Acid Balance, Dietary Acid Load, and Bone Effects-A Controversial Subject

Risk Factors for a Higher Dietary Acid Load (Potential Renal Acid Load) in Free-Living Elderly in Poland

BACKGROUND

Dietary composition is one of the factors influencing the acid-base balance of the body by providing acid or base precursors. One of the methods for assessing the acid-forming potential of a diet is to calculate its potential renal acid load (PRAL). The aim of this study was to identify the sociodemographic, lifestyle, and health factors related to the PRAL.

METHODS

Dietary intake was assessed among 133 individuals aged 70+ years using the three-day record method.

RESULTS

The average PRAL value was 15.7 mEq/day (range from -42.4 to +101.7). The diets of a majority of the participants (71.4%) had acid-forming potential (PRAL > 0). From a univariate analysis, the acid-forming potential of the diets was linked mainly to women (65.3% in PRAL > 0 group vs. 10.5% in PRAL < 0 group), people using dietary supplements, those who consumed alcohol, those who assessed their health as being at least good, people with osteoporosis, those hospitalized during the previous year, and those with rather lower physical activity.

CONCLUSIONS

From a multivariate analysis, gender was the strongest predictor of an acid-forming diet, but the following also contributed: an average self-rated health status (compared to good), a good health status (compared to poor), alcohol drinking, hospitalization, lack of nutritional knowledge, and, to a lesser extent, non-frail status (compared to pre-frail). Therefore, more extensive nutritional education in the identified groups is required.

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

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

Bone mineral density parameters and related nutritional factors in vegans, lacto-ovo-vegetarians, and omnivores: a cross-sectional study

Introduction

The growing prevalence of vegetarianism determines the need for comprehensive study of the impact of these diets on health and particularly on bone metabolism. We hypothesized that significant dietary differences between vegans, lacto-ovo-vegetarians, and omnivores also cause significant differences in their nutrient status, which may affect bone health.

Methods

The study assessed dual-energy X-ray absorptiometry parameters in lumbar spine and femoral neck, average nutrient intake, serum nutrient concentrations, serum PTH levels, and urinary pH among 46 vegans, 38 lacto-ovo-vegetarians, and 44 omnivores.

Results

There were no differences in bone mineral density (BMD) between the groups. However, the parathyroid hormone (PTH) levels were still higher in vegans compared to omnivores, despite the same prevalence of hyperparathyroidism in all groups. These findings may probably be explained by the fact that each group had its own "strengths and weaknesses." Thus, vegans and, to a lesser extent, lacto-ovo-vegetarians consumed much more potassium, magnesium, copper, manganese, and vitamins B6, B9, and C. At the same time, the diet of omnivores contained more protein and vitamins D and B12. All the subjects consumed less vitamin D than recommended. More than half of vegans and omnivores had insufficiency or even deficiency of vitamin D in the blood. Low serum concentrations of manganese with its quite adequate intake are also noteworthy: its deficiency was observed in 57% of vegans, 79% of lacto-ovo-vegetarians, and 63% of omnivores.

Discussion

Currently, it is no longer possible to conclude that lacto-ovo-vegetarians have lower BMD than omnivores, as our research supported. Vegans in our study also did not demonstrate lower BMD values, only higher PTH blood concentrations, compared to omnivores, however, a large number of studies, including recent, show the opposite view. In this regard, further large-scale research is required. Vegans and lacto-ovo-vegetarians now have a variety of foods fortified with vitamins D and B12, as well as calcium. There is also a great diversity of ethically sourced dietary supplements. The found low concentrations of manganese require further investigation.

Summatory Effects of Anaerobic Exercise and a 'Westernized Athletic Diet' on Gut Dysbiosis and Chronic Low-Grade Metabolic Acidosis

Anaerobic exercise decreases systemic pH and increases metabolic acidosis in athletes, altering the acid-base homeostasis. In addition, nutritional recommendations advising athletes to intake higher amounts of proteins and simple carbohydrates (including from sport functional supplements) could be detrimental to restoring acid-base balance. Here, this specific nutrition could be classified as an acidic diet and defined as 'Westernized athletic nutrition'. The maintenance of a chronic physiological state of low-grade metabolic acidosis produces detrimental effects on systemic health, physical performance, and inflammation. Therefore, nutrition must be capable of compensating for systemic acidosis from anaerobic exercise. The healthy gut microbiota can contribute to improving health and physical performance in athletes and, specifically, decrease the systemic acidic load through the conversion of lactate from systemic circulation to short-chain fatty acids in the proximal colon. On the contrary, microbial dysbiosis results in negative consequences for host health and physical performance because it results in a greater accumulation of systemic lactate, hydrogen ions, carbon dioxide, bacterial endotoxins, bioamines, and immunogenic compounds that are transported through the epithelia into the blood circulation. In conclusion, the systemic metabolic acidosis resulting from anaerobic exercise can be aggravated through an acidic diet, promoting chronic, low-grade metabolic acidosis in athletes. The individuality of athletic training and nutrition must take into consideration the acid-base homeostasis to modulate microbiota and adaptive physiological responses.

Impact of carbonated beverages on early onset of osteoporosis: A narrative review

Background: Processed and semi-processed foods are getting popular in the diets of the Western population. The Western diet is almost coupled with consuming carbonated beverages, either alcoholic or nonalcoholic. The presence of sugar, caffeine, and alcohol in different carbonated beverages and detrimental dietary patterns are leading causes of obesity, diabetes, and periodontal diseases in the young population. Aims: This article aims to review the impact of carbonated beverages on early onset of osteoporosis. Methods: A nonsystematic literature review searches in PubMed and Google Scholar electronic databases with predefined terms relating to carbonated beverages, caffeine intake, childhood obesity, osteoporosis, and bone softness. Results: Bone diseases significantly increase due to early exposure to caffeine and phosphoric acid in the pubertal period. Musculoskeletal growth is a dynamic and complex process, and bone mass achievement is of great importance in this process. According to the global burden of diseases, bone disorders consist of "6.8% of total disability-adjusted life-years." The consumption of soft drinks and their impact on bone accretion and bone mineral density in the young population is under research in the current literature on osteoporotic disorders. Since bone is a metabolically active tissue, it's in constant reconstruction mode. This process is regulated by genetic, hormonal, nutritional, and physical factors. Any imbalance in one of these processes might lead to mineral deposition and osteoporosis. Conclusion: Habitual intake of carbonated drinks with added sugars and caffeine is associated with increased body weight and bone fragility; stringent regulations are needed for proper education.

Nutritional therapy bridges the critical cut-off point for the closed-loop role of type 2 diabetes and bone homeostasis: A narrative review

Currently, osteoporosis-related fractures become the most cutting-edge problem of diabetes-related complications. Rational diet is not only the basis of glycemic management in type 2 diabetes patients, but also the direction of diabetic bone health. This review highlights the importance of micronutrient supplementation (including calcium, magnesium, zinc, vitamin D, vitamin K, and vitamin C) for patients with T2DM, as well as describing the constructive intermediary role of gut flora between T2DM and bone through nutrients predominantly high in dietary fiber. In addition, it is recommended to combine the Mediterranean dietary pattern with other diversified management approaches to prevent OP. Therefore, this provides a theoretical basis for the potential role of islet β-cells in promoting bone health.

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.

