Higher dietary acid load is weakly associated with higher adiposity measures and blood pressure in Japanese adults: The National Health and Nutrition Survey

Adequate Vegetable Intake Improves Metabolic Indices in Healthy Japanese Participants: A Randomized Crossover Study

AIM

We aimed to elucidate the effect of a healthy diet containing adequate amounts of protein and vegetables on metabolic indices.

METHODS

In this randomized crossover study, twenty-two healthy Japanese participants ingested two different test meals: fish diet (F) or fish diet with adequate vegetable content (FV). Each 5-day diet load test was separated by a washout period of at least seven days. Metabolic indices were measured in fasting blood and 24-h urine samples.

RESULTS

The delta (Δ) plasma glucose and Δserum low-density lipoprotein (LDL) cholesterol concentrations were significantly larger in the participants in group FV than in group F (p=0.042, p=0.013, respectively). The urinary pH in participants in group F on day 6 was significantly lower than on day 1 (p=0.008), and the Δurinary pH and Δnet gastrointestinal absorption of alkali of participants in group FV tended to be smaller than in group F (p=0.070, p=0.075, respectively).

CONCLUSIONS

This study showed that a healthy diet containing adequate protein and vegetables reduced the dietary acid load and improved plasma glucose and serum LDL concentrations in healthy Japanese participants.

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.

Many foods are more acid-forming than acid-alkaline formulas indicate

Foods contain substances impacting the acid-base balance. The Western diet is often viewed as being overly acid due to its high-level of animal-based protein and low-level of vegetable intake. Meanwhile, with ageing the ability to excrete acid compounds is reduced as kidney function declines and so there is a risk of acid retention and subsequent interstitial acidosis. Two systems used for calculating the Dietary Acid Load (DAL): the potential acid load of foods (PRAL) and the net endogenous acid production (NEAP). This report outlines weaknesses in these formulas and concludes that dietitians and nutritionists lack the necessary tools to research the acid-base hypothesis. Additionally, the report emphasizes the importance of food selection in the ageing population. Background: Foods contain substances impacting the acid-base balance. The Western diet is often viewed as being overly acid due to its high-level of animal-based protein and low-level of vegetable intake. There are concerns that the disproportionate acid intake promotes low-grade metabolic acidosis in the interstitial fluid, interstitial acidosis, and may lead to chronic disease. Two formulas are used for calculating the DAL: the PRAL and the NEAP. Both PRAL and NEAP are based on levels of protein and minerals. Aim: To identify additional food constituents that impact DAL. Methods: Review of the literature concerning the acid-forming and alkaline-forming constituents of foods. Results: Five additional food constituents were identified as potentially having a meaningful impact on DAL. The oxidation of taurine and the metabolism of fructose and purines increase acidity, whereas organic acids increase alkalinity. Additionally, polyphenols affect the microbiota which break down uric acid excreted in the intestinal tract. Conclusions: Neither PRAL nor NEAP provides complete assessments of the impact of foods on DAL. These formulas could be improved by the inclusion of dietary amino acids rather than protein, taurine, purines, fructose, organic acids and polyphenols. Currently, dietitians and nutritionists lack the necessary tools both to research the acid-base hypothesis and recommend managed diets. Managed diets are of particular importance for the elderly because of their reduced kidney function which increases the risk of acid retention and subsequent interstitial acidosis.

A high dietary acid load can potentially exacerbate cardiometabolic risk factors: An updated systematic review and meta-analysis of observational studies

AIMS

Chronic metabolic acidosis has been shown to be associated with cardiometabolic risk factors. The aim of the currently updated meta-analysis was to explore the association between Potential Renal Acid Load (PRAL) and Net Endogenous Acid Production (NEAP) with these risk factors.

