Dietary acid load and risk of hypertension: the Rotterdam Study

The dietary acid load is associated with disease severity in psoriatic arthritis

OBJECTIVES

An acidogenic diet, by disrupting the blood pH equilibrium, can contribute to metabolic acidosis and lead to inflammation. Therefore, we hypothesized that dietary acid load (DAL) increases disease activity and inflammation in psoriatic arthritis (PsA) patients.

METHODS

This study was conducted with 58 obese/overweight patients, aged 20-65 years. Dietary intake was assessed using a 3-consecutive-day 24-hour recall. The DAL was evaluated through the PRAL (potential renal acid load) and NEAP (net endogenous acid production) and divided into the low and high groups by their median values. The disease activity assessments, anthropometric measurements, dietary data, and blood parameters of patients were recorded and compared at the low and high DAL groups.

RESULTS

We observed that patients in the high NEAP and PRAL groups had worse PsA pattern scores (P < 0.05). Also, PRAL and NEAP scores were positively associated with Disease Activity Index for Psoriatic Arthritis, Health Assessment Questionnaire, and Psoriatic Arthritis Impact of Disease-12 (PSAID-12) scores. After adjusting age, sex, smoking, and body mass index, 1 mEq increase in PRAL and NEAP was associated with an elevation of Disease Activity Index for Psoriatic Arthritis (0.506 and 0.486 points, respectively).

CONCLUSIONS

These results showed a close relationship between DAL and PsA symptoms. An acidogenic diet may negatively affect PsA prognosis. Healthy eating recommendations should be part of the management of the disease.

Evaluation of the relationship between dietary acid load and cardiovascular risk factors in patients with type 2 diabetes: a case-control study

Backround

Diets high in dietary acid load are thought to be associated with metabolic diseases. However, the number of studies examining the relationship between dietary acid load and metabolic diseases in Turkey is insufficient. The aim of this study was to investigate the relationship between cardiovascular disease risk factors and dietary acid load in individuals with type 2 diabetes.

Materials and methods

In this case-control study, 51 participants aged 30-65 years with type 2 diabetes and 59 participants in the control group were included. Blood pressure and biochemical findings were measured. Anthropometric measurements and body composition measurements were made. Dietary intake was assessed using a 3-day (1 day on weekends, 2 days on weekdays) food consumption record. Dietary acid load scores, including potential renal acid load (PRAL) and net endogenous acid production (NEAP), were calculated based on dietary intake. NEAP and PRAL scores were categorized as low and high according to the median value. Smoking status, body mass index (BMI), systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), trigylceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoprotein cholesterol (LDL), waist-hip ratio (WHR), waist-to- height ratio (WtHR), hemoglobin and fat mass (%) were evaluated as cardiovascular risk factors.

Results

The cut-off values of PRAL and NEAP were 3.61 and 44.78 mEq/d, respectively. After adjustment for various covariates, a significant positive association between PRAL and TG levels was observed in the diabetic group [odds ratio (OR), 5.98; 95% CI, 1.45-24.67; p = 0.013]. In contrast, a negative association was found between PRAL and SBP in the control group [odds ratio (OR), 0.21; 95% CI, 0.05-0.83; p = 0.026]. However, these associations were not observed for NEAP values in either group.

Conslusions

A higher PRAL value was consistently associated with higher TG level, but other cardiovascular risk factors were not. More longitudinal and interventional studies are needed to better establish a causal effect between dietary acid load and cardiovascular risk factors in individuals with diabetes.

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.

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).

Association of dietary inflammatory index with obesity among children and adolescents in the United States NHANES cohort: a population-based study

BACKGROUND

Childhood obesity has become a huge challenge to childhood health, and there is a lack of understanding about the relationship between dietary inflammatory index (DII) and childhood obesity. The main objective of this study was to analyze the potential link between DII and obesity among children and adolescents residing in the United States.

METHODS

A cross-sectional analysis was performed using data obtained from the National Health and Nutrition Examination Survey between 2009 and 2018. In total, 12,454 participants were included in the analysis. DII was calculated based on dietary data from the first day of the 24-hour dietary recall. Logistic regression was used to analyze the association between DII and obesity, as well as central obesity defined by the waist-to-height ratio of 0.5 or higher or waist circumference ≥ 90th percentile for age and sex.

RESULTS

The mean dietary inflammation index was 2.05 (SE = 0.02), with higher levels in children than in adolescents (P = 0.01). According to our findings, the prevalence of central obesity was higher among adolescents (38.0%) than among children (31.4%). The adolescents in the third quartile of DII have a higher risk of overweight/obesity (OR = 1.46, 95% CI: 1.24-1.71) after adjusting for age, sex, and race. This positive association remained significant even after physical activity was added to the model. Concerning central obesity, the adolescents in the highest quartile of DII have a higher risk, independent of demographic characteristics and physical activity. However, no significant association was observed among children.

CONCLUSIONS

The dietary inflammation index was positively associated with overweight/obesity and central obesity among adolescents in the United States after adjusting for confounding factors. These findings highlight the importance of promoting anti-inflammatory diets in adolescents to prevent obesity and its associated complications.

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.

Dietary acid load, depression, and anxiety: results of a population-based study

BACKGROUND

Dietary acid load seems to be associated with psychological disorders through several mechanisms, and may barricade their treatment and recovery. The aim of current study was to evaluate the relationship between dietary acid load, using potential renal acid load (PRAL) and dietary acid load (DAL) scores, with the severity of depression and anxiety among Iranian adults.

METHODS

A total of 6531 participants aged 35-65 years were recruited in this cross-sectional study. A validated food frequency questionnaire (FFQ) was used to assess dietary intakes of participants. DAL was estimated using PRAL and DAL scores. Depression and anxiety were screened using Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI).

RESULTS

In the fully adjusted model, women with the highest DAL or PRAL had higher odds of more severe depression compared to those in the lowest category (OR = 1.20; 95% CI = 1.03-1.42 and OR = 1.20; 95% CI = 1.03-1.39, respectively). No significant association was observed between DAL and PRAL and depression severity in men and in the population as a whole. Regarding the association between PRAL and anxiety severity, there was no significant association when separated by sex. However, in the fully adjusted model for the whole population, participants in the highest tertile of PRAL had 13% greater odds of more severe anxiety than the lowest tertile (OR: 1.13, 95% CI: 1.01-1.13). No significant association was observed between DAL and anxiety severity in women, men or in the whole population.

CONCLUSION

Women, but not men, with higher dietary acid load had significantly higher odds of having more severe depression. A significant positive association was also observed between dietary acid load and anxiety in the whole population.

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

BACKGROUND AND AIMS

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

Metabolic Acidosis Results in Sexually Dimorphic Response in the Heart Tissue

Metabolic acidosis (MA) is a highly prevalent disorder in a significant proportion of the population, resulting from imbalance in blood pH homeostasis. The heart, being an organ with very low regenerative capacity and high metabolic activity, is vulnerable to chronic, although low-grade, MA. To systematically characterize the effect of low-grade MA on the heart, we treated male and female mice with NH₄Cl supplementation for 2 weeks and analyzed their blood chemistry and transcriptomic signature of the heart tissue. The reduction of pH and plasma bicarbonate levels without an associated change in anion gap indicated a physiological manifestation of low-grade MA with minimal respiratory compensation. On transcriptomic analysis, we observed changes in cardiac-specific genes with significant gender-based differences due to MA. We found many genes contributing to dilated cardiomyopathy to be altered in males, more than in females, while cardiac contractility and Na/K/ATPase-Src signaling were affected in the opposite way. Our model presents a systems-level understanding of how the cardiovascular tissue is affected by MA. As low-grade MA is a common ailment with many dietary and pharmaceutical interventions, our work presents avenues to limit chronic cardiac damage and disease manifestation, as well as highlighting the sex differences in MA-induced cardiovascular damage.

