Higher estimated net endogenous Acid production may be associated with increased prevalence of nonalcoholic Fatty liver disease in chinese adults in Hong Kong

Effects of higher dietary acid load: a narrative review with special emphasis in children

Metabolic effects of high diet acid load (DAL) have been studied for years in adults, although only recently in children. Contemporary diets, especially those of Western societies, owe their acidogenic effect to high animal-origin protein content and low contribution of base-forming elements, such as fruits and vegetables. This imbalance, where dietary acid precursors exceed the body's buffering capacity, results in an acid-retaining state known by terms such as "eubicarbonatemic metabolic acidosis," "low-grade metabolic acidosis," "subclinical acidosis," or "acid stress". Its consequences have been linked to chronic systemic inflammation, contributing to various noncommunicable diseases traditionally considered more common in adulthood, but now have been recognized to originate at much earlier ages. In children, effects of high DAL are not limited to growth impairment caused by alterations of bone and muscle metabolism, but also represent a risk factor for conditions such as obesity, insulin resistance, diabetes, hypertension, urolithiasis, and chronic kidney disease (CKD). The possibility that high DAL may be a cause of chronic acid-retaining states in children with growth impairment should alert pediatricians and pediatric nephrologists, since its causes have been attributed traditionally to inborn errors of metabolism and renal pathologies such as CKD and renal tubular acidosis. The interplay between DAL, overall diet quality, and its cascading effects on children's health necessitates comprehensive nutritional assessments and interventions. This narrative review explores the clinical relevance of diet-induced acid retention in children and highlights the potential for prevention through dietary modifications, particularly by increasing fruit and vegetable intake alongside appropriate protein consumption.

High dietary acid load predicts severity of autoimmune skin disease: a cross-sectional study

No previous study has examined the association of an acid-base imbalanced diet to autoimmune bullous disease. The present study aimed to investigate the association between dietary acid load (DAL) as either potential renal acid load (PRAL) and net endogenous acid production (NEAP) intake on the odds of high-severity Pemphigus Vulgaris (PV) disease in adult Iranian patients to fill this gap. A cross-sectional study was conducted on 138 patients, aged 18-65 years with confirmed diagnoses of PV in a referral university center for autoimmune bullous diseases. The dietary intakes of all patients during the last year before enrollment in the study were assessed using a 168-item semi-quantitative food frequency questionnaire. Dietary acid load was calculated based on the PRAL and NEAP scores. To assess PV severity, the pemphigus disease area index (PDAI) score was used. Logistic regression was used to evaluate the association between DAL and PDAI. A positive association was observed between PRAL and PDAI score in the crude (adjusted R2 = 0.088, B = 6.88, P < 0.0001) and all other adjusted models, as well as the crude model for NEAP (adjusted R2 = 0.037, B = 4.72, P = 0.013). In terms of adherence to NEAP and PRAL, those in the top tertile of PRAL and NEAP had a higher vulnerability for severe PV in unadjusted (OR = 5.18, 95% (CI) 2.19-12.25) and (OR = 2.48, 95% (CI)  1.08-5.68) respectively. In the present study, we found a significant direct association between DAL and severity of disease in PV patients. Further studies are required to confirm these findings.

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.

Dietary acid load in health and disease

Maintaining an appropriate acid-base equilibrium is crucial for human health. A primary influencer of this equilibrium is diet, as foods are metabolized into non-volatile acids or bases. Dietary acid load (DAL) is a measure of the acid load derived from diet, taking into account both the potential renal acid load (PRAL) from food components like protein, potassium, phosphorus, calcium, and magnesium, and the organic acids from foods, which are metabolized to bicarbonate and thus have an alkalinizing effect. Current Western diets are characterized by a high DAL, due to large amounts of animal protein and processed foods. A chronic low-grade metabolic acidosis can occur following a Western diet and is associated with increased morbidity and mortality. Nutritional advice focusing on DAL, rather than macronutrients, is gaining rapid attention as it provides a more holistic approach to managing health. However, current evidence for the role of DAL is mainly associative, and underlying mechanisms are poorly understood. This review focusses on the role of DAL in multiple conditions such as obesity, cardiovascular health, impaired kidney function, and cancer.