DATA SYNTHESIS

Databases were searched up to May 2023. The mean of waist circumference (WC), body mass index (BMI), high- and low-density lipoprotein-cholesterol (HDL-C and LDL-C), triglyceride (TG), total cholesterol (TC), fasting blood sugar (FBS), and systolic- and diastolic blood pressure (SBP and DBP) in highest category vs lowest categories of NEAP and PRAL were recorded. Effect sizes were generated as weighted mean difference (WMD). Results showed that SBP, DBP, and WC had a significant difference in the upper and lower categories of PRAL (WMDSBP: 1.466 mmHg; 95% CI: 2.121, -0.811; P<0.001, WMDDBP: 0.710 mmHg; 95 % CI: 1.170, -0.249; P=0.003, and WMDWC: 0.819 cm; 95% CI: 1.446, -0.192; P=0.010) or NEAP (WMDSBP: 1.690 mmHg; 95% CI: 2.789, -0.591; P=0.003, WMDDBP: 1.076 mmHg, and WMDWC: 1.325 cm; 95% CI: 1.901, -0.749; P<0.001; 95% CI: 1.938, -0.214; P =0.014). The lowest versus highest categories of dietary PRAL were associated with lower BMI (WMDPRAL: 0.297 kg/m2; 95 % CI: 0.440, -0.154; P<0.001) and TG (WMD: 2.280 mg/dl; 95%CI: 3.828, -0.732; P=0.004; I2=99.4 %; P<0.001).

CONCLUSIONS

High DAL can be considered as an independent risk factor for increasing anthropometric indices, blood pressure, and TG. This study registered in the PROSPERO database (Registration No. CRD42023402985).

The association between dietary acid load and odds of non-alcoholic fatty liver disease: A case-control study

Background: Data on the association between dietary acid load and non-alcoholic fatty liver disease (NAFLD) are scarce and controversial. Aim: This study aimed to assess the association between dietary acid-base loads and odds of NAFLD. Methods: In the current study, 196 cases of NAFLD (proven by a gastroenterologist using Fibroscan) and 803 age-matched controls were enrolled from the same clinic. Dietary intakes of patients with NAFLD and controls without hepatic steatosis were evaluated using a validated food frequency questionnaire. Dietary acid load was estimated using the validated potential renal acid load (PRAL) algorithm. Multivariable logistic regression model was used to estimate the odds of NAFLD across quintiles of PRAL. Results: The mean ± SD age of the study population (43% male) was 43.28 ± 14.02 years. The mean ± SD of PRAL was -1.90 ± 7.12 for all participants. After adjustment for all known confounders, subjects in the third quintile of PRAL (nearly with neutral PRAL) had a 54% lower odds of NAFLD compared with those in the lowest quintiles of the PRAL [(OR: 0.46; 95%CI: 0.24-0.89), (P = 0.021)]. However, the odds of NAFLD in the highest quintiles of PRAL was not different in comparison to the lowest quintiles (OR: 0.90; 95%CI: 0.41-1.57). Conclusion: In conclusion, our results have shown a modest U shaped relationship between PRAL and NAFLD. Further studies with acid-base biomarkers are needed to confirm the role of dietary acid load in the development of NAFLD and its potential mechanisms.

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

(1) Background: Current studies show conflicting results regarding the relationship between dietary acid load (DAL) and blood pressure. (2) Methods: The study used data from the Chinese Health and Nutrition Survey (CHNS) 2009. DAL was assessed on the basis of potential renal acid load (PRAL) and net endogenous acid production (NEAP). To examine the link between DAL and the risk of hypertension, a multivariate logistic regression model was utilized. (3) Results: A total of 7912 subjects were enrolled in the study, of whom 2133 participants had hypertension, a prevalence of 27.0%. After accounting for potential covariates, higher PRAL and NEAP scores were associated with a greater likelihood of developing hypertension, with ORs of 1.34 (95% CI, 1.10-1.62) and 1.29 (95% CI, 1.09-1.53) for PRAL and NEAP scores in Q4, respectively, compared with Q1. In the male group, PRAL and NEAP scores were positively linked to hypertension risk, with ORs of 1.33 (95% CI, 1.06-1.67) and 1.46 (95% CI, 1.14-1.85) for PRAL and NEAP scores in Q4, respectively, compared with Q1, while no significant associations were observed in the female group. Correlations between PRAL scores and hypertension risk lacked significance in the subgroup analyses for participants aged <60 years. There was a significant nonlinear connection observed in the dose-response relationship between DAL (based on PRAL) and hypertension; (4) Conclusions: In Chinese adults, higher PRAL and NEAP scores were positively linked to hypertension risk. This implies that a diet with a low DAL may be a favorable dietary pattern for lowering blood pressure.