Primary Contributors to Dietary Acid Load in Patients With Urolithiasis

OBJECTIVES

In susceptible individuals, high dietary acid load may contribute to the formation of certain types of kidney stones via lowering urine pH and citrate excretion. The objective of this study is to determine the contribution of dietary acid from food groups in people with urolithiasis.

DESIGN AND METHODS

Patients with calcium urolithiasis (n = 83) who completed food records were used for this retrospective analysis. Descriptive statistics were calculated for nutrients, potential renal acid load (PRAL), and estimated net endogenous acid production (NEAP_est). Pearson's correlations were calculated between PRAL and NEAP_est with each nutrient.

RESULTS

Data from a total of 83 patients were used. Average PRAL was positively correlated with energy (r = 0.260, P = .02), total protein (r = 0.463, P < .001), animal protein (r = 0.555, P < .001), total fat (P = .399, P < .001), sodium (r = 0.385, P < .001), and phosphorus (r = 0.345, P < .001) intake. PRAL was negatively correlated with fiber (r = -0.246, P = .03) intake. NEAP_est was positively correlated with total protein (r = 0.269, P = .01), animal protein (r = 0.377, P < .001), fat (r = 0.222, P = .04), and sodium (r = 0.250, P = .02) intake. NEAP_est was negatively correlated with fiber (r = -0.399, P < .001), potassium (r = -0.360, P < .001), and magnesium (r = -0.233, P = .03) intake. For PRAL, meat contributed the highest acid load (52.7%), followed by grains (19.6%) and combination foods (19.6%). Beverages contributed the greatest alkali load (35.1%), followed by vegetables (30.6%) and fruits (28.6%). For NEAP_est, cheese contributed the highest acid load (21.8%), followed by grains (19.3%) and meat (18.1%).

CONCLUSIONS

For individuals with urolithiasis promoted by acidic urine and/or low urine citrate, dietary patterns with a high dietary acid load may contribute to recurrence risk. Meat and grains were the major contributors to dietary acid load in this cohort of patients with a history of kidney stones, whereas beverages, fruits, and vegetables contributed net alkali.

The association between dietary acid load and body composition in physical education students aged 18-25 years

AIM

To find the association between dietary acid load (DAL) and body composition in physical education students.

METHODS

This study was carried out on 207 students of both genders aged 18-25 years. DAL was calculated based on potential renal acid load (PRAL) and net endogenous acid production (NEAP) methods. Anthropometric indices were measured. Bioelectric impedance was used to assess body composition and other related items.

RESULTS

The mean score of NEAP and PRAL was 80.18 ± 31.30 and 33.94 ± 22.11, respectively. The mean weight and fat mass of subjects were 64.05 ± 9.72 kg and 20.28 ± 0.67 kg, respectively. Participants in the highest tertile of PRAL had a higher weight (64.56 ± 1.14 kg) in comparison with participants in the lowest tertile (61.65 ± 1.19 kg) (P = 0.027). After adjusting for confounders, a significant positive association was found between NEAP score and hip circumference (β = 0.206, P = 0.039), body mass index (β = 0.214, P = 0.031), fat mass (β = 0.218, P = 0.001) and body adiposity index (β = 0.182, P = 0.037). Furthermore, a statistically significant negative association was observed between total body water and NEAP score (β = - 0.217, P = 0.001) and the percentage of fat-free mass and NEAP (β = - 0.229, P = 0.001).

CONCLUSION

Individuals with a higher DAL score may have a higher weight, fat mass and hip circumference and a lower fat-free mass. In addition, there might be an association between DAL and obesity.

Reduced dietary acid load in U.S. vegetarian adults: Results from the National Health and Nutrition Examination Survey

Dietary acid load (DAL) is an important determinant of systemic pH and acid-base homeostasis. Diets abundant in acidogenic foods, such as meat and meat products, induce a low-grade metabolic acidosis state that has been associated with cardiovascular disease, type-2-diabetes, and an increased cancer risk. Fruits and vegetables have alkalizing properties and beneficially affect DAL. It has thus been suggested that a plant-based diet (restricting or excluding animal products) may be a powerful tool in reducing DAL; yet studies in that particular field are scarce. To explore these associations in greater detail, we examined DAL in self-identified vegetarians from the United States National Health and Nutrition Examination Survey (2007-2010). We compared dietary intake and two widely used markers of DAL (PRAL (potential renal acid load) and NEAP (net endogenous acid production; NEAPF and NEAPR)) among 8,398 nonvegetarians and 191 lacto-ovo-vegetarians with reliable dietary intake aged 18 years or older. Vegetarians had a more favorable body mass index and consumed fewer calories (1862.31 kcal/d) than nonvegetarians (2041.12 kcal/d). Vegetarians consumed fewer protein (34.17 g/1000 kcal) and phosphorus compared to nonvegetarians (39.50 g of protein/1000 kcal) but had a higher intake of magnesium and potassium. Nonvegetarians exhibited higher median DAL scores (PRAL: 11.90 mEq/d, NEAPF: 53.59 mEq/d, NEAPR: 55.67 mEq/d) than vegetarians (PRAL: -0.44 mEq/d, NEAPF: 39.60 mEq/d, NEAPR: 41.30 mEq/d). Vegetarians had more favorable DAL scores compared to nonvegetarians in this descriptive epidemiologic study. Future (interventional) trials are warranted to examine the varying acid load in different plant-based dietary patterns.

Dietary Acid Load and Bone Health: A Systematic Review and Meta-Analysis of Observational Studies

Findings on the association between dietary acid load (DAL) and bone health are conflicting. This study aimed to summarize available studies on the association between DAL and risk of fractures or bone mineral density (BMD) in adults. Online databases including PubMed, Scopus, and Embase were searched for relevant studies published up to June 2021, using pertinent keywords. We identified observational studies (cohort, case-control, and cross-sectional) investigating the association between DAL and risk of fractures or BMD, then selected studies following these reported criteria: RRs with corresponding 95% CIs for the relationship between DAL and fracture risk; correlation coefficients for the association between DAL and BMD; and mean ± SD of BMD values across the categories of DAL. Overall, 17 studies with 80545 individuals were included. There was no significant relationship between the PRAL and fracture risk (Pooled RR: 1.18; 95% confidence interval 0.98 to 1.41, I² = 60.6%). Moreover, a similar association was observed between the NEAP and fracture risk (Pooled RR: 1.41, 95% CI: 0.79 to 2.52, I² = 54.1%). The results of five studies from four publications revealed no significant association between dietary PRAL score and femoral and spinal BMD (WMD femoral = −0.01, 95% confidence interval: −0.02 to 0.01, I² = 76.5%; WMD spinal = −0.01, 95% CI: −0.03 to 0.01, I² = 56.7%). However, being in the highest category of NEAP was significantly associated with a lower femoral and spinal BMD (WMD femoral = −0.01, 95% CI: −0.02 to −0.00, I² = 82.1%; WMD spinal = −0.02, 95% CI: −0.03 to −0.01, I² = 93%). It was showed that adopting diets high in acidity was not associated with risk of fractures. We also found a significant negative relationship between NEAP and BMD. However, DAL based on PRAL was not associated with BMD.

