SAVED
File name .JPG
File alt. text
Image should be px wide x px tall.
Select Image
home - Nutrition - Vitamins - Vitamin A Written by Dr Sebastian Zeki

Vitamin A

Occurs with single doses of >660,000 units (>200 mg) Symptoms include nausea, vomiting, vertigo, and blurry vision. Toxic dose10 x RDA (10,000 micrograms of retinol or 33,000 IU) Toxicity of vitamin A increased byLiver and kidney diseaseAlcoholismSome drugs, such as tetracyclines. Vitamin A Excess Impairment of the phagocytes and T cells. Xerophthalmia - due to inadequate function of the lacrimal glands Clinical: Night blindness and Bitot's spots (areas of abnormal squamous cell proliferation and keratinization of the conjunctiva), progressing to corneal xerosis and keratomalacia. Repalcement of hair follicles with mucus-secreting glands. Poor bone growth ReplacementTo prevent clinical vitamin A deficiency, Vitamin A supplements can be distributed at 4 to 6 month intervals at the following doses:Infants < 6 months of age -Non breast-fed: 50,000 IU orally Breast fed: 50,000 IU orallyInfants 6 to 12 months of age: 100,000 IU orallyChildren >12 months of age: 200,000 IU orallyMothers: 200,000 IU orally, within 8 weeks of deliveryPregnant women only get10,000 IU daily or 25,000 IU weekly (teratogenicity at high doses) Vitamin A- Clinical manifestations of deficiency Acute toxicity Chronic toxicity SymptomsDry skin, Nausea,HeadacheFatigue, IrritabilityHepatomegaly with stellate cell proliferation (lead to cirrhosis)AlopeciaHyperostosis, osteoporosisIncreased cerebrospinal fluid pressure (pseudotumor cerebri)Teratogenic in first trimester. Vitamin A- Clinical manifestations of deficiency and Excess Written by Dr Sebastian Zeki

Related Stories

•When vitamin D modulates the microbiota for therapeutic purposes

•Genetic prediction of serum micronutrient levels and the risk of frailty: Evidence from a Mendelian randomization study

•A bacterial methyltransferase that initiates biotin synthesis, an attractive anti-ESKAPE druggable pathway

•Vitamin D binding protein genetic isoforms, serum vitamin D, and cancer risk in the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial

•Chemical Characterization, Antioxidant Potential and Phenolic Profile of the Pulp and By-Products of Black puçá (Mouriri pusa), a Fruit from the Brazilian Cerrado region