Acid-Base Equilibrium: Investigating the Influence of Diet and Alkaline Water on the Body

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May 24

An Overview of Acid-base Equilibrium

The many systems that make up the human body delicately maintain the bodily functions. This balance is achieved through the process of homeostasis. In essence, homeostasis maintains the equilibrium of bodily internal systems in response to the ever-changing external conditions.1 One of the numerous components of managing this sensitive system is acid-base balance. The balance is measured through pH, a logarithmic which determines the acidity and alkalinity of an aqueous solution. The pH of the plasma ranges from 7.35-7.45, which roughly matches the intracellular pH under normal physiological conditions. A neutral pH is critical for the maintenance of cellular processes, including the operation of membrane transport proteins and pH-dependent enzymes, which ultimately assure the proper functioning of metabolic pathways.

Importance of Acid-base Balance

Aberration from the neutral pH level of the body can have devastating effect. Acidemia occurs when the pH falls below 7.35, which can lead to insulin resistance, immunomodulation, and neurological impairments.2 On the other hand, alkalemia, with a pH score higher than 7.45 may result in myocardial hypoperfusion, arrhythmia, seizure, and coma.3 The primary mechanism underlying these deleterious effects is the malfunction of pH-dependent enzymes and transport proteins, as well as the detrimental impact of metabolic pathways.2 So, maintaining the body’s pH within this range is necessary to guarantee optimal performance.

Acid-base Buffering System

The body maintains acid-base homeostasis through the buffering system. The term “buffering” describes the body’s natural attempt to return the pH to its ideal range in response to any deviation. There are multiple buffering systems in the body, such as protein buffers, phosphate buffers, hemoglobin buffers etc. However, two systems provide the greatest contribution; the respiratory system, which regulates the CO2 level, and the renal system, which preserves the HCO3 level (Fig-1). In the renal system, the kidneys create HCO3, recycle it from the filtered plasma, and release it into the bloodstream. In contrast, the lungs use respiratory drive to exhaust carbon dioxide and absorb oxygen, a process that is sustained by chemosensitive brain circuitry. The HCO3-/CO2 buffer system is superior to any other buffer system due to its ability to rapidly neutralize the pH. This system’s success depends on the body’s capacity to continue releasing CO2 freely in reaction to any imbalance.4

Fig-1: Overview of acid base homeostasis

pH Value in Different Organ System

While the pH of the extracellular solution is always maintained in the range of 7.35-7.45, the value of pH fluctuates within the body’s internal secretion. There is significant variation of pH among different bodily composition. This variation can be attributed to the secretions from various systems having unique composition for specific biological functions. Figure-2 provides a quick summary of the pH values of several organic systems and secretions.5

Fig-2: (a) overview of the pH value of different bodily secretion, (b) graphical representation of different pH range of different organ systems, (c) pH variation in the digestive tracts

Acid-base Balance and Diet

Among the many factors which influence the body’s pH, dietary habits have emerged as a crucial one. The diet of prehistoric hunter-gatherers has long since been discarded by humans, and the pH and net acid load of the human diet have significantly changed. 6  A study examined the value of net endogenous acid production (NEAP) between our ancestral preagricultural diet and the modern diet and discovered a notable change from negative to positive NEAP in the present era, indicating an increase in acid yield. One of the main causes found was the substitution of our ancestral diet’s high bicarbonate-yielding food plants with cereal grains and a high-energy, low-nutrient modern diet. This cereal-based diet does not contribute to net-base production. 7 The net base is produced by the consumption of different organic ions. This value is estimated by the amount of bicarbonate ions generated by the food substances and subtracting the value from the sulfuric acid and other organic acids. The net bicarbonate production of a diet can also be calculated by NEAP of the food substances. Moreover, the ratio of potassium (K+) to sodium (Na+) in the diet has significantly shifted from the ancestral 10 to 1 to the modern 1 to 3 respectively. Bicarbonate (HCO3), magnesium (Mg2+), dietary fibre, saturated fat, and simple sugar consumption level have also reduced, and chloride (Cl) levels have increased. 8  The shift of the dietary habit occurred mostly after the industrial revolution. This rapid dietary change has been linked to the “diseases of civilization,” including high rates of myocardial infarction, dyslipidemia, essential hypertension, chronic obstructive pulmonary disease, type 2 diabetes mellitus, obesity, and colon cancer. Moreover, the dietary changes outpaced the adaptation process of our genetic system.9 Hunter-gatherer (HG) societies, who even now rigidly follow a primitive diet, had a far lower incidence of these disorders. The higher mortality of the HGs was mostly due to the high rate of preventable infectious disease and after providing community education and antibiotics, there was significant reduction of mortality due to these diseases. Even after controlling their mortality and increasing their lifespan, they still had lower incidence of the diseases of civilization.10 A seminal work on palaeolithic nutrition examined in great detail the potential health consequences of our contemporary diet in contrast to that of our ancestors. As previously stated, they discovered a considerable change in the K+/Na+ balance, leading to a net acid yield, by significantly increasing the amount of Na+-based food added to the diet and decreasing the consumption of K+-based fruits and vegetables. Table-1 presents a comparison of the nutritional content of an ancient hunter-gatherer diet with a modern western diet9

