1. Water SolubleVitamins
Vitamin B1(Thiamine)
Presented by
Teke Efeti Mary
Arreyetta Bawak Augustine
UNIVERSITY OF BUEA REPUBLIC OF CAMEROON
PEACE –WORK – FATHERLAND
Coordinated
By
Prof. Achidi Aduni and Dr. Tiencheu Bernard
Senior Lecturers of Biochemistry and Molecular Biology, Faculty of Science
3. Introduction
• Water-soluble vitamins are vitamins that dissolve in
water and are not stored; they are eliminated in
urine.Therefore, requires daily supply from diet.
• The water-soluble vitamins include the vitamin B-
complex group (B1,2,3,5,6,7,9,12) and vitamin C.
• Water-soluble vitamins are easily destroyed or
washed out during food storage or preparation.
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4. Introduction
• Proper storage and preparation of food can
minimize vitamin loss.
• To reduce vitamin loss, refrigerate fresh produce,
keep milk and grains away from strong light, and use
the cooking water from vegetables and meat to
prepare soups.
• The B vitamins are widely distributed in foods, and
their influence is felt in many parts of the body.
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5. Introduction
• They function as coenzymes that help the
body obtain energy from food.
• They also are important for normal appetite,
good vision, healthy skin, healthy nervous
system and red blood cell formation.
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7. What isVitamin B1
• Vitamin B1 also called thiamine was the first B
vitamin that scientists discovered and that is
why its name carries the number 1.
• Thiamine cannot be synthesized within the
tissues of any animal species but all higher
plants can make the vitamin, thereby providing
a dietary source for animals, and it is produced
also by yeasts.
• Humans store thiamin primarily in the liver, but
in very small amounts.
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9. Metabolism ofVitamin B1
• Most dietary thiamin is in phosphorylated
forms (phosphate esters) and intestinal
phosphatases hydrolyze them to free thiamin
before the vitamin is absorbed.
• Thiamin absorption occurs through an active
transportation system in the jejunum and ileum
• Transportation of thiamin in red blood cells
among other tissues requires carriers some
which are energy dependent (ThTr1, found
especially in skeleton muscles and ThTr2 found
in the liver, kidney and heart (among others).
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10. Metabolism ofVitamin B1
• The free thiamin is phosphorylated mainly by
the liver and muscles but also by the brain,
heart and kidney.
• The phosphorylation reaction requires energy
in the form of ATP and it is catalyzed by
thiamine pyrophosphokinase.
• After this reaction, thiamin diphosphate (TDP
or TPP), triphosphate (TTP) and
monophosphate(TMP) are formed.
• About 80% of the total thiamin in the body
exist asTDP
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12. Sources ofVitamin B1
• Thiamine is widely destributed in foods. Meats
(especially pork) are major sources of this
vitamin.
• Legume,seeds and nuts, along with cereals and
grain products ( rice, bread, spaghetti, biscuits
etc) also provide thiamine in relatively high
amounts.
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15. Functions
• Thiamin plays the following roles in the body
Coenzyme role
Oxidative decarboxylation of alpha ketoglutarate.
Oxidative decarboxylation of pyruvate.
Transketolation in the pentose phosphate pathway.
Membrane and nerve conduction ( in a non
coenzyme capacity)
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16. Coenzyme Role
• Oxidative decarboxylation of alpha ketoglutarate
TDP acts as coenzyme of the alpha ketoglutarate
dehydrogenase complex, essential for the conversion of alpha
ketoglutarate to succinyl CoA and Co2.
• Oxidative decarboxylation of pyruvate
TDP acts as coenzyme of the pyruvate dehydrogenase
complex which helps in the conversion of pyruvate to Acetyl
CoA and Co2.
• Transketolation in the pentose phosphate pathway
The transketolases in the pentose phosphate pathway,TDP is
used as coenzyme.
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18. Membrane and Nerve conduction
• In nerve membrane,TTP activates ion ( especially
chloride) transport.
• TTP is also involved in nerve impulse transmission
through regulation of sodium channel.
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19. Deficiency ofVitamin B1
Beriberi (Beri means "weakness")
• One of the first symptoms of thiamin deficiency is loss of
appetite (anorexia) and thus, weight loss.
• As deficiency worsens, cardiovascular problem arise,
neurological symptoms such as apathy, confusion, short-
term memory and irritability occurs.
• There are three types that have been identified:
Dry beriberi, found predominantly in older adults,
results from chronic low thiamin intake especially if
coupled with a high carbohydrate intake. It is
characterized by muscle weakness and wasting especially
in the lower extremities, prickling sensation in the toes, a
burning sensation in the feet at night, leg cramps, muscle
atrophy, mental confusion, vomiting.
