Vitamin

Question 1

The first vitamin

Answer 1

Thiamin, the ‘“vital amine” necessary to prevent beriberi

- Discovered in 1913

Question 2

Understanding vitamins

Answer 2

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

Question 3

TRUE OR FALSE: Vitamins provide energy

Answer 3

FALSE. Vitamins do not produce energy but are needed for metabolism of energy

Question 4

Antioxidants

Answer 4

Group of compounds that neutralizes free radicals, helping to counteract the oxidation that takes place in cells

Question 5

What vitamins are antioxidants?

Answer 5

Vitamin C & E

Question 6

What other sources also act as antioxidants, stimulate the immune system and interact with hormones to prevent cancers?

Answer 6

Phytochemicals

• Carotenoids
• Flavonoids

Question 7

Fat-soluble vitamins

Answer 7

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

Question 8

Preformed Vitamin A

Answer 8

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.

Question 9

Provitamin A carotenoids

Answer 9

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

Question 10

Vitamin D

Answer 10

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

Question 11

Vitamin E

Answer 11

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

Question 12

Vitamin K

Answer 12

‘Quinones’

Made by intestinal bacteria

Function:
- Essential for the synthesis of prothrombin

Deficiency:
- vitamin K–responsive hypoprothrombinemia.

Question 13

Water -soluble vitamins

Answer 13

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

Question 14

Thiamin

Answer 14

Vitamin B1

Function:
- Metabolism of carbohydrates and branched-chain amino acids

Deficiency:

• Beriberi
• Only seen in alcoholics

Question 15

Riboflavin

Answer 15

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

Question 16

Niacin

Answer 16

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

Question 17

Vitamin B6

Answer 17

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)

Question 18

Folate

Answer 18

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

Question 19

Vitamin B12

Answer 19

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

Question 20

Vitamin C

Answer 20

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