Minerals Overview

Minerals

Overview of Reading Material

• Materials for the unit include Dr. Sreenilayam’s lecture note on minerals dated Feb. 10, 2026.

• References utilized include Marks’ Basic Medical Biochemistry, 5th Edition, Chapters 1, 4, and 42.

• Some slides modified from presentations by Dianzheng Zhang, PhD, and Francis Jenney, PhD.

Course Content Responsibility

• Students are responsible for:

  • Review of Gene Expression

  • Post-transcriptional and Translational Regulation

  • Vitamins

Learning Objectives for Minerals

• By the end of this unit, students should be able to:

  1. Identify Major Dietary Sources: For each mineral and list storage sites in the body (where applicable).

  2. Mechanism of Uptake: Describe the uptake and transport mechanisms for each mineral discussed, including inhibitors and stimulators.

  3. Diseases Related to Mineral Levels: List diseases linked to deficiency or excess of each mineral (where applicable).

  4. Cofactors and Metabolic Functions: Identify cofactor(s) for each mineral (where applicable) and describe major metabolic roles of these cofactors or enzymes utilizing them.

  5. Iron and Oxidative Stress: Explain the connection between iron and oxidative stress.

Macro Minerals

Human Body Composition

• Average adult weight: 70 kg

  • Dried body weight: ~20 kg

  • Composition: >60% water

  • After complete combustion: ~3.5-4.0 kg

  • Inorganic matter: ~5% (minerals)

  • Organic molecules: ~35%

Definition of Macro Minerals

• Macro minerals are required in amounts greater than 100 mg/day.

• They are components of body fluids and the inorganic matrix of bones and teeth:

  • Sodium

  • Potassium

  • Calcium

  • Magnesium

  • Chloride

  • Phosphate

Role of Electrolytes and Structural Components

• Electrolytes: in fluid compartments; establish ion gradients across membranes, maintain water balance, and neutralize charges on molecules.

  • Sodium

  • Potassium

  • Chloride

• Structural Components: Bones and teeth; primarily calcium and phosphorus.

Detailed Overview of Individual Macro Minerals

Sodium

• Major cation of extracellular fluid.

• Dietary sodium absorption occurs in the intestine and colon.

• Sodium levels are finely regulated by the kidneys and are linked with water balance.

• Importance of sodium:

  • Regulation of fluid & electrolyte balance

  • Blood pressure regulation

  • Blood osmolarity maintenance

  • Excitability of muscle and nerve cells

  • Nutrient transport through plasma membranes.

• Deficiency: Quite rare.

• Excess sodium: Leads to conditions such as hypertension, cardiovascular diseases (CVDs), chronic kidney disease, gastric cancer, calcium nephrolithiasis, and osteoporosis.

• Upper Limit (UL): 2300 mg/day

• Target Intake: ≤2000 mg/day

Potassium

• Most abundant intracellular cation.

• Maintains intracellular fluid volume and transmembrane electrochemical gradients.

• Essential for:

  • Nerve transmission

  • Muscle contraction

  • Kidney function (specifically Ca2+ reabsorption).

• Recommended intake: 3,500 mg/day.

• Usual intake: 4,000 – 5,000 mg/day.

• Estimated requirement for adults: 2,000 mg/day.

• Absorption: Passive diffusion primarily occurring in the intestine.

• Deficiency issues:

  • Cardiac arrest

  • Stroke

  • Hypertension

  • Heart arrhythmias

  • Muscle weakness

  • Increased blood pH (alkalosis).

Calcium

• Approximately 1 kg of calcium exists in an adult body, with 99% found in bones.

• Present in the form of calcium hydroxyapatite: $Ca<em>{10}(PO</em>4)<em>6(OH)</em>2$.

• Approximately 600 mg of calcium exchange occurs between bone and body fluids.

• Serum calcium levels are tightly regulated, with additional functions including:

  • Vascular contraction and vasodilation

  • Muscle function

  • Blood clotting

  • Nerve transmission

  • Intracellular signaling and hormonal secretion.

• Recommended Daily Allowance (RDA): 1,000 mg/day for adult males; 1,300 mg/day for adolescents and women.

Phosphorous

• The second most abundant mineral in the human body: 85% in bones & teeth, 15% elsewhere.

• Key functions:

  • Structural component of nucleic acids (DNA, RNA)

  • Part of phospholipids in cell membranes

  • Regulation of enzymes by phosphorylation

  • Energy production (ATP)

  • Acid-base balance (phosphate buffering system).

• Recommended intake: 700-1,250 mg/day.

• Deficiency is rare, but can occur under specific medical conditions.

Magnesium

• Functions as a cofactor in over 300 enzymatic reactions.

• Involves processes such as:

  • Protein synthesis

  • Energy production

  • Muscle and nerve function

  • Blood glucose control

  • Structural development of bone

  • Synthesis of DNA, RNA, and glutathione.

• Generally, 30% to 40% of dietary magnesium is absorbed.

• Deficiency symptoms: Include loss of appetite, nausea, vomiting, fatigue, and weakness. Excess can lead to diarrhea (milk of magnesia).

Micro Minerals

Overview of Micro Minerals

• Defined as micro minerals needed in amounts less than 100 mg/day.

• These trace minerals hold specialized biological functions.

Iron

• Minimum intake required is 8 mg/day to maintain iron stores with a mixed diet.

• RDA for Iron varies by age and gender:

  • Males & females aged 11-14: 12 and 15 mg respectively.

  • Adults: 10 mg/day for males, 18 mg/day for menstruating females, 30 mg/day for pregnant, 15 mg/day for lactating.

Zinc

• Second most abundant trace mineral; RDA is 15 mg/day.

• Absorbed in the small intestine with various transporters, but lacks a storage system, binding to metallothioneine for toxicity reduction.

Copper

• RDA is approximately 0.9 mg/day, absorbed in the small intestine, and transported to the liver bound to ceruloplasmin.

• Plays significant roles such as assisting Fe absorption, serving as a co-factor for certain enzymes.

Iodine

• Essential for thyroid hormone synthesis; requires about 150 μg/day. Deficiency leads to various developmental issues and goiter.

Selenium

• RDA is around 55 μg/day; it is part of various human proteins, acting primarily as an enzyme cofactor for antioxidant defense.