Examining the relationship between diet-induced acidosis and cancer

Potassium bicarbonate, not sodium bicarbonate, maintains acidosis-mediated bone dissolution

Treatments for metabolic acidosis are not well studied; however, one treatment that is commonly used is sodium bicarbonate administration. Sodium bicarbonate has been shown to help reduce symptoms of metabolic acidosis, but its benefits for bone health remain uncertain. Potassium bicarbonate has become a potential new treatment due to its reduction in bone resorption markers, unlike sodium bicarbonate. However, very few studies have looked at the connection between bone functionality and potassium bicarbonate supplementation, especially under the influence of an acidic challenge. To determine the impact of potassium bicarbonate and sodium bicarbonate on the mechanical, structural, compositional, and cellular properties of bone, acidotic mice were given either potassium bicarbonate or sodium bicarbonate for seven days. Blood gas analysis was conducted to evaluate their acidotic states throughout the study. After experimentation, the mice were euthanized, and their femurs excised for further analysis. Before bicarbonate supplementation, the acidotic mice given sodium bicarbonate were in acidosis while the acidotic mice given potassium bicarbonate were in acidemia. The bicarbonate treatment somewhat rescued the blood gas parameters in both acidosis groups, but acidemia and bone dissolution continued occurring in the acidotic mice given potassium bicarbonate, as made evident by the continuous elevation in blood sodium levels compared to the control. The acidosis group given potassium bicarbonate group also had worsened composition and structure, while the acidosis group given sodium bicarbonate had no changes in bone metrics. In this study, potassium bicarbonate was not effective at reducing bone dissolution under acidotic conditions.

Positive associations between dietary potential acid load and renal cancer incidence and mortality: Results from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening trial

OBJECTIVES

To explore the relationships between dietary potential acid load and renal cancer (RC) incidence and mortality.

STUDY DESIGN

A prospective cohort study involving 97,166 U S. adults aged 55-74 years.

METHODS

Data utilized in this study were drawn from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO). Dietary potential acid load was assessed by dietary acid load (DAL), potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores using a validated Diet History Questionnaire (DHQ). Cox proportional hazards regression was used to estimate hazard ratios (HRs) and 95 % confidence intervals (CIs) for RC incidence and mortality with adjustment for potential confounders. Restricted cubic spline (RCS) plots were utilized to reveal whether there were nonlinear associations between the DAL, PRAL, and NEAP scores and RC incidence and mortality.

RESULTS

During a follow-up period of 859,907 and 1,467,573 person-years, 423 RC cases and 221 mortality cases were documented. DAL, PRAL, and NEAP scores were positively associated with RC incidence (DAL: HR 1.41; 95% CI 1.05, 1.90; P-trend = 0.010; PRAL: HR 1.45; 95% CI 1.10, 1.91; P-trend = 0.010; NEAP: HR 1.39; 95% CI 1.04, 1.85; P-trend = 0.029). Similar associations were observed between DAL, PRAL, and NEAP scores and RC mortality. The RCS plots demonstrated a nonlinear association between DAL score and RC risk, while a linear association was observed between DAL score and RC mortality. Similar linear associations were found between PRAL and NEAP scores and RC incidence and mortality.

CONCLUSION

A higher dietary potential acid load was associated with higher risk of RC incidence and mortality in American adults.

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

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

Exploring the Potential Use of Natural Products Together with Alkalization in Cancer Therapy

Cancer treatment is a significant focus in medicine, owing to the increasing global incidence of cancers. Patients with advanced cancers that do not respond to conventional therapies have limited options and an unfavorable prognosis. Consequently, researchers are investigating complementary approaches to conventional treatments. One such approach is alkalization therapy, which aims to neutralize the acidic tumor microenvironment (TME) by increasing its pH level. The acidic TME promotes inflammation, tumor progression, and drug resistance. Alkalization therapy has been demonstrated to be effective for various cancers. In addition, natural products, such as triterpenoids, parthenolides, fulvic acid, Taxus yunnanensis, and apple pectin have the potential to alleviate symptoms, maintain physical fitness, and improve treatment outcomes of cancer patients through their anti-inflammatory, antioxidant, and anticancer properties. In this review, we focus on the effects of alkalization therapy and natural products on cancer. Furthermore, we present a case series of advanced cancer patients who received alkalization therapy and natural products alongside standard treatments, resulting in long-term survival. We posit that alkalization therapy together with supplementation with natural products may confer benefits to cancer patients, by mitigating the side effects of chemotherapy and complementing standard treatments. However, further research is warranted to validate these clinical findings.

Microbiome Taxonomic and Functional Differences in C3H/HeJ Mice Fed a Long-Term High-Fat Diet with Beef Protein ± Ammonium Hydroxide Supplementation

Studies have suggested that alkalinized foods may reduce the effects of the acidogenic Western diet in promoting obesity, metabolic syndrome, type 2 diabetes, cancer, and coronary heart disease. Indeed, a recent study in mice fed a high-fat diet containing dietary beef supplemented with ammonium hydroxide showed improvement in a suite of metabolic outcomes. However, the effects of dietary protein ammonium supplementation on the microbiome remain unknown. In this study, the effects of ammonium supplementation on beef protein towards microbiome taxa and function in a high-fat diet were analyzed. Fecal microbiomes were characterized using a shotgun metagenomic approach for 16-month-old male and female mice after long-term diet treatments. The results for ammoniated diets showed that several bacteria known to be associated with health benefits increased significantly, including Romboutsia, Oscillospiraceae, and Lactococcus cremoris. The beneficial mucin-degrader Akkermansia was especially abundant, with a high prevalence (~86%) in females. Concurrently, the phyla Actinomycetota (Actinobacteria) and Bacteroidota (Bacteroidetes) were significantly reduced. While sex was a confounding factor affecting microbiome responses to ammonium supplementation in dietary protein, it is worth noting that several putatively beneficial microbiome functions increased with ammonium supplementation, such as glycine betaine transport, xenobiotic detoxification, enhanced defense, and others. Conversely, many disease-associated microbiome functions reduced. Importantly, modifying protein pH alone via ammonium supplementation induced beneficial microbiota changes. Taken together, these results suggest that ammonium-supplemented proteins may mediate some negative microbiome-associated effects of high-fat/Western diets.

