Net Acid Research Articles

The association of diet-dependent acid load with colorectal cancer risk: a case-control study in Korea.

Acid-base disequilibrium is a contributor to cancer development because it affects molecular activities such as insulin-like growth factor 1 levels and adiponectin production. However, evidence of an association of diet-induced acid-base imbalance with colorectal cancer (CRC) is limited. We examined whether colorectal carcinogenesis is attributable to a diet with a high acid load. We recruited a total of 923 CRC cases and 1846 controls at the National Cancer Center in Korea for inclusion in a case-control study. We collected information on nutrient intake and specific clinical parameters of CRC by using a semiquantitative FFQ and medical records, respectively. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) were used to estimate diet-dependent acid load. We used an unconditional logistic regression model to analyse the association. Dietary acid load scores had a positive association with the odds of CRC (OR = 2·31 (95 % CI 1·79, 2·99) and OR = 2·14 (95 % CI 1·66, 2·76) for PRAL and NEAP, respectively, Pfor trend < 0·001). A stronger positive association was observed for females (OR = 3·09, 95 % CI 1·93, 4·94) than for males (OR = 1·71, 95 % CI 1·27, 2·31). Furthermore, acidogenic diets appeared to affect rectal cancer more strongly than colon cancer in females. Our study contributes to reinforcing epidemiological evidence regarding a detrimental effect of acidogenic diets on colorectal carcinogenesis. Thus, it is important to pay attention to the balance of acidogenic (e.g. poultry and red meat) and alkalinogenic foods (e.g. fruits and vegetables) in CRC prevention, especially for females.

5-year leaching experiments to evaluate a modified bauxite residue: remediation of sulfidic mine tailings.

The ALTEO company produces approximately 300,000 tons per year of bauxite residue after alumina extraction, which is washed and dried in a press filter to produce Bauxaline®. In this study, different ways for recovering and reusing this residue were explored, namely transformation into a vegetated soil, use in acid mine drainage depollution, and application in sulfide-mine tailings remediation. The Bauxaline® was therefore transformed into modified bauxite residue (MBR), resulting in reduced alkalinity, salinity, and sodicity. To counterbalance the net acid generation potential of two sulfidic mine tailings with 1 mol H+ kg-1 (1.5% sulfide) and 3.3 mol H+ kg-1 (5.3% sulfide), respectively, various treatments were applied. These treatments included the addition of 10% MBR or 10% MBR plus limestone, or by limestone only, within 40-l lysimeters. Six lysimeters were monitored over a 5-year period to assess the long-term emissions from treated materials. Vegetation was tested under various conditions, and its impact on emission was evaluated. The emissions of mine tailings treated with MBR and limestone were very low. The mine tailings with limestone showed intermittent peaks of emission, probably due to the coating of calcite grain by ferric oxide, hindering contact with percolating water. Vegetation successfully grew in the treated tailings. This study demonstrated that the alkalinity of limestone can temporarily immobilize elements in sulfidic mine tailings, with a reduction factor of emissions of 300 and 40 for the two mine tailings, respectively. For long-term immobilization, the alkalinity provided by both limestone and MBR and the Al and Fe oxides of MBR are more effective and necessary for long-term immobilization, with a reduction factor of 300 and 900, respectively.

Dietary acid load decreases with age and is associated with sagittal abdominal diameter: a nationally representative quantification study in US adults