Nutritional Quality and Safety Assessment of Pork Meat Cuts from Romania: Fatty Acids and Elemental Profile

In this study, the fatty acids and elemental profiles of 53 pork cut samples were determined. To offer insights into their potential health implications, we computed 18 key nutritional indices. These indices included parameters such as saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), polyunsaturated fatty acids (PUFAs), unsaturated fatty acids (UFAs), the MUFAs/SFAs ratio, PUFAs/SFAs ratio, atherogenic index (AI), thrombogenic index (TI), the hypocholesterolemic to hypercholesterolemic ratio (h/H), health-promoting index (HPI), hypocholesterolemic index (HI), unsaturation index (UI), saturation index (SI), peroxidizability index (PI), nutritional value index (NVI), hypocholesterolemic index of fatty acids (DFAs), hypercholesterolemic index of fatty acids (OFAs), and the DFAs/OFAs ratio. These indices were calculated based on their fatty acid composition to provide comprehensive nutritional information. A health risk assessment revealed the safety and minimum health risk for the population from consuming the investigated pork cuts using the Target Hazard Quotient (THQ), Hazard Index (HI), and target cancer risk (TR). The ANOVA test showed significant differences in the levels of K, Fe, Mn, Zn, MUFAs, and AI among the pork cut samples. It was noted that by employing the correlation between the fatty acids profile, nutritional indices, and elemental concentrations and an unsupervised statistical method, such as PCA, a perfect separation from the different pork cuts could not be obtained.

Effect of high in comparison to low dairy intake intervention on markers of bone and cartilage remodeling and phosphate metabolism in healthy adults with overweight

BACKGROUND

In the ageing population, issues with bone and joint health are highly prevalent. Both beneficial and potential risks of dairy products on bone and joint health are reported in epidemiological studies. Furthermore, the phosphorus (P) load from dairy could potentially lead to unfavorable changes in P metabolism.

OBJECTIVE

To investigate the effect of dairy intake on markers of bone and joint metabolism and P metabolism in an intervention study with high and low dairy intake.

METHODS

In a post hoc analysis of a randomized cross-over trial with overweight adults, the effect of a standardized high dairy intake [HDI (5-6 dairy portions per day) versus low dairy intake (LDI, ≤ 1 dairy portion/day)] for 6 weeks on markers of bone and joint health was assessed using enzyme-linked immunosorbent assays and electrochemiluminescence immunoassays. Markers indicative for cartilage breakdown, including urinary CTX-II, serum COMP and 4-hydroxyproline, and markers indicative for bone remodeling, such as serum CTX-I, PTH, 25(OH)D, osteocalcin, P1NP and FGF23, were investigated using linear mixed models. Furthermore, changes in P metabolism, including the main phosphate-regulating hormone FGF23 were explored.

RESULTS

This study was completed by 46 adults (57% female, age 59 ± 4 years, BMI 28 ± 2 kg/m2). Following HDI, markers such as urinary CTX-II excretion, COMP, 25(OH)D, PTH and CTX-I were significantly lower after HDI, as compared to LDI. For example, CTX-II excretion was 1688 ng/24 h at HDI, while it was 2050 ng/24 h at LDI (p < 0.001). Concurrently, P intake was higher at HDI than at LDI (2090 vs 1313 mg/day, p < 0.001). While plasma P levels did not differ (1.03 vs 1.04 mmol/L in LDI, p = 0.36), urinary P excretion was higher at HDI than at LDI (31 vs 28 mmol/L, p = 0.04). FGF23 levels tended to be higher at HDI than at LDI (76.3 vs. 72.9 RU/mL, p = 0.07).

CONCLUSIONS

HDI, as compared to LDI, reduced markers that are indicative for joint and bone resorption and bone turnover. No changes in P metabolism were observed.

CLINICAL TRIAL REGISTRY

This trial was registered at https://trialsearch.who.int/Trial2.aspx?TrialID=NTR4899 as NTR4899.

NaHCO3 loading causes increased arterial pressure and kidney damage in rats with chronic kidney disease

Sodium bicarbonate (NaHCO3) is commonly utilized as a therapeutic to treat metabolic acidosis in people with chronic kidney disease (CKD). While increased dietary sodium chloride (NaCl) is known to promote volume retention and increase blood pressure, the effects of NaHCO3 loading on blood pressure and volume retention in CKD remain unclear. In the present study, we compared the effects of NaCl and NaHCO3 loading on volume retention, blood pressure, and kidney injury in both 2/3 and 5/6 nephrectomy remnant kidney rats, a well-established rodent model of CKD. We tested the hypothesis that NaCl loading promotes greater volume retention and increases in blood pressure than equimolar NaHCO3. Blood pressure was measured 24 h daily using radio telemetry. NaCl and NaHCO3 were administered in drinking water ad libitum or infused via indwelling catheters. Rats were housed in metabolic cages to determine volume retention. Our data indicate that both NaHCO3 and NaCl promote hypertension and volume retention in remnant kidney rats, with salt-sensitivity increasing with greater renal mass reduction. Importantly, while NaHCO3 intake was less pro-hypertensive than equimolar NaCl intake, NaHCO3 was not benign. NaHCO3 loading significantly elevated blood pressure and promoted volume retention in rats with CKD when compared with control rats receiving tap water. Our findings provide important insight into the effects of sodium loading with NaHCO3 in CKD and indicate that NaHCO3 loading in patients with CKD is unlikely to be benign.

The Role of the Endocrine System in the Regulation of Acid-Base Balance by the Kidney and the Progression of Chronic Kidney Disease

Systemic acid-base status is primarily determined by the interplay of net acid production (NEAP) arising from metabolism of ingested food stuffs, buffering of NEAP in tissues, generation of bicarbonate by the kidney, and capture of any bicarbonate filtered by the kidney. In chronic kidney disease (CKD), acid retention may occur when dietary acid production is not balanced by bicarbonate generation by the diseased kidney. Hormones including aldosterone, angiotensin II, endothelin, PTH, glucocorticoids, insulin, thyroid hormone, and growth hormone can affect acid-base balance in different ways. The levels of some hormones such as aldosterone, angiotensin II and endothelin are increased with acid accumulation and contribute to an adaptive increase in renal acid excretion and bicarbonate generation. However, the persistent elevated levels of these hormones can damage the kidney and accelerate progression of CKD. Measures to slow the progression of CKD have included administration of medications which inhibit the production or action of deleterious hormones. However, since metabolic acidosis accompanying CKD stimulates the secretion of several of these hormones, treatment of CKD should also include administration of base to correct the metabolic acidosis.

Pathophysiology of Diet-Induced Acid Stress

Diets can influence the body's acid-base status because specific food components yield acids, bases, or neither when metabolized. Animal-sourced foods yield acids and plant-sourced food, particularly fruits and vegetables, generally yield bases when metabolized. Modern diets proportionately contain more animal-sourced than plant-sourced foods, are, thereby, generally net acid-producing, and so constitute an ongoing acid challenge. Acid accumulation severe enough to reduce serum bicarbonate concentration, i.e., manifesting as chronic metabolic acidosis, the most extreme end of the continuum of "acid stress", harms bones and muscles and appears to enhance the progression of chronic kidney disease (CKD). Progressive acid accumulation that does not achieve the threshold amount necessary to cause chronic metabolic acidosis also appears to have deleterious effects. Specifically, identifiable acid retention without reduced serum bicarbonate concentration, which, in this review, we will call "covert acidosis", appears to cause kidney injury and exacerbate CKD progression. Furthermore, the chronic engagement of mechanisms to mitigate the ongoing acid challenge of modern diets also appears to threaten health, including kidney health. This review describes the full continuum of "acid stress" to which modern diets contribute and the mechanisms by which acid stress challenges health. Ongoing research will develop clinically useful tools to identify stages of acid stress earlier than metabolic acidosis and determine if dietary acid reduction lowers or eliminates the threats to health that these diets appear to cause.

