Summary of Vitamins

Vitamin	Functions	Deficiency	Dietary Level per Day Associated with Overt Deficiency in Adults	Contributing Factors to Deficiency
A Retinol, 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
D Calciferol, 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
K Phylloquinone: menaquinones	Coenzyme in formation ofgamma carboxyglutamate in enzymes of blood clotting and bone matrix	Elevated prothrombin time, bleeding	<10 μg/d	Fat malabsorption, liver disease, antibiotic use
B1 Thiamine-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 withKorsakoff’s psychosis)	<0.3 mg/1000 kcal	Alcoholism, chronic diuretic use, hyper emesis
B2 Riboflavin 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
B3 Niacin 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.
B6 Pyridoxine, 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
B12 Cobalamine	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., H2blockers)
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
H Biotin	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
C Ascorbic 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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