Metabolomics of Dietary Acid Load and Incident Chronic Kidney Disease

OBJECTIVE

Blood biomarkers of dietary intake are more objective than self-reported dietary intake. Metabolites associated with dietary acid load were previously identified in 2 chronic kidney disease (CKD) populations. We aimed to extend these findings to a general population, replicating their association with dietary acid load, and investigating whether the individual biomarkers were prospectively associated with incident CKD.

METHODS

Among 15,792 participants in the Atherosclerosis Risk in Communities cohort followed up from 1987 to 1989 (baseline) to 2019, we evaluated 3,844 black and white men and women with dietary and metabolomic data in cross-sectional and prospective analyses. We hypothesized that a higher dietary acid load (using equations for potential renal acid load and net endogenous acid production) was associated with lower serum levels of 12 previously identified metabolites: indolepropionylglycine, indolepropionate, N-methylproline, N-δ-acetylornithine, threonate, oxalate, chiro-inositol, methyl glucopyranoside, stachydrine, catechol sulfate, hippurate, and tartronate. In addition, we hypothesized that lower serum levels of these 12 metabolites were associated with higher risk of incident CKD.

RESULTS

Eleven out of 12 metabolites were significantly inversely associated with dietary acid load, after adjusting for demographics, socioeconomic status, health behaviors, health status, and estimated glomerular filtration rate: indolepropionylglycine, indolepropionate, N-methylproline, threonate, oxalate, chiro-inositol, catechol sulfate, hippurate, methyl glucopyranoside (α + β), stachydrine, and tartronate. N-methylproline was inversely associated with incident CKD (hazard ratio: 0.95, 95% confidence interval: 0.91, 0.99, P = .01). The metabolomic biomarkers of dietary acid load significantly improved prediction of elevated dietary acid load estimated using dietary data, beyond covariates (difference in C statistics: 0.021-0.077, P ≤ 1.08 × 10-3).

CONCLUSION

Inverse associations between candidate biomarkers of dietary acid load were replicated in a general population. N-methylproline, representative of citrus fruit consumption, is a promising marker of dietary acid load and could represent an important pathway between dietary acid load and CKD.

Dietary acid load and cardiovascular diseases

Diet affects the body's acid-base balance by providing acid or alkali precursors in the metabolism. The importance of the acid-base balance of the diet for cardiovascular diseases, which have become the most important cause of morbidity on the global scale, has started to take its place in the literature. The prediction of endogenous acid production in dietary acid-base balance is expressed as dietary acid load. Although the available information about the effect of dietary acid load on cardiovascular diseases is limited, possible mechanisms are indicated as excessive calcium and magnesium excretion from the kidneys, reduced urinary citrate excretion, and excessive cortisol production. Metabolic acidosis has an important role in the development of cardiometabolic abnormalities, especially insulin resistance. Studies examining the relationship between dietary acid load and cardiovascular disease are limited and there is an inconsistency between studies. Practices for determining risk factors for cardiovascular diseases and preventing their effects are very important for the protection and improvement of health. Considering dietary acid load when planning a diet for individuals with cardiovascular diseases can help increase the effectiveness of the diet. The purpose of this review is to examine the effect of dietary acid load on cardiovascular diseases.

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.

Nutritional and dietary interventions to prolong renal allograft survival after kidney transplantation

PURPOSE OF REVIEW

Diet plays an important role in slowing progression of chronic kidney disease in native and transplanted kidneys. There is limited evidence on the association on dietary intake with renal allograft function. Mechanisms of major nutrients and dietary patterns with focusing on a plant-based diet related to kidney transplant health and longevity are reviewed.

RECENT FINDINGS

High dietary protein intake may adversely affect renal allograft. Low protein plant-focused diets such as Dietary Approaches to Stop Hypertension, plant-dominant low-protein diet and Mediterranean diets appear associated with favorable outcomes in slowing renal allograft function decline. The mechanism may be related to a change in renal hemodynamic by decreasing glomerular hyperfiltration from low dietary protein intake and plant-based ingredients. Recent observational studies of association between dietary protein intake and kidney allograft outcomes are conflicting. Although strong evidence is still lacking, a low protein diet of 0.6-0.8 g/kg/day with at least 50% of the protein source from plant-based components in kidney transplant recipients with stable kidney allograft function should be considered as the dietary target.

SUMMARY

Dietary intervention with low-protein plant-focused meals may improve outcomes in kidney transplant recipients, but the evidence remains limited and further studies are warranted.

Dietary Acid Load Is Positively Associated with the Incidence of Hyperuricemia in Middle-Aged and Older Korean Adults: Findings from the Korean Genome and Epidemiology Study

Hyperuricemia has been associated with a number of chronic diseases, such as type 2 diabetes mellitus, hypertension, and cardiovascular diseases. Dietary acid load plays a key role in regulating uric acid levels. We hypothesized that potential renal acid load (PRAL) and net endogenous acid production (NEAP) score would be positively associated with the incidence of hyperuricemia. Data from the Health Examinees study, a part of the Korean Genome and Epidemiology Study were used. The PRAL and NEAP scores were calculated to evaluate the dietary acid load. Hyperuricemia was defined as follows: >7.0 mg/dL and >6.0 mg/dL of serum uric acid levels in men and women, respectively. Multivariable Cox proportional hazard models were used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for the incidence of hyperuricemia. We identified 2500 new cases of hyperuricemia during a mean follow-up of 5.0 years (223,552 person years). The participants in the highest quartiles of the PRAL and NEAP score had 21% (HR: 1.21, 95% CI: 1.07–1.35, p for trend <0.0001) and 17% (HR: 1.17, 95% CI: 1.04–1.31, p for trend <0.0001) higher risks for hyperuricemia, respectively, than those in the lowest quartiles, after adjusting for covariates. In this prospective cohort study, a higher dietary acid load was positively associated with a higher incidence of hyperuricemia in Korean adults. This suggests that an alkaline diet may be an effective strategy to reduce the future risk of elevated uric acid levels.

A Vegan Diet Is Associated with a Significant Reduction in Dietary Acid Load: Post Hoc Analysis of a Randomized Controlled Trial in Healthy Individuals

The composition of diet strongly affects acid–base homeostasis. Western diets abundant in acidogenic foods (meat and cheese) and deficient in alkalizing foods (fruits and vegetables) increase dietary acid load (DAL). A high DAL has been associated with numerous health repercussions, including cardiovascular disease and type-2-diabetes. Plant-based diets have been associated with a lower DAL; however, the number of trials exploring this association is limited. This randomized-controlled trial sought to examine whether an isocaloric vegan diet lowers DAL as compared to a meat-rich diet. Forty-five omnivorous individuals were randomly assigned to a vegan diet (n = 23) or a meat-rich diet (n = 22) for 4 weeks. DAL was determined using potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores at baseline and after 3 and 4 weeks, respectively. After 3 weeks, median PRAL (−23.57 (23.87)) and mean NEAP_R (12.85 ± 19.71) scores were significantly lower in the vegan group than in the meat-rich group (PRAL: 18.78 (21.04) and NEAP_R: 60.93 ± 15.51, respectively). Effects were mediated by a lower phosphorus and protein intake in the vegan group. Our study suggests that a vegan diet is a potential means to reduce DAL, whereas a meat-rich diet substantially increases the DAL burden.

