Chapter 8: Minerals
Nature of Minerals in Human Nutrition
Classes of minerals
Major minerals
Intake of more than 100 mg/day
Calcium, phosphorus, sodium, potassium, magnesium, chloride,
and sulfur
Trace minerals
Intake of less than 100 mg/day
18 elements
Functions of minerals
Building tissue, influencing metabolic processes
Mineral metabolism
Digestion: minerals do not require much digestion
Absorption: absorbed in ionic forms; rate determined by food form,
body need, tissue health
Transport: enter through portal circulation, bound to proteins
Tissue uptake: controlled by hormones
Occurrence in the body: basic forms are free ions and covalently bound
Major Minerals
Calcium
Functions: bone and tooth formation, blood clotting, muscle and nerve
action, metabolic reactions
Requirements: A varied diet provides enough calcium to meet DRI
Deficiency: insufficiency during growth years increases the risk for
bone deformities
Toxicity: unlikely from food sources; excessive supplementation is
associated with calcification of soft tissue and decreased bioavailability
of several essential nutrients
Food sources: milk and milk products
, Phosphorus
Functions: bone and tooth formation, energy metabolism, acid-base
balance
Requirements: A varied diet provides enough phosphate to meet DRI
Deficiency: occurs with excessive intake of antacids containing
aluminum hydroxide.
Toxicity: unlikely from food sources; if phosphorus intake is higher than
calcium intake for a long period, bone resorption may occur
Food sources: high-protein foods, plant seeds
Sodium
Functions: water balance, muscle action, nutrient absorption
Requirements: needs vary depending on growth stage, sweat loss, and
medical conditions
Deficiency: rare, except with heavy sweating
Toxicity: increased blood pressure in salt sensitive individuals,
hypernatremia
Food sources: table salt, animal products, carrots, beets, leafy greens,
and celery
Potassium
Functions: water balance, metabolic reactions, muscle action, insulin
release, and blood pressure
Requirements: average intake adequate for women, but less than the
established AI of 3.4 g/day for men
Deficiency: rare from dietary intake, more likely from vomiting,
diarrhea, malnutrition, or surgery
Toxicity: excessive oral or IV intake causes hyperkalemia
Food sources: oranges, bananas, potatoes, leafy green vegetables,
fish, whole grains, legumes, seeds, and milk products
Chloride
Functions: digestion and respiration
