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๐Ÿฅ—Intro to Nutrition Unit 3 Review

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3.3 Major Minerals

๐Ÿฅ—Intro to Nutrition
Unit 3 Review

3.3 Major Minerals

Written by the Fiveable Content Team โ€ข Last updated September 2025
Written by the Fiveable Content Team โ€ข Last updated September 2025
๐Ÿฅ—Intro to Nutrition
Unit & Topic Study Guides

Major minerals play crucial roles in our bodies, from building bones to regulating heartbeats. These seven powerhousesโ€”calcium, phosphorus, magnesium, sodium, potassium, chloride, and sulfurโ€”are essential for countless bodily functions and maintaining overall health.

Understanding how our bodies absorb, transport, and use these minerals is key. From rich food sources to potential imbalances, knowing the ins and outs of major minerals helps us make informed choices about our diets and health.

Major Minerals Overview

Functions of seven major minerals

  • Calcium builds bones and teeth, enables muscle contraction, facilitates blood clotting, transmits nerve signals (neurotransmitter release)
  • Phosphorus strengthens bones and teeth, fuels energy metabolism (ATP formation), maintains acid-base balance (phosphate buffer system)
  • Magnesium acts as enzyme cofactor (300+ enzymatic reactions), supports muscle and nerve function (membrane stability), promotes bone health (hydroxyapatite formation)
  • Sodium regulates fluid balance (osmotic pressure), conducts nerve impulses (action potentials), enables muscle contraction (sodium-potassium pump)
  • Potassium maintains fluid balance (intracellular), regulates heart rhythm (cardiac muscle function), supports muscle and nerve function (membrane potential)
  • Chloride balances fluids (extracellular), produces stomach acid (hydrochloric acid), facilitates chloride shift in red blood cells (oxygen transport)
  • Sulfur maintains protein structure (disulfide bonds), aids detoxification processes (liver enzymes), synthesizes important molecules (glutathione, taurine)

Absorption and transport of minerals

  • Absorption
    • Small intestine primary site absorbs most minerals through specialized processes
    • Active transport mechanisms move minerals against concentration gradients (calcium, iron)
    • Passive diffusion allows some minerals to move along concentration gradients (sodium, chloride)
  • Transport
    • Blood circulation carries minerals throughout the body
    • Protein carriers bind and transport specific minerals (transferrin for iron, ceruloplasmin for copper)
    • Ion channels facilitate movement of electrolytes across cell membranes (sodium, potassium)
  • Storage
    • Bones store large amounts of calcium, phosphorus, and magnesium (99% of body calcium)
    • Soft tissues retain potassium and sulfur (muscle cells, liver)
    • Extracellular fluids hold sodium and chloride (blood plasma, interstitial fluid)

Sources and bioavailability of minerals

  • Calcium
    • Rich sources include dairy products, leafy greens, fortified foods (plant-based milks)
    • Vitamin D enhances absorption, phytates and oxalates inhibit (spinach, rhubarb)
  • Phosphorus
    • Abundant in meat, dairy, nuts, legumes (chicken, lentils)
    • Calcium intake and vitamin D status influence absorption
  • Magnesium
    • Found in nuts, seeds, whole grains, leafy greens (almonds, pumpkin seeds)
    • High fat diets and excessive alcohol consumption decrease absorption
  • Sodium
    • Common in table salt, processed foods, dairy products (canned soups, cheese)
    • Potassium intake and sweating affect sodium balance
  • Potassium
    • Plentiful in fruits, vegetables, legumes (bananas, sweet potatoes)
    • Diuretics and high sodium intake impact potassium levels
  • Chloride
    • Present in table salt, seaweed, olives (soy sauce, pickles)
    • Often absorbed alongside sodium due to their chemical relationship
  • Sulfur
    • Found in protein-rich foods like meat, eggs, legumes (chicken, soybeans)
    • Protein intake directly influences sulfur availability

Consequences of mineral imbalances

  • Calcium
    • Deficiency leads to osteoporosis, muscle cramps, increased hypertension risk
    • Toxicity causes kidney stones, hypercalcemia (elevated blood calcium)
  • Phosphorus
    • Deficiency results in weakness, bone pain, increased susceptibility to infections
    • Toxicity reduces calcium absorption, potentially damages kidneys
  • Magnesium
    • Deficiency causes muscle weakness, arrhythmias, increased osteoporosis risk
    • Toxicity induces nausea, hypotension, respiratory depression (rare from dietary sources)
  • Sodium
    • Deficiency leads to hyponatremia, muscle cramps, confusion, seizures
    • Toxicity increases hypertension risk, causes edema, strains cardiovascular system
  • Potassium
    • Deficiency results in hypokalemia, muscle weakness, arrhythmias
    • Toxicity causes hyperkalemia, heart palpitations, paralysis (life-threatening)
  • Chloride
    • Deficiency leads to hypochloremic metabolic alkalosis (blood pH imbalance)
    • Toxicity causes hyperchloremic metabolic acidosis (lowered blood pH)
  • Sulfur
    • Deficiency rarely occurs, may affect protein synthesis and structure
    • Toxicity not typically a concern from dietary sources, body regulates excretion