TABLE OF CONTENTS

Title Page    –         –         –         –         –         –         –         –         –         i

Certification           –         –         –         –         –         –         –         –         ii

Dedication             –         –         –         –         –         –         –         –         iii

Acknowledgements         –         –         –         –         –         –         –         iv

Table of Contents            –         –         –         –         –         –         –         v

CHAPTER ONE 

1.0     Introduction           –         –         –         –         –         –         –         1

CHAPTER TWO

2.1     Source of Phosphorus                –         –         –         –         –         4

2.1.1  Food Source          –         –         –         –         –         –         –         4

2.1.2  Dietary Supplements       –         –         –         –         –         –         5

2.2     Recommended Intakes of Phosphorus –         –         –         –         6

2.3     Health Risk from Excessive Phosphorus       –         –         –         8

2.4     Importance of Phosphorus in prevention of chronic disease –      10

2.4.1  Chronic Kidney Disease            –         –         –         –         –         10

2.4.2  Cardiovascular Disease              –         –         –         –         –         11

CHAPTER THREE: PHOSPHORUS DEFICIENCY

3.1     Causes of Phosphorus Deficiency        –         –         –         –         14

3.2     Symptoms of Phosphorus Deficiency            –         –         –         15

3.3     Effect of Phosphorus Deficiency         –         –         –         –         16

CHAPTER FOUR: SUMMARY AND CONCLUSION

4.1     Summary               –         –         –         –         –         –         –         18

4.2     Conclusion            –         –         –         –         –         –         –         19

References

CHAPTER ONE

INTRODUCTION

Phosphorus, an essential mineral, is naturally present in many foods and available as a dietary supplement. Phosphorus is a component of bones, teeth, DNA, and RNA (Heaney et al., 2012). In the form of phospholipids, phosphorus is also a component of cell membrane structure and of the body’s key energy source, ATP. Many proteins and sugars in the body are phosphorylated. In addition, phosphorus plays key roles in regulation of gene transcription, activation of enzymes, maintenance of normal pH in extracellular fluid, and intracellular energy storage. In humans, phosphorus makes up about 1 to 1.4% of fat-free mass. Of this amount, 85% is in bones and teeth, and the other 15% is distributed throughout the blood and soft tissues.

Many different types of foods contain phosphorus, mainly in the form of phosphates and phosphate esters.

However, phosphorus in seeds and unleavened breads is in the form of phytic acid, the storage form of phosphorus. Because human intestines lack the phytase enzyme, much phosphorus in this form is unavailable for absorption. Phosphorus undergoes passive absorption in the small intestine, although some is absorbed by active transport.

Phosphorus and calcium are interrelated because hormones, such as vitamin D and parathyroid hormone (PTH), regulate the metabolism of both minerals. In addition, phosphorus and calcium make up hydroxyapatite, the main structural component in bones and tooth enamel. The combination of high phosphorus intakes with low calcium intakes increases serum PTH levels, but evidence is mixed on whether the increased hormone levels decrease bone mineral density.

The kidneys, bones, and intestines regulate phosphorus homeostasis, which requires maintenance of urinary losses at equivalent levels to net phosphorus absorption and ensuring that equal amounts of phosphorus are deposited and resorbed from bone. Several hormones, including estrogen and adrenaline, also affect phosphorus homeostasis. When kidney function declines, as in chronic kidney failure, the body cannot excrete phosphate efficiently, and serum levels rise.

Although phosphorus status is not typically assessed, phosphate can be measured in both serum and plasma. In adults, normal phosphate concentration in serum or plasma is 2.5 to 4.5 mg/dL (0.81 to 1.45 mmol/L). Hypophosphatemia is defined as serum phosphate concentrations lower than the low end of the normal range, whereas a concentration higher than the high end of the range indicates hyperphosphatemia. However, plasma and serum phosphate levels do not necessarily reflect whole-body phosphorus content.