BackgroundDietary acid load (DAL) has been associated with frailty and hip fractures in older adults, who often have a reduced kidney function and thus compromised buffering capacities. Studies to quantify DAL in older adults are scarce and controversies persist as to whether DAL in- or decreases with age.AimTo enhance the understanding of DAL in older individuals, we examined its relationship with increasing age and selected anthropometric data in a well-characterized sample of US adults.MethodsSecondary data analysis of nationally representative data from the National Health and Nutrition Examination Surveys data (NHANES 2011–2016). The sample included n = 3018 adults aged 60+, which may be extrapolated to represent n = 45,113,471 Americans. DAL was estimated using 4 formulas, including Potential Renal Acid Load (PRAL) and Net Endogenous Acid Production (NEAP).ResultsAll employed DAL scores tended to decline with increasing age. Participants aged 80 years or older yielded the lowest DAL scores. The average US citizen aged 60+ consumed an acidifying diet, yet there were sex-specific differences in the adjusted means for some scores. NEAP was positively correlated with both body mass index (r = 0.26, p < 0.001) and the sagittal abdominal diameter (r = 0.31, p < 0.001) in this nationally representative sample.ConclusionThe previously reported phenomenon of increasing DAL values in older people in non-Western countries may not apply to the US. Our findings may constitute an important step towards a better understanding of DAL in older US adults, and highlight the need for additional population-specific research in the field.

Higher Dietary Acid Load Might Be a Potent Derivative Factor for Multiple Sclerosis: The Results from a Case-Control Study.

This study aimed to investigate the association between dietary acid load (DAL) and multiple sclerosis (MS), through the potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores. In a hospital-based case-control study of 109 patients with MS and 130 healthy individuals, a validated 168-item semi-quantitative food frequency questionnaire and a logistic regression model were used to evaluate the association between the DAL and MS. After adjusting for age (years), gender (male/female), body mass index (Kg/m2), and total calories (Kcal), the MS odds were 92% lower for those in the highest tertile of total plant-based protein (OR: 0.08, 95%CI: 0.03, 0.23; p-value < 0.001) and about four times higher for those in the highest tertile of the PRAL (OR: 4.16, 95%CI: 1.94, 8.91; p-value < 0.001) and NEAP scores (OR: 3.57, 95%CI: 1.69, 7.53; p-value < 0.001), compared to those in the lowest tertile. After further adjusting for sodium, saturated fatty acid, and fiber intake, the results remained significant for total plant-based protein intake (OR: 0.07, 95%CI: 0.01, 0.38; p-value = 0.002). In conclusion, a higher NEAP or PRAL score may be associated with increased odds of MS, while a higher intake of plant-based protein instead of animal-based protein may be protective.

The comparison of 7.5 and 15% hydrogen peroxide as oxidizing agent in static tests of acid mine drainage potential in Indonesia

Static tests of acid mine drainage potential are an important part of mining water management. Net acid generation (NAG) test is widely used in Indonesian coal mines because of its convenience. This test uses H2O2 to oxidize sulfide minerals within rock samples to determine their net acid-forming capacity. This study aimed to determine the difference between H2O2 at concentrations of 7.5% (the standard in several Indonesian coal mines) and 15% (the standard of the Acid Rock Drainage Test Handbook and Indonesian National Standard) in categorizing rocks as potentially acid-forming and non-acid-forming and in terms of NAG solution characteristics. A total of 564 rock samples collected from two Indonesian coal mining sites were analyzed using pH, NAG, total sulfur, and acid-base-accounting tests. The results of the study showed that there was no significant difference in rock classification or the behavior of contaminants in the NAG solution between 7.5% and 15% H2O2. The characteristics of sulfide minerals in Indonesian coal mines were the main factors influencing the results of the NAG test and behavior of contaminants in the NAG solution. Therefore, H2O2 at a concentration of 7.5% can be used in Indonesian coal mines with relatively low total sulfur concentrations (<5%) and minerals in framboidal form.

Dietary Acid Load and Cancer Risk: A Review of the Uruguayan Experience.

