Vitamins Part 1 Flashcards

Micronutrients Overview

• Micronutrients are essential nutrients that include vitamins and minerals.
• Required in small amounts, measured in milligrams (mg) or micrograms (µg).

Essential Vitamins

• Vitamin D and niacin are partially essential vitamins.
• Most vitamins function as protein cofactors.

Protein Cofactors

• Two categories:
  • Mobile substrates: transient in function.
  • Bound stable: can be covalent or non-covalent connections to proteins.

Vitamin Functions

• Four basic functions of vitamins:
  • Carriers: bind and release substrates, altering them.
  • Catalysts: bind and modify substrates.
  • Sensors: detect metabolic/environmental changes.
  • Signals: indicate developmental progress or physiological states.

Etymology of Vitamin

• "Vita" means life in Latin.
• "Amine" refers to the first vitamin with an amine group.

Vitamers

• Vitamers are isomers of a vitamin that may have different biological activities.

History of Vitamins

• Significant studies such as the Single Grain Experiment on cow diets showed varying effects on weight gain.
• Corn was found to have the greatest impact on calf weight gain.

Vitamin Isolation

• Thiamin was the first vitamin to be isolated.
• Vitamins previously classified into fat-soluble (A, D, E, K) and water-soluble (B vitamins, C).

Modern Classification of Vitamins

• Current division categorizes vitamins based on function:
  • Energy metabolism: B1-B6
  • Blood function: K, folate, B12
  • Antioxidants: C and E
  • Signaling molecules: A and D

Pantothenate (B5)

• Acts as an enzyme cofactor, part of Coenzyme A and fatty acid synthase.
• Exists as phosphopantetheine in fatty acid synthase, carrying acyl or acetyl groups through high-energy thiol ester bonds.

Enzymatic Roles of B5

• Plays a role in multiple enzymes, including:
  • Pyruvate dehydrogenase
  • Alpha-ketoglutarate dehydrogenase
  • Fatty acid beta-oxidation
  • Fatty acid synthase

B5 Deficiency

• Rare due to widespread food availability.
• Notable cases may occur in those with alcoholism or severe malnutrition.
• Symptoms include burning feet and neurodegeneration.

Absorption and Circulation of B5

• All forms convert to pantothenate during digestion and are absorbed via active transport.
• Circulates as pantothenate, converting to CoA in peripheral tissues.

Dietary Supplement Regulations

• Regulated by the Dietary Supplement Health and Education Act of 1994.
• Claims cannot state that products treat or prevent disease but can be misleading.

Nutrient Intake Measurements

• EAR meets requirements of half the population.
• RDA: Recommended Daily Allowance, based on EAR plus 2 standard deviations.
• AI: Adequate Intake, recommended when no EAR exists.
• UI: Upper Intake Level indicates potential for toxicity.

Testing Nutrient Intake

• Measurement methods include:
  • Direct: blood, hair, nails.
  • Homeostasis: urinary excretion, tracer methods.
  • Physiological action: monitoring metabolism or blood clotting.

Test your knowledge of essential micronutrients with these flashcards covering key concepts related to vitamins and minerals. This quiz will help you understand the basic definitions, required amounts, and the functions of different vitamins. Perfect for students looking to reinforce their understanding of nutrition concepts.