Dietary acid load and cirrhosis-related mortality: a prospective cohort study

As a global health concern, cirrhosis contributes significantly to morbidity and mortality. This prospective cohort study aimed to investigate the association between dietary acid load (DAL) and cirrhosis-related mortality. Present study was conducted on 121 patients with newly diagnosed cirrhosis who were followed up for 48 months. Anthropometric measures, nutritional status and dietary intakes were assessed and DAL was estimated based on potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores. Crude and multivariable-adjusted hazard ratios (HR) with 95% confidence intervals (CI) were estimated using Cox proportional hazard analyses. Participants in the high PRAL and NEAP scores had significantly higher intakes of grains and lower intakes of fruits and vegetables. Also, the intake of dairy products and legumes, nuts and seeds decreased significantly with increasing NEAP score. After adjustment of all the confounders, the risk of mortality in the second and third tertiles of PRAL was 5.9 times and 10.97 higher than those in the first tertile, respectively (P trend: 0.006). Similarly, comparing the risk of mortality in the second and third tertiles with the first tertile of NEAP showed a 4.46-fold and 12.3-fold increased risk, respectively (P trend: 0.010). Our findings suggested that DAL was significantly associated with cirrhosis-related mortality and highlight the need for further research to understand the underlying mechanisms and establish optimal DAL levels in cirrhotic patients.

Association of Dietary Acid Load with Nonalcoholic Fatty Liver Disease and Advanced Liver Fibrosis in US Adults: Evidence from NHANES 1999-2018

Background

Evidence for an association between dietary acid load (DAL) and non-alcoholic fatty liver disease (NAFLD) is scarce and controversial. We aimed to address whether an association exists between DAL and NAFLD/advanced liver fibrosis (AHF) among US adults in a nationally representative study.

Methods

This was a cross-sectional study. We included adult participants from the National Health and Nutrition Examination Survey 1999-2018. Potential renal acid load (PRAL) and estimated net endogenous acid production (NEAP) was calculated from the literature and NAFLD/AHF was diagnosed by noninvasive markers. We comprehensively explored these relationships using multivariate adjusted regression models, restricted cubic spline, stratification analysis, and sensitivity analysis.

Results

We enrolled a total of 18,855 participants. All DAL metrics were positively and nonlinearly associated with NAFLD (all p-values < 0.0001), whereas NEAPF and NEAPR may be associated with AHF. In the stratified analysis, we found that the correlation between DAL and NAFLD exists in all ages and genders, but the effect of DAL seems to be more obvious in middle-aged, elderly and women. Similarly, we found that the effect of DAL on AHF was more significant in 45-60-year-olds and women. Sensitivity analyses revealed stability of all results.

Conclusion

DAL including PRAL and NEAP were positively associated with NAFLD in a large nationally representative cross-sectional study. NEAPF and NEAPR may be associated with increased odds of AHF. Adjustment for diet-dependent DAL requires age- and sex-specific strategies. Future prospective studies are needed to validate our findings.

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.

Mediators of dietary diversity score (DDS) on NAFLD in Iranian adults: a structural equation modeling study

BACKGROUND

The current study examines the association between the Dietary Diversity Score (DDS) and nonalcoholic fatty liver disease (NAFLD) in Iranian adults using structural equation modeling (SEM).

METHODS

A sample of 3220 adults from the Amol Cohort Study was recruited for this cross-sectional study. Dietary acid load (DAL) and DDS were calculated using the data obtained from a validated food frequency questionnaire. Anthropometric parameters, blood pressure, biochemical measurements, and liver ultrasonography were evaluated according to standard protocols.

RESULTS

DDS was neither directly nor indirectly associated with a greater prevalence of NAFLD. In the second model (DDS sub-scores model), the association of DAL with NAFLD was fully mediated through waist circumference (WC) (of DAL to WC: β = 0.14, P < 0.0001, and of WC to NAFLD: β = 0.50, P < 0.001). Vegetable and fruit diversity scores had a significant negative indirect relationship with NAFLD prevalence through DAL (β = -0.06, P = 0.001, β = -0.10, P < 0.001, respectively). Meat diversity score was positively associated with NAFLD prevalence in a full mediational process through DAL (β = 0.12, P < 0.001). The SEM fit indices suggested a reasonably adequate fit of the data to the DDS model (Χ2/df = 4.76, GFI = 0.98, AGFI = 0.97, IFI = 0.97, CFI = 0.97, RMSEA = 0.03, and SRMR = 0.02) and its sub-scores model (Χ²/df = 4.72, GFI = 0.98, AGFI = 0.97, IFI = 0.95, CFI = 0.95, RMSEA = 0.03, and SRMR = 0.02).

CONCLUSION

Meat diversity and lack of vegetable and fruit diversity were indirectly associated with NAFLD prevalence through DAL and WC mediators. Interventions for NAFLD may be more successful if they target a lower intake of animal protein sources and dietary diversity, particularly vegetable and fruit diversity.

