Vitamin Flashcards
The first vitamin
Thiamin, the ‘“vital amine” necessary to prevent beriberi
- Discovered in 1913
Understanding vitamins
Vitamins are:
- Chemically defined
- Susceptible to destruction
- May exist in more than one form
- Essential
- May be coenzymes
- Some are antioxidants
- Used as food additives
- Drugs
TRUE OR FALSE: Vitamins provide energy
FALSE. Vitamins do not produce energy but are needed for metabolism of energy
Antioxidants
Group of compounds that neutralizes free radicals, helping to counteract the oxidation that takes place in cells
What vitamins are antioxidants?
Vitamin C & E
What other sources also act as antioxidants, stimulate the immune system and interact with hormones to prevent cancers?
Phytochemicals
- Carotenoids
- Flavonoids
Fat-soluble vitamins
Vitamin A, D, E & K
- Sources are the fat and oil portion of foods
Absorption:
- enter the lymphatic system before circulating bloodstream
Transportation:
- attaches to protein carriers because fat is not soluble in watery blood
- When consumed in excess, stored primarily in liver and adipose tissue
- Can be toxic if consumed in high intakes through supplements
- Do not have to be consumed daily
Preformed Vitamin A
Found only in animal sources
Toxic in high doses
Function: known for it’s role in
- Normal vision
- Reproduction
- Growth
- Immune system functioning
Body can store up to a year’s supply of vitamin A.
Provitamin A carotenoids
Sources:
- Natural plant pigments found in deep yellow and orange fruits and vegetables and most dark-green leafy vegetables
Function: known for it’s role in
- Normal vision
- Reproduction
- Growth
- Immune system functioning
Nontoxic
Hypercarotenemia
Vitamin D
Most can be made if exposure to sunlight is optimal and liver + kidney function are normal
Function:
- Acts like a hormone because it is synthesized in the skin and stimulates functional activity elsewhere
- Maintain normal blood concentrations of calcium and phosphorus
Deficiency:
- Poor calcium absorption
- Rickets
- Osteomalacia
Vitamin E
Function
- the primary fat-soluble antioxidant in the body
- Protect polyunsaturated fatty acids (PUFAs) and other lipid molecules, such as LDL cholesterol, from oxidative damage
- May help against atherosclerosis, some types of cancer, cataracts, age-related macular degeneration, Parkinson’s disease, and Alzheimer’s disease
Deficiency
- Peripheral neuropathy
- Ataxia
- Death
Vitamin K
‘Quinones’
Made by intestinal bacteria
Function:
- Essential for the synthesis of prothrombin
Deficiency:
- vitamin K–responsive hypoprothrombinemia.
Water -soluble vitamins
Vitamin C, Vitamin B (thiamin, riboflavin, niacin, B6, folate, B12)
Absorption:
- onto the blood
- not generally stored
- not generally building up and becoming toxic
- Need to be consumed daily
Thiamin
Vitamin B1
Function:
- Metabolism of carbohydrates and branched-chain amino acids
Deficiency:
- Beriberi
- Only seen in alcoholics
Riboflavin
Vitamin B2
Sources:
- Milk and dairy products
Function
- Is an integral component of FAD and FMN that function to release energy from nutrients in all body cells
Deficiency:
- Elderly and adolescents are at greatest
- Deficiency symptoms include sore throat, cheilosis, stomatitis, glossitis, and dermatitis
Niacin
Vitamin B3
Sources:
- exists as nicotinic acid and nicotinamide
- body can make it from the amino acid tryptophan
Function:
- part of NAD and NADP which are involved in energy transfer reaction in metabolism of glucose, fat and alcohol in body cells
- large doses used to lower total cholesterol, LDL cholesterol and raise HDL cholesterol
Deficiency:
- pellagra
- only seen in alcoholics
Vitamin B6
Pyridoxine, pyridoxal and pyridoxamine
Functions:
- plays a role in the synthesis, catabolism and transport of amino acids and in the conversation of tryptophan to niacin
Deficiency:
- of vitamin B6, folic acid and B12 leads to an increase in blood homocysteine levels
- Uncommon
- related to alcohol abuse, isoniazid (antituberculosis drug acts a vitamin B6 antagnoist)
Folate
Sources:
- Synthetic folic acid found in vitamin supplements and fortified foods
- Green leady vegetables
- Dried peas and beans,
- Seeds
- Liver
- Orange juice
Function:
- Synthesis of DNA
- Reduces risk of neural tube defects
- Large doses of folic acid can alleviate the anemia caused by vitamin B12 deficiency (a function of both vitamins)
Deficiency
- Impairs DNA synthesis and cell division
- Macrocytic anemia
High intakes can mask vitamin B12 deficiency
Vitamin B12
Cobalamin
Sources:
- Only water-soluble not in plants
- recommended that people 50+ obtain most of their requirement from fortified foods or supplements
Functions:
- Maintaining myelin sheath around nerves
- Parenteral injections given for pernicious anemia
Deficiency:
- Symptoms may take 5 -10 years or longer to develop
Vitamin C
Ascorbic acids
Sources:
- Found in citrus fruits and juices
Functions
- Prevents scurvy
- Antioxidants that protects Vitamin A, Vitamin E, PUFA and iron from destruction
Deficiency
- scurvy
