B1 Thiamine

PART 3: WATER SOLUBLE VITAMIN

Classification Of B1 Vitamin Functions

Sources Absorption & Metabolism

Deficiencies Toxicity

OVERVIEW

CLASSIFICATIONWater

soluble

B – Vitamins

Vitamin C

Dissolve in water easily

Needed in minute amount

Pass easily through the bloodstream

Remain in the body for a short time

Are needed on a daily basis

B – Complex (1-13)

B1 – ThiamineB2 – RiboflavinB3 – Niacin B6 – PyridoxineB9 – Folate B12 – Cobalamine

Provide energy indirectly

Are needed for generating energy (ATP) from macronutrients

B-complex vitamins are particularly important in assisting energy metabolism

Often function as coenzymes (molecule combining with enzyme to help release energy from the vitamin)

VITAMINS ENERGY METABOLISM

Physical Characteristics White , water soluble crystalline solid Complex structure : includes an amino (-NH2) group and a

hydroxyl group

Its amine part forms salts with acids (e.g thiamine reacts with HCL to form thiamine hydrochloride to fortify flour)

B1 – THIAMIN

Physical Characteristics Its hydroxyl part forms esters with acids (e.g thiamine

pyrophoshate coenzyme)

B1 – THIAMIN

Coenzyme thiamin pyrophosphate -TPP is required

for series of metabolic reactions to release energy

from carbohydrate mainly, branched-chain amino

acids & F.A’s

Required for normal growth in children for general

health

Assists in production of DNA and RNA and synthesis

of neurotransmitters for the proper functioning and

maintenance of the nerves (i.e. muscle coordination and a

healthy nervous system)

B1 – THIAMIN FUNCTIONS

Good sources: Pork & pork

products, All meat ;- Liver Beans, Sunflower seeds, Cereals Enriched and

whole-grains Dry beans and peas Bread, flour* Avocado Yeast Milk

SOURCES

Occurs in the upper (B12*) and lower small intestine (duodenum and jejunum)

Absorbed directly into the portal vein and transported to the liver

some B1 is stored in the liver, heart, and kidneys. Most excess thiamine is eliminated through the

kidneys in urine; some seems to be excreted in the sweat as well.

When other B vitamins become deficient, particularly folic acid and vitamin B12, absorption of vitamin B1 is compromised.

ABSORPTION

Water-Soluble Vitamins

Fat-SolubleVitamins

Absorbed in the Small Intestine Small IntestineHydrophobic or

Hydrophilic Hydrophilic Hydrophobic

Absorbed into the Blood Lymph

Stored in the body Not Generally Yes

Can build up and become toxic Not Generally Yes

Need to consume daily Yes No

usually found in pyrophosphate form

active site

METABOLISM

Essential in energy-yielding metabolism, and especially the metabolism of carbohydrates

Thiamine pyrophosphate is an essential coenzymes that catalyze the oxidative decarboxylation of α-keto acids to form an acylated coenzyme A (acyl CoA).

These include pyruvate dehydrogenase , α -keto glutarate dehydrogenase and branched-chain α-keto acid dehydrogenase.

These three enzymes operate by a similar catalytic mechanism.

Catalyzes decarboxylation of a-keto acids, a feature of primary metabolism

• e.g. pyruvic acid → acetaldehyde in glycolysis

• pyruvic acid → acetyl-CoA (Fig.2.15 p23 Dewick)

Helps metabolize carbohydrates Supports nervous system Deficiency causes beriberi (neurological

disorder)

METABOLISM

Reasons for deficiency of B1 : • people with alcoholism. With increased alcoholic intake,

thiamin is poorly absorbed and easily excreted by the body.

• poor dietary intake• Pregnancy, due to loss of appetite, vomiting

Signs and symptoms of B1deficiency : 1. Depression, irritability, difficulty in concentration,

defective memory, anxiety.2. Retarded growth in children.3. Nerves becomes inflamed and painful (neurititis),

muscles becomes weak, reflexes are reduced4. Severe deficiency leads to the disease BERI-BERI.

