Transcript Neruroscience-1 Vitamin B1x

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Tip from Tweety
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VITAMINS
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The adult human brain
Weight:
about 3 lb (1.5 kg)
Volume of around 1130-1260
cm3,
 Substantial individual variation.
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PROTECTION BY LOCATION

It is protected by the thick bones of
the skull, suspended in cerebrospinal
fluid, and isolated from the blood
stream by the blood-brain barrier.
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Susceptible to many types of
damages and diseases.
Most common forms are physical
damage
 Closed head injuries such as a
blow to the head,
 A stroke, or
 Poisoning by a wide variety of
chemicals that can act as
neurotoxins.

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Other problems
Infection of the brain is rare
because of the barriers that
protect it, but is very serious
when it occurs.
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Brain is also susceptible to
degenerative disorders

Like, Parkinson's disease, Multiple Sclerosis, and
Alzheimer's disease.

psychiatric conditions, such as
schizophrenia and depression, are widely thought
to be caused at least partially by brain
dysfunctions, although the nature of such brain
anomalies is not well understood.

Here Vitamins come to play role
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What are Vitamins ?
Vitamins are naturally occurring organic
compounds, present in very small quantity
in diet and which are essential for normal
growth and health.
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Later on it was found that
Normal metabolic functions cannot be
executed without these compounds
2. If deficient, certain specific metabolic
disorders are seen.
3. Participate as coenzyme in various
enzyme catalyzed reaction.
4. Vitamins do not provide energy.
1.
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TILL DATE
 14
different vitamins have
been isolated so far and
purified into crystalline form.
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CLASSIFICATION OF VITAMINS
Based on their solubility in solvent.
Vitamins
Water Soluble
Non B Complex
Group
Fat Soluble
(A, D, E, K)
B. Complex Group
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Storage

Water Soluble:
Not stored in our bodies. Must therefore be
present in diet to an appreciable extent for normal
health and growth.

Fat Soluble:
Are stored, if taken in excess. Stores are sufficient
to meet the demand of our body for almost
6 months, if no vitamins are taken through diet.
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THIAMIN
B1
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Biochemical Role

B1 forms the coenzyme Thiamine Diphosphate
also called thiamine pyrophosphate By the
reaction Thiamine + ATP = TPP + AMP.

The enzyme required for this conversion is
Thiamine diphosphotransferase.

TPP is coenzyme for Alfa Keto-acid Oxidative decarboxylation.
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Functions

Thiamin is vital for key reactions in energy
metabolism, especially carbohydrate metabolism
and therefore its requirement in diet is related to
energy intake.

In carbohydrate metabolism, thiamin functions in
oxidative de-carboxylation of pyruvic acid to form
acetyl coenzyme A, which then enters kreb’s
cycle.
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Pentose Phosphate pathway
TPP is also a coenzyme for the
tranketolase which is involved in PPP
of glucose metabolism.
 In thiamine deficiency there is
accumulation of of the substrates of
the reaction co-catalysed by TPP i.e.
Pyruvic Acid, Lactic Acid Pentose
sugar and the alfa ketoacids
derivatives of Amino acids.

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Deficiency Disease
( BERIBERI)
Deficiency disease of B1 has been divided into three
syndromes on the basis of most common clinical
features;

Dry beriberi with predominantly Neuromuscular
symptoms

Wet beriberi, with Neuromuscular signs and Edema,
less common form but fatal.

Cardiac beriberi, with cardiac decompensation
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Beriberi
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Deficiency Diseases
Chronic alcoholism can also lead to thiamin
deficiency, the disease produced is termed
wernicke’s syndrome.
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Symptoms of Dry Beriberi

Numbness, tingling, burning pain in extremities

Pains and cramping in the leg muscles

Difficulty with speech

Problems walking

Disturbed sense of balance
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Symptoms of Wet Beriberi

Fast heart rate

Swollen feet and legs

Enlarged heart

Enlarged and tender liver

Shortness of breath

Congestion in the lungs
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Symptoms of Infantile Beriberi

Restlessness

Difficulty sleeping

Diarrhea

Swollen arms and legs

Muscle wasting in arms and legs

Silent cry

Heart failure
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Systems affected by deficiency:

GIT

Nervous System

Cardiovascular System

Musculoskeletal System
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Risk Factors for Deficiency

Alcoholism

Cirrhosis

Malabsorption

Diabetes

Kidney Diseases

Chronic Infections
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Those at Risk are:

Elderly people

Nutritionally inadequate diets

Stress

Prolonged illness

Surgeries

Those who diet or fast frequently

Tobacco Users
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Toxic effects

Human have limited toxic reaction to thiamin.
The sign include

Edema

Sweating

Tremors

Tachycardia

Fatty liver/ tumors and

Vascular Hypotension
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TALK OF THE DAY
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ROLE OF VITAMINS IN
MENTAL HEALTH
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NUTRITIONAL FACTS






Patients today often are over or well-fed but
undernourished.
A growing body of literature links dietary choices to
brain health and the risk of psychiatric illness.
Vitamin deficiencies can affect psychiatric patients in
several ways:
deficiencies may play a causative role in mental
illness and exacerbate symptoms
psychiatric symptoms can result in poor nutrition
vitamin insufficiency—defined as subclinical
deficiency—may compromise patient recovery.
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We can safely conclude that



Vitamins are necessary for healthy life.
B vitamins are required for proper functioning of
the methylation cycle, monoamine production,
DNA synthesis, and maintenance of phospholipids
such as myelin
Fat-soluble vitamins A, D, and E play important
roles in genetic transcription, antioxidant
recycling, and inflammatory regulation in the
brain.
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The methylation cycle

Vitamins B2, B6, B10, and B12 directly impact the
functioning of the methylation cycle.

Deficiencies pertain to brain function, as neurotransmitters, myelin, and active glutathione are
dependent on one-carbon metabolism
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
Role of the 3 essential water-soluble
vitamins (B1, B2, B6, B10, B12, and C)
and 3 fat-soluble vitamins (A, D, and
E) in brain metabolism and
psychiatric pathology is important.
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B1 (thiamine): Glycolysis, TCA

Deficiency
Rare; 7% in heart failure patients

Insufficiency
5% total, 12% of older women

Symptoms Wernicke syndrome, memory impairment,
confusion, lack of coordination, paralysis

At-risk patients Older adults, malabsorptive conditions, heavy
alcohol use.
Those with diabetes are at risk because of increased clearance



Dietary sources Fish, beans, lentils, nuts, rice, and wheat.
Raw fish, tea, and betel nuts impair absorption
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CHEMISTRY

Thiamine is derived from substituted pyrimidine
and thiazole which are coupled by a methylene
bridge.

It is rapidly converted to its active form thiamin
pyrophosphate (TPP) in the brain and liver by
specific enzymes, Thiamin diphosphotransferase
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Thiamin structure
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Food sources

Important sources of Vitamin B1 are:

Fish,

Beans,

Lentils,

Nuts,

Rice,

Meat, wheat, and milk
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SENSITIVITY
Thiamin can be easily lost during cooking owing to
its solubility in water,
Destroyed in presence of alkali and
sensitivity to prolonged exposure to heat.
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Absorption & Metabolism
The bound forms of Thiamin are split in gastrointestinal tract during digestion .
Absorbed mainly from duodenum and jejunum.
Very little Thiamin is stored in body when thiamin
intake is in excess of needs it is excreted in urine
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Recommended Dietary Allowances
Infants less than 6 months
0.3 mg/day
6 months to 1 year
0.4 mg/day
1 – 3 years
0.7 mg/day
4 – 6 years
0.9 mg/day
7 – 10 years
1.0 mg/day
11 – 14 years
1.3 mg/day
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Recommended Dietary Allowances
15 – 50 years
Males 1.5 mg/day –
Females1.1 mg/day
Over 60 years
Males 1.2 mg/day –
Females 1.0 mg/day
Pregnant ladies
1.5 mg/day
Lactating
1.6 mg/day
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RIBOFLAVIN
B2
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Major source of Energy in Living
organisms

Living organisms including humans derive
most of their energy from oxidationreduction reactions.
 These are processes which involve the
transfer of electrons.
 Flavin coenzymes participate in redox
reactions in numerous metabolic
pathways.
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Major source of Energy in Living
organisms

Flavins are critical for the metabolism of
carbohydrates, fats, and proteins. Helps
in releasing energy from carbohydrates.