Dietary acid load (DAL) is recognized as a risk factor for several chronic disorders, including obesity, diabetes, and osteoporosis. Recent evidence suggests that an elevated DAL, as measured by the validated potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores, could also increase the risk for several cancers. This narrative review summarizes the potential role of DAL in Uruguayan cancer patients and outlines the potentially involved pathophysiological pathways that mediate the role of DAL in both cancer development and growth. Although Uruguay is a developing country, its average diet is a heavily meat-based Western one, translating into a supraphysiological acid burden from diet. In recent years, we have published epidemiologic evidence based on ten case-control studies involving 3736 cancer cases and 9534 hospital-based controls. Odds ratios and 95% confidence intervals were estimated for each interest variable to analyze the association between the exposure levels of DAL scores and cancer, calculated by unconditional logistic regression. In a majority of the cases, the highest DAL scores tended to double the cancer risk as compared to the lowest category. We also found high risks for methionine intake, an acidifying amino acid found in higher concentrations in animal-based foods, which may increase cancer risks at least by a joint action based on the pH and the proliferation enhancing properties of the amino acid itself.

Dietary Acid Load Is Not Associated with Serum Testosterone in Men: Insights from the NHANES.

The dietary acid load (DAL) is a novel marker of overall diet quality, which has been associated with overweight, type 2 diabetes and altered glucocorticoid secretion. A potential association with sex hormones is thus not inconceivable. We investigated whether DAL was associated with serum total testosterone concentrations of men in the National Health and Nutrition Examination Survey. The DAL scores, including the potential renal acid load (PRAL) and net endogenous acid production (NEAP), were estimated and compared between participants with low and normal testosterone levels. The investigated sample encompassed n = 377 males with a mean age of 49.50 years. Approximately 73% of the sample were of Non-Hispanic White origin. None of the examined DAL scores showed significant associations with serum testosterone levels. We observed no significant differences in the crude DAL scores between individuals with low testosterone levels and individuals with normal testosterone levels. Multivariate regression models adjusting for covariates confirmed the lack of associations between the PRAL and serum testosterone. Our results are of particular importance for those individuals who wish to lower their DAL in light of the presumable health effects of a more alkaline diet. Our data suggest that diet modifications toward a lower intake of animal protein and refined grains (which consecutively translates into a lower DAL) may not negatively affect men's testosterone levels.

Dietary Acid Load Correlates with Serum Amino Acid Concentrations after a Four-Week Intervention with Vegan vs. Meat-Rich Diets: A Secondary Data Analysis.

Chronic low-grade metabolic acidosis is now a common phenomenon in the Western world. The high dietary intake of sulfur-containing amino acids in the form of processed meats results in an excessive release of acid in the form of protons and non-metabolizable acidic anions. The kidneys produce increasing amounts of ammonia to excrete this acid. This process requires the breakdown of the nitrogenous amino acid glutamine, which the body provides by breaking down muscle tissue. Hitherto not examined, we hypothesized that a high dietary acid load (DAL) could alter the serum concentrations of selected amino acids. Using secondary data from a 4-week dietary intervention study conducted in 2017, we examined the associations between various amino acids and DAL in n = 42 individuals who either consumed a meat-rich or vegan diet. Results from this secondary data analysis suggested that DAL (as measured by the potential renal acid load and net endogenous acid production) is positively correlated with higher serum concentrations of lysine and 1-methyl-histidine (r = 0.50 and 0.43, respectively) and negatively correlated with glutamine and glycine (r = -0.43 and -0.47, respectively). The inverse association with glycine and glutamine warrants special attention, as both play an important role in many metabolic disorders and the immune system.

The Impact of Plant-Based Diets on Dietary Acid Load Metrics in Venezuela: A Cross-Sectional Study.