Acid-Base Balance in Healthy Adults: Beneficial Effects of Bicarbonate and Sodium-Rich Mineral Water in a Randomized Controlled Trial: The BicarboWater Study

Background

Noncommunicable diseases (NCDs) are a global health challenge. The complex etiology of NCDs involves genetic, environmental, and lifestyle factors, including dietary habits. Chronic latent metabolic acidosis has been associated with an increased risk of NCDs. Alkalizing diets and mineral water consumption have shown promise in improving acid-base balance and potentially impacting NCDs.

Methods

In this randomized controlled intervention study, the effect of drinking 1,500-2,000 mL of mineral water daily on acid-base balance was evaluated. Ninety-four healthy participants were divided into two groups: one consumed mineral water with a high bicarbonate and sodium content (HBS, n = 49) and the other consumed mineral water with a low bicarbonate and sodium content (LBS, n = 45). Changes in venous blood gas and urinary acid-base parameters were measured over a short-term (3 days) and long-term (28 days) intervention period. Potential renal acid load (PRAL) and nutrient intake were calculated at baseline and after 28 days.

Results

HBS water consumption led to increased urinary pH (24-hour urine and spontaneous urine, both p < 0.001) and bicarbonate levels (p < 0.001), accompanied by reduced titratable acids (p < 0.001) and ammonium (p < 0.001), resulting in a lower renal net acid excretion (p < 0.001). These changes occurred in the short term and persisted until the end of the study. LBS consumption showed no significant effects on urinary pH but led to a slight decrease in bicarbonate (p < 0.001) and NH4 + (p < 0.001), resulting in a slight decrease in NAE (p=0.011). Blood gas changes were modest in both groups. Mineral water consumption in the HBS group altered dietary intake of sodium and chloride, contributing to changes in PRAL values.

Conclusion

The study demonstrates that the consumption of mineral water high in bicarbonate and sodium (1,500 mL-2,000 mL/day) can positively influence urinary acid-base parameters and reduce NAE, suggesting potential benefits in maintaining acid-base balance without adverse effects on human health. These findings highlight the importance of mineral water composition in acid-base regulation. This trial is registered with DRKS00025341.

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.

Quantifying the potential renal acid load of edible mushrooms

The capability of any food to alter net endogenous acid or base production can be estimated using the potential renal acid load (PRAL) estimation method. The PRAL of edible mushrooms has been rarely examined; thus a quantification study of n = 37 edible mushroom species was performed. Results revealed a heterogeneous picture: although the most commonly consumed mushrooms (e.g., Agaricus bisporus, Lentinula edodes, and Pleurotus ostreatus (white)) have alkalizing properties, several acidifying species (Volvariella volvacea, Pleurotus flabellatus) were identified, which may be attributable to their high phosphorus content.

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.

Health Inequities in the USA: a Role for Dietary Acid Load? Results from the National Health and Nutrition Examination Surveys

BACKGROUND

Cardiovascular disease and obesity affect racial and ethnic minorities disproportionally. Public health research suggests that suboptimal diet is an important contributor to health disparities. Limited evidence points at an increased dietary acid load (DAL) in certain ethnic groups. DAL is determined by the balance of acidifying foods and alkaline foods, and elevated DAL scores have been associated with numerous chronic lifestyle-related conditions. The present analysis investigated DAL scores among ethnic groups in the USA.

METHODS

Using cross-sectional data from the National Health and Nutrition Examination surveys (NHANES, 2007-2016), we contrasted several markers of DAL (potential renal acid load (PRAL) and net endogenous acid production (NEAP)) between Non-Hispanic Whites, Non-Hispanic Blacks, Mexican Americans, Other Hispanics, and Other Race. The comparison included crude scores and adjusted scores following multivariate linear regression.

RESULTS

The sample for this analysis comprised 19,565 participants, which may be extrapolated to represent 156,116,471 United States Americans. When compared to Non-Hispanic Whites, Non-Hispanic Blacks and Mexican Americans had significantly higher crude DAL scores. PRALR was highest in Mexican Americans (20.42 (0.61) mEq/day), followed by Non-Hispanic Blacks (17.47 (0.42) mEq/day). Crude NEAPF was highest in Non-Hispanic Blacks (64.66 (0.43) mEq/day), and almost 9 mEq/day higher compared to Non-Hispanic Whites (55.78 (0.39) mEq/day). Multivariate linear regression adjusting for confounders revealed comparable interracial DAL differences.

CONCLUSIONS

We found significant DAL differences across the investigated ethnic groups. Whether these differences potentially play a role in population health inequity in the USA will be subject to additional research.

The 1995 potential renal acid load (PRAL) values may no longer adequately reflect the actual acid-base impact of certain foods: A hypothesis

Background: In 1995, Remer and Manz reported potential renal acid load (PRAL) values of various foods, quantifying their estimated impact on acid-base balance. Their estimation considered ionic dissociation, sulphur metabolism and intestinal absorption rates for several micronutrients and proteins. Notably, PRAL values are based on food content data from the early 1990s and may nowadays no longer adequately reflect accurate estimates. Some foods' macronutrient and mineral content has declined over the past three decades due to changes in soil mineral health. Aim: We hypothesize that the 1995 PRAL values no longer adequately reflect reliable estimates of the current acid-base impact of some foods. Methods: Based on specific examples, we argue that these values overestimate the alkalizing effects of various fruits and vegetables. Conclusion: Discussing evidence in favour of (and against) our hypothesis, we conclude that the 1995 PRAL estimates should nowadays rather be used as a relative guidance and reviewed carefully.

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.

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 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.

The association between red, processed and white meat consumption and risk of pancreatic cancer: a meta-analysis of prospective cohort studies

PURPOSE

The association between meat consumption and the risk of pancreatic cancer has not been comprehensively investigated by different types of meat. The current study was conducted to evaluate this association.