Dietary acid load and risk of cardiovascular disease: a prospective population-based study

BACKGROUND AND AIM

Considering the inconsistencies in the cardiovascular effects of dietary acid load and the impact of dietary acidity on the acid-base homeostasis within the body, we aimed to assess the association of dietary acid load and the risk of cardiovascular disease (CVD) in a prospective community-based study.

MATERIALS AND METHODS

Participants (n = 2369) free of CVD at baseline (2006-2008) were included from the Tehran Lipid and Glucose Study (TLGS) and followed up for a mean of 6.7 ± 1.4 years. Dietary intakes of the participants were assessed using a semi-quantitative food frequency questionnaire (FFQ). The dietary acid load was evaluated by Potential Renal Acid Load (PRAL) and Net Endogenous Acid Production (NEAP) scores. Both scores have used the macronutrient and micronutrient data of the Food Frequency Questionnaires. Multivariate Cox proportional hazard regression models were used to estimate the 6-years incident risk of CVDs across tertiles of PRAL and NEAP scores.

RESULTS

Mean age and body mass index of participants were 38.5 ± 13.3 years and 26.6 ± 4.8 kg/m² at baseline. Within 6.7 ± 1.4 years of follow-up, 79 cases of cardiovascular events were reported. NEAP was significantly associated with the incidence of CVDs (HRs = 0.50, CI 0.32-0.96; P for trend = 0.032); however, after adjusting for potential confounders, no significant associations were observed between PRAL and NEAP scores and the risk of CVDs.

CONCLUSIONS

This study failed to obtain independent associations between dietary acid load and the incidence of CVDs among an Asian population.

Surkan P, Azadbakht L. Associations between dietary acid load and obesity among Iranian women

Introduction: Diet-induced acid load may be associated with overweight and obesity as well as with diet quality. We aimed to study how dietary acid load is associated with overweight, obesity and diet quality indices in healthy women.

Methods: We randomly selected 306 healthy 20 to 55 year-old women from health centers affiliated with Tehran University of Medical Science. They were enrolled in a cross-sectional study between June2016 and March 2017. Potential renal acid load (PRAL), net endogenous acid production (NEAP) and dietary acid load (DAL) were calculated for each person. Dietary quality index international (DQI-I),mean adequacy ratio (MAR), and energy density (ED) were estimated. Anthropometry was measured using standard protocols. Nutritional data were obtained from food frequency questionnaires (FFQ). We used multivariable logistic regression models to assess dietary acid load indices in relation to overweight, obesity and abdominal adiposity.

Results: Participants had a mean age of 32.4 years. The number and percentage of women who were overweight, obese and who had abdominal obesity were 94(30.7), 38(12.4) and 126(41.2), respectively.The odds of obesity (adjusted odds ratio; Adj. OR = 2.41, 95% confidence interval; CI:1.01-5.74,P = 0.045) and abdominal adiposity (Adj. OR = 2.4, 95% CI:1.34-4.60, P = 0.004) increased significantly with tertile of DAL. Other dietary acid load indices (PRAL and NEAP) showed no significant association with obesity, overweight or abdominal obesity. As dietary acid load scores (PRAL, NEAP and DAL)increased, DQI-I and MAR significantly decreased whereas ED significantly increased across tertilesof dietary acid load indices (P < 0.001).

Conclusion: Dietary acid load is associated with obesity and abdominal obesity and is also considered an indicator of diet quality.

Association of dietary acid load with anthropometric indices in children and adolescents

PURPOSE

High dietary acid load (DAL) may have an influence on anthropometric indices. Given that there was no study on the association between DAL and anthropometric indices children and adolescents, the current study was aimed to examine the association between DAL and anthropometric indices in Iranian children and adolescents.

METHODS

Students aged 6-18 years were recruited using a multi-stage, cluster sampling method from 30 provinces of Iran. Dietary intake was assessed through a validated food frequency questionnaire. Height (Ht), weight (Wt), neck circumference (NC), waist circumference (WC), wrist circumference, and hip circumference (HC) were measured. WC-to-HC ratio (WHR), WC-to-Ht ratio (WHtR), body mass index (BMI) z-score, tri-ponderal mass index (TMI), and parental BMI were computed. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) were used to estimate DAL. The association between DAL and anthropometric indices was evaluated using linear regression models.

RESULTS

In total, 5326 students (46.92% girls), with mean (standard deviations (SD)) age of 12.50 (3.14) years participated in the study (response rate: 98.13%). After adjusting for confounders, there was a significant association between NEAP and NC (P < 0.05). Also, an inverse association was observed between PRAL and NEAP with parental BMI (P < 0.05).

CONCLUSION

Our findings showed a direct association between diet-induced acid load and NC and an inverse association between DAL indices and parental BMI. More well-designed clinical studies are warranted to confirm our results and the underlying mechanisms.

LEVEL OF EVIDENCE

Level V, cross-sectional descriptive study.

No Interaction Effect between Interleukin-6 Polymorphisms and Acid Ash Diet with Bone Resorption Marker in Postmenopausal Women

Background: Evidence is growing that a high-acid diet might accelerate the rate of bone loss, and gene polymorphisms such as Interleukin 6 (IL6) -174G/C and -572G/C are related to bone deterioration. However, no study of the interaction between diet and IL6 polymorphisms has been conducted among Asians. Thus, the objective of this study was to determine whether IL6 gene polymorphisms modified the association between dietary acidity and the rate of bone resorption. Methods: This cross-sectional study recruited 203 postmenopausal women (age ranged from 51 to 85 years old) in community settings. The dietary intakes of the participants were assessed using a validated interviewer-administered semi-quantitative food frequency questionnaire (FFQ), while dietary acid load (DAL) was estimated using net endogenous acid production (NEAP). Agena^® MassARRAY genotyping analysis and serum collagen type 1 cross-linked C-telopeptide (CTX1) were used to identify the IL6 genotype and as a bone resorption marker, respectively. The interactions between diet and single-nucleotide polymorphisms (SNPs) were assessed using linear regressions. Results: A total of 203 healthy postmenopausal women aged between 51 and 85 years participated in this study. The mean BMI of the participants was 24.3 kg/m². In IL6 -174 G/C, all the participants carried the GG genotype, while the C allele was absent. Approximately 40% of the participants had a high dietary acid load. Dietary acid load (B = 0.15, p = 0.031) and the IL6 -572 CC genotype group (B = 0.14, p = 0.044) were positively associated with a higher bone resorption. However, there was no moderating effect of the IL6 genetic polymorphism on the relationship between and acid ash diet and bone resorption markers among the postmenopausal women (p = 0.79). Conclusion: High consumption of an acid ash diet and the IL6 -572 C allele seem to attribute to high bone resorption among postmenopausal women. However, our finding does not support the interaction effect of dietary acidity and IL6 (-174G/C and -572G/C) polymorphisms on the rate of bone resorption. Taken together, these results have given scientific research other candidate genes to focus on which may interact with DAL on bone resorption, to enhance planning for preventing or delaying the onset of osteoporosis among postmenopausal women.