Dietary magnesium intakes among women of reproductive age in Ghana-A comparison of two dietary analysis programs

BACKGROUND

Despite the importance of magnesium to health and most importantly to women of reproductive age who are entering pregnancy, very few surveys have investigated the magnesium status of women of reproductive age, particularly in Africa. Additionally, the software and programs used to analyze dietary intake vary across countries in the region.

OBJECTIVE

To assess the dietary magnesium intake of women of reproductive age in Ghana and to compare the estimate of magnesium intake obtained from two commonly used dietary analysis programs.

METHODS

We collected magnesium intake from 63 Ghanaian women using a semiquantitative 150-item food frequency questionnaire. Dietary data was analyzed using two different dietary analysis programs, Nutrient Data Software for Research (NDSR) and the Elizabeth Stewart Hands and Associates (ESHA) Food Processor Nutrition Analysis software. We used the Wilcoxon signed rank test to compare the mean differences between the two dietary programs.

RESULTS

There were significant differences between the average dietary magnesium intake calculated by the two dietary programs, with ESHA estimating higher magnesium intake than NDSR (M±SE; ESHA: 200 ± 12 mg/day; NDSR: 168 ± 11 mg/day; p<0. 05). The ESHA database included some ethnic foods and was flexible in terms of searching for food items which we found to be more accurate in assessing the magnesium intake of women in Ghana. Using the ESHA software, 84% of the study women had intake below the recommended dietary allowances (RDA) of 320mg/day.

CONCLUSION

It is possible that the ESHA software provided an accurate estimate of magnesium in this population because it included specific ethnic foods. Concerted efforts such as magnesium supplementation and nutrition education should be considered to improve the magnesium intake of women of reproductive age in Ghana.

Chronic Sub-Clinical Systemic Metabolic Acidosis - A Review with Implications for Clinical Practice

When arterial serum pH remains near the lower pH limit of 7.35 for protracted periods of time, a low-grade, sub-clinical form of acidosis results, referred to in this review as chronic, sub-clinical, systemic metabolic acidosis (CSSMA). This narrative review explores the scientific basis for CSSMA, its consequences for health, and potential therapeutic interventions. The major etiology of CSSMA is the shift away from the ancestral, alkaline diet which was rich in fruit and vegetables, toward the contemporary, acidogenic 'Westernized' diet characterized by higher animal protein consumption and lack of base forming minerals. Urine pH is reduced with high dietary acid load and may be a convenient marker of CSSMA. Evidence suggests further that CSSMA negatively influences cortisol levels potentially contributing significantly to the pathophysiology thereof. Both CSSMA and high dietary acid load are associated with the risk and prognosis of various chronic diseases. Clinical trials show that CSSMA can be addressed successfully through alkalizing the diet by increasing fruit and vegetable intake and/or supplementing with alkaline minerals. This review confirms the existence of a significant body of evidence regarding this low-grade form of acidosis as well as evidence to support its diverse negative implications for health, and concludes that CSSMA is a condition warranting further research.

Dietary Acid Load (DAL), Glycated Hemoglobin A1c (HbA1c), and Metabolic Syndrome (MeS) Mediate the Association of the Adherence to the Dietary Approaches to Stopping Hypertension (DASH) and Mediterranean Diet (MeD) With Nonalcoholic Fatty Liver Disease

The study aimed to investigate the association of adults adhering to Dietary Approaches to Stop Hypertension (DASH) and Mediterranean diet (MeD) with nonalcoholic fatty liver disease (NAFLD) using structural equation modeling (SEM) in Iran. In this population-based cross-sectional study, 3,220 adults (44.65% female) aged ≥18 years were selected from the Amol Cohort Study (AmolCS). The dietary intakes were assessed by a validated 168-item semi-quantitative food-frequency questionnaire (FFQ). Residual method energy adjustment of MeD and DASH scores were calculated. Demographic characteristics and anthropometric and laboratory measurements were collected. NAFLD was diagnosed by an expert radiologist via ultrasound sonography. Based on the primary hypothesis, DASH, MeD, and NAFLD were fitted into models. Metabolic syndrome (MeS) as a potential risk factor directly affected NAFLD risk in all these models. In both genders, the higher adherence to DASH negatively affected NAFLD risk indirectly through the two following paths. (1) Dietary acid load (DAL) and metabolic syndrome (2) DAL and hemoglobin A1c (HbA1c). In addition, the higher DAL positively affected NAFLD risk among male participants indirectly via increasing HbA1c level and MeS (from DAL to HbA1c: β = 0.07, P < 0.001; from HbA1c to MeS: β = 0.10, P < 0.001). Similarly, in both genders, the relationship between MeD and NAFLD was mediated through (1) DAL, HbA1c, and MeS and (2) DAL and MeS. Further, among male participants, the MeD and NAFLD risk were also associated via the mediators of HbA1c and MeS. In female participants, the higher MeD score was directly associated with a reduction of NAFLD risk (β = -0.07, P = 0.008). The present study found three important mediators, including DAL, HbA1c, and MeS, in the association of DASH and MeD scores with NAFLD risk. Preventive and therapeutic interventions should target the mediators, including DAL, HbA1c, MeS, and its components, to reduce NAFLD incidence in the general population.

