Symmetry Products with Vitamin A:
NutraPack, Mega Juice, Fruit-a-Mins, Premium Plus, Aloe Plus,
Extreme Fuel, Extreme Igniton & Recovery, Ultra Vitality, Future
Star, Symmetry Natural Facial Care System
Vitamin A was identified as a
necessary growth factor in 1915 and was the first vitamin to be
discovered. It is obtained from food in a combination of two
different forms: as pre-formed vitamin A and as pro-vitamin A, which
the body can convert to vitamin A as necessary. Pre-formed vitamin
A, often in the form of retinal or retinol, is found in foods of
animal origin; pro-vitamin A, of which beta-carotene is the best
known form, is found in orange, yellow and dark green vegetables and
fruits. Both forms are fat soluble.
What does it do for your body?
Eyes - Vitamin A is
essential for eyes to function effectively. It is involved in the
growth and repair of the eye and in the production of a chemical
called visual purple, which helps in night vision.
Epithelial Cells - Vitamin A is involved in the growth and
repair of epithelial cells. These cells cover the internal and
external surfaces of the body and are found in the skin, lungs,
developing teeth, inner ear, cornea of the eye, sex organs, glands
and their ducts, gums, nose, cervix and other areas. This growth
and maintenance role is vital for many bodily functions. For
example, the good health of the digestive tract lining is
important in protecting against ulcers and maintenance of the
lining of the vagina and uterus is important in fertility.
Pregnancy - Vitamin A is necessary in pregnancy for the
development of the embryo.
Nerves - Vitamin A is involved in the production of
membranes and myelin, which coats the nerves.
Glands and Hormones - Vitamin A plays a role in the
maintenance of the adrenal gland and synthesis of certain hormones
such as thyroid hormone.
The Immunity System - Vitamin A is known as "the
anti-infective vitamin" as it is vital for the development of
the body’s natural defenses. It stimulates and enhances many
immune functions. This immune enhancing function promotes healing
of tissues and increases resistance to infection.
Adequate vitamin A intake, either from diet or supplements, is
very important, especially for children. Many studies have found
that vitamin A supplementation reduces the risk of infectious
diseases in areas where vitamin A deficiency is widespread. A
recent research review of several studies found that adequate
vitamin A intake in children resulted in many health benefits.
Children in developing countries are often at high risk of vitamin
A deficiency. In developed countries, ensuring adequate vitamin A
intake is particularly important for immune support.
Growth and Bone Formation - Vitamin A is necessary for
growth and the formation of bones and teeth, collagen synthesis,
cartilage synthesis and wound healing.
Antiviral Activity - Laboratory experiments have shown
vitamin A to have antiviral activity.
Absorption
The presence of fat and bile in the
intestines is necessary for vitamin A absorption. Around 80 to 90 %
of vitamin A in the diet is absorbed although this is reduced in
older people and those who have trouble absorbing fat, such as those
who suffer from pancreatitis, celiac disease and cystic
fibrosis, who may run the risk of vitamin A deficiency.
Vitamin A is joined to fatty acids in the intestinal lining,
combined with other substances and transported to the liver, which
stores 90% of the body’s vitamin A.
Deficiency
Vitamin A deficiency is relatively
rare in developed countries and is usually limited to those who have
absorption difficulties, liver disease or who drink a lot of
alcohol. Vitamin A deficiency is common in alcoholics and
contributes to some of the disorders of alcoholism, such as night
blindness, skin problems, cirrhosis of the liver and susceptibility
to infections.
Vitamin A deficiency symptoms:
Eyes - One of the first
symptoms of deficiency is night blindness due to lack of visual
purple. Prolonged deficiency leads to xerophthalmia, a condition
in which eyes become dry, ulcers appear on the cornea, the eyelids
become swollen and sticky and which eventually leads to blindness.
Vitamin A deficiency is the leading preventable cause of blindness
in developing countries.
Skin - Prolonged deficiency leads to thickened dry skin
which is prone to infections. Small hardened bumps of a protein
known as keratin may develop around the hair follicles.
Growth - Deficiency causes growth retardation, weight loss,
diarrhea, thickening of bone shafts, congenital malformations,
impaired hearing, taste and smell, wasting of testicles and
reduced sperm count. Inadequate vitamin A intake may lead to
improper tooth formation in children and to gum disease.
Immune System - Epithelial surfaces are adversely affected
by vitamin A deficiency, causing increased susceptibility to skin
and respiratory infections. Immune cells and antibody functions
are also affected which may lead to an increase in pre-cancerous
cells in the epithelial tissues of the mouth, throat and lungs.
Thyroid Gland - A deficiency of vitamin A can contribute to
lower levels of active thyroid hormone with symptoms of low body
temperature, depression, difficulty in losing weight, headaches
and lethargy.
Therapeutic uses
Vitamin A supplements are used in
developing countries to prevent or treat deficiency and to
protect immune system function.
Skin Disorders - The vitamin A derivatives etretinate and
isotretinoin are used topically to treat psoriasis. These compounds
inhibit the formation of some of the toxic compounds which may be
responsible for the high rate of cell division causing the scaly
build up on the skin.
Other Uses
Vitamin A eye drops have been used to treat dry eyes.
Creams containing vitamin A have been used to heal wounds in
patients taking corticosteroid drugs.
Interactions
Vitamin E and zinc are necessary for vitamin A metabolism, including
absorption, transport and release from the liver. Vitamin E may
protect against some of the effects of excess vitamin A.
Vitamin A is necessary for calcium metabolism in the formation of
healthy bones and teeth.
Vitamin A absorption is reduced by mineral oil laxatives, which bind
it. Antacids, the anti-gout drug colchicine, and the cholesterol
reducing drug cholestyramine inhibit vitamin A absorption.
Alcohol irritates the digestive tract and inhibits the absorption of
vitamin A while also depleting the body’s tissue stores.
Cautions
Pre-formed vitamin A supplements in doses of more than 3000 mg RE
should not be taken by women who may become pregnant. Pro-vitamin A
or beta-carotene are safe for pregnant women.
Vitamin A supplements should not be taken with isotretinoin or
etretinate for skin disease or in cases of impaired liver or kidney
function. If vitamin A supplements are taken with large amounts of
alcohol, liver damage may occur.
Broad spectrum antibiotics should not be taken with high doses of
vitamin A.
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