METHODS

PubMed and Web of Science databases were used to search for prospective cohort studies on meat consumption and pancreatic cancer risk through May 2022. A meta-analysis was performed using random-effects models to combine study-specific relative risks (RR). The quality of the included studies was evaluated using the Newcastle-Ottawa quality assessment scale.

RESULTS

Twenty prospective cohort studies including 3,934,909 participants and 11,315 pancreatic cancer cases were identified. The pooled RR of pancreatic cancer for the highest versus lowest white meat intake category was 1.14 (95% CI: 1.03-1.27). There was no significant association between consumption of red meat and processed meat and pancreatic cancer risk in the highest versus lowest analysis. In dose-response analyses, pooled RRs were 1.14 (95% CI: 1.01-1.28) for an increase in red meat consumption of 120 g per day and 1.26 (95% CI: 1.08-1.47) for an increase in white meat consumption of 100 g per day, respectively. Processed meat consumption showed neither a linear nor a non-linear association with pancreatic cancer risk.

CONCLUSION

Findings from this meta-analysis suggested that high consumption of red meat and white meat is associated with an increased risk of pancreatic cancer. Future prospective studies are warranted to confirm the association between meat consumption and the risk of pancreatic cancer.

Exploring the use of alternative diets in people living with cancer

There is significant use of alternative diets by people living with cancer, with data suggesting this has continued to increase since the 1980s. Commonly used alternative diets include the ketogenic diet, Gerson therapy, alkaline diets and fasting diets. This article explains the latest trends in relation to alternative diets, discusses the reasons why people may want to use these and examines their hypothesised mechanisms of action. The author outlines and critically reviews the evidence underpinning the use of such diets in those living with cancer, and suggests that this remains weak. The article also explores the challenges that nurses may experience when a person living with cancer wishes to adopt an alternative diet, and provides practical advice and recommendations on nutrition.

The underexplored links between cancer and the internal body climate: Implications for cancer prevention and treatment

In order to effectively manage and cure cancer we should move beyond the general view of cancer as a random process of genetic alterations leading to uncontrolled cell proliferation or simply a predictable evolutionary process involving selection for traits that increase cell fitness. In our view, cancer is a systemic disease that involves multiple interactions not only among cells within tumors or between tumors and surrounding tissues but also with the entire organism and its internal "milieu". We define the internal body climate as an emergent property resulting from spatial and temporal interactions among internal components themselves and with the external environment. The body climate itself can either prevent, promote or support cancer initiation and progression (top-down effect; i.e., body climate-induced effects on cancer), as well as be perturbed by cancer (bottom-up effect; i.e., cancer-induced body climate changes) to further favor cancer progression and spread. This positive feedback loop can move the system towards a "cancerized" organism and ultimately results in its demise. In our view, cancer not only affects the entire system; it is a reflection of an imbalance of the entire system. This model provides an integrated framework to study all aspects of cancer as a systemic disease, and also highlights unexplored links that can be altered to both prevent body climate changes that favor cancer initiation, progression and dissemination as well as manipulate or restore the body internal climate to hinder the success of cancer inception, progression and metastasis or improve therapy outcomes. To do so, we need to (i) identify cancer-relevant factors that affect specific climate components, (ii) develop 'body climate biomarkers', (iii) define 'body climate scores', and (iv) develop strategies to prevent climate changes, stop or slow the changes, or even revert the changes (climate restoration).

Back to basic: Trials and tribulations of alkalizing agents in cancer

"Dysregulated" metabolism is a characteristic of the cancer cell phenotype. This includes persistent use of glycolytic metabolism in normoxic environments (Warburg effect) leading to increased acid production and accumulation of protons in the interstitial space. Although often thought to be disordered, altered cancer metabolism is the outcome of intense Darwinian selection and, thus, must have evolved to maximize cancer cell fitness. In an evolutionary context, cancer-induced acidification of the microenvironment represents a niche construction strategy to promote proliferation. Ecological advantages conferred on the cancer population included remodeling of the extracellular matrix to promote local invasion, suppression of potential competitive proliferation of fibroblasts, and suppression of host immune response. Preclinical data demonstrates that increasing the serum buffering capacity (through, for example, oral sodium bicarbonate and TRIS) can neutralize the acidic tumor microenvironment with inhibition local invasion and proliferation which can be synergistic with the effects of chemotherapy and immunotherapy agents. Here, we describe the proton dynamics in cancer and their influence on tumor progression and metastasis. Additionally, we will discuss targeting the tumor acidosis with alkalizing agents including our bicarbonate clinical trial results.

CLINICAL TRIAL REGISTRATION

clinicaltrials.gov, identifier NCT01350583, NCT01198821 and NCT01846429.

Observational and clinical evidence that plant-based nutrition reduces dietary acid load

Contemporary diets in Western countries are largely acid-inducing and deficient in potassium alkali salts, resulting in low-grade metabolic acidosis. The chronic consumption of acidogenic diets abundant in animal-based foods (meats, dairy, cheese and eggs) poses a substantial challenge to the human body's buffering capacities and chronic retention of acid wherein the progressive loss of bicarbonate stores can cause cellular and tissue damage. An elevated dietary acid load (DAL) has been associated with systemic inflammation and other adverse metabolic conditions. In this narrative review, we examine DAL quantification methods and index observational and clinical evidence on the role of plant-based diets, chiefly vegetarian and vegan, in reducing DAL. Quantitation of protein and amino acid composition and of intake of alkalising organic potassium salts and magnesium show that plant-based diets are most effective at reducing DAL. Results from clinical studies and recommendations in the form of expert committee opinions suggest that for a number of common illnesses, wherein metabolic acidosis is a contributing factor, the regular inclusion of plant-based foods offers measurable benefits for disease prevention and management. Based on available evidence, dietary shifts toward plant-based nutrition effectively reduces dietary-induced, low-grade metabolic acidosis.

