Water Soluble Vitamins

Thiamin Vitamin B1

Thiamin (Vitamin B1) Thiamin is a first member of the vitamin B complex, therefore, it is also known as vitamin B1. Due to its role in the prevention of beriberi, thiamin is also called as the antiberi-beri factor. Since it has an important role in the nervous system, thiamin is also called as aneurine.

Thiamin (Vitamin B1) Structurally, thiamin consists of a pyrimidine ring, which is linked to a thiazole ring. Thiamin occurs in nature as thiamin hydrochloride. Thiamin is heat labile, but acid resistant.

Biochemical Functions Thiamin pyrophosphate (TPP), i.e. diphosphorylated form of the thiamin, is referred to as the coenzyme of vitamin B1.

Sources Rich sources of thiamin are cereal grains, yeast, liver, kidney, and heart.

Requirements Average daily requirement is 1.2-1.8 mg/day. Daily requirement however, depends upon the carbohydrate intake and has been defined as 0.4-0.5 mg/1000 Kcal. Requirement is increased during fever, in hyperthyroidism, alcoholics, and pregnancy.

Absorption & Metabolism The bound forms of Thiamin are split in gastro-intestinal tract during digestion . Absorbed mainly from duodenum and jejunum. Very little Thiamin is stored in body. Thiamin intake if in excess of needs it is excreted in urine

Biochemical Functions TPP plays an important role in carbohydrate metabolism. It is used as a coenzyme in oxidative decarboxylation of α-keto acids, e.g. Pyruvate Acetyl CoA α-Ketoglutarate Succinyl CoA TPP also acts as a coenzyme for transketolase, an enzyme of the hexose monophosphate shunt. Pyruvate dehydrogenase complex Α-Ketoglutarate dehydrogenase complex

Deficiency Symptoms Thiamin deficiency causes beriberi. Beriberi is of different types: Wet beriberi: It affects cardiovascular system and results in edema and dilated heart. Dry beriberi: It normally affects the central nervous system and causes peripheral neuropathy with myelin degeneration, leading to foot-drop, wrist-drop, and sensory changes.

Deficiency Symptoms Cerebral Beri Beri or Wernicke’s encephalopathy: It is generally observed in chronic alcoholics, who may develop CNS manifestations, ophthalmoplegia, cerebellar ataxia, and mental impairment. Thiamin deficiency may also occur in areas where people consume polished-rice or raw-fish as well as in chronic alcoholics. Deficiency symptoms include nausea, vomiting, weakness, and tenderness of the calf muscles.

Beriberi

Deficiency Diseases Chronic alcoholism can also lead to thiamin deficiency, the disease produced is termed wernicke’s syndrome.

Risk Factors for Deficiency Alcoholism Cirrhosis Malabsorption Diabetes Kidney Diseases Chronic Infections

Systems affected by deficiency GIT Nervous System Cardiovascular System Musculoskeletal System

Symptoms of Wet Beriberi Fast heart rate Swollen feet and legs Enlarged heart Enlarged and tender liver Shortness of breath Congestion in the lungs

Symptoms of Infantile Beriberi Restlessness Difficulty sleeping Diarrhea Swollen arms and legs Muscle wasting in arms and legs Silent cry Heart failure

Toxic effects Human have limited toxic reaction to thiamin.The sign include Edema Sweating Tremors Tachycardia Fatty liver/ tumors and Vascular Hypotension

Riboflavin Vitamin B2

It is named riboflavin because of its structural similarity to sugar ribose and its relationship to the flavins.

Riboflavin (Vitamin B2) Riboflavin is also called as lactoflavin, due to its high content in milk. It is sensitive to light and ultraviolet irradiation. Riboflavin is heat-stable both in acidic and neutral medium. Riboflavin contains an isoalloxazine ring with a ribitol side chain.

Riboflavin structure

Sources Milk , egg, liver, and kidney are rich sources of vitamin B2.

Flavin Adenine Dinucleotide

Requirements Its average daily requirement is 1-2 mg/day (0.5-0.6 mg/1000 Kcal).

Functions In phosphorylated form, is an essential component of flavoprotein co-enzymes. Riboflavin is also involved in oxidative degradation of short chain fatty acids and transfer of oxygen from plasma to tissues.