The effect of a low renal acid load diet on blood pressure, lipid profile, and blood glucose indices in patients with type 2 diabetes: a randomized clinical trial

BACKGROUND

Observational studies have reported that dietary renal acid load has an important role in insulin resistance and metabolic factors. The aim of the present study was to assess the effect of a low renal acid load diet (LRALD) on blood pressure, lipid profile, and blood glucose indices in patients with type 2 diabetes.

METHODS

In this parallel randomized clinical trial, 80 patients with type 2 diabetes were randomly assigned to the LRALD (n = 40) or control (n = 40) groups, for 12 weeks. Both groups received a balanced diet and a list of nutritional recommendations based on healthy eating behaviors. In the LRALD group, food items with low renal acid load were prescribed. Primary outcomes including: fasting blood glucose (FBG), hemoglobin A1c (HbA1c), fasting serum insulin, quantitative insulin sensitivity check index (QUICKI), homeostatic model assessment for insulin resistance (HOMA) and secondary outcomes including: weight, systolic blood pressure (SBP), diastolic blood pressure (DBP), triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL), and high-density lipoprotein (HDL). were measured at baseline and end of the study. The present trial was registered at IRCT.ir (IRCT20130903014551N5).

RESULTS

Seventy subjects completed the study (n = 35 in control group and n = 36 in LRALD). Weight (P < 0.001), body mass index (P < 0.001), FBG (P < 0.001), HbA1c (P < 0.001), SBP (P = 0.004), and TG (P = 0.049) were reduced and HDL (P = 0.002) was increased in both groups, compared with baseline. After adjusting for baseline values, DBP (P = 0.047) was reduced in the LRALD group compared with control group. Results had no changes after using intention to treat analysis.

CONCLUSION

A LRALD may decrease DBP in type 2 diabetic patients. However, it elicited no significant effect on lipid profile compared with a healthy diet.

TRIAL REGISTRATION

This randomized clinical trial was registered at IRCT.ir (IRCT20130903014551N5).

Purine Content and Renal Acid Load Evaluation in Healthy Japanese Diets

During the treatment of hyperuricemia, attention should be paid to purine intake as part of the diet. Additionally, many patients with obese hyperuricemic expect early weight loss through glucose restriction. However, the amounts of purine in the diet are unknown. This study aimed to compare the purine content and potential renal acid load (PRAL) of a hospital diet and a low carbohydrate (LC). We calculated the nutritional values in the menus of the normal hospital (NH), energy-control (EC) diets served at several Shizuoka general hospitals, and the menus of LC diets. The amount of purine and PRAL was determined based on the nutritional values. The average daily purine content and energy were NH 349.0 mg, 1,808 kcal, EC 340.4 mg, 1,681 kcal, and LC 697.6 mg, 1,454 kcal, respectively. LC consumed more purine than the recommended daily intake of 400 mg. The PRAL score for NH was 4.5 mEq/d, EC 3.8 mEq/d, and LC 19.0 mEq/d, with LC representing diets with a higher acid load. In terms of both purine intake and uric acid excretion, the hospital diet is preferred over the low-carbohydrate diet for patients. Dietitians should exercise caution when recommending a low-carbohydrate diet for patients with hyperuricemia.

Household Income Is Related to Dietary Fiber Intake and Dietary Acid Load in People with Type 2 Diabetes: A Cross-Sectional Study

Household income was related to habitual dietary intake in general Japanese people. This cross-sectional study investigated the relationship between household income and habitual dietary intake in people with type 2 diabetes mellitus (T2DM). Household income was evaluated using a self-reported questionnaire and categorized into high and low household income. Nutritional status was assessed using a brief-type self-administered diet history questionnaire. Among 128 men and 73 women, the proportions of participants with low household income were 67.2% (n = 86/128) in men and 83.6% (n = 61/73) in women. Dietary fiber intake (11.3 ± 4.2 vs. 13.8 ± 6.0 g/day, p = 0.006) was lower, and dietary acid load, net endogenous aid production score (NEAP) (51.7 ± 10.5 vs. 46.8 ± 10.4 mEq/day, p = 0.014) and potential renal acid load score (PRAL) (9.5 ± 10.7 vs. 3.7 ± 14.1 mEq/day, p = 0.011) were higher in men with low household income than in those without. Multivariable linear regression analyses demonstrated that log (dietary fiber intake) in men with low household income was lower than that in those with high household income after adjusting for covariates (2.35 [2.26−2.44] vs. 2.52 [2.41−2.62], p = 0.010). Furthermore, NEAP (54.6 [51.7−57.4] vs. 45.8 [42.5−49.2], p <0.001) in men with low household income were higher than in those with high household income after adjusting for covariates. Contrastingly, household income was not related to diet quality in women. This study showed that household income was related to dietary fiber intake and dietary acid load in men but not in women.