Physiochemical effects of acid exposure on bone composition and function

Bone is primarily composed of collagen and apatite, two materials which exhibit a high sensitivity to pH dysregulation. As a result, acid exposure of bone, both clinically and in the laboratory is expected to cause compositional and mechanical changes to the tissue. Clinically, Metabolic acidosis (MA), a condition characterized by a reduced physiological pH, has been shown to have negative implications on bone health, including a decrease in bone mineral density and volume as well as increased fracture risk. The addition of bone-like apatite to ionic solutions such as phosphate buffered saline (PBS) and media has been shown to acidify the solution leading to bone acid exposure. Therefore, is it essential to understand how reduced pH physiochemically affects bone composition and in turn its mechanical properties. This study investigates the specific changes in bone due to physiochemical dissolution in acid. Excised murine bones were placed in PBS solutions at different pHs: a homeostatic pH level (pH 7.4), an acidosis equivalent (pH 7.0), and an extreme acidic solution (pH 5.5). After 5 days, the bones were removed from the solutions and characterized to determine compositional and material changes. We found that bones, without cells, were able to regulate pH via buffering, leading to a decrease in bone mineral content and an increase in collagen denaturation. Both of these compositional changes contributed to an increase in bone toughness by creating a more ductile bone surface and preventing crack propagation. Therefore, we conclude that the skeletal systems' physiochemical response to acid exposure includes multifaceted and spatially variable compositional changes that affect bone mechanics.

Acidosis induces significant changes to the murine supraspinatus enthesis organic matrix

Rotator cuff pathology is a common musculoskeletal condition that disproportionately affects older adults, as well as patients with diabetes mellitus and chronic kidney disease. It is known that increased age and kidney dysfunction have been correlated to acidotic states, which may be related to the increased incidence of rotator cuff injury. In order to investigate the potential relationship between acidosis and rotator cuff composition and mechanics, this study utilizes a 14-day murine model of metabolic acidosis and examines the effects on the supraspinatus tendon-humeral head attachment complex. The elastic matrix in the enthesis exhibited significant changes beginning at day 3 of acidosis exposure. At day 3 and day 7 timepoints, there was a decrease in collagen content seen in both mineralized and unmineralized tissue as well as a decrease in mineral:matrix ratio. There is also evidence of both mineral dissolution and reprecipitation as buffering ions continually promote pH homeostasis. Mechanical properties of the tendon-to-bone attachment were studied; however, no significant changes were elicited in this 14-day model of acidosis. These findings suggest that acidosis can result in significant changes in enthesis composition over the course of 14 days; however, enthesis mechanics may be more structurally mediated rather than affected by compositional changes.

Fruit and Vegetable Consumption and the Risk of Bone Fracture: A Grading of Recommendations, Assessment, Development, and Evaluations (GRADE)-Assessed Systematic Review and Dose-Response Meta-Analysis

Researchers have examined the link between consuming fruit and vegetables and the incidence of fractures for many years. Nevertheless, their findings have been unclear. Furthermore, the dose-dependent relationship has not been examined, and the level of certainty in the evidence was not evaluated. We carried out a dose-dependent meta-analysis examining the relation between fruit and vegetables intake and fracture incidence. PubMed, Web of Sciences, and Scopus were searched until April 2023 for cohort studies evaluating the relation between fruit and vegetables and fracture incidence. Summary relative risks (RRs) were computed from complied data by applying random effects analysis. To examine the level of evidence, we utilized the approach called the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE). Ten cohort studies comprising 511,716 individuals were entered. There was a nonsignificant relation between fruit and vegetables, as well as only fruit intake and any fracture risk. In contrast, high versus low analysis presented that vegetables consumption was linked to a 16% decrease in any type of fracture incidence (RR 0.84; 95% confidence interval [CI], 0.75 to 0.95; I 2 = 83.1%; n = 6). Also, per one serving/day (200 g/day) increments in vegetables consumption, there was a 14% decline in the fracture risk (RR 0.86; 95% CI, 0.77 to 0.97; I 2 = 84.7%; n = 5; GRADE = moderate). With moderate certainty, a greater consumption of only vegetables, but not total fruit and vegetables or only fruit, might reduce the risk of fracture. These associations were also evident in dose-response analysis. Large intervention trials are demanded to approve our findings. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Association of body mass index with the development of metabolic acidosis in patients with chronic kidney disease

Aims

Higher body mass index (BMI) is associated with higher bone mass and bone serves as a buffer during the development of metabolic acidosis. The authors sought to examine the relationship between BMI and metabolic acidosis in patients with chronic kidney disease (CKD).

Materials and Methods

The study utilized a large US longitudinal data repository including over 103 million patients from healthcare provider organizations to evaluate the relationship between the exposure variable (BMI) and the prevalence and incidence of metabolic acidosis among patients with estimated glomerular filtration rate <60 ml/min/1.73 m2. Incident metabolic acidosis was identified at the first of two consecutive post-index serum bicarbonate values, 10-365 days apart, between 12 and <22 mEq/L in patients with normal index serum bicarbonate. Cox proportional hazard models were adjusted for multiple variables including demographics, comorbidities, income, education, and kidney function.

Results

103,766 patients qualified for this study; 6472 (6.2%) had metabolic acidosis at index. An inverse association between BMI category and metabolic acidosis was observed for both baseline (prevalence) and new-onset (incidence) metabolic acidosis. Compared to BMI category of 18.5 to <25 kg/m2, each category of incrementally higher BMI was associated with a decreasing risk of incident metabolic acidosis; the adjusted hazard ratios (95% confidence interval) were 0.866 (0.824-0.911), 0.770 (0.729-0.813), 0.664 (0.622-0.709), and 0.612 (0.571-0.655) for BMI 25 to <30, 30 to <35, 35 to <40, and 40+ kg/m2, respectively.

Conclusions

Among patients with CKD, an incremental increase in BMI was inversely associated with both the prevalence and incidence of metabolic acidosis. These associations suggest that increased body weight may protect against the development of metabolic acidosis, a risk factor for progressive loss of kidney function.

Influence of Geographical Origin on Isotopic and Elemental Compositions of Pork Meat

Pigs are a primary source of meat, accounting for over 30% of global consumption. Consumers' preferences are determined by health considerations, paying more attention to foodstuffs quality, animal welfare, place of origin, and swine feeding regime, and being willing to pay a higher price for a product from a certain geographical region. In this study, the isotopic fingerprints (δ2H, δ18O, and δ13C) and 29 elements of loin pork meat samples were corroborated with chemometric methods to obtain the most important variables that could classify the samples' geographical origin. δ2H and δ18O values ranged from -71.0 to -21.2‱, and from -9.3 to -2.8‱, respectively. The contents of macro- and micro-essential elements are presented in the following order: K > Na > Mg > Ca > Zn > Fe > Cu > Cr. The LDA model assigned in the initial classification showed 91.4% separation of samples, while for the cross-validation procedure, a percentage of 90% was obtained. δ2H, K, Rb, and Pd were identified as the most representative parameters to differentiate the pork meat samples coming from Romania vs. those from abroad. The mean values of metal concentrations were used to estimate the potential health risks associated with the consumption of pork meat The results showed that none of the analyzed metals (As, Cd, Sn, Pb, Cu, and Zn) pose a carcinogenic risk.

Association of Alternative Dietary Patterns with Osteoporosis and Fracture Risk in Older People: A Scoping Review

PURPOSE

Although the Mediterranean diet has been associated with a lower risk of hip fracture, the effect of other dietary patterns on bone density and risk of fracture is unknown. This scoping review aims to investigate the association between adherence to alternative dietary patterns (other than the traditional Mediterranean diet) and osteoporosis or osteoporotic fracture risk in older people.

METHODS

A systematic search was carried out on three electronic databases (Medline, EMBASE, and Scopus) to identify original papers studying the association between alternative dietary patterns (e.g., Baltic Sea Diet (BSD), modified/alternative Mediterranean diet in non-Mediterranean populations, Dietary Approaches to Stop Hypertension (DASH)) assessed using 'prior' methods (validated scores) and the risk of osteoporotic fracture or Bone Mineral Density (BMD) in people aged ≥50 (or reported average age of participants ≥ 60). Results from the included studies were presented in a narrative way.