Biochemical Functions Coenzymeforms of riboflavin are referred to as FMN and FAD. FMN (flavin mononucleotide) has a molecule of riboflavin and phosphoric acid. FAD (flavin adenine dinucleotide) is a dinucleotide of FMN and AMP. These two coenzymes form an integral part of the flavoprotein-containing enzymes and participate in oxidation-reduction reactions.

Biochemical Functions FMN FMN.H2 α-Ketoglutarate FAD.H2 +2H +2H

Biochemical Functions FMN is used as a coenzyme with cytochrome C reductase and L-amino acid oxidases. FAD is used as a coenzyme with succinate dehydrogenase, glycerol-3-phosphate dehydrogenase, sphingosine reductase, glycine oxidase, xanthine oxidase, D-amino acid oxidases, and acyl CoA dehydrogenase. FAD is important in the metabolism of carbohydrates, lipids, as well as proteins.

Metabolism of some vitamins and minerals also require riboflavin. It is important for body growth and red blood cell production and helps in releasing energy from carbohydrates. In the treatment of anemia, adding Vitamin B2 to iron supplements has shown to increase its effectiveness

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.

Deficiency Symptoms Deficiency symptoms include cheilosis (lesions at the angles of the mouth), glossitis, and ocular as well as skin changes, such as localized dermatitis of the face. There also occur functional and organic disorders of the eye, including photophobia, lacrimation, burning, and itching.

Riboflavin deficiency Deficiency can result in: Heart disease Carpal tunnel syndrome Multiple sclerosis Anxiety, stress and fatigue

Glossitis

Carpal tunnel syndrome may benefit from a treatment program including this vitamin when combined with vitamin B6. Maintenance of epithelial, eye and mucosal tissues require riboflavin .

Carpal Tunnel Syndrome

PESHAWAR MEDICAL COLLEGE Multiple sclerosis PESHAWAR MEDICAL COLLEGE

Low levels of B-2 Arthritis Colon cancer Skin lesions Light sensitivity Eye disorders Inflamed mouth or tongue, and Cracks and sores at the mouth's corner.

Arthritis

Pyridoxine Vitamin B6

Introduction Vitamin B6 is actually a collective term for three naturally occurring pyridines that are functionally and metabolically related: Pyridoxine Pyridoxal Pyridoxamine Discovered during Nutritional studies on rats in 1930

2 Methyl.3 hydroxy,4,5 dihydroxymethyl pyridine Chemical structure Pyridoxal Pyridoxine 2 Methyl.3 hydroxy,4,5 dihydroxymethyl pyridine Pyridoxamine

Active forms are Pyridoxal Phosphat Aldehyde group at position 4 can reversibly attach with NH3.

Food sources Found in wide varieties of foods. Beans, Legumes and nuts Eggs, Meats ( beef, chicken breast) Fish (Trout, Salmon, tuna) Bread and cereals Spinach and tomato Banana

Functions Vitamin B6 is involved in variety of metabolic processes. Plays a major role in amino acid metabolism Trasamination Decarboxylation Transulfuration

Functions Needed for conversion of Tryptophan to niacin Formation of melanin Breakdown of glycogen to glucose Inter conversion of glycine and serine where it functions along with Folic Acid.

Absorption and Metabolism Readily absorbed from intestine. In cytoplasm it is converted into Pyridoxal phosphate and pyradoxalamine Phosphate by pyridoxal Kinase and ATP. These are the active forms of the vitamin. Mainly found in extra-cellular fluid

Concentration is relatively high in Leukocytes Nerve tissues and Liver As water soluble, very little is stored and Any excess, is excreted in urine in the form of pyridoxic acid.

Recommended Daily Allowances The daily requirements of Vitamin B6 Directly related to protein intake RDA 2.2 mg for men and 2 mg for women.

Effects of Deficiency After prolong deficiency is commonly seen in pregnant women and infants. Dermatitis Glossitis Blood disorders

Dermatitis

Seborrheic dermatitis

Cheilosis Angular stomatitis Peripheral neuropathy and

Toxic Effects Very limited toxicity in humans