Among the many factors which influence the body’s pH, dietary habits have emerged as a crucial one. The diet of prehistoric hunter-gatherers has long since been discarded by humans, and the pH and net acid load of the human diet have significantly changed. 6  A study examined the value of net endogenous acid production (NEAP) between our ancestral preagricultural diet and the modern diet and discovered a notable change from negative to positive NEAP in the present era, indicating an increase in acid yield. One of the main causes found was the substitution of our ancestral diet’s high bicarbonate-yielding food plants with cereal grains and a high-energy, low-nutrient modern diet. This cereal-based diet does not contribute to net-base production. 7 The net base is produced by the consumption of different organic ions. This value is estimated by the amount of bicarbonate ions generated by the food substances and subtracting the value from the sulfuric acid and other organic acids. The net bicarbonate production of a diet can also be calculated by NEAP of the food substances. Moreover, the ratio of potassium (K+) to sodium (Na+) in the diet has significantly shifted from the ancestral 10 to 1 to the modern 1 to 3 respectively. Bicarbonate (HCO3), magnesium (Mg2+), dietary fibre, saturated fat, and simple sugar consumption level have also reduced, and chloride (Cl) levels have increased. 8  The shift of the dietary habit occurred mostly after the industrial revolution. This rapid dietary change has been linked to the “diseases of civilization,” including high rates of myocardial infarction, dyslipidemia, essential hypertension, chronic obstructive pulmonary disease, type 2 diabetes mellitus, obesity, and colon cancer. Moreover, the dietary changes outpaced the adaptation process of our genetic system.9 Hunter-gatherer (HG) societies, who even now rigidly follow a primitive diet, had a far lower incidence of these disorders. The higher mortality of the HGs was mostly due to the high rate of preventable infectious disease and after providing community education and antibiotics, there was significant reduction of mortality due to these diseases. Even after controlling their mortality and increasing their lifespan, they still had lower incidence of the diseases of civilization.10 A seminal work on palaeolithic nutrition examined in great detail the potential health consequences of our contemporary diet in contrast to that of our ancestors. As previously stated, they discovered a considerable change in the K+/Na+ balance, leading to a net acid yield, by significantly increasing the amount of Na+-based food added to the diet and decreasing the consumption of K+-based fruits and vegetables. Table-1 presents a comparison of the nutritional content of an ancient hunter-gatherer diet with a modern western diet9

Table 1: Qualitative difference between Hunter-gatherer diet habit and contemporary western diet9

This acidic dietary change is problematic when we consider the body’s inherent tendency towards acidification as it ages and there is progressive decline of renal function. The combined effect of an acidic diet and renal impairment augments the likelihood of developing metabolic acidosis and, as a result, additional adverse effects.11 Moreover, the introduction of low-carbohydrate, high-protein foods, along with their ensuing acid load, leads to additional modifications in urinary chemistry. Urinary magnesium, citrate, and pH levels diminish, while calcium, undissociated uric acid, and phosphate levels increase. All of these factors contribute to an increased risk of developing kidney stones.12 Another broad classification of foods is possible based on their potential renal acid loading (PRALs). This method developed by Remer and Manz (1995) estimates the net acid yield indirectly by calculating the difference between sum of remaining urinary anions namely, chloride (Cl), phosphorous (PO4), sulfate (SO4) and organic acids (non-bicarbonate anions) and minus the sum of mineral cations including sodium (Na+), Potassium (K+), Calcium(Ca+) and Magnesium (Mg+).13 Food items such as grain products, meats, dairy, fish, and beverages low in phosphorus and deficient in alkali (pale beers, cacao) contain significant amounts of acid. In contrast, negative acid load is observed in vegetables, fruit juices, potatoes, and alkali-rich, low-phosphorus beverages (mineral soda water). A succinct synopsis of the various PRALs is presented in Table-2.8