Renal and dietary factors associated with hypertension in a setting of disadvantage in rural India

Using a case-control design, we determined risk factors associated with hypertension in a disadvantaged rural population in southern India. Three hundred adults with hypertension and 300 age- and sex-matched controls were extensively phenotyped. Underweight (29%, body mass index < 18.0 kg m^-2), chronic kidney disease (25%, estimated glomerular filtration rate <60 ml min^-1 1.73 m^-2) and anemia (82%) were highly prevalent. The ratio of sodium to potassium excretion was high (8.2). In multivariable conditional logistic regression of continuous variables dichotomized by their median value, hypertension was independently associated with greater abdominal adiposity as assessed by waist-hip ratio [odds ratio (95% confidence interval), 1.89 (1.21-2.97)], lesser protein intake as assessed by 24 h urea excretion [0.39 (0.24-0.65)], and lesser plasma renin activity [0.54 (0.35-0.84)]. Hypertension tended to be independently associated with lesser serum potassium concentration [0.66 (0.44-1.01), P = 0.06]. Furthermore, those with hypertension reported less frequent intake of vegetables and urinary sodium-potassium ratio correlated positively with serum sodium-potassium ratio (r = 0.18). Hypertension was also independently associated with lesser blood hemoglobin concentration [0.48 (0.26-0.88)]. Blood hemoglobin concentration was positively associated with serum iron (r = 0.41) and ferritin (r = 0.25) concentration and negatively associated with total iron binding capacity (r = -0.17), reflecting iron-deficiency anemia. Our findings indicate potential roles for deficient intake of potassium and protein, and iron-deficiency anemia, in the pathophysiology of hypertension in a setting of disadvantage in rural India. Imbalanced intake of potassium and sodium may be driven partly by deficient intake of vegetables or fruit.

Brain structure prior to non-central nervous system cancer diagnosis: A population-based cohort study

•

In a population-based setting we studied brain structure before cancer diagnosis.

•

Brain structure was not altered before non-CNS cancer diagnosis.

•

The effect of cancer on the brain before clinical manifestation is not supported.

Purpose

Many studies have shown that patients with non-central nervous system (CNS) cancer can have brain abnormalities, such as reduced gray matter volume and cerebral microbleeds. These abnormalities can sometimes be present even before start of treatment, suggesting a potential detrimental effect of non-CNS cancer itself on the brain. In these previous studies, psychological factors associated with a cancer diagnosis and selection bias may have influenced results. To overcome these limitations, we investigated brain structure with magnetic resonance imaging (MRI) prior to cancer diagnosis.

Patients and methods

Between 2005 and 2014, 4,622 participants from the prospective population-based Rotterdam Study who were free of cancer, dementia, and stroke, underwent brain MRI and were subsequently followed for incident cancer until January 1st, 2015. We investigated the association between brain MRI measurements, including cerebral small vessel disease, volumes of global brain tissue, lobes, and subcortical structures, and global white matter microstructure, and the risk of non-CNS cancer using Cox proportional hazards models. Age was used as time scale. Models were corrected for e.g. sex, intracranial volume, educational level, body mass index, hypertension, diabetes mellitus, smoking status, alcohol use, and depression sum-score.

Results

During a median (interquartile range) follow-up of 7.0 years (4.9–8.1), 353 participants were diagnosed with non-CNS cancer. Results indicated that persons who develop cancer do not have more brain abnormalities before clinical manifestation of the disease than persons who remain free of cancer. The largest effect estimates were found for the relation between presence of lacunar infarcts and the risk of cancer (hazard ratio [HR] 95% confidence interval [CI] = 1.39 [0.97–1.98]) and for total brain volume (HR [95%CI] per standard deviation increase in total brain volume = 0.76 [0.55–1.04]).

Conclusion

We did not observe associations between small vessel disease, brain tissue volumes, and global white matter microstructure, and subsequent cancer risk in an unselected population. These findings deviate from previous studies indicating brain abnormalities among patients shortly after cancer diagnosis.

Sarcopenia in older people with chronic airway diseases: the Rotterdam study

Sarcopenia is a heterogeneous skeletal muscle disorder involving the loss of muscle mass and function. However, the prevalence of sarcopenia based on the most recent definition remains to be determined in older people with chronic airway diseases. The aim was to evaluate sarcopenia prevalence and association with chronic airway diseases and its lung function in an older population, using the European Working Group on Sarcopenia in Older People 2 (EWGSOP2) criteria. We performed a cross-sectional analysis in 5082 participants (mean age 69.0±8.8 years, 56% females) from the Rotterdam Study. Participants with interpretable spirometry and an available assessment of sarcopenia were included. The appendicular skeletal muscle mass index (ASMI) and handgrip strength (HGS) were assessed using dual-energy X-ray absorptiometry (DXA) and a hydraulic hand dynamometer, respectively. We analysed the association between sarcopenia and chronic airway diseases by using regression models adjusted for age, sex, smoking status, total fat percentage and other relevant confounders. Participants with chronic airway diseases had higher prevalence of probable sarcopenia (12.0%, 95% CI 10.2-13.8) and confirmed sarcopenia (3.0%, 95% CI 2.1-3.9) than without. Chronic airway diseases were associated with "probable sarcopenia" (OR 1.28, 95% CI 1.02-1.60), "confirmed sarcopenia" (OR 2.13, 95% CI 1.33-3.43), reduced HGS (β -0.51 (-0.90--0.11)) and reduced ASMI (β -0.19 (-0.25--0.14)). Forced expiratory volume in 1 s <80% was associated with lower HGS (β -1.03 (-1.75--0.31)) and lower ASMI (β -0.25 (-0.36--0.15)) than forced expiratory volume in 1 s ≥80%. Sarcopenia was prevalent and associated with chronic airway diseases among older population. These results suggest the need for early diagnosis of sarcopenia in older people with chronic airway diseases by applying EWGSOP2 recommendations.

Dietary Acid Load and Cardiometabolic Risk Factors-A Narrative Review

The Western, diet rich in acidogenic foods (e.g., meat, fish and cheese) and low in alkaline foods (e.g., vegetables, fruits and legumes), is deemed to be a cause of endogenous acid production and elevated dietary acid load (DAL), which is a potential cause of metabolic acidosis. Multiple authors have suggested that such a dietary pattern increases the excretion of calcium and magnesium, as well as cortisol secretion. In addition, it is associated with decreased citrate excretion. All of these seem to increase blood pressure and insulin resistance and may contribute to the development of cardiometabolic disorders. However, there are inconsistencies in the results of the studies conducted. Therefore, this narrative literature review aims to present the outcomes of studies performed in recent years that investigated the association between DAL and the following cardiometabolic risk factors: blood pressure, hypertension, carbohydrate metabolism and lipid profile. Study outcomes are divided into (i) statistically significant positive association, (ii) statistically significant inverse association, and (iii) no statistically significant association.

Association of dietary acid-base load and psychological disorders among Iranian women: A cross-sectional study

Metabolic acidosis, which can be affected by dietary acid-base load, seems to be associated with psychological disorders through different pathways. Given limited evidence on dietary acid-base load, we aimed to examine the association of dietary acid-base load with psychological disorders in Iranian women. This cross-sectional study was performed on 447 female subjects (20-50 years old). Dietary intake was assessed using a valid food frequency questionnaire for Iran. Dietary acid-base load was calculated through different indices including potential renal acid load (PRAL), net endogenous acid production (NEAP), and dietary acid load (DAL). To assess psychological disorders, an Iranian validated version of depression, anxiety, and stress scale (DASS-21) was used. The mean value of PRAL, NEAP, and DAL were -8.87mEq/da, 37.94mEq/day, and 30.77mEq/day, respectively. Considering a wide range of confounding variables, compared with the first tertile, a significant positive association was observed between dietary acid-base load and depression (OR_PRAL: 3.63; 95 %CI:1.97, 6.71; P_trend = 0.0001) (OR_NEAP:3.42; 95 %CI: 1.87, 6.23; P_trend = 0.0001) (OR_DAL: 3.02; 95 %CI: 1.64, 5.58; P_trend = 0.0001). Women in the high dietary acid-base load category had higher anxiety (OR_PRAL: 3.31; 95 %CI: 1.81, 6.06; P_trend = 0.0001) (OR_NEAP:3.47; 95 %CI: 1.90, 6.33; P_trend = 0.0001) (OR_DAL: 3.25; 95 %CI: 1.76, 5.98; P_trend = 0.0001). Moreover, there was a strong positive relationship between dietary acid-base load and psychologicaldistress (OR_PRAL: 3.79; 95 %CI: 2.09, 6.90; P_trend = 0.0001) (OR_NEAP: 3.67; 95 %CI: 2.04, 6.58; P_trend = 0.0001) (OR_DAL: 3.00; 95 %CI: 1.66, 5.43; P_trend = 0.0001). Women with higher dietary acid-base load score had greater odds for depression, anxiety, and psychological distress compared to lower ones.

