Vitamin and Nutrient Quiz

Study Notes

Learning Objectives: List water-soluble vitamins, classify B vitamins (energy-releasing or hematopoietic), describe coenzyme forms of each B vitamin, explain the role of vitamin C, and list diseases associated with deficiencies.

Classification: B vitamins can be divided into energy-releasing and hematopoietic categories.
- Energy-releasing: Thiamin, Riboflavin, Niacin, Pantothenic acid, and Biotin.
- Hematopoietic: Folic Acid and B12.

Coenzyme form: Thiamine pyrophosphate (TPP).
Function: Key role in carbohydrate metabolism and nerve impulse transmission.
Sources: Whole grains, yeast, seeds, vegetables, eggs, and milk.
Stability: Destroyed by excessive cooking.
Deficiency Disease: Beri-beri and Wernicke-Korsakoff syndrome (common in alcoholics).
- Early symptoms: Irritability, depression, fatigue, peripheral neuropathy, anorexia, dyspepsia, and weight loss.

Coenzyme forms: FMN (Flavin Mononucleotide) and FAD (Flavin Adenine Dinucleotide).
Function: Participate in oxidation-reduction reactions, coenzyme in fatty acid oxidation and the TCA cycle.
Sources: Milk, mushrooms, leafy green vegetables, meat, eggs, yeast and liver.
Stability: UV light destroys riboflavin, exposure to sunlight can inactivate 70%.
Deficiency Symptoms: Glossitis (tongue inflammation), cheilosis (swollen cracked lips), and angular stomatitis (inflammation at corners of mouth).

Forms: Nicotinic acid and Niacinamide.
Coenzyme forms: NAD+ and NADP+.
Function: Coenzymes for oxidoreductases (hydrogen acceptors and donors), crucial in many metabolic pathways, including glycolysis, TCA cycle, electron transport chain (ETC), cholesterol metabolism, and fatty acid oxidation and synthesis.
Sources: Yeast, fish, poultry, meats (high protein), liver.
Deficiency Disease: Pellagra (3Ds) - diarrhea, dermatitis, and dementia.

Coenzyme form: Pyridoxal Phosphate (PLP).
Function: Needed for amino acid metabolism, neurotransmitter synthesis, and heme synthesis.
Deficiency Symptoms: Neurological symptoms and anemia.

Pantothenic Acid: Coenzyme form is Coenzyme A (CoA-SH). Essential coenzyme in metabolic pathways.
Biotin: Coenzyme form is Biotinyl lysine, involved in carboxylation.

Coenzyme form: Tetrahydrofolate (THFA or FH4).
Function: Crucial for DNA synthesis and cell division (prevents anemia). Prevents neural tube defects in the fetus (Spina bifida and anencephaly).
Sources: Legumes, green leafy vegetables, oranges and orange juice.
Requirement: Increased need during pregnancy and lactation (400 ug/day).
Supplementation: Often routinely given during pregnancy.

Coenzyme Forms: Methylcobalamin and deoxyadenosyl cobalamin (Ado B12).
Absorption: Absorption in the GI tract needs Intrinsic factor (a protein secreted by parietal cells of the stomach).
Storage: Can be stored in the liver.
Sources: Animal products (liver, fish, eggs, meat, milk, yogurt).
Deficiency: Megaloblastic anemia, pernicious anemia (necessitates injection), and combined degeneration (demyelination and neuronal death, leading to gait instability, memory loss and confusion).

Role in Collagen Formation: Essential for normal collagen formation, connective tissue maintenance, wound healing and bone formation.
Increases Iron Absorption: Reduces ferric state to ferrous in the stomach, enhancing absorption.
Antioxidant: Protects other compounds from oxidation by donating electrons.
Deficiency Disease: Scurvy - bleeding gums, loose teeth, hemorrhages, anemia, poor wound healing, osteoporosis, and easy bone fractures.
Sources: Citrus fruits, strawberries, bell peppers, green leafy vegetables.
Stability: Unstable and easily destroyed by heating, oxygen, or light.