RESULTS

Six observational (four prospective cohort and two cross-sectional) studies were included. There was no significant association between BMD and BSD or DASH scores. Higher adherence to DASH was associated with a lower risk of lumbar spine osteoporosis in women in one study, although it was not associated with the risk of hip fracture in another study with men and women. Higher adherence to aMED (alternative Mediterranean diet) was associated with a lower risk of hip fracture in one study, whereas higher adherence to mMED (modified Mediterranean diet) was associated with a lower risk of hip fracture in one study and had no significant result in another study. However, diet scores were heterogeneous across cohort studies.

CONCLUSIONS

There is some evidence that a modified and alternative Mediterranean diet may reduce the risk of hip fracture, and DASH may improve lumbar spine BMD. Larger cohort studies are needed to validate these findings.

Administration of alendronate exacerbates ammonium chloride-induced acidosis in mice

Bone disease is highly prevalent in patients with chronic kidney disease (CKD), leading to an increased risk of bone fractures. This is due in part to metabolic acid-induced bone dissolution. Bisphosphonates (BPPs) are a potential treatment for inhibiting bone dissolution; however, there are limited studies observing the use of BPPs on acidotic patients. We aimed to determine efficacy of BPPs on maintaining bone health and pH regulation in acid-exposed mice. Using a diet-induced murine model of metabolic acidosis, we examined bone structure, composition, and mechanics as well as blood gases for three groups: control, acidosis, and acidosis + bisphosphonates (acidosis+BPP). Acidosis was induced for 14 days and alendronate was administered every 3 days for the acidosis+BPP group. The administration of BPP had little to no effect on bone structure, mechanics, and composition of the acidosis bones. However, administration of BPP did cause the mice to develop more severe acidosis than the acidosis only group. Overall, we discovered that BPPs may exacerbate acidosis symptoms by inhibiting the release of buffering ions from bone. Therefore, we propose that BPP administration should be carefully considered for those with CKD and that alkali supplementation could help minimize acidifying effects.

Hypocitraturia and Risk of Bone Disease in Patients With Kidney Stone Disease

Patients with kidney stone disease are at higher risk for bone disease. Hypocitraturia is common in patients with kidney stone disease and a key risk factor for stone recurrence. In this retrospective cohort study, we sought to determine whether hypocitraturia is also a risk factor for incident bone disease in patients with kidney stone disease. We used nationwide data from the Veterans Health Administration and identified 9025 patients with kidney stone disease who had a 24-hour urine citrate measurement between 2007 and 2015. We examined clinical characteristics of patients by level of 24-hour urine citrate excretion (<200, 200-400, and >400 mg/d) and the time to osteoporosis or fracture according to 24-hour urine citrate excretion level. Almost one in five veterans with kidney stone disease and a 24-hour urine citrate measurement had severe hypocitraturia, defined as <200 mg/d. Patients with severe hypocitraturia were at risk for osteoporosis or fracture (hazard ratio [HR] = 1.23; confidence interval [CI] 1.03-1.48), but after adjustment for demographic factors, comorbid conditions, and laboratory abnormalities associated with hypocitraturia, the association was no longer statistically significant (HR = 1.18; CI 0.98-1.43). Our results in a predominantly male cohort suggest a modest association between hypocitraturia and osteoporosis or fracture; there are likely to be other explanations for the potent association between kidney stone disease and diminished bone health. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

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.

Toxic gas removal with kaolinite, metakaolinite, radiolarite, and diatomite

In this study, some clays and dead microorganisms were compared in terms of their adsorption ability against special toxic gases. To this end, an experimental investigation was conducted to explore the adsorption kinetics of kaolinite, metakaolinite, radiolarite, and diatomite to ammonia (NH₃), ethylene (C₂H₄), and carbon dioxide (CO₂). Numerous analyses, such as x-ray fluorescence (XRF), x-ray diffraction (XRD), thermo-gravimetric analysis (TGA), scanning electron microscopy (SEM), and particle size distribution, have been performed for mineralogical and structural characterization of studied materials. Also, adsorption characteristics were investigated with the help of an ultra-precision scale and computer-controlled multi-gas control system. Since ammonia has the highest dipole moment among all studied gases, its removal efficiency was found as the highest in all materials. Regarding clay substances, metakaolinite indicated a lower response than kaolinite due to phase transformation. But, considering the microorganisms, diatomite toxic gas uptake is at least five times better than examined clays while the gas uptake behavior of radiolarite is analog to metakaolinite. Moreover, the adsorption behaviors of proposed materials are clarified with Langmuir isotherms, The results could facilitate improvements in applying microorganisms to the toxic gas environment as a natural adsorbent material.

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

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

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.

Urinary Potential Renal Acid Load (uPRAL) among Vegans Versus Omnivores and Its Association with Bone Health in the Cross-Sectional Risks and Benefits of a Vegan Diet Study

Both veganism and high dietary acid load are linked to unfavorable bone health. However, the specific role of dietary alkali or acid load for the bone health of vegans is so far unknown. Thus, the renal biomarker for dietary acid or alkali load, i.e., urinary potential renal acid load (uPRAL), was measured in 24 h urine samples of 34 vegans and 35 omnivores (50.7% males). Bone health was assessed via calcaneal quantitative ultrasound. Associations between uPRAL and bone health indices were examined using multivariable general linear models. Compared to omnivores, vegans had a significantly lower uPRAL (mean difference = −34.5 mEq/24 h, p < 0.0001), a lower 24 h urinary phosphate excretion (p = 0.0004), a lower 24 h urinary sulfate excretion (p = 0.01), and a higher urine pH value (p < 0.0001). Broadband ultrasound attenuation (BUA) was lower among vegans versus omnivores (p = 0.037), yet it was not associated with uPRAL irrespective of adjustments. This study confirms different acid-base profiles of vegans and omnivores, with a pronounced alkaline excess among vegans and a rather low acid load among a group of omnivores with moderate protein intake. Within this spectrum of alkaline to low acid load, no association with bone health was found.

Dietary Acid Load Was Positively Associated with the Risk of Hip Fracture in Elderly Adults

Previous studies have shown that dietary acid load (DAL) harms bone health, but the evidence is inconsistent and insufficient. This study examined the relationships between DAL and the risk of hip fracture. This case−control study contained 1070 pairs of 1:1 age-, city-, and gender-matched incident cases and controls (mean age, 71 years) recruited in Guangdong, China. Dietary information was collected using a validated 79-item food frequency questionnaire through face-to-face interviews. DAL was estimated based on established algorithms for the potential renal acid load (PRAL) and net endogenous acid production (NEAP). Higher PRAL and NEAP were dose-dependently associated with a higher risk of hip fracture in both the conditional logistic regression model and restricted cubic spline analysis after adjusting for potential covariates. The multivariate-adjusted odds ratios and 95% CI of hip fracture for tertiles 2 and 3 (vs. 1) of DAL were 1.63 (1.18, 2.25) and 1.92 (1.36, 2.71) for PRAL and 1.81 (1.30, 2.53) and 2.55 (1.76, 3.71) for NEAP in all participants (all p-trends < 0.001), respectively. Subgroup analyses showed more pronounced associations in participants with a lower body mass index. Our findings suggested positive associations between the estimated DAL and the risk of hip fractures in the elderly Chinese population.

Modifiable risk factors for bone health & fragility fractures

Osteoporosis is an ageing disorder characterised by poor microstructural architecture of the bone and an increase in the risk of fragility fractures, which often leads to hospitalisation and eventually a loss of mobility and independence. By 2050, it is estimated that more than 30 million people in Europe will be affected by bone diseases, and European hospitalisation alone can approximately cost up to 3.5 billion euros each year [1]. Although inherited variation in bone mineral density (BMD) is pre-determined by up to 85% [2], there is a window of opportunity to optimise BMD and reduce fracture risk through key modifiable lifestyle factors during the life course. An optimal diet rich in micronutrients, such as calcium, vitamin D, and potassium, has long been considered an important modifiable component of bone health, which is attributed to their direct roles within bone metabolism. Recently, there has been emerging evidence to suggest that protein and even an adequate intake of fruit and vegetables may also play an important role in improving BMD [3,4]. Maintaining a physically active lifestyle is not only protective from non-communicable diseases such as cardiovascular disease but it also has been shown to lessen the risk of fractures later in life, thereby making it an imperative modifiable factor for bone health, particularly as it also supports peak bone mass attainment during childhood/adolescence and can facilitate the maintenance of bone mass throughout adulthood [5]. Other key lifestyle factors that could be potentially modified to reduce the risk of osteoporosis or osteoporotic fractures later in life include smoking status, alcohol intake, and body composition [6]. Therefore, the principle aim of this review is to highlight the recent evidence pertaining to modifiable lifestyle factors that contribute to optimal bone health and the prevention of fragility fractures in later life.