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20. Deficiency ofVitamin B1
Wet beriber results in more extensive
cardiovascular system involvements than dry
beriberi. Right-side heart failure leads to
respiratory involvements and oedema.
Acute or infant beriberi Affecting mostly
children between two to six months who are
breastfeed by thiamin deficiency mothers.It
can be characterized by symptoms like pale
skin, hoarseness, diarrhoea, oedema, vomiting,
weight loss. It requires immediate attention
and treatment as the acute form might be fatal
for the infants.
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24. Deficiency ofVitamin B1
Wernicke-Korsakoff syndrome(WKS)
• A brain disorder that is about 8–10 times more common in
people with chronic alcoholism than in the general population,
but it can also develop in patients who have severe
gastrointestinal disorders, rapidly progressing hematologic
malignancies, drug use disorders, or AIDS.
• The syndrome is actually two separate conditions that can
occur at the same time, Wernicke’s disease (WD) also
known as Wernicke’s encephalopathy (a type of brain
injury that mostly happens to people who drink a lot of
alcohol) and Korsakoff syndrome (results from prolonged
WD and it is sometimes know as alcohol-related dementia'
because it causes symptoms that are similar to dementia)
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25. DeficiencyVitamin B1
• Dementia is a condition that affects a person’s
thinking, their behavior and their ability to perform
everyday tasks.
• Symptoms of WKS may include confusion, changes
to the eyes and vision, or exaggerated storytelling,
hallucinations, difficulty understanding the meaning
of information, amnesia, loss of muscle
coordination or ataxia (Impaired balance or
coordination, can be due to damage to brain,
nerves or muscles) which may interfere with
walking.
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26. DeficiencyVitamin B1
Alzheimer’s disease
• According to animal model studies, thiamin deficiency
might play a role in the development of Alzheimer’s
disease. For example, thiamin deficiency produces
oxidative stress in neurons, death of neurons, loss of
memory, plaque formation, and changes in glucose
metabolism—all markers of Alzheimer’s disease.
• Autopsy studies have shown that transketolase and
other thiamin-dependent enzymes have decreased
activity in the brains of people with Alzheimer’s
disease
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29. People at risk ofVitamin B1
deficiency
• People with alcohol dependence
Up to 80% of people with chronic alcoholism develop thiamin
deficiency because ethanol reduces gastrointestinal absorption
of thiamin, thiamin stores in the liver, and thiamin
phosphorylation.Also, people with alcoholism tend to have
inadequate intakes of essential nutrients including thiamin.
• Older Adults
Up to 20%–30% of older adults have laboratory indicators that
suggest some degree of thiamin deficiency. Possible reasons
include low dietary intakes, a combination of chronic diseases,
concomitant use of multiple medications, and low absorption
of thiamin as a natural result of aging.
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30. People at risk ofVitamin B1
deficiency
• People with HIV/AIDS
The association between thiamin deficiency and
HIV/AIDS is probably due to malnutrition as a result of
the catabolic state associated with AIDS.
• People with diabetes
These lower thiamin levels might be due to increases in
clearance of thiamin by the kidneys.The relevance of
these effects to clinical prognosis or outcomes is not
known.
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31. People at risk ofVitamin B1
deficiency
• People who have undergone bariatric
surgery
Bariatric surgery for weight loss is associated with
some risks, including severe thiamin deficiency since
some procedures limit how much you can eat or
the body's ability to absorb nutrients.
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32. Vitamins B1 toxicity
• Thiamin is considered safe.There are no reports
of adverse after the intake of high amounts of
food or supplements.
• This is partly because excess thiamin is quickly
excreted from the body as urine.
• As a result, a tolerable upper intake level of
thiamin has not been established.However, this
doesn't rule out possible symptoms of toxicity
at very high intakes.
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33. References
• Advanced Nutrition and Human Metabolism by
Sareen Gropper, Jack Smith, James L. Groff fourth
edition.
• Handbook ofVitamins fourth edition.
• Department of Nutrition for Health and
Development of theWorld Health Organization
(WHO), 1999
• Harvard T.H CHAN School of Public Health. at
(https://www.hsph.harvard.edu/nutritionsource/vitami
n-b1/), 2020.
• National Institute of Health office of dietary
supplements. Thiamin. 2020.
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34. References
• Netmeds.com. at (https://m.netmeds.com/health-
library/post/vitamin-b1-functions-food-sources-
deficiencies-and-toxicity), 2019.
• Healthline. at
(https://www.healthline.com/health/wernicke-
korsakoff-syndrome), 2017.
• Nishio M, Fujiwara M, Kitamura S, et al., (1948)
symptoms with experimental B1 deficiency and B1
requirements ( In Japanese ).Vitamin 1, 256-258
• Vitamin; structure and functions by RASAQ, N.O
• Nutri-facts; understanding vitamins and more.
www.nitrifacts.org
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