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.

Crosstalk between Acidosis and Iron Metabolism: Data from In Vivo Studies

Iron absorption requires an acidic environment that is generated by the activity of the proton pump gastric H(+)/K(+)ATPase (ATP4), expressed in gastric parietal cells. However, hepcidin, the iron regulatory peptide that inhibits iron absorption, unexpectedly upregulates ATP4 and increases gastric acidity. Thus, a concept of link between acidosis and alterations in iron metabolism, needs to be explored. We investigated this aspect in-vivo using experimental models of NH4Cl-induced acidosis and of an iron-rich diet. Under acidosis, gastric ATP4 was augmented. Serum hepcidin was induced and its mRNA level was increased in the liver but not in the stomach, a tissue where hepcidin is also expressed. mRNA and protein levels of intestinal DMT1(Divalent Metal Transporter 1) and ferroportin were downregulated. Serum iron level and transferrin saturation remained unchanged, but serum ferritin was significantly increased. Under iron-rich diet, the protein expression of ATP4A was increased and serum, hepatic and gastric hepcidin were all induced. Taken together, these results provide evidence of in-vivo relationship between iron metabolism and acidosis. For clinical importance, we speculate that metabolic acidosis may contribute in part to the pathologic elevation of serum hepcidin levels seen in patients with chronic kidney disease. The regulation of ATP4 by iron metabolism may also be of interest for patients with hemochromatosis.

Relationship between dietary macronutrient composition and non-alcoholic fatty liver disease in lean and non-lean populations: a cross-sectional study

OBJECTIVE

The current study aimed to customize dietary changes for lean patients with non-alcoholic fatty liver disease (NAFLD).

DESIGN

The current study was done with a population-based cross-sectional design. The FFQ was used to analyse dietary macronutrient intake and ultrasonography results for NAFLD diagnosis. The study subjects were divided into the lean and non-lean groups based on their BMI (< 25 and ≥ 25). Multivariable logistic regression was used to evaluate the relationship between dietary macronutrients and NAFLD. Substitution analyses were also performed.

SETTING

Amol and its suburban areas in Iran.

PARTICIPANTS

Adults in the age range of 18 to < 65 with full relevant data.

RESULTS

Among the total study subjects (2308), 46·7 % had fatty liver. The substitution of polysaccharides for animal protein and SFA in the lean group resulted in a significant NAFLD reduction, whereas the substitution of SFA for all types of macronutrients, except for n-6 and mono-disaccharides, led to a significant increase in NAFLD (P < 0·05). In non-lean participants, the substitution of MUFA for mono-disaccharides resulted in a significant reduction of NAFLD (P < 0·05). In this group, the substitution of SFA and mono-disaccharides for MUFA, and n-6 for all macronutrients, except vegetable protein and SFA, were significantly related to an increase in NAFLD (P < 0·05).

CONCLUSIONS

Lower lean NAFLD is correlated with increasing polysaccharides in exchange for SFA and animal protein intake, whereas lower non-lean NAFLD is correlated with increasing MUFA in exchange for mono-disaccharides and reducing n-6 and SFA.

Non-alcoholic fatty liver disease: a metabolic burden promoting atherosclerosis

Non-alcoholic fatty liver disease (NAFLD) has become the fastest growing chronic liver disease, with a prevalence of up to 25% worldwide. Individuals with NAFLD have a high risk of disease progression to cirrhosis, hepatocellular carcinoma (HCC), and liver failure. With the exception of intrahepatic burden, cardiovascular disease (CVD) and especially atherosclerosis (AS) are common complications of NAFLD. Furthermore, CVD is a major cause of death in NAFLD patients. Additionally, AS is a metabolic disorder highly associated with NAFLD, and individual NAFLD pathologies can greatly increase the risk of AS. It is increasingly clear that AS-associated endothelial cell damage, inflammatory cell activation, and smooth muscle cell proliferation are extensively impacted by NAFLD-induced systematic dyslipidemia, inflammation, oxidative stress, the production of hepatokines, and coagulations. In clinical trials, drug candidates for NAFLD management have displayed promising effects for the treatment of AS. In this review, we summarize the key molecular events and cellular factors contributing to the metabolic burden induced by NAFLD on AS, and discuss therapeutic strategies for the improvement of AS in individuals with NAFLD.