Dietary acid load (DAL) is an important determinant of the acid-base balance in humans and has been associated with several chronic non-communicable diseases. Plant-based diets, including vegetarian and vegan diets, decrease DAL-although their alkalizing potential varies substantially. Their net effect on common DAL scores, including potential renal acid load and net endogenous acid production, has been insufficiently quantified and is poorly understood-particularly in populations outside of Europe and North America. We assessed the associations between three plant-based dietary patterns (flexitarian vs. lacto-ovo-vegetarian vs. vegan diet) and DAL scores in a healthy Venezuelan population in the metropolitan area of Puerto La Cruz, Venezuela. Substantial differences in DAL scores were observed, whereby the vegan diet yielded the highest alkalizing potential, followed by the lacto-ovo-vegetarian and the flexitarian diet. DAL scores were substantially lower in comparison to European and North American plant-based populations, probably due to the higher potassium intake (exceeding 4000 mg/d in vegans), the higher magnesium intake (390.31 ± 1.79 mg/d in vegans) and the lower intake of protein in vegans and lacto-ovo-vegetarians. Additional studies in other non-industrialized populations are warranted to allow for a better understanding of the (numeric) impact of plant-based dietary patterns on DAL scores, potentially allowing for an establishment of reference ranges in the near future.

Associations between Net Gastrointestinal Alkali Absorption, 24-Hour Urine Lithogenic Factors, and Kidney Stones.

It is not clear whether kidney stone formers have an abnormal handling of alkali and acid precursors in the gut, which might affect urine composition and ultimately stone formation. In this study, we aimed to investigate the determinants of net gastrointestinal alkali absorption and its associations with key urinary parameters in a large group of stone formers and non-stone formers. Data were collected from three independent cohorts with at least one 24-hour urine collection. We explored potential determinants of net gastrointestinal alkali absorption and the association between net gastrointestinal alkali absorption, urinary parameters, and stone former status. Finally, we estimated the proportion of the association between urine parameters and stone former status explained by differences in net gastrointestinal alkali absorption. The analysis included 6067 participants (1102 men and 4965 women; 698 and 1804 of whom were stone formers, respectively). Average net gastrointestinal alkali absorption values were consistently lower in stone formers across the three cohorts (from -15.0 to -4.9 mEq/d). Age was directly associated with net gastrointestinal alkali absorption, whereas body mass index and net endogenous acid production were inversely associated. Net gastrointestinal alkali absorption was inversely associated with supersaturation for calcium oxalate, uric acid, and renal net acid excretion and directly associated with supersaturation for calcium phosphate, urine pH, and citrate. The odds of being a stone former was 15% (13%-17%) lower per 10 mEq/24 hours higher net gastrointestinal alkali absorption. Differences in net gastrointestinal alkali absorption explained a modest amount of the differences between stone formers and non-stone formers for supersaturation for calcium oxalate (6.3%) and a sizable amount for supersaturation for uric acid (15.2%), urine pH (38.3%), citrate (26.2%), and renal net acid excretion (63.4%). Kidney stone formers have lower net gastrointestinal alkali absorption, and this explains differences in urine composition and the likelihood of stone formation.

Relationship between Dietary Acid Load with Kidney Function among Chronic Kidney Disease Patients

Chronic kidney disease (CKD) affects the structure and function of the kidneys. The burden of disease from CKD is expected to increase as the prevalence of CKD increases from year to year. The quality of the diet plays a role in the management and treatment of CKD. The diet quality of CKD patients is assessed using dietary acid load (DAL) which is estimated based on protein and potassium intake. A high score of DAL can lead to more rapid decline in renal function, rapid decline in GFR, and low-grade subclinical acidosis. This study was aimed to analyze the relationship between dietary acid load and kidney function in CKD patients with hemodialysis at the Bogor City Hospital. This study used a cross sectional design involving 50 subjects with CKD on hemodialysis. Data was collected by interview using a questionnaire for data characteristics and Semi Quantitative Food Frequency Questionnaire (SQ-FFQ) for data intake. There was a significant relationship between DAL and eGFR, urea, and creatinine (p&lt;0,05). The level of DAL plays an important role in the development and severity of CKD. Therefore, dietary recommendations for patients CKD on hemodialysis need to focus to the dietary acid load derived from foods and to the condition of hyperkalemia. Further research is expected to be carried out with an intervention, case control or cohort design, as well as using different equations in estimating DAL such as the net acid excretion (NAE), potential renal acid load (PRAL) equation.

