Monday, October 22, 2012

Summary of Vitamins

Vitamin


FunctionsDeficiencyDietary Level per Day Associated with Overt Deficiency in AdultsContributing 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/dFat 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/dAgeing,
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 presentOccurs 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 matrixElevated prothrombin time,
bleeding
<10 μg/dFat 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 kcalAlcoholism,
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 mgRiboflavin 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 equivalentsAlcoholism,
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 mgAlcoholism, isoniazid
Folic acidCoenzyme in transfer of one-carbon fragments in nucleic acid and amino acid metabolismMegaloblastic anemia,
atrophic glossitis,
depression,
homocystinuria
<100 μg/dAlcoholism,
Sulfasalazine,
Pyrimethamine,
Triamterene,
Methotrexate

B12
Cobalamine
Coenzyme in transfer of one-carbon fragments and metabolismMegaloblastic anemia,
loss of vibratory and position sense,
abnormal gait,
dementia,
impotence,
loss of bladder and bowel control,
homocystinemia
methylmalonic aciduria

<1.0μ g/dGastric atrophy (pernicious anemia), terminal ileal disease, strict vegetarianism, acid reducing drugs (e.g., H2blockers)
Pantothenic acidFunctional 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 humansAlcoholism
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/dSmoking, alcoholism


------------------------------------------ Best Wishes: Dr.Ehab Aboueladab, Tel:01007834123 Email:ehab10f@gmail.com,ehababoueladab@yahoo.com ------------------------------------------
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