Association between dietary acid load and cancer risk and prognosis: An updated systematic review and meta-analysis of observational studies

Epidemiological studies have suggested that dietary acid load (DAL) might be related to the risk and prognosis of cancer, whereas the evidence is contentious. Several high-quality observational studies have been published following a prior systematic review with only one study included. Consequently, we conducted an updated systematic review and meta-analysis to comprehensively investigate the relationship between DAL and cancer risk and prognosis. A systematic literature search was conducted in the PubMed, Embase, and Web of Science databases from inception to 26 October 2021. Summary relative risks (RRs) with 95% CIs were calculated using a random-effects model. Publication bias, subgroup, meta-regression, and sensitivity analyses were also conducted. Ten observational studies (six cohorts and four case–control studies) with 227,253 participants were included in this systematic review and meta-analysis. The summary RRs revealed a statistically significant associations between DAL and cancer risk (RR = 1.58, 95% CI = 1.23–2.05, I² = 71.9%, n = 7) and prognosis (RR = 1.53, 95% CI = 1.10–2.13, I² = 77.1%, n = 3). No evidence of publication bias was observed in the current analysis. Positive associations were observed in most subgroup analyses stratified by predefined factors, including region, study design, study quality, study population, participants’ gender, age of participants, cancer type, DAL assessment indicator, and adjustment of potential confounding parameters. No evidence of heterogeneity between subgroups was indicated by meta-regression analyses. The high DAL might be associated with an increased risk of cancer, as well as a poor prognosis of cancer. More high-quality prospective studies are warranted to further determine the associations between DAL and risk and prognosis for specific cancers.

Association between dietary acid load and metabolic health status in overweight and obese adolescents

The relationship between dietary acid load (DAL) and metabolic health status in adolescents has not been studied yet. We aimed to examine the association between DAL and metabolic health status in Iranian overweight/obese adolescents. This cross-sectional study included 203 overweight/obese adolescents selected by a multistage cluster random sampling method. Dietary intakes were assessed using a validated 147-item food frequency questionnaire (FFQ). Anthropometric indices and blood pressure values were measured. Fasting blood samples were obtained to determine glucose, insulin, and lipid profiles. Based on two methods (International Diabetes Federation (IDF) criteria and combination of IDF with Homeostasis Model Assessment Insulin Resistance (HOMA-IR)), participants were classified into metabolically healthy obese (MHO) or unhealthy obese (MUO). Adolescents in the highest tertile of potential renal acid load (PRAL) and net endogenous acid production (NEAP), compared with those in the lowest tertile, had 172% (95% CI 1.32–5.59) and 161% (95% CI 1.26–5.41) higher odds of MUO status, based on IDF criteria. This association was significant after adjustment for age, sex, and energy intake (PRAL: OR 2.42; 95% CI CI 1.13–5.15; NEAP: OR 2.52; 95% CI 1.17–5.41); but it disappeared after adjustment for other confounders. Based on IDF/HOMA-IR definition, there was a significant positive association between PRAL and being MUO only in the crude model (OR 2.37; 95% CI 1.13–4.96). The stratified analysis revealed that these associations for NEAP scores were stronger among overweight subjects than obese individuals, based on both metabolic status definitions. However, after adjustment for all potential confounders these relations were insignificant. Having higher DAL might be associated with higher odds of MUO phenotype in Iranian overweight/obese adolescents. More prospective studies are warranted to confirm this finding.

Dietary pH Enhancement Improves Metabolic Outcomes in Diet-Induced Obese Male and Female Mice: Effects of Beef vs. Casein Proteins

(1) Consumption of diets that are caloric dense but not nutrient dense have been implicated in metabolic diseases, in part through low-grade metabolic acidosis. Mitigation strategies through dietary intervention to alleviate acidosis have not been previously reported. Our objective is to determine the effects of pH enhancement (with ammonia) in high fat diet-induced obese mice that were fed beef or casein as protein sources compared to low fat diet-fed mice. (2) Methods: B6 male and female mice were randomized (n = 10) into eight diets that differ in protein source, pH enhancement of the protein, and fat content, and fed for 13 weeks: low fat (11% fat) casein (LFC), LF casein pH-enhanced (LFCN), LF lean beef (LFB), LFBN, high fat (46%) casein (HFC), HFCN, HF beef (HFB), and HFBN. Body weights and composition, and glucose tolerance tests were conducted along with terminal serum analyses. Three-way ANOVA was performed. (3) Results: A significant effect of dietary fat (LF vs. HF) was observed across all variables in both sexes (final body weight, fat mass, glucose clearance, and serum leptin). Importantly, pH enhancement significantly reduced adiposity (males only) and final body weights (females only) and significantly improved glucose clearance in both sexes. Lastly, clear sex differences were observed across all variables. (4) Conclusions: Our findings demonstrate metabolic benefits of increasing dietary pH using ammonia, while high fat intake per se (not protein source) is the major contributor to metabolic dysfunctions. Additional research is warranted to determine mechanisms underlying the beneficial effects of pH enhancement, and interactions with dietary fat content and proteins.

Nutrient Intake and Dietary Acid Load of Special Diets in the NHANES: A Descriptive Analysis (2009-2018)

Western diets are characterized by a high dietary acid load (DAL), which has been associated with adverse clinical outcomes, including type-2-diabetes and metabolic syndrome. Effective dietary strategies to lower DAL are urgently warranted. Plant-based diets (PBD), including vegetarian and vegan diets, are an effective measure to reduce DAL. Notably, not every individual wishes to adopt a PBD. Instead, many people rely on special diets promising comparable health benefits. The effects of those diets on DAL have rarely been investigated. Using data from the National Health and Nutrition Examination Surveys, we aimed to quantify DAL and nutrient intake in the most popular special diets in the United States, including weight-loss, low fat, low salt, low sugar, and diabetic diets. Our analysis included 3552 individuals on a special diet. The most popular diets were the weight-loss diet (n = 1886 individuals) and the diabetic diet (n = 728). Energy intake was below 2000 kcal/d for all diets; however, there were no statistically significant intergroup differences. DAL scores were positive for all special diets (>9 mEq/d), suggesting acidifying properties. Acid load scores of special diets did not differ significantly and were comparable to a standard Western diet. None of the examined diets was associated with alkaline properties.