Dietary acid load is associated with waist circumference in university students with low adherence to the Mediterranean diet: The potential role of ultra-processed foods

Dietary acid load (DAL), as expressed by potential renal acid load (PRAL) and net acid production (NEAP), is connected to cardiometabolic disorders and obesity. Mediterranean diet relates to lower, while western diets to higher DAL values. The present study aimed to assess the association of PRAL and NEAP with adiposity measures in young adults (19.61±3.15 years, mean±standard deviation) and explore the implication of Mediterranean diet adherence and ultra-processed foods (UPF) intake in this relation. 346 students (269 women) participated. Anthropometry was performed, and a food frequency questionnaire was administered. The MedDietScore was calculated, UPF consumption was calculated based on the NOVA classification and PRAL/NEAP was estimated from published equations. Waist Circumference (WC) was transformed to WC-1 (1/WC) in order to achieve normality and run linear regression models. In subjects with MedDietScore≤28.00, PRAL and NEAP were negatively associated with 1/WC (B=-1.594×10-5± 8×10-6, p=0.044 for PRAL and B=-2.84×10-5±1×10-5, p=0.048 for NEAP). Moreover, in this subgroup, subjects with medium to high UPF intake i.e., in the 2nd or 3rd tertile of UPF intake representing more than 34.16% of energy, PRAL (2nd tertile B=-0.00007, SE=0.00003, p=0.018; 3rd tertile B=-0.00002, SE=0.00001, p=0.024) and NEAP (2nd tertile B=-0.00004, SE=0.00002, p=0.040; 3rd tertile B=-0.00007, SE=0.00004, p=0.055) were connected to central obesity. In similar models, PRAL and NEAP were not significant predictors of BMI. The DAL may be related to central obesity, especially in individuals with worse dietary quality, as reflected by lower adherence to the Mediterranean diet, and high intake of UPF. Nutrition guidance aiming at the reduction of DAL may be useful in the reduction of central obesity in these subgroups.

Dietary acid load in children with chronic kidney disease: its association with nutritional status and health-related quality of life.

This study aimed to determine the dietary acid load of children with chronic kidney disease (CKD) and to evaluate the relationship between dietary acid load, nutritional status, and health-related quality of life (HRQOL). A total of 67 children aged 3-18 years with a diagnosis of CKD stages II-V were included in the study. Anthropometric measurements (body weight, height, mid-upper arm circumference, waist, and neck circumference) and 3-day food consumption records were taken to evaluate the nutritional status. The net endogenous acid production (NEAP) score was calculated to determine the dietary acid load. "Pediatric Inventory of Quality of Life (PedsQL)" was used to assess the participants' HRQOL. The mean NEAP was 59.2 ± 18.96 mEq/day. Stunted and malnourished children had significantly higher NEAP than those who were not (p < 0.05). There were no significant differences in terms of HRQOL scores according to NEAP groups. The multivariate logistic regression analysis showed that waist circumference (OR: 0.890, 95% CI: 0.794-0.997), serum albumin (OR: 0.252, 95% CI: 0.068-0.929), and glomerular filtration rate (GFR) (OR: 0.985, 95% CI: 0.970-1.000) were negatively associated with high NEAP. This study shows that a diet shifted in an acidic direction in children with CKD and a higher dietary acid load are associated with lower serum albumin, GFR, and waist circumference, but not HRQOL. These results suggest that dietary acid load might affect nutritional status and CKD progression in children with CKD. Future studies with larger samples are needed to confirm these results and to understand underlying mechanisms. A higher resolution version of the Graphical abstract is available as Supplementary information.

