Minerals in the Body Overview

Minerals are inorganic elements vital for life, comprising approximately 4% of body weight. They play critical roles in various functions like maintaining fluid balance, building bones and teeth, regulating body processes, and acting as cofactors for enzymes.

Major minerals, also known as macrominerals, are required in larger quantities by the body. These include calcium (Ca), phosphorus (P), magnesium (Mg), sodium (Na), potassium (K), chloride (Cl), and sulfur (S).

Calcium is crucial for strong bones and teeth, nerve transmission, muscle contraction, blood clotting, enzyme regulation, and maintaining cell membrane function.

Calcium absorption is affected by factors like vitamin D, parathyroid hormone (PTH), and calcitonin, which regulate calcium levels in the blood, bones, kidneys, and intestines.

Calcium deficiency can lead to muscle cramps, weakened bones (osteopenia and osteoporosis), and other health issues. Adequate calcium intake is essential, particularly for children, adolescents, and older adults.

A primary transporter of phosphorus in the kidneys, responsible for reabsorbing filtered phosphate.

A transporter protein primarily located in the small intestine, responsible for absorbing phosphorus from the gut. It's regulated by calcitriol.

A phosphorus transporter primarily found in the kidneys and potentially related to growth.

Parathyroid hormone (PTH), Fibroblast growth factor 23 (FGF23), and calcitriol (vitamin D) are key hormones involved in regulating phosphorus levels in the body.

Phospholipase C breaks down phospholipids during digestion, releasing inorganic phosphorus.

Alkaline phosphatase, an enzyme found in the intestinal brush border, hydrolyzes phosphorus bound to organic molecules, making it available for absorption.

The majority of dietary phosphorus is absorbed through passive diffusion along the small intestine, particularly in the ileum.

Phosphorus absorption is highest in infants and children, decreasing with age. Adults absorb around 55-80% of dietary phosphorus.

Phosphorus absorbed into the bloodstream exists in various forms: mainly as HPO42-, complexed with calcium, magnesium, sodium, and bound to proteins.

The majority of the body's phosphorus is stored in the skeleton, making it a crucial component of bone health.

The kidneys play a crucial role in regulating serum phosphorus levels, reabsorbing a significant portion of filtered phosphate.

PTH and FGF23 suppress phosphorus reabsorption in the kidneys, while calcitriol may promote it.

A high phosphorus diet in individuals with kidney problems can lead to increased phosphorus excretion, possibly due to limited reabsorption capacity.

Under normal phosphorus status, urinary phosphorus levels typically reflect the amount of phosphorus absorbed from the diet.

Phosphorus plays various crucial roles in the body, including being a main anion in cells, contributing to the skeleton, energy metabolism, second messenger signaling, phosphorylation of substrates, and maintaining acid-base balance.