Exam 2 Lecture Materials Flashcards
What are vitamins
Vitamins are organic compounds that are essential for normal metabolism and present in minute amounts in natural foodstuffs. They can be fat or water soluble
What are the fat soluble vitamins
A
D
E
K
A,D,E- some body storage
A,D can be toxic
Functions of Vitamin A aka Retinoids (required by all animals)
Carotenoids (Beta-Carotene) can be precursors to Vitamin A –> Retinol
Functions: Night vision, bone formation and remodeling, reproduction, antioxidant activity with carotenoids
Functions of Vitamin D aka Cholecalciferol
Vitamin D2 (plant) and D3 (animal)
Dietary sources are fish and dairy products. They are sterol precursors in plants and skin require UV light to produce Vitamin D.
Functions: Normal bone mineralization (Ca and P), immune system and T-cells, conversion and storage in liver
Functions of Vitamin E aka Tocopherol
Very unstable compound found in most animal tissue but limited biological activity
Dietary sources are multigrain cereals, nuts, oils, and leafy greens
Interactions with minerals and PUFAs
Functions: antioxidant- free radical scavenger, nucleic acid and protein metabolism, cell membrane structure.
Functions of Vitamin K
Essentials for blood-clotting functions
What are the water soluble vitamins
B and C, biotin, choline, and folacin
They are relatively non-toxic
No body storage (except for B12) –> deficiencies
Adult ruminants generally do not require dietary source
Functions of Thiamin (B1)
Thiamin is present in most foodstuffs- cereal grains, soybean meal, green, leafy hay, and animal products (pork)
Important coenzyme in the Citric Acid Cycle (Krebs) for cellular respiration –> energy
Carbohydrate and lipid metabolism
Functions of Riboflavin (B2)
Good sources are animal products, green forages, and vegetables. Sensitive to light.
Makes up a group on flavoproteins and functions in oxidoreduction reactions, transformed into coenzymes, FMN and FAD inside the cells and are important in metabolism as Electron Carriers.
Helps the body release energy from protein, fat, and carbohydrates during metabolism
Functions of Niacin (Vitamin B3)
Nicotinic Acid can be synthesized from tryptophan in most species (conditionally essential)
Good sources are meats, yeast, leafy plants
Coenzyme for oxidoreductase reactions, active Niacin is NAD+ or NADP+ and are electron carriers. Important in DNA damage repair.
Involved in carbohydrate, protein, and fat metabolism
Functions of Pantothenic acid (Vitamin B5)
Coenzyme A (CoA) is the active form. Most foodstuff has pantothenic acid- grain is lower
Required for fatty acid, carbohydrate and protein metabolism (Acetyl CoA, Succinyl CoA, etc)
Helps release energy from fats and vegetables
Functions of Folate (yes it is the same as Folacin)
Aids in genetic material development; involved in red blood cell production
Functions Vitamins B6
5 forms: pyridoxine, pyridoxal (phosphate), and pyridoxamine (phosphate)
Good sources are meats, liver, cereal grains, and vegetables. Requirements increase with protein intake, pregnancy, and lactation.
Functions: Amino Acid metabolism- transamination, deamination, and formation of hormones. Glycogen metabolism- muscle
Functions of Vitamin B12 (Cobalamin)
Primary source is microbial synthesis- not made by plants or animals. Dietary sources are animal products- smallest requirement of ANY vitamin. Absorbed poorly but stored well in most animals (except cats)
Coenzyme for a few important metabolic enzymes. Important in ruminant metabolism- need a cobalt source. Closely associated with Folacin. Helps absorption of nutrients in GI.
Aids cells development, functioning of the nervous system, and the metabolism of protein and fat
Functions of Biotin aka Vitamin H
Microbial synthesis in GI tract
Good dietary sources are eggs, liver, kidneys, yeast, fruits and veggies
Coenzyme for 4 important enzymes required for carbohydrate metabolism, fatty acid synthesis, gluconeogenesis, and AA deamination
Functions of Ascorbic Acid aka Vitamin C
Found in citrus fruits, potatoes and cabbage, leafy veggies, and animal products. Can make it from glucose except in some species (primates, some fish, snakes and birds, fruit bats and guinea pigs)
Good reducing agent- water soluble antioxidant, reduces metal ions and enhances Fe absorption
Collagen synthesis- connective tissue
Formation of epinephrine
Attributes of fat soluble vitamins
Soluble in fat, not water
Absorption occurs along with lipids, requires bile salts
Carrier proteins- present
Stored in liver
Deficiency manifests only when stores are depleted
Toxicity- hypervitaminosis may result
Major vitamins- A,D,E,K
Attributes of water soluble vitamins
Soluble in water not fat
Absorption simple (except Vitamin B12)
No carrier proteins (except Vitamin B12)
No storage (except Vitamin B12)
Deficiency manifests rapidly as there is no storage (except Vitamin B12)
Toxicity is unlikely since excess is excreted
Major vitamins- B and C
Why do we not really see toxicity with water soluble vitamins
toxicity is unlikely since excess is excreted
General functions of most vitamins
Coenzymes of metabolic process
Affect multiple body systems
Many water-soluble vitamins affect growth
Deficiencies and toxicity of Vitamin E aka Tocopherol
Deficiencies- nutritional muscular dystrophy (white muscle disease), and encephalomalacia, neurological dysfunction
Increased requirement with omega fatty acids (PUFAs)- protects them from oxidation
Selenium spares Vitamin E and prevents deficiency
Toxicity: relatively non-toxic, can antagonize Vitamin K, Selenium toxicity
Deficiencies and toxicity of Vitamin D (aka Cholecalciferol)
Deficiencies: abnormal skeletal growth/formation (rickets/children, Osteomalacia/adult). Cancer. Symptoms- Ca/P deficiencies- bowed legs, lameness, and sore joints
Toxicities: calcification of soft tissues (kidney, aorta, lungs
Deficiencies and toxicities of Vitamin A aka Retinoids
Deficiencies: night blindness, anorexia, infection, and death, dry eyes, rough skin, slower bone growth, and improper tooth development
Toxicities: anorexia, dermatitis, thinning bones, hemorrhage
- Livers contain high levels of Vitamin A
- Apex predators
Functions of Vitamin K
K1 (phylloquinone)- plant/green vegetables
K2 (menaquinone)- microbial synthesis in GI
K3 (menadoine)- synthetic
Required for normal blood clotting
Bone metabolism