Aortic Arch Calcification and the Risk of Cancer: A Population-Based Cohort Study

Background: Atherosclerosis and cancer share multiple disease pathways. Yet, it is unclear if atherosclerosis is associated with a subsequent higher cancer risk. We determined the association of atherosclerotic calcification in the aortic arch, as proxy for systemic atherosclerosis, with the risk of cancer.

Methods: Between 2003 and 2006, 2,404 participants (mean age: 69.5 years, 52.5% women) from the prospective population-based Rotterdam Study underwent computed tomography to quantify calcification in the aortic arch. Participants were followed for the onset of cancer, death, loss to follow-up, or January 1st, 2015, whichever came first. We computed sex-specific tertiles of aortic arch calcification volumes. Next, we examined the association between the volume and severity (i.e., tertiles) of aortic arch calcification and the risk of cancer using Cox proportional hazard models.

Results: During a median (interquartile range) follow-up of 9.6 years (8.9–10.5), 348 participants were diagnosed with cancer. Participants with the greatest severity of aortic arch calcification had a higher risk of cancer [hazard ratio for the third tertile compared to the first tertile of aortic arch calcification volume in the total population is 1.39 (95% CI = 1.04–1.86)].

Conclusions: Individuals with the most severe aortic arch calcification had a higher risk of cancer. While this could reflect the impact of long-term exposure to shared risk factors, it might also point toward the co-occurrence of both conditions.

Higher Plasma Amyloid-β Levels Are Associated with a Higher Risk of Cancer: A Population-Based Prospective Cohort Study

BACKGROUND

Various studies show an inverse relation between Alzheimer disease and cancer, but findings are likely to be biased by surveillance and survival bias. Plasma amyloid-β (Aβ) is defined as a preclinical feature of Alzheimer disease, with lower levels of Aβ42 being associated with a higher risk of Alzheimer disease. To get more insight into the biological link between Alzheimer disease and cancer, we investigated plasma Aβ levels in relation to the risk of cancer.

METHODS

Between 2002 and 2005, we measured plasma Aβ40 and Aβ42 levels in 3,949 participants from the population-based Rotterdam Study. These participants were followed until the onset of cancer, all-cause dementia, death, loss to follow-up, or January 1, 2014, whichever came first. We used Cox proportional hazards models to investigate the association between plasma Aβ40 and Aβ42 levels, and the risk of cancer. Analyses were stratified by cancer site.

RESULTS

During a median (interquartile range) follow-up of 9.0 years (6.9-10.1), 560 participants were diagnosed with cancer. Higher levels of log₂ plasma Aβ40 and Aβ42 were associated with a higher risk of cancer [hazard ratio per standard deviation increase for Aβ40 = 1.12 (95% confidence interval, CI = 1.02-1.23) and Aβ42 = 1.12 (95% CI = 1.03-1.23)]. These effect estimates were most pronounced for hematologic cancers, urinary tract cancers, and cancers of unknown primary origin.

CONCLUSIONS

We found that higher levels of both plasma Aβ40 and Aβ42 were associated with a higher risk of cancer.

IMPACT

Our study suggests a potential biological link between Alzheimer disease and cancer. The pathophysiologic role of Aβ in cancer and its causality warrant further investigation.

Increased Acid-Producing Diet and Past Smoking Intensity Are Associated with Worse Prognoses Among Breast Cancer Survivors: A Prospective Cohort Study

Current dietary guidelines do not consider cancer survivors’ and past smokers’ low capacity to regulate their acid–base balance. People with a low capacity to regulate their acid–base balance are more susceptible to acid-producing diets. We studied a cohort of 2950 early stage breast cancer survivors who provided dietary information at baseline and during follow-up. We assessed the intakes of acid-producing diets via two commonly used dietary acid load scores: potential renal acid load (PRAL) and net endogenous acid production (NEAP). We assessed past smoking intensity by pack-years of smoking. After an average of 7.3 years of follow-up, there were 295 total deaths, 249 breast cancer-specific deaths, and 490 cases of recurrent breast cancer. Increased intakes of dietary acid load and pack-years of smoking were each independently and jointly associated with increased total mortality and breast cancer-specific mortality; tests for trends and overall associations were statistically significant for NEAP and marginally significant for PRAL. Compared to women in the lowest tertile of NEAP and pack-year of smoking = 0, women in the highest tertile of NEAP and pack-years of smoking >15 had the greatest increased risk of total mortality (HR = 3.23, 95%CI 1.99–5.26). Further, dietary acid scores were associated with increased breast cancer recurrence among women with pack-years of smoking >0 but not in those with pack-years of smoking = 0 (p values for interactions <0.05). Our study provides valuable evidence for adding dietary acid load scores to dietary guidelines for breast cancer survivors and developing specific guidelines for past smokers among these survivors.

Dietary acid load, blood pressure, fasting blood sugar and biomarkers of insulin resistance among adults: Findings from an updated systematic review and meta-analysis

OBJECTIVES

There is no clear summarised report of the association between dietary acid load components including potential renal acid load (PRAL) and net-endogenous acid production (NEAP) with cardiometabolic risk factors. In the current meta-analysis, we aimed to systematically review and summarise the eligible observational studies evaluating the association between PRAL and NEAP with blood pressure and hypertension and markers of glucose haemostasis among adults.

DESIGN AND SETTING

In a systematic search from PubMed, SCOPUS, Web of Sciences and Cochrane electronic databases up to May 2019, relevant studies were included in the literature review. Observational studies evaluating the association between PRAL and NEAP with the systolic blood pressure (SBP), diastolic blood pressure (DBP), fasting blood glucose, insulin, homeostatic model assessment of insulin resistance (HOMA-IR), haemoglobin A₁ C (HbA₁ C), HOMA-β and quantitative insulin check index (QUICKI) and also prevalence or odds of hypertension, hyperglycaemia and diabetes were included.

RESULTS

Total number of studies included in the 14 separate meta-analyses were as follows: Mean (SD) of SBP (PRAL, n = 12; NEAP, n = 6), mean (SD) of DBP (PRAL, n = 8; NEAP, n = 3), mean (SD) of FBS (PRAL, n = 12; NEAP, n = 5), mean (SD) of HbA₁ C (PRAL, n = 6; NEAP, n = 4), mean (SD) of HOMA-IR (PRAL, n = 7), mean (SD) of insulin (PRAL, n = 7; NEAP, n = 2); OR of type 2 diabetes mellitus (T₂ DM) (PRAL, n = 8; NEAP; n = 6), HTN prevalence (PRAL, n = 9; NEAP, n = 9), T₂ DM prevalence (PRAL, n = 7; NEAP, n = 6). According to our results, being in the highest PRAL categories was associated with higher SBP (WMD = 0.98; CI: 0.51, 1.45; P < .001), DBP (WMD = 0.61; CI: 0.089, 1.135; P = .022), insulin (WMD = -0.235, CI: 0.070, 0.400; P = .005), higher odds of diabetes (OR = 1.19; CI: 1.092, 1.311; P < .001), higher prevalence of T₂ DM (13% and 11% in highest vs lowest category). While, being in the highest category of NEAP was only associated with higher odds of diabetes (OR = 1.22; CI: 1.14, 1.31, P < .001). In subgroup analysis for finding the possible source of heterogeneity, the continent, dietary assessment tool, sample size and gender were the potent sources of heterogeneity. No association between PRAL and NEAP with HbA₁ C, HOMA-IR was reported.