The effects of diet quality and dietary acid load on insulin resistance in overweight children and adolescents

INTRODUCTION

This study aimed to investigate the association of diet quality (DQ) and dietary acid load (DAL) with insulin resistance (IR) in overweight children and adolescents.

MATERIALS AND METHODS

The study was conducted on 135 overweight participants aged 6-17 years. DQ was assessed using the Healthy Eating Index 2015 (HEI-2015) and the HEI-2015-TUBER, revised in accordance with the Turkey Dietary Guidelines (TUBER). Estimation of DAL was made calculating the potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores.

RESULTS

The HEI-2015-TUBER score was lower in those with IR than in those without IR (p=0.021). Higher PRAL and NEAP scores were found in those with IR (p=0.060 and p=0.044, respectively). Moreover, a one-unit increase in the HEI-2015-TUBER score and the DAL score was associated with a reduction of 4.2% and a rise of approximately 3% in IR risk, respectively.

CONCLUSIONS

Healthy eating habits in overweight paediatric groups may help to reduce the IR risk, improving DQ and decreasing DAL.

Dietary Acid Load is Associated with Hypertension and Diabetes in the Elderly

BACKGROUND

Diet can affect the body's acid-base balance due to its content of acid or base precursors. There is conflicting evidence for the role of metabolic acidosis in the development of cardiometabolic disorders, hypertension (HT), and insulin resistance (IR).

OBJECTIVE

We hypothesize that dietary acid load (DAL) is associated with adverse metabolic risk factors and we aimed to investigate this in the elderly.

METHODS

A total of 114 elderly participants were included in the study. The participants were divided into four groups such as HT, diabetes (DM), both HT and DM, and healthy controls. Anthropometric, biochemical, and clinical findings were recorded. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) results were obtained from three-day, 24-hour dietary records via a nutrient database program. (BeBiS software program).

RESULTS

The groups were matched for age, gender, and BMI. There was a statistically significant difference between the groups in terms of NEAP (p=0.01) and no significant difference for PRAL (p=0.086). The lowest NEAP and PRAL levels were seen in the control group while the highest in the HT group. Both NEAP and PRAL were correlated with waist circumference (r=0,325, p=0.001; r=0,231, p=0,016, respectively).

CONCLUSION

Our data confirmed that subjects with HT and DM had diets with greater acid-forming potential. High NEAP may be a risk factor for chronic metabolic diseases, particularly HT. PRAL couldn't be shown as a significantly different marker in all participants. Dietary content has a significant contribution to the reduction of cardiovascular risk factors such as HT, DM, and obesity.

Dietary Acid Load and Its Interaction with IGF1 (rs35767 and rs7136446) and IL6 (rs1800796) Polymorphisms on Metabolic Traits among Postmenopausal Women

The objective of this study was to explore the effects of dietary acid load (DAL) and IGF1 and IL6 gene polymorphisms and their potential diet–gene interactions on metabolic traits. A total of 211 community-dwelling postmenopausal women were recruited. DAL was estimated using potential renal acid load (PRAL). Blood was drawn for biochemical parameters and DNA was extracted and Agena^® MassARRAY was used for genotyping analysis to identify the signalling of IGF1 (rs35767 and rs7136446) and IL6 (rs1800796) polymorphisms. Interactions between diet and genetic polymorphisms were assessed using regression analysis. The result showed that DAL was positively associated with fasting blood glucose (FBG) (β = 0.147, p < 0.05) and there was significant interaction effect between DAL and IL6 with systolic blood pressure (SBP) (β = 0.19, p = 0.041). In conclusion, these findings did not support the interaction effects between DAL and IGF1 and IL6 single nucleotide polymorphisms (rs35767, rs7136446, and rs1800796) on metabolic traits, except for SBP. Besides, higher DAL was associated with higher FBG, allowing us to postulate that high DAL is a potential risk factor for diabetes.