Quantifying dietary acid load in U.S. cancer survivors: an exploratory study using NHANES data

BACKGROUND

Diet is an important determinant of systemic pH and acid-base regulation. A frequent consumption of acid-inducing foods (including processed meats and cheese) combined with a low intake of base-inducing foods (such as fruits, legumes and vegetables) increases Dietary Acid Load (DAL), which has been associated with an increased risk for certain cancers. DAL also appears to be of paramount importance in cancer survivors, in whom it was associated with increased mortality and poor overall physical health. Literature on DAL in cancer survivors, however, is scarce and limited to a few studies.

METHODS

Using cross-sectional data from the National Health and Nutrition Examination Surveys (NHANES), we sought to quantify DAL in U.S. cancer survivors and contrasted the results to the general population. DAL was estimated using established formulas (Potential Renal Acid Load (PRAL) and Net Endogenous Acid Production (NEAP)).

RESULTS

Our study comprised 19,413 participants, of which 1444 were self-reported cancer survivors. Almost 63% of cancer survivors were female (weighted proportion) with a mean age of 61.75 (0.51) years. DAL scores were consistently higher in cancer survivors (as compared to the general population) after adjustment for confounders in multivariate regression models. These differences, however, were not statistically significant (p = 0.506 for NEAPF, 0.768 for PRALR and 0.468 for NEAPR, respectively). Notably, DAL scores were positive throughout (> 0 mEq/d) in cancer survivors, suggesting an acidifying diet. Specific examples include mean PRALR scores > 11 mEq/d in cancer survivors aged 55 years and mean NEAPF scores > 50 mEq/d in cancer survivors aged 40-60 years).

CONCLUSIONS

The acidifying diet in this sample of cancer survivors warrants caution and requires further investigation. Comparably high DAL scores have been associated with adverse health outcomes and an increased mortality in previous studies in breast cancer survivors. Thus, increased awareness as well as additional clinical trials in this field are urgently warranted.

Dietary acid load and the risk of cancer: a systematic review and dose-response meta-analysis of observational studies

AIMS

Recent evidence suggests the link between adherence to an acidogenic diet and the risk of some types of cancers, such as colorectal and breast cancers. This systematic review and meta-analysis aimed to clarify the association between dietary acid load and cancer risk.

DATA SEARCH AND SYNTHESIS

Online databases (PubMed, Scopus, EMBASE, Scholar Google and ISI web of sciences) were searched between January 1990 and May 2021. The risk ratio (RR) was extracted from eligible studies and random-effects meta-analysis was performed to calculate pooled RR of studies. Nine studies (three cohorts, six case-control) were included. Higher dietary acid load scores [including potential renal acid load (PRAL) and net endogenous acid production (NEAP)] were associated with the increased risk of cancer [RRPRAL, 1.77; 95% confidence interval (CI), 1.27-2.46; n = 8; RRNEAP, 1.58, 95% CI: 1.20-2.09, n = 7). Dose-response analysis suggested that a 20-score increase in dietary PRAL and NEAP was associated with 27 and 8% higher risk of cancer, respectively (RRPRAL, 1.27; 95% CI, 1.02-1.60; nonlinearity P = 0.12; RRNEAP, 1.08; 95% CI, 1.02-1.13, nonlinearity P = 0.06). A significant positive relationship between dietary PRAL and risk of cancer was only observed in the subgroup of women. Associations were significant in both men and women for dietary NEAP. Subgroup analyses based on cancer type were only possible for breast cancer. There was no significant association between dietary acid load (PRAL and NEAP) and breast cancer risk.

CONCLUSION

Our analysis showed that high adherence to an acidogenic diet is associated with an increased risk of cancer. The protocol for this meta-analysis was registered in PROSPERO registration no. CRD42019146460.

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.

A Case-Control Study on Dietary Acid Load in Relation to Glioma

Limited data are available linking dietary factors to glioma. The current study was conducted to investigate the association between Dietary Acid Load (DAL) and odds of glioma in Iranian adults. This case-control study was done on 128 newly diagnosed patients with glioma and 256 healthy controls in Tehran, Iran. A validated detailed food frequency questionnaire (FFQ) was used to assess dietary intakes of participants. DAL was estimated using the protein to potassium ratio (Pro: K). Glioma was diagnosed based on pathological tests. A detailed questionnaire including several non-dietary confounders was also completed. Participants in the highest tertile of DAL score had a non-significant higher odds of glioma as compared to those in the lowest tertile (OR: 1.50; 95% CI: 0.88-2.57), which remained after controlling for some potential confounders (OR: 1.66; 0.70-3.91). After further adjustment for dietary intakes of meats and processed meats, legumes and nuts, fruits, salt tea, and coffee, those in the top tertile of DAL score were significantly more likely to have glioma than those in the bottom tertile (OR: 3.09; 95% CI: 1.06, 8.99; P = 0.03). This association was also reached following further adjustment for BMI (OR: 3.05; 95% CI: 1.04, 8.91; P = 0.03). We found a significant positive association between dietary acid load, as estimated by Prot:K ratio, and odds of glioma among adults. Further studies, in particular prospective cohorts with long-term follow up, are required to confirm these findings.

Independent and Joint Impacts of Acid-Producing Diets and Depression on Physical Health among Breast Cancer Survivors

The purpose of this study was to examine the independent and joint associations of acid-producing diets and depressive symptoms with physical health among breast cancer survivors. We studied a cohort of 2944 early stage breast cancer survivors who provided dietary, physical health, demographic, and lifestyle information at baseline, year 1, and year 4. 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). Physical health was measured using the Rand 36-Item Short Form Health Survey (SF-36), consisting of physical functioning, role limitation due to physical function, bodily pain, general health, and overall physical health subscales. Increased dietary acid load and depression were each independently and significantly associated with reduced physical health subscales and overall physical health. Further, dietary acid load and depression were jointly associated with worse physical health. For instance, depressed women with dietary acid load higher than median reported 2.75 times the risk (odds ratio = 2.75; 95% confidence interval: 2.18–3.47) of reduced physical function and 3.10 times the risk of poor physical health (odds ratio = 3.10; 95% confidence interval: 2.53–3.80) compared to non-depressed women with dietary acid load lower than median. Our results highlight the need of controlling acid-producing diets and the access of mental care for breast cancer survivors.

