Vitamins: Chapter 7 Flashcards
What Are Vitamins?
Definition: Organic compounds containing carbon, hydrogen, and oxygen.
Types: 13 essential vitamins.
Sources: These are mostly obtained through diet; some are synthesized by the body (e.g., Vitamin D, K, niacin, and biotin).
Functions are essential for growth, reproduction, and overall health; they are involved in metabolic processes but do not provide energy.
Fat-Soluble Vitamins
Absorption: Need dietary fat, absorbed in the small intestine, and transported via the lymph system.
Storage: Stored in the body, can accumulate in adipose tissue.
Examples: Vitamins A, D, E, K.
Water-Soluble Vitamins:
Absorption: Absorbed with water into the bloodstream, not stored for long periods.
Examples: B vitamins (e.g., B1, B2, B3, B6, B12), Vitamin C.
Antioxidant Function
Definition: Substances that counteract oxidation by neutralizing free radicals.
Free Radicals: Unstable molecules that can damage cells, produced by metabolic reactions and environmental exposure.
Antioxidant Vitamins: Vitamins A, C, E.
Bioavailability and Vitamin Loss
Bioavailability: The degree to which nutrients are absorbed and used by the body.
Factors Influencing Bioavailability: Food preparation, individual nutritional status, natural vs. synthetic vitamins, storage, and preparation methods.
Excessive Vitamin Intake
Risks: More likely with supplements than diet; toxicity risks are higher for fat-soluble vitamins.
Guidelines: Follow Dietary Reference Intakes (DRIs) and Upper Intake Levels (ULs).
Provitamins
Provitamins: Inactive forms converted to active vitamins in the body (e.g., beta-carotene to Vitamin A).
Preformed Vitamins
Preformed Vitamins: Active forms found in foods.
Vitamin A (Fat-Soluble Vitamins)
Other Names: Retinol, beta-carotene.
Sources: Liver, dairy, eggs, carrots, leafy greens.
Functions: Vision, immune function, reproduction, growth.
Deficiency: Eye problems, skin issues, respiratory problems.
Toxicity: Nausea, headache, dizziness.
Vitamin D (Fat-Soluble Vitamins)
Sources: Sun exposure, fortified foods, fish.
Functions: Bone health, calcium absorption.
Deficiency: Rickets, osteomalacia.
Toxicity: Hypercalcemia.
Vitamin E (Fat-Soluble Vitamins)
Sources: Nuts, seeds, vegetable oils.
Functions: Antioxidant, immune function.
Deficiency: Rare, but can cause nerve and muscle damage.
Toxicity: Hemorrhage.
Vitamin K (Fat-Soluble Vitamins)
Sources: Leafy greens, fermented foods.
Functions: Blood clotting, bone health.
Deficiency: Bleeding disorders.
Toxicity: Rare.
Vitamin C (Water-Soluble Vitamins)
Other Names: Ascorbic acid.
Sources: Citrus fruits, tomatoes, potatoes.
Functions: Antioxidant, immune support, iron absorption.
Deficiency: Scurvy.
Thiamin (B1); Water-Soluble Vitamins
Energy metabolism, nerve function.
Riboflavin (B2); Water-Soluble Vitamins
Energy production, skin health.
