Role of Phosphorus in Human Health

Introduction Second Most Abundant mineral. This mineral lays the foundation of a strong skeletal structure to ensure health and functional living. One of the recent discoveries of phosphorous also link it to heart health, meaning that with a proper intake, you can better protect yourself from a range of cardiovascular diseases.

Phosphorous P At. No. 15 Atomic Mass: 30.77

PHOSPHORUS

Learning Objectives Total body contents and Distribution Important functions Dietary sources Daily Requirements Absorption and excretion How its level is maintained Deficiency diseases

Body Distribution in adult human Phosphorus Body Distribution in adult human Total Content 0.7-1.0 kg 80 % is bones and teeth as Hydroxyapatite which is an insoluble crystalline mineral 20 % is in Soft Tissues and ECF and blood

Normal Plasma contain inorganic Phosphate 3.0-4.5 mg/dl in adults 4.5-6.5 mg/dl in infant Plasma Phosphate exists in Three forms Free inorganic PO--4 40 % Phosphate complexed with cations ( Na, K , Ca ) 50 % Phosphate bound with proteins 10 %

Function 1. Along with Calcium is required for mineralization of bones and teeth

Functions 2. Component of many compounds involved in many metabolic reactions. 3. Sugar – PO4 linkage in DNA and RNA 4. Phospholipids  Transport of fat in blood Phospholipids  cell membrane control transport of substances into and out of cell

Function 5. Is required for the formation of various bio organic substances like : Coenzymes NAD, NADP, FAD, FMN, TPP, PP Nucleotides ( UDP, CDP , AMP , ADP, GTP ) Second Messengers (cAMP and c GMP)

Functions 6. Phosphorylation Necessary for glucose absorption from intestine Glucose uptake by individual cells Resorption of glucose by kidney

Functions Monosaccharides are Phosphorylated several times during metabolic break down to yield energy. Involved in storage and release of Energy through high energy phosphate bond of ATP and ADP.

Functions 7 Essential part of body’s delicate buffer system 8. Many B vitamins becomes active only when combine with phosphate.

Important Sources of Phosphorus Widely distributed in both animal and plant foods. Food items like Meat, Fish , Eggs and Milk and Milk products. Nuts, legumes, rice, potatoes, broccoli and peas are amongst Phosphorus rich food and Soft drinks specially Coke and Pepsi

Dietary Source Present in all foods, Dietary deficiency is therefore unknown. Distribution is similar to Ca++ Adequate, intake of one ensures that of the other Best sources (Milk and milk products) Lean meat is also a good source.

Recommended Dietary Allowance Infants Up to 6 months 240 mg 6 m – 1.0 year 360 mg Children 1 – 3 800 mg 4 – 6 800 mg 7 – 10 800 mg

Recommended Dietary Allowance Adults (Male/Females) 11 – 14 1200 mg 15 – 18 1200 mg 19 – 22 800 mg 23 – 50 800 mg 51+ 800 mg Pregnant and lactating women should take an additional 400 mg.

Digestion Phosphorus plays an important role in facilitating effective digestion in the human body. It does this by stimulating the digestion of riboflavin and niacin in an efficient way. These two vitamins are also essential for human health, so any way that their uptake can be maximized is a good thing. These two varieties of vitamin B are responsible for everything from energy metabolism to neurological and emotional response systems.

Absorption and Metabolism Most of phosphorus in food is in combined form, absorption requires splitting off of PO4 by intestinal enzymes (Phosphatases). Organic phosphate in food is hydrolyzed in GIT by Pancreatic & intestinal enzymes. Inorganic phosphorus is released and absorbed Normally about 70% of dietary P is absorbed (For calcium 10 – 30%).

Absorption and Metabolism Absorption and Excretion depend upon Ca : P ratio in diet. Excess of either one causes, an increased excretion of other. Mid jejunum is the main site of absorption for free PO4 . In ileum absorption occurs via active process.

Absorption and Metabolism Its absorption decreases during period of increased utilization of carbohydrate

Absorption and Metabolism Factors affecting Ca++ absorption also apply to Phosphorus, like enhancement by Vit D and PTH and inhibition by binding agents i.e. Iron and Aluminium.

Excretion Phosphate level is regulated by urinary excretion 3.5 mg / dl is the renal thresh hold 500 mg / day is excreted in urine

EXCRETION P is mainly excreted in Urine (60%) and 40 % in feces. Fecal excretion is increased when intake is increased. Intestinal absorption is decreased then In Hyperparathyroidism excretion is more. PTH effect on PO4

Excretion General factors affecting intestinal absorption Plasma concentration and Hydrolysis of PO4 esters by phosphatases in the kidney. Decrease Ca++ intake will increase urinary PO4 excretion

Ratio of P : Ca, Ideal 1 : 1 Specially during the period of rapid growth (childhood), pregnancy and lactation. Ratio in other age groups if different, have no serious adverse effect

In Infants Care should be exercised as kidneys can’t handle high phosphate load. For Prevention of hypocalcemic tetany Ca : P ratio be 1.5 : 1 Ratio should be reduced to 1:1 by age 1 yr

Hypo-Phosphatemia Diminished Supply: Starvation Malnutrition Vit D – Deficiency Increased excretion / loss Hyperparathyroidism Hyper thyroidism Renal defects

Hypo-Phosphatemia Intracellular shift of phosphorus Glucose induced Insulin induced Respiratory alkalosis Electrolytes administration Hypercalcaemia Hypomagnesimia

Deficiency Symptoms of Phosphorus The most significant deficiency symptoms of phosphorus include weak bones and discomfort in various body joints. Phosphorus acts in a similar way as calcium does in providing strength to bones, so a deficiency of phosphorus may lead to weakness, tooth decay, rickets and other related bone problems. People may also experience a loss of appetite and diminished body stamina to perform routine activities.

Deficiency Symptoms of Phosphorus A deficiency of phosphorus may also invite numbness, anxiety, tremors, weight loss and stunted growth. It is an essential part of our diet, particularly as children, when the most growth and development occurs, and needs to happen regularly and with a full backing of the proper nutrients.

Hyper-Phosphatemia Endocrine disease 2. Renal Diseases Increased growth hormones (acromegaly) Hypo parathyroidism low calcium Pseudo hypo parathyroidism 2. Renal Diseases Chronic renal insufficiency Acute renal failure

Hyper-Phosphatemia 3. Catabolic states Excess intake or Absorption Stress or injury Chemotherapy for malignant disease Excess intake or Absorption Laxatives or Enemas containing phosphate Hyper vitaminosis – D

Clinical Importance

Regulation of Plasma Phosphorus Like Calcium PTH and Vitamin D regulates it in blood. Vit D maintains the normal Po4 level in hypophoshtemic state. Low plasma PO4 level stimulates the renal enzyme hydoxylase which enhances the conversion of Calcidiol to Calcitriol. It effects the intestine to absorb more P, on bones to release more P and on kidneys to reduce excretion.

These benefits of phosphorous make it an important constituent of our diet. Healthy bone formation Improved digestion Regulated excretion Protein formation Hormonal balance Improved energy extraction Cellular repair Optimized chemical reactions and Proper nutrient utilization.

Beyond the uptake of vitamins and minerals, phosphorous directly clears up digestion and constipation diarrhea, and generally tones up the digestive system for regular, healthy bowel movements. This increases the health of the digestive system, as well as that of the kidneys, since the toxins are being eliminated from the body, rather than recycling through the kidneys and stressing that system.

Thanks