Carbonic anhydrases reduce the acidity of the tumor microenvironment, promote immune infiltration, decelerate tumor growth, and improve survival in ErbB2/HER2-enriched breast cancer

BackgroundCarbonic anhydrases catalyze CO2/HCO3– buffer reactions with implications for effective H+ mobility, pH dynamics, and cellular acid–base sensing. Yet, the integrated consequences of carbonic anhydrases for cancer and stromal cell functions, their interactions, and patient prognosis are not yet clear.MethodsWe combine (a) bioinformatic analyses of human proteomic data and bulk and single-cell transcriptomic data coupled to clinicopathologic and prognostic information; (b) ex vivo experimental studies of gene expression in breast tissue based on quantitative reverse transcription and polymerase chain reactions, intracellular and extracellular pH recordings based on fluorescence confocal microscopy, and immunohistochemical protein identification in human and murine breast cancer biopsies; and (c) in vivo tumor size measurements, pH-sensitive microelectrode recordings, and microdialysis-based metabolite analyses in mice with experimentally induced breast carcinomas.ResultsCarbonic anhydrases—particularly the extracellular isoforms CA4, CA6, CA9, CA12, and CA14—undergo potent expression changes during human and murine breast carcinogenesis. In patients with basal-like/triple-negative breast cancer, elevated expression of the extracellular carbonic anhydrases negatively predicts survival, whereas, surprisingly, the extracellular carbonic anhydrases positively predict patient survival in HER2/ErbB2-enriched breast cancer. Carbonic anhydrase inhibition attenuates cellular net acid extrusion and extracellular H+ elimination from diffusion-restricted to peripheral and well-perfused regions of human and murine breast cancer tissue. Supplied in vivo, the carbonic anhydrase inhibitor acetazolamide acidifies the microenvironment of ErbB2-induced murine breast carcinomas, limits tumor immune infiltration (CD3+ T cells, CD19+ B cells, F4/80+ macrophages), lowers inflammatory cytokine (Il1a, Il1b, Il6) and transcription factor (Nfkb1) expression, and accelerates tumor growth. Supporting the immunomodulatory influences of carbonic anhydrases, patient survival benefits associated with high extracellular carbonic anhydrase expression in HER2-enriched breast carcinomas depend on the tumor inflammatory profile. Acetazolamide lowers lactate levels in breast tissue and blood without influencing breast tumor perfusion, suggesting that carbonic anhydrase inhibition lowers fermentative glycolysis.ConclusionsWe conclude that carbonic anhydrases (a) elevate pH in breast carcinomas by accelerating net H+ elimination from cancer cells and across the interstitial space and (b) raise immune infiltration and inflammation in ErbB2/HER2-driven breast carcinomas, restricting tumor growth and improving patient survival.

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

This study evaluates the association between dietary acid load (DAL) and hyperuricemia in Chinese adults. The China Health and Nutrition Survey (CHNS) in 2009 was used in this cross-sectional study. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) were applied to estimate DAL. A multiple logistic regression model was used to test the relationship between DAL and hyperuricemia risk. A total of 7947 participants were included in this study, of whom 1172 had hyperuricemia. The PRAL score was positively related to the prevalence of hyperuricemia, even when potential covariates were taken into account. In comparison with Q1, the ORs were 1.12 (95% CI, 0.92-1.38), 1.20 (95% CI, 0.97-1.47) and 1.42 (95% CI, 1.16-1.75) in Q2, Q3 and Q4. However, there was no significant relationship between NEAP scores and hyperuricemia. Every 10 g increase in energy-adjusted fat, protein and animal protein intakes caused a 10%, 17% and 18% increase in hyperuricemia risk, respectively (OR: 1.10, 95% CI: 1.04-1.16; OR: 1.17, 95% CI: 1.11-1.25; OR: 1.18, 95% CI: 1.12-1.24, respectively). An obvious linear correlation was also suggested by the restricted cubic spline. Hyperuricemia risk was associated with higher PRAL among Chinese adults. This means that a diet low in PRAL scores could be a very valuable uric acid-lowering dietary pattern.