Association of Polygenic Variants with Type 2 Diabetes Risk and Their Interaction with Lifestyles in Asians

Over the last several decades, there has been a considerable growth in type 2 diabetes (T2DM) in Asians. A pathophysiological mechanism in Asian T2DM is closely linked to low insulin secretion, β-cell mass, and inability to compensate for insulin resistance. We hypothesized that genetic variants associated with lower β-cell mass and function and their combination with unhealthy lifestyle factors significantly raise T2DM risk among Asians. This hypothesis was explored with participants aged over 40. Participants were categorized into T2DM (case; n = 5383) and control (n = 53,318) groups. The genetic variants associated with a higher risk of T2DM were selected from a genome-wide association study in a city hospital-based cohort, and they were confirmed with a replicate study in Ansan/Ansung plus rural cohorts. The interacted genetic variants were identified with generalized multifactor dimensionality reduction analysis, and the polygenic risk score (PRS)-nutrient interactions were examined. The 8-SNP model was positively associated with T2DM risk by about 10 times, exhibiting a higher association than the 20-SNP model, including all T2DM-linked SNPs with p < 5 × 10−6. The SNPs in the models were primarily involved in pancreatic β-cell growth and survival. The PRS of the 8-SNP model interacted with three lifestyle factors: energy intake based on the estimated energy requirement (EER), Western-style diet (WSD), and smoking status. Fasting serum glucose concentrations were much higher in the participants with High-PRS in rather low EER intake and high-WSD compared to the High-EER and Low-WSD, respectively. They were shown to be higher in the participants with High-PRS in smokers than in non-smokers. In conclusion, the genetic impact of T2DM risk was mainly involved with regulating pancreatic β-cell mass and function, and the PRS interacted with lifestyles. These results highlight the interaction between genetic impacts and lifestyles in precision nutrition.

The relationship between dietary acid load and intensity of musculoskeletal pain condition: A population-based study

Pain is a globally prevalent problem, and a comprehension of its pathophysiology is important with respect to patient's health. Musculoskeletal pain conditions (MPs) may be associated with physical, lifestyle, and nutrition status, while dietary acid load (DAL) may be inversely associated with musculoskeletal health in adults. This cross-sectional study consisted of 175 adults experiencing pain. Anthropometric measurements, physical activity (PA), and pain intensity were assessed via specific questionnaires. Dietary data were collected using a 7-day 24-h recall. Foods and beverages were analyzed with Nutritionist IV software for extracting the total energy and nutrients. Net endogenous acid production (NEAP) and potential renal acid load (PRAL) were evaluated for assessing the DAL. Linear regression and Spearman correlation were used to investigate the association of exposure and input variables. Linear regression showed a positive relationship between PRAL and NEAP and pain intensity in the crude model. This significant positive relationship remained after adjusting for all confounders. A lower consumption of potassium, magnesium, vitamin B9 and C, and fiber was seen in the following quartiles of PRAL and NEAP. In addition, MPs intensity and PRAL and NEAP had a weak, positive correlation. This study suggests that a higher DAL may be associated with MPs. However, further research is needed.

Dietary acid load and mortality from all causes, CVD and cancer: results from the Golestan Cohort Study

Given the limited studies and controversial results on association between dietary acid load and mortality from CVD and cancers, we aimed to investigate this association in a large population cohort study in Middle East, with a wide range of dietary acid load. The study was conducted on the platform of the Golestan Cohort Study (GCS), which enrolled 50 045 participants in 2004-2008. Dietary intake was assessed using a validated FFQ. Dietary potential renal acid load (PRAL) score was calculated from nutrient intake. Death and its causes were identified and confirmed by two or three physicians. Cox proportional hazards regression was used to estimate hazard ratio (HR) and 95 % CI for total and cause-specific mortalities. Then, the associations were modelled using restricted cubic splines. PRAL range was -57·36 to +53·81 mEq/d for men and -76·70 to +49·08 for women. During 555 142 person-years of follow-up, we documented 6830 deaths, including 3070 cardiovascular deaths, 1502 cancer deaths and 2258 deaths from other causes. For overall deaths, in final model after adjustment for confounders, participants in the first and fifth quintiles of PRAL had a higher risk of mortality compared with the second quintile of PRAL (HR: 1·08; 95 % CI1·01, 1·16 and HR: 1·07; 95 % CI 1·01, 1·15, respectively); Pfor trend < 0·05). Participants in the first and fifth quintiles of PRAL had a 12 % higher risk of CVD mortality compared with the Q2 of PRAL (HR: 1·12; 95 % CI 1·01-1·25 and HR: 1·12; 95 % CI 1·01, 1·26, respectively; Pfor trend < 0·05). We found that all-cause and CVD mortality rates were higher in the lowest and highest PRAL values, in an approximately U-shaped relation (P-values for the overall association and the non-linear association of energy-adjusted PRAL with total mortality were < 0·001 and < 0·001, and with CVD mortality were 0·008 and 0·003, respectively). Our results highlight unfavourable associations of high acidity and alkalinity of diet with the increased total and CVD mortality risk. It may be important to consider a balanced acid-base diet as a protective strategy to prevent pre-mature death, especially from CVD.

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

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

Dietary Acid Load 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.

Drinking Natural Mineral Water Maintains Bone Health in Young Rats With Metabolic Acidosis

Introduction

Metabolic acidosis affects bone health. It remains unclear whether drinking natural mineral water is better for maintaining bone health in the youth with metabolic acidosis.

Materials and Methods

Sixty young female rats (3-weeks-old) were randomly divided into three groups and drank purified water (PW, as control), bicarbonate-rich natural mineral water (Bic-NMW), or sulfate-rich natural mineral water (Sul-NMW), which, respectively, contained calcium (0.17, 155, and 175 mg/L), bicarbonate (0.1360, and 139 mg/L) and sulfate (0, 35.6, and 532 mg/L), for 16 weeks. In the last 3 weeks, metabolic acidosis was induced in 10 rats per group by adding NH₄Cl (0.28 mM) to drinking water. The rats' blood, urine, and femur were collected for assessing acid-base status, calcium metabolism, bone microstructure, and strength. The difference between the three groups was determined using one-way ANOVA followed by the Student–Newman–Keuls test or Dunnett's T3 test.

Results

Compared with the PW rats, the Bic-NMW rats and the Sul-NMW rats had less urine net acid excretion (−1.51, 0.20 vs. 10.77, EQ/L), higher bone mineral density (442.50, 407.49 vs. 373.28, mg/mm³), growth cartilage width (271.83, 283.83 vs. 233.27, μm) and cortical trabecular area (9.33, 9.55 vs. 5.05, mm²), and smaller cortical marrow cavity area (5.40, 5.49 vs. 7.27, mm²) in the femur (P < 0.05). Besides, the Bic-NMW rats had less serum calcium (2.53 vs. 2.68, mmol/L) and C-terminal cross-linked telopeptide of type-I collagen (1.35 vs. 1.93, ng/mL), and higher serum calcitonin (0.61 vs. 0.39, μg/L), femoral trabecular thickness (0.10 vs. 0.09, μm), bone volume/total volume (0.42 vs. 0.34, %), cortical bone area (15.91 vs. 12.80, mm²), and ultimate stress (35.12 vs. 29.32, MPa) (P < 0.05). The Sul-NMW rats had more osteoclasts (22.50 vs. 11.54, cells/field) (P < 0.05).