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.

Diet-Dependent Acid Load-The Missing Link Between an Animal Protein-Rich Diet and Nonalcoholic Fatty Liver Disease?

OBJECTIVE

Our group recently showed that animal protein was independently associated with nonalcoholic fatty liver disease (NAFLD). We hypothesize that this may be explained by a high diet-dependent acid load [dietary acid load (DAL)].

METHODS

This cross-sectional study is embedded in a prospective population-based cohort. We estimated DAL proxies via food-frequency questionnaires using potential renal acid load (PRAL; using dietary protein, phosphorus, potassium, calcium, and magnesium intake), net endogenous acid production (NEAP; using protein and potassium intake), and the animal protein-to-potassium ratio (A:P). We defined NAFLD using ultrasound after excluding secondary steatogenic causes. We used logistic regression models-adjusted for sociodemographic, lifestyle, and metabolic traits-on categorized [quartile (Q)1 to 4] and continuous DAL proxies (allowing for nonlinearity) and NAFLD.

RESULTS

We included 3882 participants, of which 1337 had NAFLD. All DAL proxies were higher, meaning more acidic, in individuals with NAFLD (PRAL, -2.9 vs -5.5 mEq/d; NEAP, 37.0 vs 35.1 mEq/d; and A:P, 13.3 vs 12.4; all P < 0.001). The highest Q of DAL proxies was associated with NAFLD independent of sociodemographic and lifestyle confounders, but significance dissipated after correction for metabolic confounders and multiple testing. However, the P value for nonlinearity was significant in all DAL proxies (P < 0.001). Natural cubic splines performed better with than without DAL proxies in the fully adjusted model (all P ≤ 0.038). The highest probability of NAFLD was found for an acidic diet.

CONCLUSIONS

This study showed an independent nonlinear association between an acidic diet and NAFLD. Further studies with acid-base biomarkers are needed, but our findings might provide a mechanistic explanation for the harmful association between an animal protein-rich diet and NAFLD.

Association of dietary macronutrient composition and non-alcoholic fatty liver disease in an ageing population: the Rotterdam Study

OBJECTIVE

A healthy lifestyle is the first-line treatment in non-alcoholic fatty liver disease (NAFLD), but specific dietary recommendations are lacking. Therefore, we aimed to determine whether dietary macronutrient composition is associated with NAFLD.

DESIGN

Participants from the Rotterdam Study were assessed on (1) average intake of macronutrients (protein, carbohydrate, fat, fibre) using a Food Frequency Questionnaire and (2) NAFLD presence using ultrasonography, in absence of excessive alcohol, steatogenic drugs and viral hepatitis. Macronutrients were analysed using the nutrient density method and ranked (Q1-Q4). Logistic regression analyses were adjusted for sociodemographic, lifestyle and metabolic covariates. Moreover, analyses were adjusted for and stratified by body mass index (BMI) (25 kg/m²). Also, substitution models were built.

RESULTS

In total, 3882 participants were included (age 70±9, 58% female). NAFLD was present in 1337 (34%) participants of whom 132 were lean and 1205 overweight. Total protein was associated with overweight NAFLD after adjustment for sociodemographic and lifestyle covariates (OR_Q4vsQ1 1.40; 95% CI 1.11 to 1.77). This association was driven by animal protein (OR_Q4vsQ1 1.54; 95% CI 1.20 to 1.98). After adjustment for metabolic covariates, only animal protein remained associated with overweight NAFLD (OR_Q4vsQ1 1.36; 95% CI 1.05 to 1.77). Monosaccharides and disaccharides were associated with lower overall NAFLD prevalence (OR_Q4vsQ1 0.66; 95% CI 0.52 to 0.83) but this effect diminished after adjustment for metabolic covariates and BMI. No consistent associations were observed for fat subtypes or fibre. There were no substitution effects.

CONCLUSION

This large population-based study shows that high animal protein intake is associated with NAFLD in overweight, predominantly aged Caucasians, independently of well-known risk factors. Contrary to previous literature, our results do not support a harmful association of monosaccharides and disaccharides with NAFLD.

