thiamine Flashcards
what type of vitamin is thiamine
a water soluble-vitamin, also known as vitamin B1
what is The co-enzyme formed from dietary thiamin
thiamin pyrophosphate (TPP), a cofactor required in energy metabolism
thiamine requirements relate to what
energy expenditure and intakes
what is the EAR and RNI for thiamine in adults
EAR ; 0.3 mg/1, 000 kcal
RNI; 0.4 mg/1, 000 kcal
This equates to:
0.8 mg/day females
1 mg/day males
how is thiamine influenced by dietary factors
requirements are higher for carbohydrate-rich diet
folate deficiency reduces absorption of thiamine
high intakes of alcohol appear also to reduce thiamine absorption
how is thiamine influenced by therapeutic drugs
e.g. furosemide (diuretic) reduces thiamine by increasing urinary excretion
food sources of thiamine
bovril
marmite
cornflakes
liver
wholemeal bread
feel
lamb
boiled pulses
thiamine during cooking
Thiamine is very unstable and easily lost in food preparation, including when cooking in water
what food process removes large amounts of thiamine
Polishing or refining
how may losses of niacin during food prep and cooking be replaced
Some of this may be replaced by fortification of refined foods e.g. flour, cereals
in the body around 30mg of thiamine is needed for what
liver
skeletal muscle
heart
kidney
brain
how is thiamine important in the nervous system
in tri-phosphorylated form, thought to be involved in controlling impulse transmission by regulating ion transport (Na, Cl)
what is used to diagnose thiamine deficiency
Erythrocyte transketolase activity coefficient
Substantive increase in activity (>16 %) following saturating dose of thiamine indicates what
deficiency
In beri-beri, urinary ‘thiamine excretion’ is less than what
15 micro g/d
beri beri occurs at intakes less than what
0.2 mg/1, 000 kcals.
what are symptoms of dry beri beri
muscle weakness
wasting
peripheral
neuropathy
what are symptoms of wet beri beri
cardiomegaly
tachycardia
oedema
(- proteinuria)
what are some early symptoms of beri beri
loss of appetite
tingling of hands and legs
numbness, aches and pains
weakness and wasting of leg muscle
difficulty walking
how does infantile beri beri occur and whats its symptoms
is breast fed from mother vit B deficient
fretful
vomiting
weight loss
swelling
convulsions
what causes acute beri beri, and what can this cause
Parenteral nutrition high in dextrose, low in thiamin
Acute beri beri occurs in hospitals when patients can’t eat.
the low thiamine will cause Anorexia, vomiting, lactic acidosis(reducing PH of blood), cardiac dysfunction
what are sympotoms of Wernicke’s encephalopathy (Wernicke-Korsakoff syndrome; other causes – alcoholism; AIDs)
opthalmoplegia – paralysis of ocular muscles- cant move eyes without moving head as well
nystagmus – involuntary eyeball movement, such as eyeballs shaking
ataxia – poor muscle coordination
loss of short-term memory & confusion
Alcohol intereferes with thiamine absorption.
what are causes of thiamine deficiency
congestive heart failure, increases need for thiamine
increased clearance
some bowel disorders
decreased dietary absorption e.g. IBD
how can alcoholism mask alcohol deficiency
Alcholism can mask fact of thiamin deficiency as symptoms (memory and confusion, and muscle coordination) are same In both
