Deficiencies Of Water Soluble Vitamins

Deficiencies of water soluble vitamins Dr. Mehzabin Ahmed

Deficiencies of Water-soluble Vitamins 

This group comprises of Vitamins B complex and C.

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Vitamins B complex is made up of a number of vitamins, but the principle ones are listed below.    

Thiamine Niacin Riboflavin Folic acid

Thiamine It is available widely in a number of foods, except refined foods. It is phosphorylated into its active form- thiamine pyrophosphate, which functions to: 1)

Synthesize ATP

2)

Maintains the neural membranes and the nerve conduction in the peripheral nerves.

3)

Acts as a coenzyme in metabolic pathway.

Deficiency state may result from: 1)

Deficient intake- diet comprising mainly of polished rice.

2)

Chronic alcoholism

3)

Chronic diarrheal diseases

4)

Persistent vomiting

5)

Extended intravenous glucose therapy.

Targets of the deficiency 

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1)

Peripheral nerves- dry beriberi-

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usually a symmetrical nonspecific polyneuropathy,

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with myelin degeneration, starting usually in the legs.

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The patient presents with toedrop, footdrop, and later wristdrop and a progressive sensory loss accompanied by motor weakness.

2)

Cardiovascular system- wet beriberi-

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peripheral vasodilation and cardiac failure resulting in edema.

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the heart may also undergo enlargement and dilation with the myocardium appearing pale and flabby.

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Mural thrombi may also be seen.

3)

Central nervous system-Wernicke- Korsakoff syndrome-

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Wernicke encephalopathy presents as ophthalmoplegia, nystagmus, ataxia, mental derangement.

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Korsakoff psychosis presents as retrograde amnesia, inability to acquire new information and confabulation.

Riboflavin 

It is a component of coenzymes, which participate in the oxidation- reduction reactions, and some of the mitochondrial enzymes.

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It is available in meat, dairy products and in vegetables.

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It is seen in cases of deficient intake of multiple vitamins, patients with recurrent infections, advanced cancer, debilitating diseases and in chronic alcoholics.

Clinical features 1)

Cheilosis: cracks and fissures at the angles of the mouth.

2)

Glossitis: the tongue becomes atrophic and reddish blue in color

3)

Eye: corneal opacities and ulcerations

4)

Skin: scaling lesions starting from the nasolabial folds and extending over the cheeks are seen. In well-defined cases atrophy of the skin is seen.

Niacin 

Also called nicotinic acid. It is a component of the coenzymes NAD & NADP, both of which are enzymes in carbohydrate fat and amino acid metabolism.

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It is available in grains, seeds and legumes and in small quantities in meat.

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It can also be synthesized endogenously from tryptophan.

Pellagra 

Deficiency state is known as pellagra and is seen in deficiencies of niacin and tryptophan.

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Causes of the deficiency include chronic illnesses, chronic protein deficiency, chronic alcoholism and long-term administration of isoniazid and 6mercaptopurine.

Features of Pellagra It is characterized by three D’s: 1) Dermatitis: bilateral, symmetrical and on the exposed parts of the body. The skin becomes red, thickened and rough and then begins to scale and desquamate producing fissures. Similar lesions may be seen in the mucous membranes. 2) Diarrhea: due to atrophy of the epithelium of the GIT followed by inflammation and ulceration. 3) Dementia: due to degeneration of the neurons in the brain as well as the corresponding tracts in the spinal cord

Collar of Casal

Dermatitis on the sun exposed areas

Folate 

Requires Vitamin B12 for the activation of the folic acid. 

Vitamin B12 requires intrinsic factor secreted by the gastric parietal cells for its absorption.

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The absence of intrinsic factor thus causes vitamin B12 deficiency, which results in Megaloblastic anemia and is called Pernicious anemia

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They are essential cofactors in the synthesis of nucleic acids.

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Rapidly dividing cells of the fetus are more vulnerable to folate deficiency.

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Deficiency is seen in those with    

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inadequate dietary intake, intestinal malabsorption, chronic smokers and alcoholics and patients on long-term anticonvulsants, and oral contraceptive pills.

Deficiency of vitamin B12 (cyanocobalamin) causes  

Myelin degeneration in the sensory and motor pathways. Pernicious anemia (due to intrinsic factor deficiency)

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The deficiency of either vitamin B12 or folic acid results in megaloblastic anemia.

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It has been noted that folic acid deficiency in the early stages of pregnancy results in neural tube defects in the fetus resulting in meningocele and meningomyelocele.

Megaloblastic anemia RBCs are large & neutrophils are hypersegmented

Vitamin C- Ascorbic acid 

It is found in milk and animal products and a variety of fruits and vegetables.

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It is important in the hydroxylation of the procollagen, which then can be cross-linked.

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Deficiency of vitamin C thus causes a deficient production of collagen. The collagen that is produced lacks the tensile strength and are more vulnerable to enzymatic degradation.

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Vitamin C also acts as an antioxidant for the free radicals. It can also act indirectly by regenerating the antioxidant form of vitamin E.

Scurvy Deficiency of vitamin C cause scurvy characterized by: 1) Hemorrhages: because deficient collagen results in weakening of the walls of the capillaries and venules. This results in formation of hematomas, and bleeding into skin, joints and intracranial spaces. 2) Skeletal changes: deficient formation of the osteoid matrix resulting in bowing and deformities of the bones. 3) Deficient wound healing

Gingival hemorrhages

Periungual hemorrhages

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