It is useful for exam preparation and revise

1. VITAMIN B1
GANTA SAI SURYA ABHINAV
TVMC

2. SYNOPSIS
• INTRODUCTION
• STRUCTURE
• FUNCTION
• CLINICAL MANIFESTATIONS
• BIOCHEMICAL PARAMETERS
• RDA

3. THIAMINE
• Thiamine (Vit B1) is a water soluble hormone
• It was also known as anti beri-beri factor
• SOURCES :
1. It is mainly present in the
aleurone layer of food grains
2. Yeast is also a
good source of Vit B1

4. STRUCTURE
• Thiamine consists of : 1) Substituted pyrimidine ring
2) Substituted thiazole ring
• These rings are connected to each other by a methylene
bridge. This is the inactive form of Vit B1
• This inactive thiamine is converted to its active form by
addition of two phosphate groups (Pyrophosphate)
• The activation is catalysed by thiamine pyrophosphate
transferase

6. PHYSIOLOGICAL ROLE
PYUVATE
DEHYDROGENASE
(IN GLYCOLYSIS)
Oxidative
decarboxylation
of pyruvate
ALPHA
KETOGLUTARATE
DEHYDROGENASE
(IN TCA CYCLE)
TRANSKETOLASE
(IN HMP SHUNT)

7. DEFICIENCY MANIFESTATIONS
Deficiency of Vit B1 can lead to the following clinical
conidtions
1. Beri beri
2. Wernicke - Korsakoff syndrome
3. Polyneuritis

8. BERI BERI
• The early symptoms of this disease are anorexia,
dyspnea, heaviness and weakness.
1. Wet beriberi - Cardiovascular manifestations, edema of
face, legs and serous cavities, palpitaion, breathlessness
and deah due to cardiac failure
2. Dry beriberi - CNS manifestations occurs which makes
walking becomes difficult. Peripheral neuritis with
sensory disturbance leads to complete paralysis
3. Infantile - Restlessness and sleeplessness are
observed.

9. Wernicke-Korsakoff syndrome
• It is also called as cerebral beriberi. Carl Wernicke in
1894 and Sergiei
• Sergievich Korsakoff in 1887 described the condition.
• it only occurs when thiamine is very deficient
• Clinical features are same as those of encephalopathy:
1. Ophthalmoplegia
2. Nystagmus
3. Cerebellar ataxia
4. Psychosis.

10. BIOCHEMICAL PARAMETERS
• In thiamine deficiency - blood thiamine decreased but pyruvate,
alpha ketoglutarate and lactate are increased.
• Earliest manifestion : Reduced activity for erythrocyte
transketolase
• Erythrocyte transketolase levels reduced - Comatose patients,
alcoholics, chronic renal failure, malnutrition(Elderly people)
• Many in ICU may suffer from low thiamine levels
• A lipid soluble acylated derivative (benfotiamine) is now being
recommended for diabetic patients to decrease glycation of
proteins (AGE) and to improve diabeteic neuropathy

11. Recommended Daily Allowance
• It depends on calorie intake i.e, 0.5 mg of thiamine per
1000 calories consumed
• So approximately 0.5 - 1.5 mg of thiamine is required per
day
• Thiamine is useful in the treatment of beriberi, alcoholic
polyneuritis, neuritis of pregnancy and neuritis of old age.

12. THANK YOU