Vitamins

Question 1

Water soluble vitamins

Answer 1

B and C

Readily excreted via kidney
Required daily in small amounts

Question 2

Lipid soluble

Answer 2

A, D, E and K

Stored in the body (liver)
Excessive intake can cause toxicity

Question 3

Definition of vitamins

Answer 3

Organic substances essential for normal metabolic processes and which, when absent in the diet produce deficiency states

Question 4

Coenzyme

Answer 4

Non-protein organic compound, produced in living cells, which plays on intimate and frequently essential role in the activation of enzymes

Question 5

B group vitamins

Answer 5

Necessary for growth
Found in some foods
Differ in structure and function
Most can be synthesised by intestinal flora

Question 6

B1

Answer 6

Thiamine

Found in cells
Present in all natural foods
Acts as a coenzyme as its phosphorite Ester: thiamine pyrophosphate
Synthesised in the intestinal mucosa from dietary thiamine and ATP

Deficiency

1. Wet beriberi
   - cardiac failure
   - decreases permeability of capillary walls
   - odema
2. Dry beriberi
   - peripheral neuritis
   - wastage
   - paralysis

Question 7

B2

Answer 7

Riboflavin

Found in milk, liver, kidneys, heart, eggs, whole cereal grains, green veg
Metabolism of fats, carbs and proteins
Heterocyclic system acts as the hydrogen acceptor or donor
Involved in respiration, growth and reproduction

Deficiency

• cause by malnutrition
• inflammation of mouth and tongue, lesions to intestinal mucosa, dermatitis, defective vision and injury to bone marrow
• rare in developed countries

Question 8

B3

Answer 8

Niacin and nicotinamide

Present in yeast, liver, lean meats, peanuts, peas, beans, whole wheat and rice grains
In the coenzymes NAD and NADP
require by many oxioreductase enzymes

Deficiency

• body not entirely dependant on dietary intake as niacin is formed from tryptophan in vivo
• pellagra = dermatitis, diarrhoea and dementia
• alcoholics, malabsorption, mellitus, B6 deficiency all at risk

Toxicity
- skin flushes, liver damage

Question 9

B6

Answer 9

Pyridoxine

Found in veg or animal origin
In several enzymes concerned with tryptophan metabolism
Synthesised by intestinal flora

Deficiency

• rare as most diets contains adequate amounts
• disorders of CNS, skin and mucous membrane

Toxicity
-peripheral neuropathy

Question 10

B5

Answer 10

Pantothemic avid

Found in liver, yeast, egg yolk and fresh veg
Constituent of Coenzyme A (Krebs)

Question 11

B7

Answer 11

Biotin

Found in egg yolk, liver, wheatgerm, milk and yeast
Cofactors for carboxyl group transferase in fat metabolism

Question 12

B9

Answer 12

Folic Acid

Found in liver, kidney, yeast, lemons, strawberries and fresh veg
Folic acid reduced to tetrahydrofolate
THF used to transfer hydroxymethal forme and methyl groups in a many reactions

Deficiency

• cause by inadequate diet, malabsorption, malignant disease, medication and alcohol abuse
• anaemia
• supplements may mark b12 deficiency resulting in damage to nervous system

Question 13

B12

Answer 13

Cyanocobalmin

Found in meat, shellfish, salmon, milk, cheese, eggs, fortified breakfast cereals
1.5mg daily requirement
Essential for normal erythropoisesis

Deficiency

• pernicious anaemia
• degradation of spinal cord

Question 14

C

Answer 14

Asorbic acid

Found in citrus fruits, green plants, veg
Most powerful reducing agent known to occur naturally in living tissue
Collagen cofactor

Used in

• hydroxylation of dopamine to noradrenaline
• hydroxylation in steroid synthesis
• electron donor in conversion of folic acid to THF
• iron absorption
• antioxidant
• role in fighting infection and wound healing
• helps reduce chance of common cold and cancer

Deficiency
-scurvy; swollen glands, bruising, haemorrhage, bone fracture, loose teeth, poor wound healing, anaemia

Toxicity
-stomach pains

Question 15

A

Answer 15

Retinol