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Vitamin A (Beta-carotene, Retinol)

Basic Information

Beta-carotene is a previtamin-A compound found in plants. The
body converts beta-carotene to vitamin A.
Brand names:
Vitamin-A Capsules
Afaxin(R)
Alphalin(R)
Aquasol A(R)
Vitamin-A Oral Solution
Aquasol A(R)
Vitamin-A Tablets
Available from natural sources? Yes
Available from synthetic sources? Yes
Prescription required? No
Fat-soluble or water-soluble: Fat-soluble

NATURAL SOURCES

Apricots, fresh
Asparagus
Broccoli
Cantaloupe
Carrots, sliced
Endive, raw
Kale
Leaf lettuce
Liver
Mustard greens
Pumpkin
Spinach
Squash, winter
Sweet potatoes
Watermelon

REASONS TO USE

  • Aids in treatment of many eye disorders, including prevention of night blindness and formation of visual purple in the eye.
  • Promotes bone growth, teeth development, reproduction.
  • Helps form and maintain healthy skin, hair, mucous membranes.
  • Builds body's resistance to respiratory infections.
  • Helps treat acne, impetigo, boils, carbuncles, open ulcers when applied externally.

    UNPROVED SPECULATED BENEFITS

  • Helps control glaucoma.
  • Buffers against cancer.
  • Guards against effects of pollution and smog.
  • Cushions against stress.
  • Speeds healing.
  • Helps in removal of age spots.
  • Fights infections.
  • Fights skin diseases.
  • Shortens duration of some illnesses.

    WHO NEEDS ADDITIONAL AMOUNTS?

  • Anyone with inadequate caloric or nutritional dietary intake or increased nutritional requirements.
  • Pregnant or breast-feeding women.
  • Those who abuse alcohol or other drugs.
  • People with a chronic wasting illness, excess stress for long periods or who have recently undergone surgery.
  • Those with a portion of the gastrointestinal tract surgically removed.
  • People with recent severe burns or injuries.

    DEFICIENCY SYMPTOMS

  • Night blindness
  • Lack of tear secretion
  • Changes in eyes with eventual blindness if deficiency is severe and untreated
  • Susceptibility to respiratory infection
  • Dry, rough skin
  • Changes in mucous membranes
  • Weight loss
  • Poor bone growth
  • Weak tooth enamel
  • Diarrhea
  • Slow growth

    UNPROVED SPECULATED SYMPTOMS

  • Bone thickening
  • Kidney stones
  • Diarrhea
  • Birth defects
  • Reduced production of steroid hormones

    LAB TESTS TO DETECT DEFICIENCY

    Many months of deficiency required before lab studies reflect
    deficiency.

  • Plasma vitamin A and plasma carotene
  • Dark-adaptation test
  • Electronystagmogram
  • Electroretinogram

    DOSAGE AND USAGE INFORMATION


    Recommended Dietary Allowance (RDA):
    Estimate of adequate daily intake by the Food and Nutrition
    Board of the National Research Council, 1980. See Glossary.
    RDA for vitamin A is expressed in retinol equivalents (RE).
    One RE = 1mcg retinol or 6mcg beta-carotene. IU = International
    units.
    Retinol International
    Age Equivalents Units
    0-6 months 420RE 2,100IU
    6-12 months 400RE 2,100IU
    1-3 years 400RE 2,000IU
    4-6 years 500RE 2,500IU
    7-10 years 700RE 3,300IU
    MALES
    11+ years 1,000RE 5,000IU
    FEMALES
    11+ years 800RE 4,000IU
    Pregnant +200RE +1,000IU
    Lactating +400RE +2,000IU
    What this vitamin does:

  • Essential for normal function of retina. Combines with red pigment of retina (opsin) to form rhodopsin, which is necessary for sight in partial darkness.
  • May act as co-factor in enzyme systems.
  • Necessary for growth of bone, testicular function, ovarian function, embryonic development, regulation of growth, differentiation of tissues.

    Miscellaneous information:

  • Many months of a vitamin-A-deficient diet are required before symptoms develop. Average person has a 2-year supply of vitamin A stored in the liver.
  • Steroids are produced by the adrenal gland and are part of the natural response to stress and immune function. Failure to make these important hormones leaves immune system in a less-than- ideal atate.

    Available as:

  • Extended-release capsules or tablets: Swallow whole with full glass of liquid. Don't chew or crush. Take with or immediately after food to decrease stomach irritation.
  • Oral solution: Dilute in at least 1/2 glass water or other liquid. Take with meals or 1 to 1-1/2 hours after meals unless otherwise directed by your doctor.
  • A constituent of many multivitamin/mineral preparations.
  • Some forms available by generic name.