The Association Between Dietary Acid Load and Odds of Migraine: A Case-Control Survey

INTRODUCTION

It has been shown that a high acid load in the human body can affect inflammatory factors and the nitric oxide pathway. These factors are also thought to play an important role in the initiation of migraine attacks. We have therefore explored the association between dietary acid load and odds of migraine in a case-control study.

METHODS

The migraine group (n = 514, diagnosed according to the International Classification of Headache Disorders 3rd edition [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. A validated 168-item semiquantitative food frequency questionnaire was used for dietary intake assessments. Estimation of the dietary acid load was performed using three different measures: potential renal acid load (PRAL) score, net endogenous acid production (NEAP) score, and protein/potassium ratio.

RESULTS

Multivariable logistic regression analysis showed that, in comparison with the lowest tertile, the highest tertile of dietary acid load measures, including PRAL (odds ratio [OR] 7.208, 95% confidence intervals [CI] 3.33-15.55), and NEAP (OR 4.108, 95% CI 1.924-8.774) scores and the protein/potassium ratio (OR 4.127, 95% CI 1.933-8.814), significantly increased the odds of migraine (P value for trend ≤ 0.001).

CONCLUSION

In this study, high dietary acid load was associated with higher odds of migraine. It is therefore possible that restricting dietary acid load could reduce the odds of migraine in susceptible subjects. However, due to the preliminary nature of the current evidence, caution is advised in drawing a definitive conclusion. More well-designed studies are required for a better understanding of this important issue.

The association between dietary acid load with cardiometabolic risk factors and inflammatory markers amongst elderly men: A cross-sectional study

BACKGROUND

Existing epidemiological data on dietary acid load and cardiovascular disease (CVD) are controversial. There is no literature evaluating the association between dietary acid load (DAL) with cardiometabolic risk factors and inflammatory markers in elderly.

OBJECTIVE

To evaluate the association between DAL and cardiometabolic risk factors amongst Iranian elders.

METHOD

A cross-sectional study was completed using 357 Iranian elders above >60 years of age. Anthropometric, clinical, and biochemical measurements were performed. Dietary intake was assessed using a validated and reliable food frequency questionnaire. DAL was estimated using the Potential Renal Acid Load (PRAL) score, Net Endogenous Acid Production (NEAP) and the Net Endogenous Acid Excretion (NAE) score. Metabolic syndrome (MetS) was defined according to the ATP-III criteria. Multivariable-adjusted odds ratios (ORs) of CVD risk factors were estimated using logistic regression.

RESULTS

After adjustment for confounders, a higher PRAL score was associated with higher odds of hypertriglyceridemia (OR: 2.28, 95% CI: 1.15, 4.50). We also observed that the NEAP score was positively associated with MetS (OR: 17.2, 95% CI: 2.34, 127). Finally, there was a positive association between NAE and lipid accumulation product (LAP) (OR: 1.81, 95% CI: 1.04, 3.17) and hypertriglyceridemia (OR: 2.46 95% CI: 1.22, 4.95).

CONCLUSION

Men with higher DAL scores had a higher risk of MetS, hypertriglyceridemia and LAP. Our findings suggest that further prospective studies are required to appraise DAL-CVD risk factors in populations with varying dietary patterns.

Estimates of renal net acid excretion and their relationships with serum uric acid and hyperuricemia in a representative German population sample

BACKGROUND/OBJECTIVE

Preliminary interventional data suggest that a reduction of dietary acid load raises renal uric acid excretion and decreases serum uric acid (SUA). In line with this, in a recent cross-sectional analysis of a representative adult population sample, a higher potential renal acid load (PRAL) was found to associate with higher SUA levels. Against this background, we re-examined the relationship of the body's acid load with SUA and hyperuricemia using nutrition-derived estimates of renal net acid excretion (NAE).