Table-2: Different food groups and food with associated PRAL8

Role of minerals in acid base balance

Among the different minerals, calcium plays a substantial role maintaining the acid base balance in the form of phosphate and carbonate salts. When acid loads occur the calcium phosphate and calcium salts are discharged into the bloodstream to preserve the acid-base balance. According to one estimate, the daily urinary calcium loss over a twenty-year period is approximately 480 grams, which is equivalent to nearly half of the calcium skeletal mass.14 The intestinal absorption of bone minerals lost in the urinary pathway is often insufficient to fully replenish the nutrients lost. This additional loss can contribute to the development of osteoporosis. Serum 1,25(OH)2D level is the active form of vitamin D. Serum 1,25(OH)2D value greater than or equal to 80 nmol/L is sufficient for intestinal absorption of calcium, magnesium, and phosphate when required.15 However, a substantial proportion of the global populace, an estimated 15.7% according to one study, suffers from some form of vitamin D deficiency.16 Additionally, minerals such as magnesium and potassium are also necessary for pH balance maintenance; and a diet deficient in these minerals are considered acidogenic, which can further disrupt acid base homeostasis. Thus, a multimineral rich diet and multimineral supplements can also have a role in increasing pH.17

Fig-1: Electrochemical preparation of alkaline water

Alkaline water is defined as water with a pH level higher than the neutral pH of regular water. It contains several minerals that have alkaline qualities and a negative oxidation reduction potential. Alkaline water can be produced by employing several methods such as electrolysis, ultra-sonication, irradiation, impact, or treatment with particular minerals.18 While the health benefits of alkaline water are limited; its application has demonstrated encouraging outcomes. Here are a few examples:

Alkaline water has been found to have various benefits, including treating reflux disease, antioxidant activity, anti-aging property, and antibacterial activity. Studies have shown that natural alkaline water can denature human pepsin, acting as buffering agents. In a study, alkaline water was found to be effective in treating reflux diseases. 19

Koufman and Johnston20 examined the impact of alkaline water on the management of Gastroesophageal reflux disease (GERD). The researchers determined that alkaline water’s ability to rapidly neutralize and permanently suppress pepsin makes it a promising treatment for GERD.

In another study, researchers from Japan investigated the effect of alkaline electrolyzed water for multiple health problems and found the participants who consumed alkaline water had significant improvement in their sleep pattern and potentially greater normalization of intestinal integrity.21

Another study conducted to evaluate the efficacy in absorption of drug in Alkaline Electrolyzed Water (AEW), purified water, and drinking water respectively. The results showed significant antioxidant activity and improved biological absorbance after consuming AEW water which potentially can improve the drug’s efficacy. However, drinking water (DW) did not show any significant increase in drugs antibacterial activity. 22
Alkaline water has been found to be a powerful strength booster for sports men, enhancing hydration, improving acid-base balance, and anaerobic exercise performance. Studies have shown that drinking alkaline water can prevent exercise-induced metabolic acidosis, improve wound healing, and reduce the risk of diseases like heart disease, toxins, skin disease, allergies, diabetes treatment, and acidosis. In a study, sixteen well-trained sports athletes were tested for the effect of alkaline water on their anaerobic performance. The results showed a significant increase in mean power when compared to the control group, which received table water.23

Studies also found that high-pH water reduced high-shear viscosity by an average of 6.30% compared to 3.36% with standard purified water.24 Due to being a non-Newtonian fluid, the viscosity of blood is calculated with shear rate. The higher the shear rate the more viscous the blood and the higher the risk of developing thrombus.25Additionally, ionized water has been used in various clinical trials on human sports volunteers in Japan, promoting optimal physical performance, and protecting DNA from oxidative damage. 24

Conclusion

Maintaining physiological function and preventing ailments require the delicate acid-base equilibrium of the body. For the long-term maintenance of the homeostatic system, a balanced diet consisting of sufficient nutrients, including optimal minerals, is of the utmost importance. In certain circumstances, alkaline pH may play an additional function in optimizing the pH of the body; however, additional research is necessary.

Authors of this article
  1. Dr. Faisal Chowdhury, MBBS, Chittagong Medical College
  2. Professor Syed Mahbubul Alam, MBBS (DMC) & FCPS (Surgery), Former Principal Dhaka Medical College &Former Head of the Department (Surgery), Sir Salimullah Medical College Dhaka, & is the Editor-In-Chief of The Coronal.
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