Essential Vitamins

Fat-Soluble Vitamins

• Stored in lipid deposits; daily intake not strictly required
• Excess intake can lead to hypervitaminosis (toxicity)

Water-Soluble Vitamins

• Not stored in the body; daily intake is necessary for B vitamins
• Vitamin C synthesized in cats and dogs
• Deficiencies possible with excessive water loss (polyuria, diarrhea), GI issues affecting intestinal flora

Vitamin A

• Source: Animal products (pre-formed vitamin A), plants (provitamin A/carotenoids)
• Function: Vision, bone growth, reproduction, tooth development, epithelial cell maintenance
• Deficiencies: Epithelial lesions (infection), reproductive problems, night blindness
• Toxicity (excess): Skeletal malformation, fractures, internal bleeding
• Cat Requirement: Pre-formed vitamin A from animal sources (fish, organ meats, dairy, eggs)

Vitamin D

• Cat/Dog Sunlight Absorption: Different from humans
• Function: Regulates calcium and phosphorus metabolism
• Source: Harvested plants (not living tissue)
• Function (details): Aids in absorption, mobilization, retention, bone deposition, calcium & phosphorus mineralization and bone remodeling
• Deficiencies: Rickets, osteoporosis, enlarged costochondral junctions
• Toxicity: Hypercalcemia, soft tissue calcification, death
• Source example: Fish oils

Vitamin E

• Function: Antioxidant, protects vitamin A
• Use in pet food: Preservative
• Dog Deficiencies: Degenerative skeletal muscles, impaired sperm production, gestation failure
• Cat Deficiencies: Steatites, myocarditis, skeletal muscle myositis
• Toxicity: Rare
• Source: Plants (green leaves)

Vitamin K

• Unique fat-soluble: Absorbed or synthesized
• Source: Green leafy plants (kale, cabbage, cauliflower), animal sources (liver, egg, fish), some synthesis in the large intestine (coprophagy increases absorption in dogs)
• Function: Blood clotting, bony growth
• Deficiencies: Rare unless ingestion of rat poison, or malabsorption issues (possible spontaneous bleeding)
• Toxicity: Only with oral versus SQ or IV vitamin K therapy

Vitamin B Complex

• Vital for converting food to energy, cell maintenance & growth, and blood cell synthesis

Thiamin (B1)

• Source: Brewer's yeast, whole grains, organ meats, egg yolk
• Breakdown: Progressively destroyed by cooking
• Deficiency: Intake of thiaminases (antagonist) in raw fish, shellfish, bacteria, yeast, or fungi (destroyed by cooking)

Riboflavin (B2)

• Source: Dairy products, organ/muscle meat, eggs, green plants, yeast
• Deficiencies: Uncommon; Dermatitis, erythema, weight loss, cataracts

Niacin (B3)

• Conversion Enhancement: Processing helps release bound niacin
• Cat Sensitivity: Can't synthesize from tryptophan (common in corn/grain diets); dermatitis, diarrhea, death (rare in dogs)
• Source: Yeast, animal/fish byproducts, cereals, legumes, oilseeds

Pyridoxine (B6)

• Cat Sensitivity: Oxalate crystalluria, reduced growth, kidney lesions (reported in owner-made diets)
• Source: Meats, whole grains, vegetables, nuts

Pantothenic Acid (B5)

• Ubiquitous: Found in virtually all foods; no common deficiencies
• Breakdown: Destroyed by freezing, canning, and refining

Folic Acid (B9)

• Daily Requirement: Necessary
• Deficiencies: Poor weight gain, anemia, leukocytopenia
• Source: Green leafy vegetables, organ meats, egg yolks

Biotin (B7)

• Deficiency: Raw egg whites, oral antibiotics; poor growth, dermatitis, lethargy
• Egg Whites: Avidin (in egg whites) binds biotin, making it unavailable; cooking destroys avidin
• Source: Oilseeds, egg yolks, alfalfa meal, liver, yeast

Cobalamin (B12)

• Deficiency: Vegetarian diets, microwave heating; poor growth, neuropathies
• Storage: Excess stored in the liver
• Source: Organ meats, fish, dairy products

Vitamin C (Ascorbic Acid)

• Synthesis: Synthesized by plants and many animals (including dogs & cats)
• Function: Antioxidant, free radical scavenger, drug/steroid metabolism, electron transport
• Animal Source: Animal synthesizes via glucose
• Deficiency/Toxicity: Not typically seen in dogs or cats