This document discusses vitamin B1 (thiamine). It notes that thiamine is a water-soluble vitamin that acts as a coenzyme involved in carbohydrate metabolism. The key points are: - Thiamine's coenzyme, thiamine pyrophosphate, facilitates the conversion of pyruvate to acetyl-CoA and links glycolysis to the TCA cycle. - Deficiency can cause beriberi disease, characterized by neuropathy, edema, and heart failure. - Good dietary sources include cereals, legumes, nuts and meat. Cooking can reduce thiamine levels in foods.

1. Mr.A.Ajith
Lecturer
College of allied health sciences
Sri venkateswaraa university ettayapuram.
Vitamin B1

2. Vitamin B1- Thiamine
 Thiamine (anti-beri-beri or antineuritic vitamin) is
water soluble.
 It has a specific coenzyme, thiamine
pyrophosphate (TPP) which is mostly
associated with carbohydrate metabolism
 Thiamine contains a pyrimidine ring and a
thiazole ring held by a methylene bridge
 Thiamine is the only natural compound with
thiazole ring

3.  The alcohol (OH) group of thiamine is esterfied
with phosphate (2 moles) to form the coenzyme,
thiamine pyrophosphate
 The pyrophosphate moiety is donated by ATP
and the reaction is catalysed by the enzyme
thiamine pyrophosphate transferasee (TPP or
cocarboxylase).
 Thiamine is a sulfur containing water soluble
vitamin

4. Pyrimidine
Pyrophosphat
e
Methylene bridge

5.  Thiamine: thiamine is carried by the portal blood
to the liver, present as free thiamine
 Storage:
 Mainly stored in skeletal muscle and also
present in the significant amount of liver , heart,
kidney, erythrocytes and nervous system.
 Co enzyme : TPP

6. BIOCHEMICAL FUNCTIONS
 The coenzyme , thiamine pyrophosphate or
cocarboxylase is intimately connected with the
energy releasing reactions in the carbohydrate
metabolism.
 Pyruvate dehydrogenase complex:
 Its catalyses the irreversible conversion of
pyruvate to acetyl coA.
 Its essential for complete oxidation of glucose
 Its links glycolysis and TCA cycle

7. PHD complex
NAD+
NADH + H+
 Transketolase is

8. RECOMMENDED DIETARY
ALLOWANCE
 The daily requirement of thiamine depends on
the intake of carbohydrate.
 A dietary supply of 1-1.5 mg/day is
recommended for adults (about 0.5 mg/1,000
Cals of energy ).
 For children RDA is 0.7-1.2 mg/day
 The requirement marginally increase in
pregnancy and lactation (2 mg/day ),old age and
alcoholism.

9. DIETARY SOURCES
 Cereals , pulses , oil seeds , nuts and yeast are
good sources
 Thamine is mostly concentrated in the outer layer
(bran) of cereals
 Polishing of rice removes about 80% of thiamine.
 Vitamin B1 is also present in animals food like
pork ,liver , heart, kidney, milk etc..
 In the parboiled (boiling of paddy with husk) and
milled rice ,thiamine is not lost in polishing
 Since thiamine is a water soluble vitamin, it is
extracted into the water during cooking process.
 Such water should not be discarded.

10. DEFICIENCY SYMPTOMS
 The deficiency of vitamin B1 results in a condition
called beri –beri
 Beri –beri is mostly seen in populations
consuming exclusively polished rice as staple
food .
 The early symptoms of thamine deficiency are
loss of appetite (anorexia)
weakness,conspitation,nausea,mental depression
,peripheral neuropathy, irritability etc..
 Numberness in the legs complaints of ‘ pins and
needles sensations are reported.

12. BIOCHEMICAL CHANGES IN B1
DEFICIENCY
 Carbohydrate metabolism is impaired .Accumulation
of pyruvate occurs in the tissues which is harmful .
 Pyruvate concentration in plasma is elevated and it is
also excreted in urine.
 Normally pyruvate does not cross the blood-brain
barrier and enter the brain
 However , in thaimaine deficiency an alteration occurs
in the blood –brain barrier permitting the pyruvate to
enter the brain directly
 It is believed that pyruvate accumulation in the brain
results in disturbed metabolism that may be
responsible for polyneuritis.

15.  Thiamine deficiency leads to impairment in nerve
impulse transmission due to lack of TPP.
 The transketolase activity in erythrocytes is
decreased.
 Measurement of RBC transketolase activity or a
reliable diagnostic test to asses thiamaine
deficiency.
 In adults two types beri beri namely wet beri beri
and dry beri beri occur.
 Infantile beri-beri that differs from adult beri beri
is also seen

16. Wet beri -beri
 Breathlessness and palpitation and present
 The muscles are slightly swollen.
 The systolic blood pressure is elevated while
diastolic is decreased
 This is characterized by edema of legs ,face
,trunk ,and sources cavities
 Fast and bouncing pulse is observed
 The heart becomes weak and death may occur
due to heart failure.

17. Dry beri- beri
 This is associated with neurological
manifestations resulting in peripheral neuritis
 Edema is not commonly seen
 The muscles become progressively weak and
walking becomes difficult.
 The affected individuals depend on support to
walk and become bedridden, and may even die if
not treated.
 The symptoms of beri –beri are often mixed in
which case it is referred to as mixed beri-beri

18. INFANTILE BERI-BERI
 This is seen in infants born to mothers suffering
from thaimine deficiency.
 The breast milk of these mothers contains low
thaimine content .
 Infantile beri-beri is characterized by
sleeplessness ,restlessness ,vomiting
,convulsions and bouts of screaming that
resemble abdominal colic
 Most of these symptoms are due to cardiac
dilatation.
 Death may occur suddenly due to cardiac failure.

20. WERNICKE-KORSAKOFF
SYNDROME
 This is a disorder mostly seen in chronic
alcoholics.
 The body demands of thiamine increase in
alcoholism.
 Insufficient intake or impaired intestinal
absorption of thiamine will lead to this syndrome.
 It is characterized by loss of memory ,apathy and
a rhythmical to and fro motion of the eye balls

21. THIAMINE DEFICIENCY DUE TO
THIAMINASE AND PYRITHAIMINE
 The enzyme thiaminase is present in certain sea
foods
 Their inclusion in the diet will destroy thiamine by
a cleavage action and lead to deficiency.
 Pyrithiamine, a structural analogue and an ant
metabolite of thiamine is found in certain plants
like ferns.
 Horses and cattle often develop thiamine
deficiency due to the overconsumption of the
plant fern.

22. Allergic reactions—skin rash,
itching, hives, swelling of the face,
lips, tongue, or throat