Dietary acid load and cardiometabolic risk factors: a systematic review and meta-analysis of observational studies

OBJECTIVE

Dietary acid load (DAL) might contribute to change the levels of cardiometabolic risk factors; however, the results are conflicting. The present review was conducted to determine the relationship between DAL and cardiometabolic risk factors.

DESIGN

Systematic review and meta-analysis.

SETTING

A systematic search was conducted in electronic databases including ISI Web of Science, PubMed/MEDLINE, Scopus and Google Scholar for observational studies which assessed cardiometabolic risk factors across DAL. Outcomes were lipid profile, glycaemic factors and anthropometric indices. Effect sizes were derived using a fixed- or random-effect model (DerSimonian-Laird). Also, subgroup analysis was performed to find the probable source of heterogeneity. Egger's test was performed for finding any publication bias.

RESULTS

Thirty-one studies were included in the current review with overall sample size of 92 478. There was a significant relationship between systolic blood pressure (SBP; weighted mean difference (WMD) = 1·74 (95 % CI 0·25, 3·24) mmHg; P = 0·022; I2 = 95·3 %), diastolic blood pressure (DBP; WMD = 0·75 (95 % CI 0·07, 1·42) mmHg; P = 0·030; I2 = 80·8 %) and DAL in cross-sectional studies. Serum lipids, glycaemic parameters including fasting blood sugar, glycated Hb, serum insulin, homeostatic model assessment of insulin resistance and waist circumference had no significant relationship with DAL. No publication bias was found. BMI was not associated with DAL in both cross-sectional and cohort studies.

CONCLUSIONS

Higher DAL is associated with increased SBP and DBP. More studies are needed to find any relationship of DAL with lipid profile and glycaemic factors.

Metabolic Syndrome Features: Is There a Modulation Role by Mineral Water Consumption? A Review

Metabolic syndrome (MetSyn) promotes, among others, the development of atherosclerotic cardiovascular disease and diabetes. Its prevalence increases with age, highlighting the relevance of promoting precocious MetSyn primary prevention and treatment with easy-to-implement lifestyle interventions. MetSyn features modulation through mineral water consumption was reviewed on Pubmed, Scopus and Google Scholar databases, using the following keywords: metabolic syndrome, hypertension, blood pressure (BP), cholesterol, triglycerides, apolipoprotein, chylomicron, very low-density lipoprotein, low-density lipoprotein, high-density lipoprotein (HDL), glucose, insulin, body weight, body mass index, waist circumference (WC), obesity and mineral(-rich) water. Twenty studies were selected: 12 evaluated BP, 13 assessed total-triglycerides and/or HDL-cholesterol, 10 analysed glucose and/or 3 measured WC. Mineral waters were tested in diverse protocols regarding type and composition of water, amount consumed, diet and type and duration of the study. Human and animal studies were performed in populations with different sizes and characteristics. Distinct sets of five studies showed beneficial effects upon BP, total-triglycerides, HDL-cholesterol and glucose. WC modulation was not reported. Minerals/elements and active ions/molecules present in mineral waters (and their pH) are crucial to counterbalance their inadequate intake and body status as well as metabolic dysfunction and increased diet-induced acid-load observed in MetSyn. Study characteristics and molecular/physiologic mechanisms that could explain the different effects observed are discussed. Further studies are warranted for determining the mechanisms involved in the putative protective action of mineral water consumption against MetSyn features.

Dietary Acid Load: mechanisms and evidence of its health repercussions

Diet composition has long been known to influence acid-base balance by providing acid or base precursors. In general, foods rich in protein, such as meat, cheese, eggs, and others, increase the production of acid in the body, whereas fruit and vegetables increase alkalis. The capacity of acid or base production of any food is called potential renal acid load (PRAL). Diets high in PRAL induce a low-grade metabolic acidosis state, which is associated with the development of metabolic alterations such as insulin resistance, diabetes, hypertension, chronic kidney disease, bone disorders, low muscle mass and other complications. The aim of this paper is to review the available evidence which evaluates the association of the PRAL of the diet with the incidence of chronic diseases and metabolic disorders, as well as related mechanisms involved in their development.

The Associations of Dietary Acid Load with Insulin Resistance and Type 2 Diabetes: A Systematic Review of Existing Human Studies

BACKGROUND

Type 2 diabetes is a multifactorial disorder influenced by both genetic and environmental factors and is rising dramatically throughout the world. Recently, consideration to dietary acid-base load has been raised as a nutritional indicator that could have metabolic effects.