CONCLUSIONS

In the current meta-analysis, we found potent negative effects of high dietary acid load particularly higher PRAL scores cardiometabolic risk factors. Therefore, lower acidogenic food ingredients in the diets are suggested for the prevention of cardiovascular risk factors and diabetes.

Hemoglobin A1c Levels Modify Associations between Dietary Acid Load and Breast Cancer Recurrence

BACKGROUND

Metabolic acidosis promotes cancer metastasis. No prospective studies have examined the association between dietary acid load and breast cancer recurrence among breast cancer survivors, who are susceptible to metabolic acidosis. Hyperglycemia promotes cancer progression and acid formation; however, researchers have not examined whether hyperglycemia can modify the association between dietary acid load and breast cancer recurrence.

METHODS

We studied 3081 early-stage breast cancer survivors enrolled in the Women's Healthy Eating and Living study who provided dietary information through 24-h recalls at baseline and during follow-up and had measurements of hemoglobin A1c (HbA1c) at baseline. We assessed dietary acid load using two common dietary acid load scores, potential renal acid load (PRAL) score and net endogenous acid production (NEAP) score.

RESULTS

After an average of 7.3 years of follow-up, dietary acid load was positively associated with recurrence when baseline HbA1c levels were ≥ 5.6% (median level) and ≥5.7% (pre-diabetic cut-point). In the stratum with HbA1c ≥ 5.6%, comparing the highest to the lowest quartile of dietary acid load, the multivariable-adjusted hazard ratio was 2.15 (95% confidence interval [CI] 1.34-3.48) for PRAL and was 2.31 (95% CI 1.42-3.74) for NEAP. No associations were observed in the stratum with HbA1c levels were <5.6%. P-values for interactions were 0.01 for PRAL and 0.05 for NEAP.

CONCLUSIONS

Our study demonstrated for the first time that even at or above normal to high HbA1c levels, dietary acid load was associated with increased risk of breast cancer recurrence among breast cancer survivors.

IMPACTS

Our study provides strong evidence for developing specific dietary acid load guidelines based on HbA1c levels.

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.

Apolipoprotein B/Apolipoprotein A-I Ratio Is a Better Predictor of Cancer Mortality Compared with C-Reactive Protein: Results from Two Multi-Ethnic US Populations

BACKGROUND

There is a lack of evidence regarding the link between apolipoproteins and cancer mortality. By using two nationally representative samples of US adults, we prospectively evaluated the associations between apolipoprotein B (apoB) levels and apoB/apoA-I ratio with cancer mortality. We also examined the role of C-reactive protein (CRP) in these associations.

MATERIALS AND METHODS

Adults aged ≥20 years, enrolled in the 3rd National Health and Nutrition Examination Survey (NHANES III, 1988-1994) and continuous NHANES (2005-2010), and followed up to 31 December 2011, were included in the analysis. Multiple Cox regressions were applied to evaluate the associations between the variables of interest and cancer mortality.

RESULTS

Overall, 7695 participants were included (mean age: 49.2 years; 50.4% men, median follow-up: 19.1 years). In the fully adjusted model, participants in the highest quartile (Q4) of apoB/apoA-I had a significantly greater risk for cancer mortality (hazard ratio (HR): 1.40; 95% confidence interval (CI): 1.25-1.93) compared with those in the first quartile (Q1). In the same model, a positive and significant association between apoB levels and cancer mortality was observed for individuals in Q3 (HR: 1.12; 95% CI: 1.09-1.16) and Q4 (HR: 1.17; 95% CI: 1.09-1.25) compared with those in Q1. When CRP levels were added in the analysis, the apoB/apoA-I ratio, but not apoB levels, remained significantly related to cancer mortality (Q4 = HR: 1.17; 95% CI: 1.09-1.25). In contrast, CRP levels were not able to predict cancer death after correction for apoB/apoA-I ratio.

CONCLUSIONS

In a large representative sample of the US adult population, the apoB/apoA-I ratio and apoB levels significantly predicted cancer mortality, independently of several cardiometabolic risk factors. The predictive value of apoB/apoA-I, but not apoB levels, remained significant after taking into account CRP, whereas CRP was not associated with cancer mortality after adjustment for apoB/apoA-I ratio. If further evidence supports our findings, apoA-I and apoB measurements could be considered in general healthcare policies.

Pathology-confirmed versus non pathology-confirmed cancer diagnoses: incidence, participant characteristics, and survival

Cancer diagnoses which are not confirmed by pathology are often under-registered in cancer registries compared to pathology-confirmed diagnoses. It is unknown how many patients have a non pathology-confirmed cancer diagnosis, and whether their characteristics and survival differ from patients with a pathology-confirmed diagnosis. Participants from the prospective population-based Rotterdam Study were followed between 1989 and 2013 for the diagnosis of cancer. Cancer diagnoses were classified into pathology-confirmed versus non pathology-confirmed (i.e., based on imaging or tumour markers). We compared participant characteristics and the distribution of cancers at different sites. Furthermore, we investigated differences in overall survival using survival curves adjusted for age and sex. During a median (interquartile range) follow-up of 10.7 (6.3–15.9) years, 2698 out of 14,024 participants were diagnosed with cancer, of which 316 diagnoses (11.7%) were non pathology-confirmed. Participants with non pathology-confirmed diagnoses were older, more often women, and had a lower education. Most frequently non pathology-confirmed cancer sites included central nervous system (66.7%), hepato-pancreato-biliary (44.5%), and unknown primary origin (31.2%). Survival of participants with non pathology-confirmed diagnoses after 1 year was lower compared to survival of participants with pathology-confirmed diagnoses (32.6% vs. 63.4%; risk difference of 30.8% [95% CI 25.2%; 36.2%]). Pathological confirmation of cancer is related to participant characteristics and cancer site. Furthermore, participants with non pathology-confirmed diagnoses have worse survival than participants with pathology-confirmed diagnoses. Missing data on non pathology-confirmed diagnoses may result in underestimation of cancer incidence and in an overestimation of survival in cancer registries, and may introduce bias in aetiological research.

