Vitamins

Question 0

Factors increasing vitamin availability

Answer 0

Provitamins-> converted in body to a vitamin -> beta carotene, nicotinic acid
Colonic bacteria-> intestinal bacteria-> B 12 and K synthesis
Folate

Question 1

Define vitamins and their classes

Answer 1

Organic substances required in small amounts for normal metabolism but which cannot be synthesised by the body
B,C fat soluble
A,D,E,K fat soluble

Question 2

Decrease vitamin availability

Answer 2

Biliary dysfunction-> vit K
Binding-> nicotinic acid
Less/different intestinal bacteria

Question 3

Thiamin sources and uses

Answer 3

Found in plants seeds, meat and fish 
For glucose production-> TCA cycle
Deficiency-> beriberi disease
Poly neuropathy 
Encephalopathy 
Enlarged heart

Question 4

Nicotinic acid, sources and uses

Answer 4

Found in fish, liver, cereals
Functional part of NADH
Deficiencies
Pellagra-> underweight, erythema, digestive/neurological disease

Question 5

Anaemia prevention

Answer 5

B1:
Found in animal products
For DNA synthesis and regulation
Fatty acid synthesis 
Energy production 
Deficieny-> megloblastic anaemia, neuropathy
Folate:
Found in green veg
For DNA synthesis, DNA repair, DNA methylation, cofactor 
Deficiencies-> anaemia
Methionine synthase-> yields free folate from tissues via methylation of homocysteine to methionine 
Link between the two

Question 6

Antioxidants

Answer 6

Ascorbic acid 
Found in citrus fruits, potatoes, vegetables
Important  for: 
Hydroxyproline (collagen) 
Intra cellular matrix
Capillaries, bones, teeth, connective tissue 
Tissue protection and repair
Iron absorption 
Deficiencies-> scurvy

Question 7

Vitamin A

Answer 7

Found in animal products
Precursor-> beta carotene-> carrots and green veg
Normal requirements 600-1000 micro grams per day
Actions:
Vision in dim light
Epithelial maintenance
Growth and repair of skin
Retinoic acid-> gene expression and cell differentiation
Deficiencies-> night blindness, cornea problems
Toxicity:
Acute->nausesa, vomiting, headache
Chronic-> increased CSF pressure, enlarged liver, joint paint, Teratogenesis

Question 8

Vitamin D

Answer 8

Found in fish oils, egg yolk, butter
D3 undergoes liver and kidney hydroxylations
Converted to vit D3 from pre vit D3 by sunlight
Low levels of Ca stimulate calcidiol production
Actions:
Intestinal Ca absorption
Renal Ca and phosphorus reabsorption
Neuromuscular and immune function
Deficiencies-> rickets or osteomalacia
Toxicity-> weakness, nausea, appetite loss, headache, abdo pains, hypercalcaemia,