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

BACKGROUND

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

OBJECTIVE

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

METHOD

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

RESULTS

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

CONCLUSION

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

Dietary acid load and lung cancer risk: A case-control study in men

BACKGROUND

Dysregulation of the endogenous acid-base balance can contribute to inflammation and cancer development if metabolic acidosis is sustained. The epidemiologic evidence on the association between diet-dependent acid load and cancer risk is scarce and inconsistent. We aim to explore the possible role of dietary acid load in lung cancer (LC) risk.

METHODS

A case-control study was performed on 843 LC cases and 1466 controls by using a multi-topic questionnaire, including a food frequency questionnaire. Controls were matched to cases by age-frequency, urban/rural residence, and region. Food-derived nutrients were calculated from available databases. The dietary acid load was calculated using validated measures as potential renal acid load (PRAL) score and net endogenous acid production (NEAP) score. Odds ratios (ORs) were estimated by logistic regression.

RESULTS

We found direct associations between dietary acid load and LC risk. The highest quartile of the NEAP score was significantly associated (OR=2.22, p_trend<0.001). The PRAL score displayed similar associations in simpler regression models, but there was no association when a more complex one was used (OR=0.99, p_trend =0.94). The NEAP score was associated with a significant risk increase in all cell types, except for small cell cancers, but the PRAL score did not show any association.

CONCLUSIONS

The NEAP scores, directly associated with meat intake and inversely associated with plant-based foods intake, suggest that a high acid load dietary style may increase LC risk. Studies focused on food groups, and nutritional patterns are in line with our findings. Although the data shown here represent the first one to be published on this issue, further studies are needed to confirm these findings.

Dietary Acid Load and the Risk of Pancreatic Cancer: A Prospective Cohort Study

BACKGROUND

Modern Western diets are rich in acidogenic foods. Human and in vitro studies suggest a potential link between dietary acid load and cancer risk. However, no epidemiologic studies have investigated the association of dietary acid load with the risk of pancreatic cancer. Therefore, we conducted a prospective cohort study to fill this gap.

METHODS

A population-based cohort of 95,708 American adults was identified. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) were used to assess dietary acid load of each subject, with greater values indicating greater dietary acid load. Cox regression was used to estimate risk estimates for pancreatic cancer incidence. Predefined subgroup analysis was used to identify the potential effect modifiers.

RESULTS

A total of 337 pancreatic cancer cases were observed during 848,534.0 person-years of follow-up. PRAL score was found to be positively associated with the risk of pancreatic cancer [fully adjusted HR_{quartile 4 vs. 1}: 1.73; 95% confidence interval (95% CI), 1.21-2.48; P _trend = 0.001] in a nonlinear dose-response pattern (P _nonlinearity = 0.012). Subgroup analysis found that the positive association of PRAL score with the risk of pancreatic cancer was more pronounced in subjects aged <65 years than in those ≥65 years (P _interaction = 0.018). Similar results were obtained for NEAP score.

CONCLUSIONS

Higher dietary acid load is associated with a higher risk of pancreatic cancer. Future studies should validate our findings in other populations and settings.

IMPACTS

This is the first epidemiologic study suggesting that reducing dietary acid load may be useful in primary prevention of pancreatic cancer.

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.

Diet-dependent acid load and the risk of colorectal cancer and adenoma: a case-control study

OBJECTIVES

Colorectal cancer (CRC) is the third and second most prevalent cancer in men and women, respectively. Various epidemiological studies indicated that dietary factors are implicated in the aetiology of CRC and its precursor, colorectal adenomas (CRA). Recently, much attention has been given to the role of acid-base balance in the development of chronic diseases including cancers. Therefore, the aim of the current study is to examine the association of diet-dependent acid load and the risk of CRC and CRA.

DESIGN

In this case-control study, potential renal acid load (PRAL) was computed based on dietary intake of participants assessed via a validated FFQ. Negative PRAL values indicated a base-forming potential, while positive values of PRAL implied acid-forming potential of diet. Logistic regression was used to derive OR and 95 % CI after adjusting for confounders.

SETTING

Tehran, Iran.

PARTICIPANTS

A total of 499 participants aged 30-70 years were included in the study (240 hospital controls, 129 newly diagnosed CRC and 130 newly diagnosed CRA). The current study was conducted between December 2016 and September 2018.

RESULTS

After adjusting for potential confounders, a higher PRAL was associated with increased odds of CRC and CRA. The highest v. the lowest tertile of PRAL for CRC and CRA was OR 4·82 (95 % CI 2·51-9·25) and OR 2·47 (95 % CI 1·38-4·42), respectively.

CONCLUSIONS

The findings of the current study suggested that higher diet-dependent acid load is associated with higher risk of CRC and CRA.

Serum Bicarbonate Concentration and Cause-Specific Mortality: The National Health and Nutrition Examination Survey 1999-2010

OBJECTIVE

To assess the association between serum bicarbonate concentration and cause-specific mortality in the US general population.

METHODS

A total of 31,195 individuals enrolled in the National Health and Nutrition Examination Survey between 1999 and 2010 were followed for a median 6.7 (interquartile range, 3.7-9.8) years. Cause-specific mortality was defined as cardiovascular, malignancy, and noncardiovascular/nonmalignancy causes. Cox proportional hazards adjusted for demographics, comorbidities, medications, and renal function were used to test the association between baseline serum bicarbonate and the outcomes of interest.

RESULTS

Of the 2798 participants who died, 722 had a cardiovascular- and 620 had a malignancy-related death. Compared with participants with serum bicarbonate 22 to 26 mEq/L, those with a level below 22 mEq/L had an increased hazard of all-cause and malignancy-related mortality (hazard ratio [HR], 1.54; 95% CI, 1.30-1.83; and HR, 1.46; 95% CI 1.00-2.13, respectively). The hazard for cardiovascular mortality was increased by 8% with each 1 mEq/L increase in serum bicarbonate above 26 mEq/L (HR, 1.08; 95% CI, 1.01-1.15). The findings were consistent in participants with or without chronic kidney disease, with no significant interactions observed.