Conclusions

Drinking natural mineral water, especially bicarbonate-rich natural mineral water, is effective in improving bone health in young rats with metabolic acidosis. These benefits include maintaining bone mineral density, and improving bone microstructure and biomechanical properties via moderating metabolic acidosis.

The Molecular Effects of Dietary Acid Load on Metabolic Disease (The Cellular PasaDoble: The Fast-Paced Dance of pH Regulation)

Metabolic diseases are becoming more common and more severe in populations adhering to western lifestyle. Since metabolic conditions are highly diet and lifestyle dependent, it is suggested that certain diets are the cause for a wide range of metabolic dysfunctions. Oxidative stress, excess calcium excretion, inflammation, and metabolic acidosis are common features in the origins of most metabolic disease. These primary manifestations of "metabolic syndrome" can lead to insulin resistance, diabetes, obesity, and hypertension. Further complications of the conditions involve kidney disease, cardiovascular disease, osteoporosis, and cancers. Dietary analysis shows that a modern "Western-style" diet may facilitate a disruption in pH homeostasis and drive disease progression through high consumption of exogenous acids. Because so many physiological and cellular functions rely on acid-base reactions and pH equilibrium, prolonged exposure of the body to more acids than can effectively be buffered, by chronic adherence to poor diet, may result in metabolic stress followed by disease. This review addresses relevant molecular pathways in mammalian cells discovered to be sensitive to acid - base equilibria, their cellular effects, and how they can cascade into an organism-level manifestation of Metabolic Syndromes. We will also discuss potential ways to help mitigate this digestive disruption of pH and metabolic homeostasis through dietary change.

Effect of Alkaline Drinking Water on Bone Density of Postmenopausal Women with Osteoporosis

OBJECTIVES

Postmenopausal women are predisposed to osteoporosis, and those on acidic diets are at a higher risk, because it has been demonstrated that such diets have adverse effects on bone health. In this study, the effect of alkaline drinking water on bone mineral density was evaluated in postmenopausal women with osteoporosis.

METHODS

One hundred postmenopausal women with osteoporosis (T-score ≤ -2.5) were equally divided into an intervention group and a control group (n = 50 each). The intervention group received calcium D (daily), alkaline drinking water (1.5 L daily with pH 8.6 ± 0.3), and Osteofos tablet (70 mg weekly), whereas the control group received only calcium D and Osteofos tablet for 3 months. T-scores of the femur and spine bones were obtained using bone densitometry before and 3 months after the intervention.

RESULTS

After the intervention, the mean T-scores of the femur and spine bones significantly increased in both the control and intervention groups (P < 0.05). However, the mean changes in the spine T-score were significantly higher in the intervention group (0.39 ± 0.07) than in the control group (0.08 ± 0.01) (P < 0.05). No significant differences were observed in the mean changes in the femur T-score between the two groups.

CONCLUSION

Our findings demonstrate that drinking alkaline water improves spine T-scores in postmenopausal women with osteoporosis. Hence, alkaline water can be used to treat osteoporosis due to increased bone density in postmenopausal women. Long-term interventions are necessary to confirm the effects of alkaline water on femur density.

Nutritional Supplements and Skeletal Health

PURPOSE OF REVIEW

Nutrition influences skeletal health throughout the lifespan, from the impact of maternal intakes during development, through the development of peak bone mass, to the rate of bone loss during aging. However, there are limited data available on the effects of nutritional supplements on bone density, let alone fracture risk. This review will assess the current literature, focusing on human studies, and emphasizing nutrients where bone density or fracture data are available.

RECENT FINDINGS

Calcium and vitamin D supplements, in combination, reduce fracture risk, particularly in populations with low intakes. Extensive recent analyses have supported the safety of these interventions at recommended intakes. There is growing evidence that specific isoflavones may improve bone density although fracture data are lacking. Multiple other nutrient supplements may benefit skeletal health, but data are limited. The effect size of nutrient interventions are relatively small, requiring large sample sizes for trials with bone outcomes, may be difficult to blind, and the impact of supplementation may depend on baseline intake. However, nutrition is the only intervention that can be implemented life long and on a population wide basis. Further investigation is needed into the potential benefits of nutritional supplements to determine in which settings supplements may add benefit in addition to dietary intakes.

Promoting bone health in children and adolescents following solid organ transplantation

Solid organ transplantation in children and adolescents provides many benefits through improving critical organ function, including better growth, development, cardiovascular status, and quality of life. Unfortunately, bone status may be adversely affected even when overall status is improving, due to issues with pre-existing bone disease as well as medications and nutritional challenges inherent post-transplantation. For all children and adolescents, bone status entering adulthood is a critical determinant of bone health through adulthood. The overall health and bone status of transplant recipients benefits from attention to regular physical activity, good nutrition, adequate calcium, phosphorous, magnesium and vitamin D intake and avoidance/minimization of soda, extra sodium, and obesity. Many immunosuppressive agents, especially glucocorticoids, can adversely affect bone function and development. Minimizing exposure to "bone-toxic" medications is an important part of promoting bone health in children post-transplantation. Existing guidelines detail how regular monitoring of bone status and biochemical markers can help detect bone abnormalities early and facilitate valuable bone-directed interventions. Attention to calcium and vitamin D supplementation, as well as tapering and withdrawing glucocorticoids as early as possible after transplant, can provide best bone outcomes for these children. Dual-energy X-ray absorptiometry can be useful to detect abnormal bone mass and fracture risk in this population and newer bone assessment methods are being evaluated in children at risk for poor bone outcomes. Newer bone therapies being explored in adults with transplants, particularly bisphosphonates and the RANKL inhibitor denosumab, may offer promise for children with low bone mass post-transplantation.

Effects and interaction of dietary electrolyte balance and citric acid on growth performance, intestinal histomorphology, digestive enzyme activity and nutrient transporters expression of weaned piglets

Fifty-six piglets were weaned at 21 days and randomly assigned to 1 of 8 dietary treatments with 7 replicate pens for a 14-day experimental period. The eight experimental diets were prepared via a 2 × 4 factorial arrangement with citric acid (CA; 0 and 0.3%) and dietary electrolyte balance (dEB, Na +K - Cl mEq/kg of the diet; -50, 100, 250, and 400 mEq/kg). Varying dEB values were obtained by altering calcium chloride and sodium bicarbonate contents. Dietary CA significantly increased (p < .05) villus height (VH) and villus height:crypt depth (VH:CD) in the jejunum. Piglets fed a 250 mEq/kg diet increased (p < .05) VH and VH:CD values in the duodenum. Jejunal VH and VH:CD increased (quadratic; p < .05), and ileal VH:CD (liner and quadratic; p < .05) decreased as dEB was increased in diets without CA, but no such effect was observed on the diets containing CA (dEB ×CA; p < .05). The CD in jejunum (quadratic; p < .05) increased as dEB was increased in diets containing CA, whereas it was decreased (linear; p < .05) in the diets without CA (dEB ×CA; p < .001). Dietary CA increased maltase activity and reduced the number of Ki67-positive cells (p < .05). Increasing dEB values in diets without CA increased sucrose and lactase activities (quadratic; p < .05), but no such effect was observed in the diets with CA (dEB ×CA; p < .05). An interaction effect between dEB and CA on the number of Ki67-positive cells was observed (p < .001). In conclusion, 250 mEq/kg dEB diet with CA improved piglet intestinal digestion and absorption function by improving intestinal morphology and increasing digestive enzyme activities. However, these improvements were also observed in piglets fed the 100 mEq/kg dEB diet without CA.

U-Shaped Association between Dietary Acid Load and Risk of Osteoporotic Fractures in 2 Populations at High Cardiovascular Risk

BACKGROUND

Bone contributes to maintaining the acid-base balance as a buffering system for blood pH. Diet composition also affects acid-base balance. Several studies have linked an imbalance in the acid-base system to changes in the density and structure of bone mass, although some prospective studies and meta-analyses suggest that acid load has no deleterious effect on bone.