SUBJECTS/METHODS

Cross-sectional analyses were performed in n = 6894 participants (18-79 y) of the German Health Interview and Examination Survey for Adults (DEGS1). Two different approaches were used to estimate NAE, one based on the sum of food frequency questionnaire (FFQ)-derived PRAL and body-surface area-derived organic acids (eNAE_PRAL+OA) and the other based on FFQ-derived protein and potassium intake ratios (eNAE_Prot/K). The associations of eNAE_PRAL+OA and eNAE_Prot/K with SUA were analyzed in multiple linear regression models. Multiple logistic regressions were used to calculate odds ratios (OR) for hyperuricemia comparing higher (T3) and lower (T1) tertiles of the NAE estimates.

RESULTS

After adjusting for relevant confounders, eNAE_PRAL+OA (p = 0.0048) and eNAE_Prot/K (p = 0.0023) were positively associated with SUA. In addition, participants with a higher eNAE_PRAL+OA or eNAE_Prot/K had higher ORs for having hyperuricemia (OR: 1.73, 95% CI: 1.24-2.40, OR: 1.51, 95% CI: 1.10-2.08, respectively).

CONCLUSION

The results substantiate findings of a previous analysis that dietary acid load is a potential influencing factor on SUA. This implicates that a lower dietary acid load may have beneficial effects on SUA.

Association of Dietary Acid Load with the Prevalence of Metabolic Syndrome among Participants in Baseline Survey of the Japan Multi-Institutional Collaborative Cohort Study

The association between dietary acid load and metabolic syndrome (MetS) has not been fully investigated. A cross-sectional study was performed on 14,042 men and 14,105 women (aged 35-69 years) who participated in a baseline survey of the Japan Multi-Institutional Collaborative Cohort study. Dietary acid load was assessed using the net-endogenous-acid-production (NEAP) score that is closely correlated with the rate of renal net acid excretion. MetS was diagnosed according to the Joint Interim Statement Criteria of 2009 using body-mass index instead of waist circumference. After adjusting for potential confounders, higher NEAP scores were associated with a significantly increased odds ratio (OR) of MetS, obesity, high blood pressure, and high fasting blood glucose. These associations remained significant after further adjustment for carbohydrate intake or two nutrient-pattern scores significantly associated with MetS. After adjustment for fiber, iron, potassium, and vitamin pattern scores, the OR of MetS for the highest quartile of NEAP scores, relative to the lowest quartile, was 1.25 (95% confidence interval 1.12-1.39). There was no significant interaction between sex, age, or body-mass index and NEAP. Higher dietary acid load was associated with a higher prevalence of MetS and several of its components, independently of carbohydrate intake or nutrient patterns.

Association between dietary acid load and the risk of hypertension among adults from South China: result from nutrition and health survey (2015-2017)

Background

Higher dietary acid load (DAL) was considered to be associated with an elevated risk of hypertension, while related data from mainland China remains scarce and incomplete. We aim to evaluate the association between DAL and the risk of hypertension among adults from South China.

Methods

We conducted a nutrition and health survey in Guangdong Province located in southern China from 2015 to 2017. A four-stage probability sampling method was utilized to select representative samples of citizens aged ≥18 years old. DAL was assessed by potential renal acid load (PRAL) and net endogenous acid production (NEAP). Participants were divided to 4 groups (Q1-Q4) according to the quartile points of PRAL or NEAP distributions. Generalized linear mixed effects models were applied to evaluate the association between DAL and the risk of hypertension.

Results

A total of 3501 individuals were eligible for this study and 45.9% was male participants. Hypertension rate was 30.7%. A higher PRAL was associated with higher prevalence rate of hypertension among the male (P-trend = 0.03). OR for Q2 was 1.34 (95%CI, 0.94–1.91), Q3 was 1.53 (95%CI = 1.08, 2.16) and Q4 was 1.51 (95%CI, 1.08–2.16) among the male. However, as for total participants, the female, the participants with ≤55 years or participants with > 55 years, the associations were lack of significance. With respect to association between NEAP and hypertension, non-significant results were identified.

Conclusions

The current study indicated male hypertension was associated with higher PRAL, while given to this study was cross-sectional design, further studies are warranted to verify the association.

Dietary Acid Load: A Novel Nutritional Target in Overweight/Obese Children with Asthma?