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 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 choline is positively related to overall and cause-specific mortality: results from individuals of the National Health and Nutrition Examination Survey and pooling prospective data

Little is known about the association between dietary choline intake and mortality. We evaluated the link between choline consumption and overall as well as cause-specific mortality by using both individual data and pooling prospective studies by meta-analysis and systematic review. Furthermore, adjusted means of cardiometabolic risk factors across choline intake quartiles were calculated. Data from the National Health and Nutrition Examination Survey (1999–2010) were collected. Adjusted Cox regression was performed to determine the risk ratio (RR) and 95 % CI, as well as random-effects models and generic inverse variance methods to synthesise quantitative and pooling data, followed by a leave-one-out method for sensitivity analysis. After adjustments, we found that individuals consuming more choline had worse lipid profile and glucose homeostasis, but lower C-reactive protein levels (P < 0·001 for all comparisons) with no significant differences in anthropometric parameters and blood pressure. Multivariable Cox regression models revealed that individuals in the highest quartile (Q4) of choline consumption had a greater risk of total (23 %), CVD (33 %) and stroke (30 %) mortality compared with the first quartile (Q1) (P < 0·001 for all comparison). These results were confirmed in a meta-analysis, showing that choline intake was positively and significantly associated with overall (RR 1·12, 95 % CI 1·08, 1·17, I2 = 2·9) and CVD (RR 1·28, 95 % CI 1·17, 1·39, I2 = 9·6) mortality risk. In contrast, the positive association between choline consumption and stroke mortality became non-significant (RR 1·18, 95 % CI 0·97, 1·43, P = 0·092, I2 = 1·1). Our findings shed light on the potential adverse effects of choline intake on selected cardiometabolic risk factors and mortality risk.

Dietary acid load significantly predicts 10-years survival in patients underwent coronary artery bypass grafting (CABG) surgery

BACKGROUNDS

Numerous studies have revealed the role of dietary acid load as a potential risk factor for cardiovascular events and blood pressure. However, its role in predicting the mortality rate in patients underwent coronary artery bypass grafting surgery (CABG) has not been reported. In the current study we aimed to evaluate the relationship of dietary acid load and cardio-metabolic risk factors with ten year survival among patients underwent CABG.

METHODS

The current prospective cohort study comprises 454 patients underwent CABG. Anthropometric, clinical and biochemical measurements were performed. Dietary acid load was calculated as either potential renal acid load (PRAL) or net endogenous acid production (NEPA) using the data obtained from a semi-quantitative food frequency questionnaire (FFQ). Survival analysis was performed using Kaplan-Meier method followed by log-rank test. The association between all-cause mortality and study parameters was performed with Cox-proportional hazard model.

RESULTS

Patients in the higher PRAL and NEAP quartiles had lower BMI and lower ejection fraction rate (P <0.05). Moreover, lower hematocrit values were observed in patients of higher PRAL quartiles. Higher PRAL scores were associated with higher mortality rate and reduced survival days (adjusted hazard ratio: 1.023 (1.00-1.04; P-value = 0.01). However, there was no relationship between NEAP and survival.

CONCLUSIONS

We revealed that high PRAL scores are positive predictors of 10-year mortality in patients underwent CABG. The results of our study suggest that maintaining an adequate acid-base balance can contribute to longevity by reducing the risk of mortality.

Dietary Approaches to Stop Hypertension and risk of chronic kidney disease: A systematic review and meta-analysis of observational studies

BACKGROUND & AIMS

Dietary Approaches to Stop Hypertension (DASH) diet has been favorably linked to important risk factors associated with development of chronic kidney disease (CKD), such as insulin resistance, hypertension, and dyslipidemia. However, the protective role of DASH dietary patterns in development of CKD, as measured by estimated glomerular filtration rate (eGFR), remains inconsistent in the literature. The aim of the current systematic review was to summarize the findings of previous observational studies and quantify the potential association between DASH dietary patterns and the risk of CKD using meta-analysis.

METHODS

A comprehensive search was done with the use of MEDLINE, EMBASE, Web of Sciences, and Scopus databases to find relevant articles published prior to June 2019. Search terms included: ([Dietary Approaches to Stop Hypertension] OR [DASH]) AND ([Kidney Failure, Chronic] OR [Renal Insufficiency, Chronic] OR [Chronic Kidney Disease], OR [CKD] OR [End-Stage Renal Disease] OR [ESRD] OR [Kidney] OR [Renal]). To pool the risk estimates, fixed-effects and random-effects models were applied. Cochrane Q test was performed to detect sources of heterogeneity among the included studies.

RESULTS

Out of the seven studies included in the systematic review, six were eligible for inclusion in the meta-analysis. The total sample size was 568,213 participants including 16,694 cases of CKD. Combined risk estimates for 2 cross-sectional and 4 prospective cohort studies showed an inverse association between DASH dietary patterns and risk of CKD (Pooled risk estimate: 0.77, 95% CI 0.63-0.94; p = 0.01). Stratified analysis showed a marginally significant relationship between DASH dietary patterns and risk of CKD in prospective cohort studies (Pooled risk estimate: 0.79, 95% CI 0.61-1.01; p = 0.05), and no significant association in cross-sectional studies (Pooled risk estimate: 0.71, 95% CI 0.38-1.34; p = 0.29), respectively. A significant association was observed between DASH dietary patterns and risk of CKD in the studies extracted DASH based on nutrients (Pooled risk estimate: 0.78, 95% CI 0.63-0.97; p = 0.02), compared to the studies extracted DASH based on food groups (Pooled risk estimate: 0.66, 95% CI 0.28-1.58; p = 0.35).

CONCLUSIONS

The results of the present study showed a significant inverse association between DASH dietary patterns and the risk of developing CKD. Adherence to DASH dietary patterns might have protective effects against CKD development and progression. Further research is required to confirm the certainty of estimates.

Associations between Dietary Acid Load and Biomarkers of Inflammation and Hyperglycemia in Breast Cancer Survivors

Metabolic acidosis can lead to inflammation, tissue damage, and cancer metastasis. Dietary acid load contributes to metabolic acidosis if endogenous acid-base balance is not properly regulated. Breast cancer survivors have reduced capacities to adjust their acid-base balance; yet, the associations between dietary acid load and inflammation and hyperglycemia have not been examined among them. We analyzed data collected from 3042 breast cancer survivors enrolled in the Women's Healthy Eating and Living (WHEL) Study who had provided detailed dietary intakes and measurements of plasma C-reactive protein (CRP) and hemoglobin A1c (HbA1c). Using a cross-sectional design, we found positive associations between dietary acid load and plasma CRP and HbA1c. In the multivariable-adjusted models, compared to women with the lowest quartile, the intakes of dietary acid load among women with the highest quartile showed 30-33% increases of CRP and 6-9% increases of HbA1c. Our study is the first to demonstrate positive associations between dietary acid load and CRP and HbA1c in breast cancer survivors. Our study identifies a novel dietary factor that may lead to inflammation and hyperglycemia, both of which are strong risk factors for breast cancer recurrence and comorbidities.

Dietary Patterns and Renal Health Outcomes in the General Population: A Review Focusing on Prospective Studies

Healthy dietary patterns may promote kidney health and prevent adverse renal outcomes. Although reviews have summarized the findings from studies on dietary patterns for chronic kidney disease (CKD) management, less is known about dietary patterns for maintaining kidney health prior to CKD development. The current review summarized the results from observational studies from March 2009 to March 2019 investigating associations between dietary patterns and renal outcomes in the general population. The main renal outcome assessed was CKD (estimated glomerular filtration rate < 60 mL/min/1.73 m2). A total of twenty-six research articles met the inclusion criteria. Adherence to the Dietary Approaches to Stop Hypertension (DASH) and Mediterranean diets were significantly associated with a decreased risk of CKD in the majority of the studies. Furthermore, a posteriori "unhealthy" dietary patterns were associated with an increased risk of CKD. In conclusion, the findings from this review suggest that adherence to DASH and Mediterranean dietary patterns may be useful in promoting kidney health and preventing CKD in the general population. More studies, in particular among minorities, are warranted to investigate the role of diet, a potentially modifiable factor, in promoting kidney health.