Vitamin Deficiency Disorders

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Vitamin Deficiency Disorders

• Abdelaziz Elamin
• MD, PhD, FRCPCH
• Professor of Child Health
• College of Medicine
• Sultan Qaboos University
• Muscat, Oman
• azizmin_at_hotmail.com

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BACKGROUND

• Vitamins are organic substances that are
  essential for several enzymatic functions in
  human metabolism

• Thiamine was discovered in 1912 was thought to
  be a vital amine compound thus the term vitamin
  was invented

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VITAMINS

• Vitamins are classified according to solubility
  into fat soluble water soluble.

• 13 vitamins are known, 4 fat soluble (KEDA) 9
  water soluble (C, Folate the B
  group).

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VITAMIN A

• Vitamin A is a generic term for many related
  compounds.

• Retinol (alcohol), Retinal (aldehyde) are often
  called preformed vitamin A. Retinal can be
  converted by the body to retinoic acid which is
  known to affect gene transcription.

• Body can convert b-carotene to retinol, thus
  called provitamin A.

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FUNCTIONS

• Vision integrity of eye formation of rodopsin
  necessary for dark adaptation.

• Regulation of gene expression vital to cell
  differentiation physiologic processes

• Immunity important for activation of T
  lymphocyte, maturation of WBC integrity of
  physiological barrier.

• Growth development

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Nutrient Interactions

• Zinc deficiency interfere with vitamin A
  metabolism in several ways
• It decreases the synthesis of retinol binding
  protein, which transports retinol to tissues.
• It decreases the activity of the enzyme retinyl
  palmitate, which is necessary for release of
  retinol from the liver.
• Zn is needed for the enzyme that convert retinol
  into retinal.

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Nutrient Interactions/2

• Iron vitamin A.
• Vitamin A deficiency may exacerbate IDF
• Vitamin A supplementation improves iron status
  among children pregnant women.
• Combining vitamin A with iron controls IDA more
  quickly effectively than using iron alone.

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VITAMIN A UNITS

• 1 mg of retinol 6 mg of b-carotene.
• 3 mg of retinol 10 international units of
  vitamin A.
• 100 mg carrots contain 10 mg of b-carotene.

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Recommended Allowance
Life stage mg/day
Infants 400-500
Children 300-600
Adolescent 900M- 700F
Adult 900M- 700F
Pregnant women 750-800
Lactating women 122-1300
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RICH DIETARY SOURCES
Animal Foods Plant Foods
Cod liver oil Sweet potato
Liver kidney Carrots
Egg Cantaloupe
Butter Spinach
Milk cheese Apricot
Fish meet Papaya
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Vitamin A deficiency

• Deficiency of vitamin A leads to
• Night blindness xerophthalmia
• Growth retardation
• Acquired immune deficiency
• Keritinization of epithelia in RT, GIT UT with
  increased risk of RTI, malabsorption UTI.

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THERAPEUTIC USES

• Vitamin A deficiency
• Boosting immunity of infants
• Skin disorders
• Acute promyelotic leukemia
• Cancer prevention (lung breast)

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TOXICITY

• Vitamin A in excess leads to
• Dermatitis with xanthosis cutis
• Hepatosplenomegaly
• Bone pain increased risk of fracture
• Pseudotumor Cerebri

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VITAMIN D

• Vitamin D comprises a group of sterols the most
  important of which are cholecalciferol (vitamin
  D3) ergosterol (vitamin D2).
• Humans animal utilize only vitamin D3 they
  can produce it inside their bodies from
  cholesterol.
• Cholesterol is converted to 7-dehydro-cholesterol
  (7DC), which is a precursor of vitamin D3.

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VITAMIN D

• Exposure to the ultraviolet rays in the sunlight
  convert 7DC to cholecalciferol.
• Vitamin D3 is metabolically inactive until it is
  hydroxylated in the kidney the liver to the
  active form 1,25 Dihydroxycholecalciferol.
• 1,25 DHC acts as a hormone rather than a vitamin
  endocrine paracrine properties.

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FUNCTIONS

• Calcium metabolism vitamin D enhances ca
  absorption in the gut renal tubules.

• Cell differentiation particularly of collagen
  skin epithelium

• Immunity important for Cell Mediated Immunity
  coordination of the immune response.

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Vitamin D deficiency

• Deficiency of vitamin D leads to
• Rickets in small children.
• Osteomalacia
• Osteoporosis

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GROUPS AT RISK

• Infants
• Elderly
• Dark skinned
• Covered women
• Kidney failure patients
• Patients with chronic liver disease
• Fat malabsorption disorders
• Genetic types of rickets
• Patients on anticonvulsant drugs

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Sources of Vitamin D

• Sunlight is the most important source
• Fish liver oil
• Fish sea food (herring salmon)
• Eggs
• Plants do not contain vitamin D3

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THERAPEUTIC USES

• Rickets Osteomalacia
• Osteoporosis
• Psoriasis
• Cancer prevention (prostate colorectal)
• Autoimmune diseases

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TOXICITY

• Hypervitaminosis D
• causes hypercalcemia, which manifest as
• Nausea vomiting
• Excessive thirst polyuria
• Severe itching
• Joint muscle pains
• Disorientation coma.

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RICKETS