Water Soluble Vitamins

Front 1

What is some of the other names of Thiamin?

Back 1

Vitamin B1, Aneurine, Thiamine

Front 2

Can phosphlorylated thiamin be absorbed?

Back 2

No

Front 3

What happens to Phosphorylated thiamin in the intestines?

Back 3

The intestinal phosphatases hydrolyse the phosphate group prior to absorption.

Front 4

What are the 2 active names of thiamin?

Back 4

Thiamin pyro phosphate (TPP) & thiamin diphosphate (TDP)

Front 5

What is required for the conversion of free thiamin to thiamin pyro phosphate?

Back 5

Magnesium & ATP

Front 6

Where is free thiamin converted to it's coenzyme form?

Back 6

In the liver

Front 7

What is the definition of a co-enzyme?

Back 7

An organic non-protein molecule, often phosphorylated derivative of a water soluble vitamin

Front 8

What is phosphorylation?

Back 8

The addition of phosphate group usually transferred from ATP

Front 9

What form is 80-90% of total thiamin in the body?

Back 9

Exists as TPP

Front 10

Is thiamin saturated at high or low concentrations in the body?

Back 10

Low

Front 11

T/F is thiamine absorption at high or low doses by active transport?

Back 11

Low 2mg.

Front 12

What factors inhibit absorption of thiamin?

Back 12

Alcohol,
conditions such as diarrhoea/vomiting,
ulcerative colitis,
neoplasia (abnormal proliferation of cells)
hepatic disease,
achlorhydria (absent or low gastric acid)

Front 13

What is the free thiamin bound to whilst circulating in blood?

Back 13

Bound to protein- usually albumin

Front 14

Are there any storage sites in the body for thiamin?

Back 14

No,so daily uptake is important

Front 15

What level of thiamin is usually contained in the body?

Back 15

25-30 mg of thiamin

Front 16

How is an excess of thiamin excreted for the body?

Back 16

Via urine

Front 17

What conditions can cause a significant loss of thiamin?

Back 17

Diuresis (excessive urine production) and sweating

Front 18

When there is a thiamin deficiency does urinary excretion increase or decrease?

Back 18

Decreases, indicating that there is renal conservation mechanism

Front 19

What are the 2 main roles of thiamin?

Back 19

Co-enzyme and component of neural membranes

Front 20

What are the functions of thiamin as a co-enzyme?

Back 20

1. Synthesis and metabolism of neurotransmitters.
2. ATP production in krebs cycle.
3. Metabolism of carbohydrates
4. Metabolism of branched chain amino acids and lipids
5. Production of RNA and DNA and niacin coenzyme

Front 21

What are the functions of thiamin as a component of neural membranes?

Back 21

Nerve transmission and activation of ion transport in nerve membranes

Front 22

Name some of the neurotransmitters that thiamin is important for?

Back 22

Acetylcholine, GABA, glutamate and aspartate

Front 23

How many coenzymes is thiamin part of?

Back 23

At least 24 enzymes

Front 24

What are the two most important coenzymes that thiamin assists in the functioning of?

Back 24

Dehydrogenase enzyme complex, transketolase enzymes

Front 25

What is the biochemical role of dehydrogenase enzyme complex

Back 25

Catalyses decarboxylation - removal of carboxyl groups - COOH

Front 26

What is believed to be the function of thiamin triphosphate in the neuronal channels?

Back 26

Activates high conductance chloride and sodium channels

Front 27

Explain the absorption process of thiamin

Back 27

Free thiamin is absorbed from the proximal jejunum of the small intestine

Front 28

Why is thiamin important in the kreb cycle

Back 28

Thiamin catalysts pyruvate to form Acetyl COA, catalyses alpha ketoglutarate to succinyl CoA, both of which are integral parts of the kreb cycle.
Thiamin also assists with pentose shunt pathway which provides glucose which is the beginning of the krebs cycle

Front 29

List four sub clinical signs of thiamine deficiency

Back 29

Nervous system mainly affecting lower extremities, headaches, muscle wasting and tiredness

Front 30

What population group is most at risk of thiamin deficiency?

Back 30

Alcoholics

Front 31

List 5 other groups at risk of developing WKS

Back 31

Anorexics, diabetics, those on dialysis, diets of highly polished rice, and long term parenteral therapy

Front 32

What is the dosage for dysmenorrhea ?

Back 32

100mg daily

Front 33

Is there conclusive evidence for the therapeutic use of thiamin in Alzheimer's disease?

Back 33

No - the results have been insufficient in some individuals

Front 34

Give 5 rich food sources of thiamin?

Back 34

Wheat germ, peas, lean pork, lentils, fortified breakfast cereals

Front 35

Are there toxicity issues with thiamin? WHat does this suggest about it's safety?

Back 35

There are no reported issues with oral toxicity but adverse affect noted from high doses parenteral nutrition. Appears very safe for consumption.

Front 36

Where are thiaminases and where are they found?

Back 36

Thiaminase is an enzyme found in some fish which affects the uptake of thiamin

Front 37

T/F An excess intake of sugar and white bread increase the need for thiamin

Back 37

True - even though a small amount of thiamin is added back into Bread the overall impact of eating too much flour and sugar increases the need for thiamin

Front 38

What Vitamin is this?

Back 38

Thiamin