DEFICIENCIES

Severe Deficiency: Beriberi Symptoms :- a condition that involves poor appetite, weight loss, fatigue,

enlargement of heart with rapid heartbeat and heart failure (Wet Beri-Beri).

causes confusion, muscle wasting, nerve degeneration & damage, where the nervous system is badly affected and may lead to partial paralysis and muscular weakness (Dry Beri-Beri).

Usually only seen in the United States in babies who are fed formula that isn't supplemented with Vitamin B1

seen in people who drink large amounts of alcohol as they develop neuropathic syndrome affecting legs, balance and cognitive function. (need vitamin B1 supplements).

Dramatic: loss of memory-making capacity (Korsakoff’s psychosis) together with acute paralysis of the muscles which moves the eyes ;full syndrome known as:- Weirnicke’s encephalopathy*.

DEFICIENCIES

We have not been able to find any reports of toxicity related to dietary intake of vitamin B1. When supply of the vitamin exceeds our needs, we urinate out the excess. Reflecting the lack of evidence of toxicity, The National Academy of Sciences has not chosen to establish a Tolerable Upper Intake Level (UL) for vitamin B1.

TOXICITY

It can be taken only if strongly prescribed by the doctor, that is in case where a patient is suffering from a chronic disease.

Otherwise there is no need as it is possible to obtain all necessary vitamins and minerals by following a healthy diet.

Sometimes healthy people choose to take multivitamins as “insurance” to make sure they obtain all the vitamins and minerals they need each day. And statistics states that Americans spend billions of dollars on vitamin and mineral supplements each year.

For those requiring supplements: (Note: Vitamin tablets should be taken with a meal or snack to increase absorption. Otherwise the vitamins or minerals will likely be excreted in the urine and wasted)

SUPPLEMENTATION OF VITAMIN B1 Supplements often occur in the form of a tablet,

which usually contains synthetic forms of single or mixed vitamins and minerals.

supplement of vitamin B1 is very limited in our existence as it is found commonly in the form of B-Complex.

Ways to retain the vitamin content of food when cooking:- Refrigerate fresh produce Keep milk and grains away from strong light Avoid washing food too much e.g rice*, fruits and vegetables

during food preparation and storage If you take vitamin supplements, store them at room temperature

in a dry place that's free of moisture Cook food for a short time. Use cooking methods such as: Steaming, microwaving, and stir-

frying to preserve maximum vitamins. To prevent leaching of vitamins or minerals, do not soak

vegetables. Instead, rinse them thoroughly and drain.

STORAGE OF VITAMIN B1

Water soluble vitamins dissolve in water but not in fat, and are generally not stored in the body.

Essential to life, growth, and body maintenance.

Come from food or are produced within the body.

Food should be the source of our nutrients.

Many of the B vitamins, such as thiamin, riboflavin, and niacin, are found in enriched and whole-grain products.

SUMMARY Fat soluble vitamins are

soluble in fat but not in water, and they can be stored in the body’s fat tissue.

essential to life, growth, and body maintenance.

come from food or are produced within the body.

Food should be the source of our nutrients.

The fat-soluble vitamins have both plant and animal sources.

Vitamin B12 is found only in animal products.

Consuming too many can be harmful to health.

Whole food and fortified food can contribute to total water soluble vitamin consumption.

Toxic amounts of each are usually the result of taking high-dose supplements every day.

SUMMARY For example, vitamin A

comes from dairy products and the precursor beta-carotene comes from orange vegetables like squash and carrots.

Consuming too many can be harmful to health.

Whole food and fortified food can contribute to total fat soluble vitamin consumption.

Toxic amounts of each are usually the result of taking high-dose supplements every day.

Text books 1. Food and Nutrition by Anita

Tull. Oxford university press 1996

2. Fox and Cameron’s Food Science Nutrition & Health 7th edition by Micheal E.J. Lean. Oxford university press 2006

Websites1. To insert

SOURCES

Journals 1. To insert

Powerpoints 1. To insert

THANK YOU VERY MUCH FOR YOUR ATTENTION

Author: Nirma Banee

Suggestions most welcomed