PHOSPHORUS
INTRODUCTION AND NUTRITIONAL SIGNIFICANCE
Phosphorus is an essential macromineral and the second most abundant mineral in
the human body after calcium. It is a fundamental structural and functional
component of biological systems, playing a central role in energy metabolism,
skeletal integrity, cellular signaling, acid–base balance, and genetic material
structure. Due to its involvement in nearly every metabolic pathway, phosphorus is
indispensable for normal growth, development, and maintenance of physiological
functions
CHEMICAL NATURE AND FORMS OF PHOSPHORUS
Phosphorus is a non-metal element that exists in biological systems primarily in the
form of phosphate (PO₄³⁻). In nutrition, phosphorus is not present as elemental
phosphorus but as inorganic phosphate salts or organic phosphate esters.
Organic phosphorus is found in compounds such as phospholipids, nucleotides
(ATP, ADP), nucleic acids (DNA and RNA), and phosphoproteins, where it
participates in structural and regulatory roles. Inorganic phosphorus exists as free
phosphate ions and mineral salts, particularly in bone tissue in association with
calcium.
ABSORPTION, DISTRIBUTION, AND HOMEOSTASIS
Phosphorus absorption occurs mainly in the small intestine, particularly the
jejunum, through both passive diffusion and active transport mechanisms
, mediated by vitamin D. Absorption efficiency ranges from 60% to 70% and is
enhanced by adequate vitamin D intake.
Once absorbed, phosphorus is distributed throughout the body, with
approximately 85% stored in bones and teeth as hydroxyapatite, 14% in soft
tissues, and about 1% in extracellular fluids. Phosphorus homeostasis is tightly
regulated by the coordinated actions of parathyroid hormone (PTH), vitamin D, and
fibroblast growth factor-23 (FGF-23), which control intestinal absorption, renal
excretion, and bone turnover.
BIOLOGICAL FUNCTIONS OF PHOSPHORUS
Skeletal Structure and Mineralization
Phosphorus is a critical component of bone and teeth, forming calcium phosphate
crystals that provide structural strength and rigidity. Adequate phosphorus intake is
essential for proper bone mineralization, particularly during periods of rapid
growth, pregnancy, and lactation.
Energy Metabolism
Phosphorus plays a central role in energy transfer and storage. It is a key
component of adenosine triphosphate (ATP), the universal energy currency of the
cell. Phosphorylation and dephosphorylation reactions regulate metabolic
pathways such as glycolysis, oxidative phosphorylation, and signal transduction.
Cellular Structure and Function
INTRODUCTION AND NUTRITIONAL SIGNIFICANCE
Phosphorus is an essential macromineral and the second most abundant mineral in
the human body after calcium. It is a fundamental structural and functional
component of biological systems, playing a central role in energy metabolism,
skeletal integrity, cellular signaling, acid–base balance, and genetic material
structure. Due to its involvement in nearly every metabolic pathway, phosphorus is
indispensable for normal growth, development, and maintenance of physiological
functions
CHEMICAL NATURE AND FORMS OF PHOSPHORUS
Phosphorus is a non-metal element that exists in biological systems primarily in the
form of phosphate (PO₄³⁻). In nutrition, phosphorus is not present as elemental
phosphorus but as inorganic phosphate salts or organic phosphate esters.
Organic phosphorus is found in compounds such as phospholipids, nucleotides
(ATP, ADP), nucleic acids (DNA and RNA), and phosphoproteins, where it
participates in structural and regulatory roles. Inorganic phosphorus exists as free
phosphate ions and mineral salts, particularly in bone tissue in association with
calcium.
ABSORPTION, DISTRIBUTION, AND HOMEOSTASIS
Phosphorus absorption occurs mainly in the small intestine, particularly the
jejunum, through both passive diffusion and active transport mechanisms
, mediated by vitamin D. Absorption efficiency ranges from 60% to 70% and is
enhanced by adequate vitamin D intake.
Once absorbed, phosphorus is distributed throughout the body, with
approximately 85% stored in bones and teeth as hydroxyapatite, 14% in soft
tissues, and about 1% in extracellular fluids. Phosphorus homeostasis is tightly
regulated by the coordinated actions of parathyroid hormone (PTH), vitamin D, and
fibroblast growth factor-23 (FGF-23), which control intestinal absorption, renal
excretion, and bone turnover.
BIOLOGICAL FUNCTIONS OF PHOSPHORUS
Skeletal Structure and Mineralization
Phosphorus is a critical component of bone and teeth, forming calcium phosphate
crystals that provide structural strength and rigidity. Adequate phosphorus intake is
essential for proper bone mineralization, particularly during periods of rapid
growth, pregnancy, and lactation.
Energy Metabolism
Phosphorus plays a central role in energy transfer and storage. It is a key
component of adenosine triphosphate (ATP), the universal energy currency of the
cell. Phosphorylation and dephosphorylation reactions regulate metabolic
pathways such as glycolysis, oxidative phosphorylation, and signal transduction.
Cellular Structure and Function