CONCLUSION

In a large cohort of US adults, serum bicarbonate concentration level below 22 mEq/L was associated with malignancy-related mortality, whereas a concentration above 26 mEq/L was associated with cardiovascular mortality. Further studies to evaluate potential mechanisms for the differences in cause-specific mortality are warranted.

Higher dietary acid load is not associated with risk of breast cancer in Iranian women

BACKGROUND

Dietary acid load (DAL) may play a key role in certain cancers, including breast cancer (BC); however, evidence showing a causal relationship is lacking.

AIM

We examined the relationship between DAL, assessed with both the potential renal acid load (PRAL) and the net endogenous acid production (NEAP) scores, and BC risk.

METHODS

We identified 150 women who had a diagnosis of BC recently and 150 age-matched apparently healthy controls. Data from dietary intake and anthropometric measures were collected from participants and eventually, PRAL and NEAP scores were obtained from nutrient intakes. Multivariate odds ratios (OR) with 95% confidence intervals (CI) were used to evaluate the relationship of BC risk with PRAL and NEAP scores.

RESULTS

The odds ratios (OR) of BC according to tertiles of PRAL and NEAP scores by multivariate logistic regression models revealed that both PRAL (P-trend = 0.8) and NEAP (P-trend = 0.1) scores were not significantly associated with BC risk. After controlling confounders, multiple logistic regressions still remained non-significant which indicated no significant associations between PRAL (P-trend = 0.9), NEAP (P-trend = 0.4) scores and risk of BC.

CONCLUSION

The results of our study suggested that there is no significant relationship between DAL and BC incidence among Iranian women.

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.

Diverse Stakeholders of Tumor Metabolism: An Appraisal of the Emerging Approach of Multifaceted Metabolic Targeting by 3-Bromopyruvate

Malignant cells possess a unique metabolic machinery to endure unobstructed cell survival. It comprises several levels of metabolic networking consisting of 1) upregulated expression of membrane-associated transporter proteins, facilitating unhindered uptake of substrates; 2) upregulated metabolic pathways for efficient substrate utilization; 3) pH and redox homeostasis, conducive for driving metabolism; 4) tumor metabolism-dependent reconstitution of tumor growth promoting the external environment; 5) upregulated expression of receptors and signaling mediators; and 6) distinctive genetic and regulatory makeup to generate and sustain rearranged metabolism. This feat is achieved by a "battery of molecular patrons," which acts in a highly cohesive and mutually coordinated manner to bestow immortality to neoplastic cells. Consequently, it is necessary to develop a multitargeted therapeutic approach to achieve a formidable inhibition of the diverse arrays of tumor metabolism. Among the emerging agents capable of such multifaceted targeting of tumor metabolism, an alkylating agent designated as 3-bromopyruvate (3-BP) has gained immense research focus because of its broad spectrum and specific antineoplastic action. Inhibitory effects of 3-BP are imparted on a variety of metabolic target molecules, including transporters, metabolic enzymes, and several other crucial stakeholders of tumor metabolism. Moreover, 3-BP ushers a reconstitution of the tumor microenvironment, a reversal of tumor acidosis, and recuperative action on vital organs and systems of the tumor-bearing host. Studies have been conducted to identify targets of 3-BP and its derivatives and characterization of target binding for further optimization. This review presents a brief and comprehensive discussion about the current state of knowledge concerning various aspects of tumor metabolism and explores the prospects of 3-BP as a safe and effective antineoplastic agent.

GC/MS and LC/MS-based Tissue Metabolomic Analysis Detected Increased Levels of Antioxidant Metabolites in Colorectal Cancer

Late-stage colorectal cancer is resistant to current treatments. Understanding the biological processes responsible for the development and progression of colorectal cancer could aid the development of new diagnostic and treatment approaches. We used gas chromatography/mass spectrometry and liquid chromatography/mass spectrometry-based metabolomic analysis to measure metabolite levels in pairs of colorectal cancer tissue samples and samples of the adjacent macroscopically normal mucosal tissue from 10 colon cancer patients. Regarding nucleotide metabolomic intermediates, the colorectal cancer tissue contained lower levels of ribulose 5-phosphate and higher levels of xanthine, adenine, and hypoxanthine than the normal tissue. The levels of antioxidant metabolites, such as sulfur-containing amino acids, were also significantly higher in the colorectal cancer tissue. The level of tryptophan was decreased, and the levels of molecules downstream of the tryptophan pathway, such as kynurenine and quinolinic acid, which protect colorectal cancer against the host's immune system and function in de novo nicotinamide adenine dinucleotide synthesis, were increased in the colorectal cancer tissue. The colorectal cancer tissue samples also contained higher levels of lysophospholipids and fatty acids, especially stearic acid and polyunsaturated fatty acids, including arachidonic acid and docosahexaenoic acid. Thus, understanding these cancer-specific alterations could make it possible to detect colorectal cancer early and aid the development of additional treatments for the disease, leading to improvements in colorectal cancer patients' quality of life.

Dietary Acid Load: mechanisms and evidence of its health repercussions

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

Higher diet-dependent acid load is associated with risk of breast cancer: Findings from the sister study

