Introduction to Minerals
Minerals are inorganic substances required for enzymatic function, electrolyte balance, structural integrity, and countless metabolic processes. Unlike vitamins, minerals are not destroyed by heat or storage, though their bioavailability may vary based on food matrix and preparation.
Essential minerals include major minerals (calcium, phosphorus, potassium, sulfur, sodium, chloride, magnesium) and trace minerals (iron, zinc, copper, manganese, iodine, selenium, cobalt, fluoride).
Macrominerals: The Structural and Functional Foundation
Calcium and Phosphorus
Work together to form the mineral matrix of bones and teeth. Calcium also plays roles in muscle contraction, nerve transmission, and blood coagulation. Found in dairy products, fortified plant-based alternatives, leafy greens, and legumes.
Magnesium
Required for ATP synthesis, enzyme function, muscle relaxation, and neurological health. Sources include green leafy vegetables, nuts, seeds, whole grains, and legumes.
Potassium and Sodium
Critical electrolytes maintaining fluid balance, nerve impulse transmission, and muscle contraction. Potassium is abundant in fruits, vegetables, and legumes. Sodium's dietary sources and appropriate intake levels remain subjects of ongoing nutritional science.
Trace Minerals: Essential in Small Quantities
Iron
Essential for oxygen transport in hemoglobin and myoglobin. Exists in two dietary forms: heme iron (more bioavailable from animal sources) and non-heme iron (from plant sources, with absorption enhanced by vitamin C). Important for energy production and neurological function.
Zinc
Required for immune function, protein synthesis, wound healing, and taste perception. Found in oysters, beef, poultry, legumes, nuts, and seeds. Bioavailability varies among sources.
Copper
Works with iron in oxygen transport and participates in collagen synthesis and antioxidant defense. Sources include nuts, seeds, legumes, and whole grains.
Selenium
Integral component of selenoproteins involved in antioxidant defense and thyroid hormone metabolism. Brazil nuts, seafood, and whole grains are primary sources.
Iodine
Essential for thyroid hormone synthesis, regulating metabolism and development. Seafood, seaweed, and dairy products are primary sources; iodized salt is a common fortification strategy.
Mineral Balance and Absorption
Minerals often function in balance with one another. Calcium absorption is enhanced by adequate vitamin D; iron absorption is increased by vitamin C and certain amino acids. Plant-based minerals may have lower bioavailability due to compounds like phytates and oxalates in some foods.
Individual factors affecting mineral status include age, gender, digestive health, medication interactions, and genetic variation.
Dietary Diversity and Mineral Adequacy
A varied diet incorporating vegetables, fruits, whole grains, legumes, nuts, seeds, and appropriate protein sources typically provides adequate mineral intake for most populations. Geographic variation in soil mineral content can affect regional patterns of mineral availability.
Population Considerations
Different life stages and population groups have varying mineral needs. Males across adulthood, for instance, have consistent iron requirements (distinct from menstruating females), while calcium and other mineral needs may shift with age.