FAD is part of the electron transport
(respiratory) chain, which is central to
energy production.
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OTHER FUNCTIONS
B-2 is important for body growth and RBCs
production
 In treating anemia, adding Vitamin B-2 to
iron supplements, increase its
effectiveness.
 Flavins also participate in the metabolism
of some vitamins , minerals, drugs and
toxins

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OTHER FUNCTIONS

Riboflavin also helps to shore up the
immune system by reinforcing antibody
reserves, the body's first line of defense
against infection.
 In addition, the body uses extra riboflavin
to keep tissue in good repair and speed
healing of wounds, burns and other
injuries.
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Added Benefits of B-2

Carpal tunnel syndrome patients may benefit when
B-2 and B-6 combination therapy is given.

Epithelial and mucosal tissues require riboflavin
for their maintenance .

B-2 is also involved in oxidative degradation of
short chain fatty acids.

It also has a role in transfer of oxygen from
plasma to tissues.
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B2 (riboflavin): FMN, FAD cofactors in
glycolysis and oxidative pathways. B6, folate,
and glutathione synthesis





10% to 27% of older adults
<3%; 95% of adolescent girls
Fatigue, cracked lips, sore throat, bloodshot eyes
Older adults, low intake of animal and dairy
products, heavy alcohol use
Dairy, meat and fish, eggs, mushrooms, almonds,
leafy greens, and legumes
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Added Benefits of B-2

Riboflavin is helpful for maintaining the skin, nails,
eyes, mouths, lips and tongue.

It is required for normal vision and prevention of
cataracts.

Riboflavin is also thought to decrease the duration
and frequency of migraine headaches in some
people, When used with beta blockers
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Riboflavin deficiency
Deficiency can result in:

Skin lesions

Light sensitivity

Eye disorders

Inflamed mouth or tongue, and

Cracks and sores at the mouth's corner.
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Low levels of B-2

Arthritis

Colon cancer

Heart disease

Carpal tunnel syndrome

Multiple sclerosis

Anxiety, stress and fatigue
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Arthritis
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Carpal Tunnel Syndrome
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Multiple sclerosis
Peshawar Medical College
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Glossitis
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Why Called Riboflavin ?
It is named riboflavin because of its
structural similarity to Ribose (Sugar)
and its relationship to the flavins.
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Chemical structure of Riboflavin
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Flavin Adenine Dinucleotide
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Food Sources

The richest sources of riboflavin include
organ meats such as liver, kidney and
heart.
 Milk, yeast, cheese, fish, eggs and dark
green leafy vegetables are also rich
sources.
 Flour and cereals are enriched with
riboflavin.
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Absorption and Metabolism
Riboflavin is rapidly absorbed form
upper part of small intestine and then
phosphorylated in intestinal wall to its
active form.
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Distribution and excretion

Riboflavin is found in all cells of the body
but maximum concentration is found in
liver and kidneys.

With an increase in intake above needs,
vitamin is excreted by kidneys.
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Recommended Dietary Allowances (RDA)

Daily intake of 0.6 mg per 1000 calories for
persons of all ages is recommended
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RECOMMENDED DAILY INTAKE
Age
Males mg/day
Females mg/day
0—12 months
0.3-0.4
0.3-0.4
Children
1-3
0.5
0.5
Children
4-8
0.6
0.6
Children
9-13
0.9
0.9
Adolescents
14-18
1.3
1.0
19+
1.3
1.1
Life stage
Infants
Adults
Pregnancy
All ages
1.4
Lactation
All ages
1.6
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Response to Physical state

Riboflavin is Heat stable but light
sensitive.

It is easily destroyed by light, and
foods stored in clear containers will
lose their riboflavin content in a short
period of time.

It can leach into cooking water
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Deficiency of vitamin B2
Deficiency of riboflavin is one of the most
common deficiency disease
 A shortage of this vitamin may manifest
itself as cracks and sores at the corners of
the mouth, eye disorders, inflammation of
the mouth/ tongue, and skin lesions.

Dermatitis, dizziness, hair loss, insomnia,
light sensitivity, poor digestion, retarded
growth, and slow mental responses have
also been reported.
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