Soil Contaminated with Hazardous Waste Materials at Rio Tinto Mine (Spain) Is a Persistent Secondary Source of Acid and Heavy Metals to the Environment

Mineralogical analysis and laboratory-based leaching tests coupled with speciation modeling were undertaken to quantify the potential for short-term acid generation and the release of trace elements from soils heavily contaminated with mine waste at Rio Tinto. Three different waste materials were considered as case studies: roasted pyrite, copper slags, and leached sulfide ores. The results showed elevated values of net acid generation (up to 663 mmol H+/kg), the major pools being potential sulfidic acidity and acidity retained in jarosite. Remarkable contents of As and toxic heavy metals were found especially in the slag-contaminated soil. Copper, Zn, and Pb were the most abundant metals in the acid leach solutions resulting from mine soil-water interaction, with peak values of 55.6 mg L−1, 2.77 mg L−1, and 2.62 mg L−1, respectively. Despite the high total contents of trace elements occurring in soil, the mobile fraction was limited to maximum release values of 12.60% for Cd and 10.27% for Cu, according to the test leaching. Speciation calculations indicated that free metal ions (M2+) and sulfate species (MSO40) accounted for most of the dissolved load. Acid soil drainage is a secondary source of acid and heavy metals in the mine site and, therefore, an effective land reclamation program should ensure that acidity and metal mobility are reduced to environmentally sustainable levels.

Diet-dependent acid load and the risk of breast cancer: A case–control study

Dietary acid load causes metabolic acidosis, which leads to inflammation and cell change, both of which are related to cancer development. Even though a high acid load has been associated with an increased risk of breast cancer (BC), epidemiologic evidence correlating diet-dependent acid load and cancer risk, particularly for BC, is still lacking. As a result, we intend to investigate its potential role. The potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores were calculated in this case-control study using the dietary intake of individuals as determined by a verified FFQ. Logistic regression was used to calculate odds ratios (ORs), which were adjusted for probable confounders. Using multivariate logistic regression models, the odds ratios (OR) of BC according to quartiles of PRAL and NEAP scores revealed that neither PRAL (P-trend=0.53) nor NEAP (P-trend=0.19) scores were significantly associated with BC risk. Multiple logistic regressions remained non-significant after controlling for covariates, indicating no significant relationships between PRAL (P-trend=0.96) and NEAP (trend=0.45) scores and the odds of BC. According to the findings of our study, there is no relation between DAL and the risk of BC in Iranian women.

Association between obstructive sleep apnea and 24-h urine chemistry risk factors for urinary stone disease

The effect of obstructive sleep apnea (OSA) on 24-h urine parameters and resultant kidney stone risk is unknown. We sought to compare urinary lithogenic risk factors among patients with kidney stone disease with and without OSA. We performed a retrospective cohort study of adult patients with nephrolithiasis undergoing both polysomnography and 24-h urine analysis. Measures of acid load including gastrointestinal alkali absorption, urinary titratable acid, and net acid excretion were calculated from 24-h urine. We performed univariable comparisons of 24-h urine parameters between those with and without OSA and fit a multivariable linear regression model adjusting for age, sex, and BMI. Overall, there were 127 patients who underwent both polysomnography and a 24-h urine analysis from 2006 to 2018. There were 109 (86%) patients with OSA and 18 (14%) without. Patients with OSA were more commonly male, had greater BMI and had higher rates of hypertension. Patients with OSA had significantly higher levels of 24-h urinary oxalate, uric acid, sodium, potassium, phosphorous, chloride, and sulfate; higher supersaturation of uric acid; higher titratable acid, and net acid excretion; and lower urinary pH and supersaturation of calcium phosphate (p < 0.05). The difference in urinary pH and titratable acid, but not net acid excretion, remained significant when adjusting for BMI, age, and gender (both p = 0.02). OSA is associated with changes in urinary analytes that promote kidney stone formation, similar to those observed with obesity. After accounting for BMI, OSA is independently associated with lower urine pH and increased urinary titratable acid.

