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Micronutrients and Vitamins Lecture Review

Micronutrients: Study Notes Overview

  • Micronutrients are essential for proper body function, though required in smaller amounts.

  • They play a key role in metabolic processes and tissue maintenance.

  • The body cannot naturally produce micronutrients; they must be obtained through dietary intake.

  • Vitamins are organic substances categorized into two main types: fat-soluble and water-soluble.

Water-Soluble Vitamins

  • This category includes: B complex vitamins (Thiamin, Riboflavin, Niacin, Biotin, Pantothenic Acid, Vitamin B6, Folate/Folic Acid, Cobalamin B12), Choline, and Vitamin C.

  • Water-soluble vitamins require regular replenishment because the body eliminates them through urine, preventing long-term storage.

B Vitamins

  • Thiamin (B1)

    • Action: Essential for muscle energy, energy metabolism (particularly carbohydrates), and appetite stabilization.

    • Sources: Found in meats (especially organ meats like liver and kidney), legumes, fortified grains, and nuts.

    • Deficiency: Can lead to weight loss, fatigue, headache, and the disease Beriberi.

  • Riboflavin (B2)

    • Action: Crucial for energy production, cell respiration, maintaining vision, and the health of skin, nails, and hair. Also contributes to antibody and red blood cell formation.

    • Sources: Rich in dairy products, eggs, meats, and dark leafy vegetables.

    • Deficiency: May result in skin eruptions, cracked lips, and a red, swollen tongue.

  • Niacin (B3)

    • Action: Involved in energy and protein metabolism, maintenance of skin and tongue health, and improvement of circulation.

    • Sources: Significant sources include liver, nuts, and legumes.

    • Deficiency: Can cause symptoms such as dementia, gastrointestinal (GI) issues, and central nervous system (CNS) findings.

    • Caution: Niacin can dilate blood vessels, potentially causing a flushing sensation.

  • Biotin (B7)

    • Action: Plays a vital role in various metabolic processes and is known for its contribution to hair and nail growth.

    • Sources: Found in liver, dairy products, eggs, nuts, and sweet potatoes.

    • Deficiency: Can manifest as rashes, hair loss, brittle nails, fatigue, and insomnia.

  • Pantothenic Acid (B5)

    • Action: Assists in the metabolism of macronutrients (carbohydrates, fats, and proteins).

    • Sources: Present in meats, eggs, dairy products, mushrooms, and broccoli.

    • Deficiency: Symptoms include fatigue, insomnia, depression, and a sensation of numbness or burning in the extremities (paresthesia).

  • Vitamin B6 (Pyridoxine)

    • Action: Essential for red blood cell production, cellular function, and the synthesis of neurotransmitters.

    • Sources: Good sources include meats, grains, and legumes.

    • Deficiency: Can lead to anemia, poor growth, and insomnia.

  • Folate/Folic Acid (B9)

    • Action: Important for amino acid and hemoglobin synthesis, and critical for fetal neural tube formation.

    • Sources: Abundant in liver, legumes, and dark leafy vegetables.

    • Deficiency: Associated with anemia and central nervous system (CNS) disturbances.

    • Note: Increased intake of Folate/Folic Acid is especially crucial pre-pregnancy for proper fetal development.

  • Vitamin B12 (Cobalamin)

    • Action: Primarily involved in nerve function, red blood cell production, and the activation of folate.

    • Sources: Found in meats, clams, oysters, eggs, and dairy products.

    • Deficiency: Can result in anemia, poor muscle coordination, and paresthesia (tingling/numbness) of the hands and feet.

Other Water-Soluble Nutrients

  • Choline

    • Note: Although vital, Choline is not technically classified as a vitamin.

    • Action: Supports brain function, including memory, mood, and muscle control. It also aids the liver in utilizing fatty acids.

    • Sources: Found in meats, eggs, dairy products, and cruciferous vegetables.

    • Deficiency: Can lead to fatigue, cognitive impairment, and fatty liver disease.

  • Vitamin C (Ascorbic Acid)

    • Action: Functions as an antioxidant, plays a crucial role in tissue building, and enhances iron absorption.

    • Sources: Rich in citrus fruits and their juices, as well as various vegetables.

    • Deficiency: Causes Scurvy, characterized by decreased iron absorption and bleeding gums.

Fat-Soluble Vitamins

  • This group includes Vitamins A, D, E, and K.

  • Unlike water-soluble vitamins, fat-soluble vitamins are stored in the body for longer periods, which increases the risk of toxicity if consumed in excessive amounts.

  • Ingesting very large quantities of these vitamins can be lethal.

  • Vitamin A

    • Action: Essential for vision, tissue strength, proper growth, and immune system function.

    • Sources: Found in orange/yellow fruits and vegetables, fatty fish, and dairy products.

    • Deficiency: May cause reduced night vision, dry and thick corneas, and changes in mucosa.

  • Vitamin D

    • Action: Maintains healthy serum calcium and phosphorus levels, and is critical for bone development.

    • Sources: Obtained from fish, fortified dairy products, egg yolks, and exposure to sunlight.

    • Deficiency: Leads to low serum calcium, fragile bones, and Rickets in children.

  • Vitamin E

    • Action: Primarily functions to protect vitamin A from oxidation within the body.

    • Sources: Present in vegetable oil, grains, nuts, and dark green vegetables.

    • Deficiency: In infants, deficiency can cause anemia, edema, and skin lesions.

  • Vitamin K

    • Action: Essential for the synthesis of prothrombin, a protein vital for blood clotting, and aids in bone metabolism.

    • Sources: Rich in green leafy vegetables and eggs.

    • Deficiency: Results in increased bleeding times.

Antioxidants

  • Antioxidants are molecules that neutralize harmful free radicals in the body.

  • Free Radicals: These are unstable atoms that possess an unpaired electron, originating from internal body functions (like normal cell metabolism) or external sources (such as air pollution). They cause damage to cells, proteins, and DNA, and are linked to chronic diseases and the aging process.

  • Examples of Antioxidant Nutrients: Vitamin A, Vitamin C, Vitamin E, and Beta-Carotene.

  • Sources: Abundantly found in various fruits (e.g., grapes, blueberries, bananas, pomegranate) and vegetables (e.g., broccoli, spinach, carrots, beets).

Glossary

  • Metabolism: The sum of chemical processes that occur within a living organism to maintain life.

  • Antioxidant: A substance that inhibits oxidation, used to counteract the deterioration of stored food products or remove potentially damaging oxidizing agents in a living organism.

  • Free Radical: An unstable atom or molecule with an unpaired electron that can cause damage to cells, proteins, and DNA.

  • Prothrombin: A protein present in blood plasma that is converted into active thrombin during coagulation.

  • Paresthesia: An abnormal sensation, typically tingling, pricking, or numbness ("pins and needles"), caused chiefly by pressure on or damage to peripheral nerves.

  • Hemoglobin: A red protein responsible for transporting oxygen in the blood of vertebrates.

  • Macronutrients: Substances required in relatively large amounts by living organisms, such as carbohydrates, fats, and proteins.

  • Beriberi: A disease caused by a deficiency of Thiamin (Vitamin B1), characterized by inflammation of the nerves and heart failure.

  • Scurvy: A disease caused by a deficiency of Vitamin C, characterized by swollen and bleeding gums and the opening of previously healed wounds.

  • Rickets: A disease of children caused by Vitamin D deficiency, characterized by soft, weak bones.