OBJECTIVE

The aim of this study was to examine the associations between potential renal acid load (PRAL) and net endogenous acid production (NEAP) and the risk of osteoporotic fractures and bone mineral density (BMD) in 2 middle-aged and elderly Mediterranean populations.

METHODS

We conducted a longitudinal analysis including 870 participants from the PREvención con DIeta MEDiterranea (PREDIMED) Study and a cross-sectional analysis including 1134 participants from the PREDIMED-Plus study. Participants were adults, aged 55-80 y, either at high cardiovascular risk (PREDIMED) or overweight/obese with metabolic syndrome (PREDIMED-Plus), as defined by the International Diabetes Federation, the American Heart Association, and the National Heart Association. PRAL and NEAP were calculated from validated food-frequency questionnaires. BMD was measured using DXA scans. Fracture information was obtained from medical records. The association between mean PRAL and NEAP and fracture risk was assessed using multivariable-adjusted Cox models. BMD differences between tertiles of baseline PRAL and NEAP were evaluated by means of ANCOVA.

RESULTS

A total 114 new fracture events were documented in the PREDIMED study after a mean of 5.2 y of intervention and 8.9 y of total follow-up. Participants in the first and third PRAL and NEAP tertiles had a higher risk of osteoporotic fracture compared with the second tertile, showing a characteristically U-shaped association [HR (95% CI): 1.73 (1.03, 2.91) in tertile 1 and 1.91 (1.14, 3.19) in tertile 3 for PRAL, and 1.83 (1.08, 3.09) in tertile 1 and 1.87 (1.10, 3.17) in tertile 3 for NEAP]. Compared with the participants in tertile 1, the participants in the top PRAL and NEAP tertiles had lower BMD [PRAL: mean total femur BMD: 1.029 ± 0.007 and 1.007 ± 0.007 g/cm2; P = 0.006 (tertiles 1 and 3); NEAP: mean total femur BMD: 1.032 ± 0.007 and 1.009 ± 0.007 g/cm2; P = 0.017 (tertiles 1 and 3)].

CONCLUSIONS

The results of our study suggest that both high and low dietary acid are associated with a higher risk of osteoporotic fractures, although only high dietary acid was found to have a negative relation to BMD in senior adults with existing chronic health conditions. This trial was registered at http://www.isrctn.com/ as ISRCTN3573963 (PREDIMED) and ISRCTN89898870 (PREDIMED-Plus).

Chemical Compound Chemical Treatment in Animal Husbandry

The acidulant is widely used in the production of animal husbandry, and its use is affected by many factors, including environmental factors, dosage, diet composition, and animal’s own factors, so only the correct use of the acidulant can bring good results in animal production and financial income. This article takes acidifier as an example to study the application of compound chemical treatment in livestock farms. In this paper, the effect of using acidulant in the first 1 to 3 weeks after early weaning of piglets is obvious through this experimental study. The effect gradually decreases after 3 weeks and basically has no effect after 4 weeks. Experimental studies have found that the combination of organic acids, antibiotics, and high copper is the most effective. These three have different functions and have complementary or additive effects. Under harsh feeding conditions, especially when the environmental sanitation and environmental conditions are relatively poor, the effect of acidulants is better than good feeding conditions. Experimental data show that fulvic acid depletes milk’s somatic cells in a short period of time and then quickly activates immune function, which is indicated by the increase in lymphocytes in the blood. When a large number of somatic cells migrate to the breast, the somatic cells in milk will also increase, thereby improving the immunity mediated by human cells. The experimental results show that the BFA formula added 1% to the cattle feed. After the research control of this experiment, the milk output increased by 9–17%, and the quality milk output increased by 19.12%, so the use of acidulant increased feed compensation and reduces gastrointestinal diseases and the reproduction of microorganisms in the rumen of dairy cows.

Nanoparticle-directed and ionically forced polyphosphate coacervation: a versatile and reversible core-shell system for drug delivery

A drug encapsulation/delivery system using a novel principle is described that is based on an intra-particle migration of calcium ions between a central Ca²⁺-enriched nanoparticle core and the surrounding shell compartment. The supply of Ca²⁺ is needed for the formation of a coacervate shell around the nanoparticles, acting as the core of drug-loadable core–shell particles, using the physiological inorganic polymer polyphosphate (polyP). This polyanion has the unique property to form, at an alkaline pH and in the presence of a stoichiometric surplus of calcium ions, water-insoluble and stabile amorphous nanoparticles. At neutral pH a coacervate, the biologically active form of the polymer, is obtained that is composed of polyP and Ca²⁺. The drug-loaded core–shell particles, built from the Ca–polyP core and the surrounding Ca–polyP shell, were fabricated in two successive steps. First, the formation of the nanoparticle core at pH 10 and a superstoichiometric 2:1 molar ratio between CaCl₂ and Na–polyP into which dexamethasone, as a phosphate derivative, was incorporated. Second, the preparation of the coacervate shell, loaded with ascorbic acid, by exposure of the Ca–polyP core to soluble Na–polyP and L-ascorbate (calcium salt). EDX analysis revealed that during this step the Ca²⁺ ions required for coacervate formation migrate from the Ca–polyP core (with a high Ca:P ratio) to the shell. Electron microscopy of the particles show an electron-dense 150–200 nm sized core surrounded by a less sharply delimited electron-sparse shell. The core–shell particles exhibited strong osteogenic activity in vitro, based on the combined action of polyP and of dexamethasone and ascorbic acid, which reversibly bind to the anionic polyP via ionic Ca²⁺ bonds. Drug release from the particles occurs after contact with a peptide/protein-containing serum, a process which is almost complete after 10 days and accompanied by the conversion of the nanoparticles into a coacervate. Human osteosarcoma SaOS-2 cells cultivated onto or within an alginate hydrogel matrix showed increased growth/viability and mineralization when the hybrid particles containing dexamethasone and ascorbic acid were embedded in the matrix. The polyP-based core–shell particles have the potential to become a suitable, pH-responsive drug encapsulation/release system, especially for bone, cartilage and wound healing.

Can a carnivore diet provide all essential nutrients?

PURPOSE OF REVIEW

The aim of this study was to summarize current contributions affecting knowledge and predictions about the nutritional adequacy of plant-free diets, contextualized by historical accounts.

RECENT FINDINGS

As demonstrated in recent experiments, nutrient interactions and metabolic effects of ketogenic diets can impact nutritional needs, sometimes resulting in nutrient-sparing effects. Other studies highlight conflicting hypotheses about the expected effect on metabolic acidosis, and therefore mineral status, of adding alkaline mineral-rich vegetables.

SUMMARY

A carnivore diet is a newly popular, but as yet sparsely studied form of ketogenic diet in which plant foods are eliminated such that all, or almost all, nutrition derives from animal sourced foods. Ketogenic diets are already nutritionally controversial due to their near-complete absence of carbohydrate and high dietary fat content, but most ketogenic diet advocates emphasize the inclusion of plant foods. In this review, we discuss the implications of relying solely on animal sourced foods in terms of essential nutrient status.

Associations between age-related changes in bone microstructure and strength and dietary acid load in a cohort of community-dwelling, healthy men and postmenopausal women

BACKGROUND

The importance of dietary acid load (DAL) in the pathogenesis of osteoporosis is still debated. Age-related changes in bone microstructure and strength in relation to DAL remain largely unexplored.

OBJECTIVES

We investigated the associations between changes in areal and volumetric bone mineral density (BMD), bone microstructure and strength, fracture risk, and DAL in a prospective cohort of 65-y-old healthy men and postmenopausal women.