Obesity has been repeatedly linked to asthma, and several potential mechanisms have been proposed in the etiologies of the obese-asthma phenotype. Considering that lungs play an important role in systemic pH and acid–base regulation, are a key organ in asthma development, and that nutritional inadequacy of several nutrients and high dietary acid load can affect airway inflammation and reactivity, we aimed to test the hypothesis that dietary acid load may be associated with asthma in children. Data on 699 children (52% females), aged 7–12 years, were analyzed. Anthropometric measurements were performed to assess body mass index. Dietary acid load was calculated using potential renal acid load (PRAL) equations from a 24 h dietary recall administrated to children. Adjusted PRAL for total energy intake was applied with the use of the residual method. Lung function and airway reversibility were assessed with spirometry. Asthma was defined by a positive bronchodilation or self-reported medical diagnosis with reported symptoms (wheezing, dyspnea, or dry cough) in the past 12 months. After adjustment for energy intake, sex, age, parent’s education level, and physical activity, positive and significant associations were found between asthma and PRAL [odds ratio (OR) = 1.953, 95% CI = 1.024, 3.730) in overweight/obese children. Our findings suggest that dietary acid load might be a possible mechanism in overweight/obese-asthma phenotype development.

Diet quality scores in relation to metabolic risk factors in Japanese adults: a cross-sectional analysis from the 2012 National Health and Nutrition Survey, Japan

OBJECTIVE

Associations between the overall quality of Japanese diets and metabolic risk factors are largely unknown. This cross-sectional study investigated this issue using data from the 2012 National Health and Nutrition Survey, Japan.

METHODS

Dietary intake was assessed by a 1-day weighed dietary record in 15,618 Japanese adults aged ≥ 20 years. Overall diet quality was assessed by adherence to the Japanese Food Guide Spinning Top (JFG score), its modified version (modified JFG score), the Mediterranean diet score (MDS) and the Dietary Approaches to Stop Hypertension (DASH) score. Metabolic risk factors included BMI, waist circumference, blood pressure, total, HDL- and LDL-cholesterol and glycated haemoglobin.

RESULTS

While DASH score was consistently associated with favourable nutrient intake patterns (including higher micronutrient and dietary fibre intakes and lower SFA and sodium intakes), other scores were associated with both favourable and unfavourable aspects (e.g., lower micronutrient intakes for JFG score, higher SFA intakes for modified JFG score and higher sodium intakes for MDS). The associations with metabolic risk factors were also inconsistent and unexpected, including positive associations of JFG and modified JFG scores with LDL-cholesterol, inverse associations of MDS with HDL-cholesterol and null associations of DASH score with blood pressure.

CONCLUSIONS

This study did not show expected and consistent associations of the four available diet quality scores with nutrient intakes and metabolic risk factors in Japanese adults. This in turn suggests the need for a scientific base on which to develop an appropriate tool for assessing the quality of diets in the Japanese context.

Elevated hypertension risk associated with higher dietary acid load: A systematic review and meta-analysis

BACKGROUND & AIMS

The association between dietary acid load and hypertension risk is inconclusive. We conducted a systematic review and meta-analysis to summarize effect of dietary acid load on blood pressure.

METHODS

A comprehensively search was performed in electronic databases including EMBASE, PubMed, Web of Science and Chinese National Knowledge Infrastructure. Summary ORs and their corresponding 95% CIs were computed assuming a randomized model or fixed model.

RESULTS

Ten publications comprising 4 cohort and 6 cross-sectional studies were eligible for meta-analysis. There were 8 studies about potential renal acid load (PRAL) and 4 about net endogenous acid production (NEAP). Essential hypertension was statistically associated with higher PRAL (OR = 1.14, 95% CI = 1.02-1.17). Our findings also demonstrated a positive impact of higher PRAL on elevating both diastolic pressure (WMD = 0.96, 95% CI = 0.67-1.26) and systolic pressure (WMD = 1.57, 95% CI = 1.12-2.03). A 35% increased risk of hypertension associated with higher NEAP was identified (OR = 1.35, 95% CI = 1.03-1.78).

CONCLUSIONS

The current study suggests that dietary acid load might be potential risk factor of hypertension.