Vitamins: Biochemical Roles and Functions

Vitamins: Biochemical Roles

• "Vitamin" means "vital for life"
• Vitamins are micronutrients (required in small amounts - mg or µg) needed for everyday bodily functions
• Vitamins cannot be synthesized in the body; they must be obtained through diet
• Vitamins are essential components of healthy diets and play vital roles in cellular metabolism
• Although present in small amounts, their absence can lead to deficiency diseases

What are Vitamins?

• Vitamins are non-caloric organic nutrients
• They facilitate bodily processes like digestion, absorption, metabolism, and growth
• Some vitamins are found in food as precursors or provitamins

Vitamins as Coenzymes

• Vitamins often function as coenzymes
• Coenzymes are small molecules that work with enzymes to enhance their activity
• A coenzyme tightly bound to an enzyme protein is called a prosthetic group
• A complete, active enzyme along with its coenzyme is a holoenzyme
• The protein part of this enzyme is the apoenzyme or apoprotein

Vitamin Measurement

• Humans require at least 12 vitamins
• A well-balanced diet usually provides necessary vitamins
• Some vitamins are chemically altered to become active in the body
• Vitamins are measured in International Units (I.U.s) for biological activity, or milligrams (mg) or micrograms (µg) based on weight

US FDA Recommendations

• The Food and Drug Administration (FDA) sets daily reference intakes to meet the needs of 95% of the population
• Dietary Reference Intakes (DRIs) include Estimated Average Requirements (EARs), Recommended Dietary Allowances (RDAs), Adequate Intakes (AIs), and Tolerable Upper Intake Levels (ULs)

Vitamin Categories

• Vitamins are categorized into water-soluble and fat-soluble groups
• Water-soluble vitamins include the B vitamins (e.g., Pantothenic acid, Biotin, Folic acid) and Vitamin C
• Fat-soluble vitamins include Vitamins A, D, E, and K

Water-soluble vs. Fat-soluble Vitamins

• Water-soluble vitamins are not stored in the body and are excreted in urine; regular intake is needed; they are unstable to heat and light
• Fat-soluble vitamins are stored in the body; excess can accumulate to toxic levels; they are fairly stable at normal cooking temperatures

Water-soluble Vitamins (detailed)

• Found in vegetables, fruits, grains, and meats
• Absorbed directly into the bloodstream
• Not stored in substantial quantities; toxicity is rare
• Cooking can reduce absorption, substances like alcohol can elevate elimination

B Vitamins

• A group of 8 water-soluble vitamins act as coenzymes

• Essential for proper cellular function

• Examples include Thiamin (B1), Riboflavin (B2), Niacin (B3), Pantothenic Acid (B5), Pyridoxine (B6), Biotin (B7), Folic Acid (B9), and Cyanocobalamin (B12)

• Note that there are tables relating specific roles/reactions associated with each individual B vitamin in the provided text

Vitamin C

• Ascorbic acid, a water-soluble vitamin
• Antioxidant, protects from free radicals
• Important for collagen formation and wound healing
• Needed to absorb iron
• Boosts immunity and helps prevent heart disease and cancer
• Large doses can be harmful

Vitamin A

• Fat-soluble vitamin; important for vision
• Found in carrots or as beta-carotene for conversion into vitamin A
• Helps with vision and can cause side effects in large amounts
• Important for vision and other body functions

Vitamin D

• Fat-soluble vitamin; essential for calcium absorption and bone health is sometimes called the "sunshine vitamin"
• Synthesized by the body via exposure to UV light
• Important for calcium regulation, promoting calcium-binding protein synthesis
• Deficiency leads to conditions like rickets

Vitamin E

• Fat-soluble antioxidant vitamin
• Plays a vital role in nerve and muscle functions, and protects cell membranes.
• Important for preventing cell damage
• Necessary for certain bodily functions and can be detrimental if ingested in large quantities

Vitamin K

• Fat-soluble vitamin; crucial for blood coagulation (clotting)
• Synthesized by bacteria in the digestive tract, and found in green leafy vegetables
• Essential for proper blood clotting and other bodily functions
• Interference with anticlotting medication is possible with high intake

Explore the crucial roles that vitamins play in our body. This quiz will test your knowledge on the biochemical functions of vitamins, their importance in the diet, and their roles as coenzymes. Understand how these essential nutrients contribute to cellular metabolism and overall health.