METHODS

Potential renal acid load (PRAL; mEq/d) was calculated as a DAL proxy to characterize participants' diet as alkaline (Alk-D; PRAL < -5), neutral (Neut-D; -5 ≤ PRAL ≤ 5), or acidic (Acid-D; PRAL >5). We measured areal BMD (aBMD) by DXA, and distal radius and tibia bone microstructure using high-resolution peripheral quantitative computed tomography, at baseline (n = 853) and after 6.1 ± 1.4 y (n = 708). Bone strength was estimated using finite element analyses at baseline and after 3.0 ± 0.5 y (n = 613). Prevalent and incident fractures were recorded.

RESULTS

The majority of the participants (59%) had an Alk-D, while 23% had a Neut-D, and 18% an Acid-D. Baseline aBMD and bone microstructure and strength did differ or were slightly better in women or men with an Acid-D versus those consuming an Alk-D or Neut-D. Indeed, women with an Acid-D had higher trabecular number (P = 0.010 vs. Alk-D; P = 0.001 vs. Neut-D), while men had higher hip and radius aBMD (P = 0.008 and 0.024 vs. Neut-D, respectively) and radius strength (P = 0.026 vs. Neut-D). Over the follow-up, women in the Acid-D group experienced lower cortical and endocortical bone loss at the radius than did the Alk-D and Neut-D groups (cortical thickness, P = 0.008 and < 0.001; trabecular area, P = 0.001 and < 0.001, respectively). No association between fractures and PRAL was observed.

CONCLUSIONS

These null or favourable associations between baseline values or changes in aBMD, bone microstructure and strength, and DAL in this cohort of 65-y-old healthy individuals do not support adverse DAL-mediated effects on bone. This trial was registered at http://www.isrctn.com as ISRCTN11865958.

Effects of vegetarian diet on bone mineral density

Factors, such as hormonal changes in postmenopausal women, natural aging degeneration, race, gender, body size, lifestyle, physical activity, sunlight, dietary intake, medications, or other environmental issues, can affect the rate of bone formation or reabsorption, cause changes in bone mineral content, and influence the development of osteoporosis. Do vegetarian diets adversely affect bone mineral density (BMD)? Among postmenopausal Buddhists, long-term practitioners of vegan vegetarian were found to have a higher risk exceeding the lumbar fracture threshold and a lower level of hip BMD after controlling for other variables. However, results of several prospective longitudinal studies failed to show a harmful effect of vegetarianism on bone health. In the Taiwanese adult population, researchers also did not find that a vegetarian diet significantly affects age-related BMD decline. Due to the various levels of nutrients in the diet (such as protein, alkali, calcium, Vitamin K, and phytoestrogens) and major lifestyle factors (such as smoking and physical exercise), determining the impact of a vegetarian diet on bone health is very complex. Good-quality vegetarian food can provide a healthy foundation for building and maintaining healthy bones and preventing fractures.

Dietary acid-base load and its association with risk of osteoporotic fractures and low estimated skeletal muscle mass

BACKGROUND/OBJECTIVES

Age-related decline in skeletal muscle mass and strength, loss of bone density, and increased risk of osteoporotic fractures are important public health issues. Systemic acid-base balance is affected by dietary intake and may be relevant to these conditions. We therefore investigated associations of dietary acid-base load with skeletal muscle mass, bone density status, and fracture risk.

SUBJECTS/METHODS

We analysed the European Prospective Investigation into Cancer and Nutrition-Norfolk cohort of >25,000 individuals, 39-79 years at baseline. Potential renal acid load (PRAL) was calculated from 7-day food diary data. As a proxy for skeletal muscle mass, we estimated fat-free mass from bioelectrical impedance analysis and scaled this for BMI (FFM_BMI). Bone density status was assessed by heel-bone broadband ultrasound attenuation (BUA), and fracture rates were obtained from health-care records. Multivariable regression was used to test musculoskeletal outcomes across sex-specific quintiles of PRAL.

RESULTS

PRAL in quintiles was negatively associated with FFM_BMI in men (n = 6350, p < 0.001) and women (n = 7989, p < 0.001), with quintile 5 vs 1 differences of -1.5% and -3.2% (both p < 0.001). PRAL was also negatively associated with BUA in women (n = 8312, p = 0.016; quintile 5 vs 1 difference -1.5%, p = 0.024). The combined hazard of hip, wrist and spine fractures (mean ± SD follow-up 17.9 ± 4.9 years) was higher with increasing quintiles of PRAL in men (610 fractures; n = 11,511; p = 0.013) and women (1583 fractures; n = 13,927; p = 0.009), with quintile 5 vs 1 hazard ratios of 1.33 (95% CI: 1.03-1.72, p = 0.029) and 1.21 (95% CI: 1.03-1.42, p = 0.022), but associations were not consistent for all fractures sites and age groups tested.

CONCLUSIONS

This study provides strong evidence, albeit observational, for a negative association between PRAL and musculoskeletal health in middle to older age men and women, and thus supports the rationale for a less acidic dietary load.

Animal, Plant, Collagen and Blended Dietary Proteins: Effects on Musculoskeletal Outcomes

Dietary protein is critical for the maintenance of musculoskeletal health, where appropriate intake (i.e., source, dose, timing) can mitigate declines in muscle and bone mass and/or function. Animal-derived protein is a potent anabolic source due to rapid digestion and absorption kinetics stimulating robust increases in muscle protein synthesis and promoting bone accretion and maintenance. However, global concerns surrounding environmental sustainability has led to an increasing interest in plant- and collagen-derived protein as alternative or adjunct dietary sources. This is despite the lower anabolic profile of plant and collagen protein due to the inferior essential amino acid profile (e.g., lower leucine content) and subordinate digestibility (versus animal). This review evaluates the efficacy of animal-, plant- and collagen-derived proteins in isolation, and as protein blends, for augmenting muscle and bone metabolism and health in the context of ageing, exercise and energy restriction.

Effect of high bicarbonate hemodialysis solution on biochemical parameters and anthropometric indices

INTRODUCTION

Protein energy wasting is an adverse consequence of renal failure, which is correlated with increased mortality and morbidity. Metabolic acidosis has a major role in the development of protein energy wasting in hemodialysis patients. Every effort that could ameliorate this catabolic state would be beneficial to stabilize body composition. The aim of this study was to investigate the possible beneficial effects of high bicarbonate dialysis on anthropometric indices and biochemical parameters of nutrition.

METHODS

Fifty-six hemodialysis patients were randomly enrolled in two groups: an intervention group that underwent hemodialysis for 6 months with high bicarbonate dialysate concentration (36 mmol/L, N = 26) and a control group that underwent hemodialysis using a bicarbonate dialysate concentration of 30 mmol/L (N = 30). Biochemical parameters of nutrition and weight, body mass index (BMI), total body water, percent body fat, and other anthropometric indices were measured at the beginning and the end of the trial.

FINDINGS

At the end of the 6 month evaluation period, plasma levels of albumin, phosphorus, K, calcium, and bicarbonate showed no significant changes. Body weight and BMI increased significantly in high bicarbonate arm but did not change significantly in the control group. Percent body fat in the arms and legs did not change in intervention arm, but decreased significantly in the controls.

DISCUSSION

The results suggest that higher bicarbonate dialysis can have beneficial effects on nutritional status and might protect against loss of fat mass.

Role of Citrate in Pathophysiology and Medical Management of Bone Diseases

Citrate is an intermediate in the "Tricarboxylic Acid Cycle" and is used by all aerobic organisms to produce usable chemical energy. It is a derivative of citric acid, a weak organic acid which can be introduced with diet since it naturally exists in a variety of fruits and vegetables, and can be consumed as a dietary supplement. The close association between this compound and bone was pointed out for the first time by Dickens in 1941, who showed that approximately 90% of the citrate bulk of the human body resides in mineralised tissues. Since then, the number of published articles has increased exponentially, and considerable progress in understanding how citrate is involved in bone metabolism has been made. This review summarises current knowledge regarding the role of citrate in the pathophysiology and medical management of bone disorders.