Dietary factors that contribute to chronic low-grade metabolic acidosis have been linked to breast cancer risk, but to date no epidemiologic study has examined diet-dependent acid load and breast cancer. We used data from 43,570 Sister Study participants who completed a validated food frequency questionnaire at enrollment (2003-2009) and satisfied eligibility criteria. The Potential Renal Acid Load (PRAL) score was used to estimate diet-dependent acid load. Higher scores reflect greater consumption of protein and phosphorus, and lower consumption of potassium, calcium and magnesium. The association between PRAL and breast cancer was evaluated using multivariable Cox proportional hazards regression. We identified 1,614 invasive breast cancers diagnosed at least 1 year after enrollment (mean follow-up, 7.6 years). The highest PRAL quartile, reflecting greater acid-forming potential, was associated with increased risk of breast cancer (HR_{highest vs. lowest quartile} : 1.21 [95% CI, 1.04-1.41], p_trend = 0.04). The association was more pronounced for estrogen receptor (ER)-negative (HR_{highest vs. lowest quartile} : 1.67 [95% CI, 1.07-2.61], p_trend = 0.03) and triple-negative breast cancer (HR_{highest vs. lowest quartile} : 2.20 [95% CI, 1.23-3.95], p_trend = 0.02). Negative PRAL scores, representing consumption of alkaline diets, were associated with decreased risk of ER-negative and triple-negative breast cancer, compared to a PRAL score of 0 representing neutral pH. Higher diet-dependent acid load may be a risk factor for breast cancer while alkaline diets may be protective. Since PRAL scores are positively correlated with meat consumption and negatively correlated with fruit and vegetable intake, results also suggest that diets high in fruits and vegetables and low in meat may be protective against hormone receptor negative breast cancer.

Dietary acid load and mortality among Japanese men and women: the Japan Public Health Center-based Prospective Study

Background: Diet-induced metabolic acidosis has been linked to cardiometabolic abnormalities including hypertension and type 2 diabetes. However, there are limited data on its association with other chronic diseases and mortality.Objective: The present study aimed to examine the association between dietary acid load and total and cause-specific mortality.Design: This study was a large-scale, population-based, prospective cohort study in Japan involving 42,736 men and 49,742 women, aged 45-75 y, who had no history of cancer, stroke, ischemic heart disease (IHD), or chronic liver disease at baseline. Dietary intake was assessed by using a validated 147-item food-frequency questionnaire. Potential renal acid load (PRAL) and net endogenous acid production (NEAP) scores were derived from nutrient intake. Death and cause of death were identified by using the residential registry and death certificates. Cox proportional hazards regression was used to estimate HRs and 95% CIs for total and cause-specific mortality with adjustment for potential confounding variables.Results: During a median follow-up of 16.9 y, 12,993 total deaths occurred. A higher PRAL score was associated with higher total mortality: the multivariable-adjusted HR for total mortality for the highest compared with the lowest quartiles of PRAL scores was 1.13 (95% CI: 1.07, 1.18; P-trend < 0.001). This score was positively associated with mortality from cardiovascular disease (CVD) and particularly from IHD; the HRs (95% CIs) for the highest compared with the lowest quartile of PRAL score were 1.16 (1.06, 1.28) and 1.16 (1.02, 1.33) for CVD and IHD mortality, respectively. There was no association between PRAL score and cancer mortality. Similar associations were observed between NEAP score and total and cause-specific mortality.Conclusion: A high dietary acid load score was associated with a higher risk of total mortality and mortality from CVD, particularly from IHD, in Japanese adults.

Stressor-driven extracellular acidosis as tumor inducer via aberrant enzyme activation: A review on the mechanisms and possible prophylaxis

When the extracellular pH of human body vacillates in either direction, tissue homeostasis is compromised. Fluctuations in acidity have been linked to a wide variety of pathological conditions, including bone loss, cancer, allergies, and auto-immune diseases. Stress conditions affect oxygen tension, and the resultant hypoxia modulates the expression and/or activity of membrane-tethered transporters/pumps, transcription factors, enzymes and intercellular junctions. These modifications provoke erratic gene expression, aberrant tissue remodeling and oncogenesis. While the physiological optimization of pH in tissues is practically challenging, it is at least theoretically achievable and can be considered as a possible therapy to resolve a broad array of diseases.

Associations between Sleep, Cortisol Regulation, and Diet: Possible Implications for the Risk of Alzheimer Disease

Accumulation of proteinaceous amyloid β plaques and tau oligomers may occur several years before the onset of Alzheimer disease (AD). Under normal circumstances, misfolded proteins get cleared by proteasome degradation, autophagy, and the recently discovered brain glymphatic system, an astroglial-mediated interstitial fluid bulk flow. It has been shown that the activity of the glymphatic system is higher during sleep and disengaged or low during wakefulness. As a consequence, poor sleep quality, which is associated with dementia, might negatively affect glymphatic system activity, thus contributing to amyloid accumulation. The diet is another important factor to consider in the regulation of this complex network. Diets characterized by high intakes of refined sugars, salt, animal-derived proteins and fats and by low intakes of fruit and vegetables are associated with a higher risk of AD and can perturb the circadian modulation of cortisol secretion, which is associated with poor sleep quality. For this reason, diets and nutritional interventions aimed at restoring cortisol concentrations may ease sleep disorders and may facilitate brain clearance, consequentially reducing the risk of cognitive impairment and dementia. Here, we describe the associations that exist between sleep, cortisol regulation, and diet and their possible implications for the risk of cognitive impairment and AD.

Systematic review of the association between dietary acid load, alkaline water and cancer

OBJECTIVES

To evaluate the evidence for a causal relationship between dietary acid/alkaline and alkaline water for the aetiology and treatment of cancer.

DESIGN

A systematic review was conducted on published and grey literature separately for randomised intervention and observational studies with either varying acid-base dietary intakes and/or alkaline water with any cancer outcome or for cancer treatment.

OUTCOME MEASURES

Incidence of cancer and outcomes of cancer treatment.

RESULTS

8278 citations were identified, and 252 abstracts were reviewed; 1 study met the inclusion criteria and was included in this systematic review. No randomised trials were located. No studies were located that examined dietary acid or alkaline or alkaline water for cancer treatment. The included study was a cohort study with a low risk of bias. This study revealed no association between the diet acid load with bladder cancer (OR=1.15: 95% CI 0.86 to 1.55, p=0.36). No association was found even among long-term smokers (OR=1.72: 95% CI 0.96 to 3.10, p=0.08).

CONCLUSIONS

Despite the promotion of the alkaline diet and alkaline water by the media and salespeople, there is almost no actual research to either support or disprove these ideas. This systematic review of the literature revealed a lack of evidence for or against diet acid load and/or alkaline water for the initiation or treatment of cancer. Promotion of alkaline diet and alkaline water to the public for cancer prevention or treatment is not justified.