Vitamins Flashcards
Why are vitamins important?
They act as co-enzymes and co-factors in Biological Reactions
What are the water soluble vitamins?
- B1 (Thiamine)
- B2 (Riboflavin)
- B6 (Pyridoxine)
- B12 (Cobalamin)
- C
- Choline
- Folates
- Niacin (Nicotinic Acid)
- Pantothenic Acid
What are the fat soluble vitamins?
- A
- D
- E
- K
What are the dietary sources of Thiamine?
Liver, fresh veg and husk cereal grains
What is thiamine a co-factor in?
Oxidative decarboxylation reactions
What is Pyruvate Dehydrogenase?
Multienzyme complex located in the mitochondria that links glycolysis and the Krebs cycle
what are the 3 subunits of Pyruvate dehydrogenase and their co-factors?
- Pyruvate dehydrogenase (Thiamine Pyrophosphate)
- Dihydropropyl transacetylase (CoA, Lipoate)
- Dihydropropyl dehydrogenase (FAD/NAD+)
What are the symptoms of Beri Beri (Thiamine deficiency)?
- Parasthesia (Pins and Needles)
- Enlarged heart
- Wrist and foot drop
- Muscle weakness and atrophy
- Digestive disturbance
What demographics can beri beri occur in?
- Alcoholics
- Communities subsisting on polished rice
What are the two types of beri beri?
- Wet (oedema and heart failure)
- Dry (Neuropathies)
What is Wernicke’s Encephalopathy?
- Nystagmus (involuntary eye movement)
- Opthalmoplegia (eye paralysis)
- Ataxia (unsteady movements)
What is Korsakoff’s Syndrome?
Amnesia and other additional psychiatric manifestations
What are dietary sources of Niacin (Nicotinic Acid)?
Liver, Legumes, Lean Meats, Cereals
What reaction/enzyme is niacin a cofactor for?
Lactase dehydrogenase, in the reaction:
Pyruvate + NADH –> Lactate + NAD
Where is pellagra (niacin deficiency) common?
In remote areas where veg, fruit and animal protein are hard to find and primarily eat grains like maize where nicotinic acid is bound tightly
What are the 4 Ds of Pellagra?
Dermatitis
Diarrhoea
Dementia
Death
What are the details of the dermatitis experienced by sufferers of Pellagra?
- Butterfly, gauntlet and boot rash.
- Perineal Lesion
What is absorption of B12 dependent upon?
Gastric Intrinsic Factor
What is GIF (Gastric Intrinsic Factor) secreted be?
Parietal cells of the stomach
What are the two key features of cobalamin (B12) deficiency?
- Megaloblastic Anaemia
- Neurological Disorder
What can B12 deficiency be caused by?
- Lack of HCL in the stomach
- Dietary deficiency
- GIF deficiency from Gastrectomy
What are the symptoms of megaloblastic anaemia?
- Excessive tiredness
- Breathlessness
- Fatigue
- Pallor
Why does B12 deficiency cause megaloblastic anaemia?
B12 is a cofactor for methionine synthase. Decreased methionine leads to decreased protein synthesis in cells with high turnover, e.g. blood cells
