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Vitamin 

 

Functions Deficiency Dietary Level per Day Associated with Overt Deficiency in Adults Contributing Factors to Deficiency
ARetinol, Retinaldehyde, Retinoic acid, carotene Visual pigments in the retina; 

Regulation of gene expression and cell differentiation

Beta carotene is an antioxidant),

 

Formation of glycoproteins.

Xerophthalmia, night blindness, 

 Bitot’s spots,

 

follicular hyperkeratosis,

 

impaired embryonic development,

immune dysfunction

<300 μg/d Fat malabsorption, infection,

measles,

alcoholism,

protein-energy malnutrition

DCalciferol,

 

1,25 Dihydroxy vitamin D

Maintenance of calcium balance; enhances intestinal absorption of Ca2+ and

mobilizes bone mineral;

regulation of gene expression cell differentiation and

antiproliferative hormone.

Rickets: skeletal deformation, rachitic rosary, bowed legs;

osteomalacia

In adults

<2.0 μg/d Ageing, lack of sunlight exposure,

fat malabsorption,

deeply pigmented skin

E 

Tocopherols, tocotrienols

Antioxidant, especially in cell membranes; role in cell signaling Peripheral neuropathy, spinocerebellar ataxia,

skeletal muscle atrophy,

retinopathy

Not described unless underlying contributing factor is present Occurs only with fat malabsorption, or genetic abnormalities of vitamin E

metabolism/transport

KPhylloquinone: menaquinones Coenzyme in formation of gamma carboxyglutamate in enzymes of blood clotting and bone matrix Elevated prothrombin time, bleeding <10 μg/d Fat malabsorption, liver disease,

antibiotic use

B1Thiamine-pyrophosphate Coenzyme in pyruvate and alpha ketoglutarate dehydrogenases, and Transketolase; 

Regulates Cl channel in nerve conduction.

 

Important in carbohydrate and amino acid metabolism

Beriberi: neuropathy, muscle weakness and wasting, cardiomegaly, edema, ophthalmoplegia, confabulation (Wernicke’s encephalopathy with Korsakoff’s psychosis) <0.3 mg/1000 kcal Alcoholism, chronic diuretic use,

hyper emesis

 

 

B2Riboflavin

Flavin mononucleotide (FMN) and Flavin Adenine dinucleotide

(FAD)

Coenzyme in oxidation and reduction reactions; prosthetic group of flavoproteins Magenta tongue, angular stomatitis, 

seborrhoea, Cheilosis

<0.6 mg Riboflavin Deficiency Is Widespread But Not Fatal 
B3Niacin

Nicotinic acid, nicotinamide

Coenzyme in oxidation and reduction reactions, functional part of NAD and NADP; role in intracellular calcium regulation and cell signaling Pellagra: pigmented rash of sun-exposed areas, bright red tongue, diarrhea, apathy,

memory loss, disorientation, death in untreated cases

<9.0 niacin equivalents Alcoholism, vitamin B6 deficiency, riboflavin deficiency,

Tryptophan deficiency,

Isoniazid therapy,

carcinoid syndrome, hart nup disease.

 

B6Pyridoxine,

Pyridoxal,

Pyridoxamine

and the

phosphorylated derivatives.

Coenzyme in transamination and

decarboxylation of

amino acids and

glycogen phosphorylase;

modulation of steroid hormone action

Seborrhea, glossitis,

convulsions,

neuropathy,

depression,

confusion,

microcytic anemia

<0.2 mg Alcoholism, isoniazid
Folic acid Coenzyme in transfer of one-carbon fragments in nucleic acid and amino acid metabolism Megaloblastic anemia, atrophic glossitis,

depression,

homocystinuria

<100 μg/d Alcoholism, Sulfasalazine,

Pyrimethamine,

Triamterene,

Methotrexate

 

B12Cobalamine Coenzyme in transfer of one-carbon fragments and metabolism Megaloblastic anemia, loss of vibratory and position sense,

abnormal gait,

dementia,

impotence,

loss of bladder and bowel control,

homocystinemia

methylmalonic aciduria

 

<1.0μ g/d Gastric atrophy (pernicious anemia), terminal ileal disease, strict vegetarianism, acid reducing drugs (e.g., H2 blockers)
Pantothenic acid Functional part of CoA and acyl carrier protein: fatty acid synthesis and metabolism Peripheral nerve damage (nutritional melalgia or

“burning foot syndrome”)

The vitamin is widely distributed in all food stuffs, and deficiency has not been unequivocally reported in humans Alcoholism
HBiotin Co enzyme in carboxylation reactions in gluconeogenesis and fatty acid synthesis; role in regulation of cell cycle Impaired fat and carbohydrate metabolism,

dermatitis

Deficiency is unknown, except total parenteral nutrition, and egg white injury
CAscorbic Acid Co enzyme in hydroxylation of proline and lysine in collagen synthesis; antioxidant; enhances absorption of iron Scurvy: petechiae, ecchymoses, coiled hairs,

inflamed and bleeding gums, joint effusion, poor wound healing, fatigue

<10 mg/d Smoking, alcoholism

 

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