS

Hyperuricemia was defined as blood uric acid level >7.0 mg/dl. One quarter of this population had hyperuricemia. Dietary information was collected by using a food frequency questionnaire. We collected information on anthropometric measurements and lifestyle factors and other potential confounding factors and disease history via interviews. Total protein consumption was not associated with hyperuricemia. We found a positive association between protein from animal sources and prevalence of hyperuricemia and an inverse association between protein from plant sources and hyperuricemia. However, these associations failed to reach significance in mutually adjusted analysis. Seafood intake was associated with higher prevalence of hyperuricemia. The ORs for quintiles of seafood intake (including fish and shellfish) were 1.00, 1.49, 1.35, 1.34, and 1.56 (p for trend: 0.01). An inverse association approaching significance between soy food consumption and hyperuricemia was observed (ORs: 1.00, 0.90, 0.70, 0.89, and 0.77 for quintiles of intake; p for trend: 0.07). No associations between consumption of purine-rich vegetables or meat and prevalence of hyperuricemia were observed.

CONCLUSIONS

Our data suggest a direct association between seafood consumption and hyperuricemia and an inverse association between consumption of soy food and hyperuricemia among middle-aged, Chinese men.

Dietary intake and the risk of hyperuricemia, gout and chronic kidney disease in elderly Taiwanese men

INTRODUCTION

This study was conducted to examine the relationship between dietary intake and the risk of chronic kidney disease (CKD), treated hyperuricemia (or gout) without CKD, and untreated hyperuricemia without CKD in elderly men.

METHODS

The study population comprised 752 men aged 65 or older who had been included in the Elderly Nutrition and Health Survey (1999-2000) (Elderly NAHSIT).

RESULTS

Statistical analysis using a polychotomous logistic regression model revealed that compared with the individuals in the normouricemic group, the individuals in the other groups exhibited a significant association between a higher prevalence of CKD and the following factors: advanced age, drug use for hypertension, egg and shellfish consumption and consumption of poultry with the skin and meat with fat. The significant risk factors for the patients who did not have CKD and were undergoing treatment for hyperuricemia were as follows: BMI ≥ 25 kg/m(2); drug use for hypertension; intake of poultry with skin; increased daily consumption of shellfish, fried food, sugar and juice.

CONCLUSIONS

Men who use anti-hypertensive drugs and who consume fewer soy products and more shellfish may be at a higher risk of developing hyperuricemia or CKD.

Simultaneous determination of nucleosides and nucleotides in dietary foods and beverages using ion-pairing liquid chromatography-electrospray ionization-mass spectrometry

A method using ion-pairing liquid chromatography-electrospray ionization (ESI)-mass spectrometry (MS) was developed for the simultaneous determination of 23 types of purine or pyrimidine nucleosides and nucleotides in dietary foods and beverages. Dihexylammonium acetate (DHAA) was used as an ion-pairing agent and an ultra performance liquid chromatography (UPLC) system with a reversed-phase column and a gradient program was employed for the separation of nucleosides and nucleotides. Positive-ion ESI-MS was applied for the detection of nucleosides, and negative-ion ESI-MS was used for nucleotides. Lower limits of quantitation ranged from 0.02 micromol/L (UMP and AMP) to 1.3 micromol/L (CDP). The present method was validated, and sufficient reproducibility and accuracy was obtained for the quantitative measurement of the 23 types of nucleosides and nucleotides. The method was subsequently applied to their determination in a range of Japanese foods and beverages that are considered to contain significant amounts of umami flavor compounds. Because dietary purine nucleosides and nucleotides are known to be related to hyperuricemia and gout, the determination of their concentrations in dietary foods is useful for both evaluating umami flavor and assessing the effects of dietary food on purine metabolism.

A case-control study of the association of diet and obesity with gout in Taiwan

BACKGROUND

Gout has been a significant metabolic disorder for Chinese men in Taiwan; however, there is insufficient information on diet and lifestyle risk factors in this population.

OBJECTIVE

The purpose of this case-control study was to explore potential dietary and lifestyle risk factors associated with gout in Chinese men.

DESIGN

Between 1998 and 1999, we recruited and conducted face-to-face interviews with patients from outpatient clinics in Taipei who had incident gout (n = 92) and with their healthy coworkers (controls; n = 92).

RESULTS

Systolic blood pressure, diastolic blood pressure, waist-to-hip ratio, waist-to-height ratio, and body mass index were significantly higher in cases than in controls. Family histories of gout and diabetes mellitus were strong risk factors for gout. Frequencies of vegetable and fruit consumption were significantly lower in cases than in controls. Logistic regression analyses showed that high alcohol intake and low intakes of fiber, folate, and vitamin C increased the risk of gout, but no association was found with purine intake. After covariates were controlled for, the adjusted odds ratios for the middle and highest tertiles of waist-to-height ratio (0.50-0.54 and >/==" BORDER="0"> 0.55, respectively) were 3.89 (95% CI: 1.32, 11.46) and 4.37 (1.18, 16.22), respectively, but no linear association was found for waist-to-hip ratio and waist circumference.

CONCLUSIONS

Consumption of alcohol, but not of purine, may be a significant dietary risk factor for gout. Food sources rich in dietary fiber, folate, and vitamin C, such as fruit and vegetables, protect against gout. Waist-to-height ratio, which indicates central obesity, has a significant linear effect on gout occurrence, independent of body mass index.