Shift work is not associated with dietary acid load in the NHANES

PurposeChanges in eating habits and food preferences caused by circadian rhythm disruptions in shift workers increase the risk for chronic diseases. Several studies demonstrated that shift work exerts adverse effects on various risk factors for cardiometabolic disease and cancer. Moreover, shift work leads to altered eating patterns, including diets low in alkaline foods (such as vegetables, fruit and legumes) and high in acidogenic foods (such as meat, fish and cheese). Previously not examined, this imbalance could result in a high dietary acid load (DAL). DAL has been linked to low-grade metabolic acidosis, tissue inflammation and other metabolic alterations. The aim of this study was to investigate the hypothesis that shift work is positively associated with an increased DAL.Design/methodology/approachThe authors used cross-sectional data from the National Health and Nutrition Examination Surveys (2007–2010). The sample for this analysis was drawn from a representative multistage-probability sample of US civilians. DAL estimations included potential renal acid load (PRAL) and net endogenous acid production (NEAP). Acid load scores and nutrient intake were compared between regular day workers (n = 3,814; mean age, 43.7 ± 0.3; mean body mass index (BMI), 28.6 ± 0.1; females 46.9%) and shift workers (n = 881; age, 37.4 ± 0.6; BMI, 28.4 ± 0.3; females 48.1%). Evening/night shift workers combined with rotating shift workers were contrasted to participants on a regular daytime schedule.FindingsPotassium and magnesium intake were significantly lower in shift workers, whereas no significant differences with regard to total energy intake were found. The authors found significantly higher crude NEAPF scores in shift workers (mean: 61.8 ± 1.2 mEq/day) compared to regular day workers (mean: 58.7 ± 0.5 mEq/day, P = 0.023). After adjustment for confounders, however, this association remained no longer significant. There were no significant intergroup differences regarding NEAPR and PRALR.Research limitations/implicationsThis study revealed significant differences in crude NEAPF scores between shift workers and day workers. After adjustment for confounders, this association was no longer significant. Such discrepancy is probably because of the scarce homogeneity in the analyzed sample which represents the main limitation of this study. Thus, the results did not confirm the hypothesis that shift work is associated with elevated DAL scores. Importantly, the data suggest significant intergroup differences in nutrient intakes without confirming our initial hypothesis with regard to DAL.Originality/valueIn light of the detrimental health outcomes associated with an increased DAL, this study reinforces the call for evidence-based dietary guidelines in shift workers. Studies in other shift working populations are thus warranted.

Examining dietary acid load in individuals with type 2 diabetes: a case-control study.

Diabetes is a chronic disease that can cause various complications and has a high prevalence. Evidence increasingly shows that acid-base homeostasis is critical to maintaining normal metabolic function. This case-control study aims to evaluate the relationship between dietary acid load and the risk of type 2 diabetes. This study recruited 204 participants, 92 of whom had just been diagnosed with type 2 diabetes, and 102 healthy controls who were matched in age and gender as controls. Twenty-four dietary recall was used for dietary intake assessments. Dietary acid load was approximated using two different methods: potential renal acid load (PRAL) and net endogenous acid production (NEAP), both calculated from dietary recalls. In the case and control groups, the dietary acid load mean scores were 4.18±26.8, 20.84±29.54 mEq/day for PRAL, and 55.11±29.23, 68.43±32.23 mEq/day for NEAP, respectively. When it came to the multiple possible confounders, the participants in the highest tertile of PRAL (OR 4.43, 95% CI: 1.38-23.81, ptrend<0.001) and NEAP (OR: 3.15, 95% CI: 1.53-9.59, ptrend<0.001) had a significantly higher risk of developing type 2 diabetes compared to those in the lowest tertile. The findings of the present study suggest that a high acid load in the diet may increase the risk of type 2 diabetes. Therefore, it is possible that limiting dietary acid load could lower type 2 diabetes risk in vulnerable individuals.