Phosphorus acid-base balance

Factors that can predispose patients to developing metabolic bone disease include deficiencies of phosphorus, calcium, and vitamin D vitamin D and/or aluminum toxicity amino acids and hypertonic dextrose infusions chronic metabolic acidosis corticosteroid therapy and lack of mobility.35,39 Calcium deficiency (due to decreased intake or increased urinary excretion) is one of the major causes of metabolic bone disease in patients receiving PN. Provide adequate calcium and phosphate with PN to improve bone mineralization and help to prevent metabolic bone disease. Administration of amino acids and chronic metabolic acidosis also appear to play an important role. Provide adequate amounts of acetate in PN admixtures to maintain acid-base balance. 

Minerals include sodium, potassium, calcium, phosphorus, magnesium, manganese, sulphur, cobalt and chlorine trace minerals include iron, zinc, copper, selenium, iodine, fluorine and chromium. Their roles may be generalised within the areas of providing structure in the formation of bones and teeth, maintenance of normal heart rhythm, muscle contractility, neural conductivity, acid-base balance and the regulation of cellular metabolism through their activ-ity/structural associations with enzymes and hormones. The daily requirements of minerals can be obtained from a well-balanced diet. 

Lewis, N. M Marcus, M. S., Behling, A- K., and Creger, J. L. (1989). Calcium supplements and milk Effects on acid-base balance and on retention of calcium, magnesium, and phosphorus. Am.Cfin. Wulr. 49,527-533. 

Phosphorus has more known functions in the animal body than any other mineral element. Together with calcium, phosphorus plays a major role in the formation of bones and teeth, as well as eggshells. It is a component of nucleic acids, which control cell multiplication, growth and differentiation. In combination with other elements, phosphorus has a role in the maintenance of cellular osmotic pressure and the acid-base balance. Energy transfer processes in all living cells involve interconversion of the phosphate-containing nucleotides, adenosine diphosphate (ADP) and ATP, and thus phosphorus participates in all biological events. Other roles include its presence in phospholipids, where it functions in cell-wall structure, fatty acid transport and protein as well as amino acid formation. 

Phosphorus Milk, cheese, meat, fish, grains, legumes, nuts Enzyme component, acid-base balance, bone and tooth formation Weakness, calcium loss, weak bones... 

Elements such as sodium, potassium and chlorine have primarily an electrochemical or physiological function and are concerned with the maintenance of acid-base balance, membrane permeability and the osmotic control of water distribution within the body. Some elements have a structural role, for example calcium and phosphorus are essential components of the skeleton and sulphur is necessary for the synthesis of structural proteins. Finally, certain elements have a regulatory function in controlling cell replication and differentiation zinc acts in this way by influencing the transcription process, in which genetic information in the nucleotide sequence of DNA is transferred to that of an RNA molecule. It is not uncommon for an element to have a number of different roles for example, magnesium functions catalytically, electrochemically and structurally. 

The functions of the mineral elements are many and various. Some act as essential structural components, others fulfil a catalytic or regulatory role, while some do both. Calcium and phosphorus are notable examples. Most proteins contain sulphur, some contain phosphorus, some iron and one, thyroglobulin, contains iodine. Other elements, notably sodium, potassium, chlorine and phosphorus, play an essential part in the maintenance of osmotic and acid/base balance and many ions are components of enzyme systems. 

Most of the calcium that is lost from the body is excreted in the faeces, this being mainly unabsorbed dietary calcium. However, the digestive secretions all contain small amounts of calcium, and individuals on a calcium-free diet continue to excrete faecal calcium. The normal daily excretion is of the order of 0-1-0-3 g (2-5-7-5 mmol). The quantity of phosphorus excreted daily varies with the dietary intake. As with calcium an appreciable proportion of ingested phosphorus remains unabsorbed and is eliminated in the faeces. Phosphorus is also excreted in the urine, almost entirely in the form of orthophosphates (e.g. NaH2P04 and Na2HP04). Their role in the regulation of acid-base balance is discussed on page 395. Urinary excretion of phosphate is increased in hyperparathyroidism. 

This refers to the potential acidity or alkalinity of food, which depends upon the reaction they yield after being broken down (metabolized) in the body, thus releasing their mineral elements. These minerals function in maintaining the acid-base balance in the body. Acid-forming elements are chlorine, phosphorus, and sulfur, while base (alkaline)- forming elements are calcium, sodium, potassium, and magnesium. Foods can be classified as acid foods, alkaline (basic) foods, or neutral foods according to their mineral content... 

Sodium, potassium and chloride are the primary dietary ions that influence the electrolytic balance and acid-base status, and the proper dietary balance of sodium, potassium and chloride is necessary for growth, bone development, eggshell quality and AA utilization. Potassium is the third most abundant mineral in the body after calcium and phosphorus, and is the most abundant mineral in muscle tissue. It is involved in electrolyte balance and neuromuscular function. The content of potassium in poultry diets is usually adequate. Chloride is present in gastric juice and chlorine is part of the HC1 molecule which assists in the breakdown of feed in the proventriculus. Sodium is essential for nerve membrane stimulation and ionic transport across cell membranes. Signs of sodium, potassium or chloride deficiency include reduced appetite, poor growth, dehydration and increased mortality. 

Carbon dioxide is an important component of the body and would not be expected to have a chronic toxicity. Flowever, long-term exposures to levels as low as 0.5-1%, while being generally well tolerated, can alter the acid base and calcium-phosphorus balance resulting in metabolic acidosis and increased calcium deposits in soft tissues. Long-term exposures in the range of 1-2% can stress the adrenal cortex because of constant respiratory stimuli and this level of exposure is considered dangerous after several hours. Exposure to 2% for several hours produces... 

Maintenance of fluid volume, osmolarity, electrolyte balance, and acid-base status are aU regulated in large part by the kidney. Homeostasis of sodium, potassium, chloride, calcium, magnesium, and phosphorus is altered due to changes in urinary excretion that occur in patients with impaired kidney function. A comprehensive discussion... 

There are three major tubular functions to be recognised (1) salt and water balance, (2) potassium and acid/base homeostasis, and (3) calcium and phosphorus balance. 

---