    WARNINGS AND PRECAUTIONS

    Don't take if you:

  • Are allergic to any preparation containing vitamin A.

    Consult your doctor if you have:

  • Cystic fibrosis
  • Diabetes
  • Intestinal disease with diarrhea
  • Kidney disease
  • Liver disease
  • Overactive thyroid function
  • Disease of the pancreas

    Over age 55:

  • More likely to be malnourished and need supplement.
  • Dosage must be taken carefully to avoid possible toxicity.

    Pregnancy:

  • Daily doses exceeding 6,000 IU can produce growth retardation and urinary-tract malformations of fetus.
  • Don't take megadoses.

    Breast-feeding:

  • Don't take megadoses.

    Effect on lab tests:

  • With chronic vitamin-A toxicity, lab tests show INCREASED blood glucose, blood-urea nitrogen, serum calcium, serum cholesterol, serum triglycerides.
  • Poor results on dark-adaptation test (See Glossary)
  • Poor results on electronystagmogram (See Glossary)
  • Poor results on electroretinogram (See Glossary)

    Storage:

  • Store in cool, dry place away from direct light, but don't freeze.
  • Store safely out of reach of children.
  • Don't store in bathroom medicine cabinet. Heat and moisture may change action of vitamin.

    Others:

  • Children are more sensitive to vitamin A and are more likely to develop toxicity with dosages exceeding the RDA.
  • Toxicity is slowly reversible on withdrawal of vitamin A but may persist for several weeks.

    OVERDOSE/TOXICITY

    Signs and symptoms:
    Bleeding from gums or sore mouth, bulging soft spot on head in
    babies, sometimes hydrocephaly ("water on brain"), confusion or
    unusual excitement, diarrhea, dizziness, double vision,
    headache, irritability, dry skin, hair loss, peeling skin on
    lips, palms and in other areas, seizures, vomiting, enlarged
    spleen and liver.
    NOTE: Toxicity symptoms usually appear about 6 hours after
    ingestion of overdoses of vitamin A. Symptoms may also develop
    gradually if overdose is milder and over a long period of time.

    What to do:

  • For symptoms of overdosage: Discontinue vitamin, and consult doctor. Also see ADVERSE REACTIONS OR SIDE EFFECTS section below.
  • For accidental overdosage (such as child taking entire bottle): Dial 911 (emergency), 0 for operator or your nearest Poison Control Center.

    ADVERSE REACTIONS OR SIDE EFFECTS

    Reaction or effect What to do
    Abdominal pain Discontinue. Call doctor immediately.
    Appetite loss Discontinue. Call doctor when
    convenient.
    Bone or joint pain Discontinue. Call doctor immediately.
    Discomfort, tiredness or weakness Discontinue. Call doctor when
    convenient.
    Drying or cracking of skin or Discontinue. Call doctor
    lips immediately.
    Fever Discontinue. Call doctor immediately.
    Hair loss Discontinue. Call doctor immediately.
    Headache Discontinue. Call doctor when
    convenient.
    In children, premature closure Discontinue. Call doctor
    of epiphyses (the end parts of immediately.
    bones where growth occurs from
    birth through adolescence)
    Increase in frequency of Discontinue. Call doctor when
    urination convenient.
    Increased sensitivity of skin Discontinue. Call doctor when
    to sunlight convenient.
    Irritability Discontinue. Call doctor immediately.
    Vomiting Seek emergency treatment.
    Yellow-orange patches on soles Seek emergency treatment.
    of feet, palms of hands or skin
    around nose and lips

    INTERACTION WITH MEDICINE, VITAMINS OR MINERALS

    Interacts with Combined effect
    Antacids Decreases absorption of
    vitamin A and fat-soluble
    vitamins D, E, K.
    Anti-coagulants Increases likelihood of
    spontaneous or hidden
    bleeding.
    Cholestyramine, colestipol Decreases absorption of vitamin A.
    Mineral oil, neomycin, sucralfate, isioretinoin vitamin-A toxicity. Increases likelihood of
    Oral contraceptives Increases vitamin-A concentrations.
    Vitamin E and utilization of vitamin A. Normal amount facilitates absorption, storage in liver
    Excessive dosage may deplete vitamin-A stores in liver.

    INTERACTION WITH OTHER SUBSTANCES

  • Tobacco decreases absorption. Smokers may need supplementary vitamin A.
  • Chronic alcoholism interfers with the body's ability to transport and use vitamin A.

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