OBJECTIVE

The aim of this study was to systematically investigate the associations of dietary acid load indices with glucose/insulin homeostasis and type 2 diabetes in a patent based review.

METHODS

Systematic literature review was conducted using PubMed, Scopus and Google Scholar, from inception up to 10 January 2018. All human studies publications investigated the association of dietary acid load indices (PRAL or NEAP or Pro:K) and incidence of diabetes or glucose/insulin metabolism were included.

RESULTS

In all, 174 studies were included for the title and abstract screening. A total of 164 articles were excluded because they did not meet the inclusion criteria. Finally, 10 articles (five crosssectional studies and five cohort studies) in accordance with our inclusion criteria were chosen for further evaluations that were published between 2008 and 2017.

CONCLUSION

Although there are some evidence of an association between dietary acid load and type 2 diabetes, definitive declarations in this regard will be needed to intervention human studies modifying acid-base dietary intake.

Protein and vitamin B6 intake are associated with liver steatosis assessed by transient elastography, especially in obese individuals

BACKGROUND/AIMS

Although the detrimental effects of several dietary components on the promotion of nonalcoholic fatty liver disease are well known, no studies have assessed the role of dietary vitamin B6. Moreover, studies on the associations between dietary components or body composition indices and liver steatosis assessed by transient elastography are rare. Our aim was to identify the nutritional factors and anthropometric parameters associated with liver steatosis.

METHODS

In this cross-sectional study, we enrolled 168 individuals (35% obese) who underwent a liver steatosis assessment by Controlled Attenuation Parameter measurement and nutritional assessment.

RESULTS

Tertiles of vitamin B6 intake were positively associated with hepatic steatosis (B=1.89, P=0.026, confidence interval [CI] 0.03-0.80) as well as with triglycerides, glucose, alanine aminotransferase (ALT), and body mass index . In obese individuals, after multivariable analysis, the Controlled Attenuation Parameter score was still associated with triglycerides, ALT, and total protein intake (B=0.56, P=0.01, CI 0.10-1.02). Participants in tertile I (low intake) had a lower Controlled Attenuation Parameter than those in tertile III (P=0.01).

CONCLUSIONS

We found a positive association between hepatic steatosis or Controlled Attenuation Parameter score and vitamin B6/total protein intake, probably related to the high intake of meat. Vitamin B6 might have a pathogenic role related to the increase of hepatic steatosis.

Diet-Induced Low-Grade Metabolic Acidosis and Clinical Outcomes: A Review

Low-grade metabolic acidosis is a condition characterized by a slight decrease in blood pH, within the range considered normal, and feeding is one of the main factors that may influence the occurrence of such a condition. The excessive consumption of acid precursor foods (sources of phosphorus and proteins), to the detriment of those precursors of bases (sources of potassium, calcium, and magnesium), leads to acid-base balance volubility. If this condition occurs in a prolonged, chronic way, low-grade metabolic acidosis can become significant and predispose to metabolic imbalances such as kidney stone formation, increased bone resorption, reduced bone mineral density, and the loss of muscle mass, as well as the increased risk of chronic diseases such as type 2 diabetes mellitus, hypertension, and non-alcoholic hepatic steatosis. Considering the increase in the number of studies investigating the influence of diet-induced metabolic acidosis on clinical outcomes, this review gathers the available evidence evaluating the association of this disturbance and metabolic imbalances, as well as related mechanisms. It is necessary to look at the western dietary pattern of most countries and the increasing incidence of non-comunicable diseases for the balance between fruit and vegetable intake and the appropriate supply of protein, mainly from animal sources, so that it does not exceed the daily recommendations.

Association between dietary acid load and the risk of cardiovascular disease: nationwide surveys (KNHANES 2008-2011)

BACKGROUND

Acid-base imbalance has been reported to increase incidence of hypertension and diabetes. However, the association between diet-induced acid load and cardiovascular disease (CVD) risk in the general population has not been fully investigated.

METHODS

This was a population-based, retrospectively registered cross-sectional study using nationally representative samples of 11,601 subjects from the Korea National Health and Nutrition Examination Survey 2008-2011. Individual CVD risk was evaluated using atherosclerotic cardiovascular disease (ASCVD) risk equations according to 2013 ACC/AHA guideline assessment in subjects aged 40-79 without prior CVD. Acid-base status was assessed with both the potential renal acid load (PRAL) and the dietary acid load (DAL) scores derived from nutrient intake.

