Vitamin A (Beta-carotene, Retinol) |
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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 |
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convenient. |
| Bone or joint pain |
Discontinue. Call doctor immediately. |
| Discomfort, tiredness or weakness Discontinue. Call doctor when |
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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 |
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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 |
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INTERACTION WITH MEDICINE, VITAMINS OR MINERALS
| Interacts with |
Combined effect |
| Antacids |
Decreases absorption of |
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vitamin A and fat-soluble |
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vitamins D, E, K. |
| Anti-coagulants |
Increases likelihood of |
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spontaneous or hidden |
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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. |
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| Vitamin E and utilization of vitamin A. |
Normal amount facilitates absorption, storage in liver |
| Excessive dosage may deplete vitamin-A stores in liver. |
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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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