RESULTS

Individuals in the highest PRAL tertile had a significant increase in 10 year ASCVD risks (9.6 vs. 8.5 %, P < 0.01) and tended to belong to the high-risk (10 year risk >10 %) group compared to those in the lowest PRAL tertile (odds ratio [OR] 1.23, 95 % confidence interval [CI] 1.22-1.35). The association between higher PRAL score and high CVD risk was stronger in the middle-aged group. Furthermore, a multiple logistic regression analysis also demonstrated this association (OR 1.20 95 % CI 1.01-1.43). Subgroup analysis stratified obesity or exercise status; individuals in unhealthy condition with lower PRAL scores had comparable ASCVD risk to people in the higher PRAL group that were in favorable physical condition. In addition, elevated PRAL scores were associated with high ASCVD risk independent of obesity, exercise, and insulin resistance, but not sarcopenia. Similar trends were observed with DAL scores.

CONCLUSION

Diet-induced acid load was associated with increased risk of CVD, independent of obesity and insulin resistance.

Association between Dietary Vitamin C Intake and Non-Alcoholic Fatty Liver Disease: A Cross-Sectional Study among Middle-Aged and Older Adults

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) has become one of the most prevalent chronic liver disease all over the world. The objective of this study was to evaluate the association between dietary vitamin C intake and NAFLD.

METHOD

Subjects were diagnosed with NAFLD by abdominal ultrasound examination and the consumption of alcohol was less than 40g/day for men or less than 20g/day for women. Vitamin C intake was classified into four categories according to the quartile distribution in the study population: ≤74.80 mg/day, 74.81-110.15 mg/day, 110.16-146.06 mg/day, and ≥146.07 mg/day. The energy and multi-variable adjusted odds ratio (OR), as well as their corresponding 95% confidence interval (CI), were used to determine the relationship between dietary vitamin C intake and NAFLD through logistic regression.

RESULT

The present cross-sectional study included 3471 subjects. A significant inverse association between dietary vitamin C intake and NAFLD was observed in the energy-adjusted and the multivariable model. The multivariable adjusted ORs (95%CI) for NAFLD were 0.69 (95%CI: 0.54-0.89), 0.93 (95%CI: 0.72-1.20), and 0.71 (95%CI: 0.53-0.95) in the second, third and fourth dietary vitamin C intake quartiles, respectively, compared with the lowest (first) quartile. The relative odds of NAFLD was decreased by 0.71 times in the fourth quartile of dietary vitamin C intake compared with the lowest quartile. After stratifying data by sex or the status of obesity, the inverse association remained valid in the male population or non-obesity population, but not in the female population or obesity population.

CONCLUSION

There might be a moderate inverse association between dietary vitamin C intake and NAFLD in middle-aged and older adults, especially for the male population and non-obesity population.

Diet-Quality Scores and Prevalence of Nonalcoholic Fatty Liver Disease: A Population Study Using Proton-Magnetic Resonance Spectroscopy

Dietary pattern analysis is an alternative approach to examine the association between diet and nonalcoholic fatty liver disease (NAFLD). This study examined the association of two diet-quality scores, namely Diet Quality Index-International (DQI-I) and Mediterranean Diet Score (MDS) with NAFLD prevalence. Apparently healthy Chinese adults (332 male, 465 female) aged 18 years or above were recruited through a population screening between 2008 and 2010 in a cross-sectional population-based study in Hong Kong. DQI-I and MDS, as well as major food group and nutrient intakes were calculated based on dietary data from a food frequency questionnaire. NAFLD was defined as intrahepatic triglyceride content at ≥5% by proton-magnetic resonance spectroscopy. Multivariate logistic regression models were used to examine the association between each diet-quality score or dietary component and prevalent NAFLD with adjustment for potential lifestyle, metabolic and genetic factors. A total of 220 subjects (27.6%) were diagnosed with NAFLD. DQI-I but not MDS was associated with the prevalence of NAFLD. A 10-unit decrease in DQI-I was associated with 24% increase in the likelihood of having NAFLD in the age and sex adjusted model (95% CI: 1.06-1.45, p = 0.009), and the association remained significant when the model was further adjusted for other lifestyle factors, metabolic and genetic factors [OR: 1.26 (95% CI: 1.03-1.54), p = 0.027]. Multivariate regression analyses showed an inverse association of the intake of vegetables and legumes, fruits and dried fruits, as well as vitamin C with the NAFLD prevalence (p<0.05). In conclusion, a better diet quality as characterized by a higher DQI-I and a higher consumption of vegetables, legumes and fruits was associated with a reduced likelihood of having NAFLD in Hong Kong Chinese.