Vitamin A

"A deficiency of vitamin A is not only disease causing, but it can kill [the author probably mentioned this because vitamin A helps to fight off infections such as measles]."

Wikipedia: Retinol

Overdoses of Vitamin A

"On the other hand, overdoses of vitamin A are also lethal. The livers of certain animals, especially those adapted to polar environments, often contain amounts of vitamin A that would be toxic to humans."

Wikipedia: Retinol

Birth Defects

"Avoid

· Vitamin A supplements, as well as

· Any cosmetic or skin care item containing retinols,

if you are pregnant or trying to conceive - vitamin A can be toxic to the fetus and can cause birth defects."

eHow.com: How to Best Absorb Vitamin A Supplements

Large Doses

"Avoid taking mega doses of vitamin A - more than 50,000 IU per day - unless directed to do so by your doctor. Because vitamin A is stored in fatty tissue, it can build up in your body and cause adverse reactions. The recommended dose is 7,500 to 10,000 IU per day."

eHow.com: How to Best Absorb Vitamin A Supplements

Prescription Medicines

"If you taking prescription medicine, consult with your doctor or pharmacist before taking supplements."

eHow.com: How to Best Absorb Vitamin A Supplements

What is Vitamin A?

Two Forms

"Vitamin A is fat soluble and is most commonly found in two forms: preformed vitamin A (or retinol) and beta-carotene."

eHow.com: How to Best Absorb Vitamin A Supplements

Dosage

"The dosage underneath is the Recommended Dietary Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.

Male 5,000 IU [minimum] per day (1,000 µg equivalent), female 4,000 IU [minimum] per day (800 µg retinol equivalent), although 10,000 IU per day is normally used in supplementation."

Sallamander Concepts: Vitamin A (retinol and beta-carotene) information page

"Dosages exceeding 15,000 IU per day must be taken under medical supervision. Toxicity can appear in some individuals at relatively low dosages and the symptoms may include nausea, dizziness, menstrual problems, skin changes and dryness, itchiness, irritability, vomiting, headaches and long term use can cause hair loss, bone and muscle pain, headache, liver damage, and an increase in blood lipid concentrations."

Sallamander Concepts: Vitamin A (retinol and beta-carotene) information page

"Pregnant women must be careful as a high intake of this vitamin can cause birth defects."

Sallamander Concepts: Vitamin A (retinol and beta-carotene) information page

"[In general] Pro-vitamin A - beta-carotene [carotene is also known as pro-vitamin A] does not cause toxicity. Be careful if you in the unlikely event run across polar bear on a menu - 500 gram (about ½ a pound) of polar bear liver will deliver about 9,000,000 IU to your diet - a very lethal dose. Headaches, blurred vision, loss of hair, drowsiness and diarrhea, enlargement of the spleen and liver can all be indications when your intake is too high."

Sallamander Concepts: Vitamin A (retinol and beta-carotene) information page

"There seems to be no toxicity when ingesting large amounts of beta-carotene - you might however have a slightly orange colored skin, as the carotene gets stored in your skin."

Sallamander Concepts: Vitamin A (retinol and beta-carotene) information page

Effects

Deficiency of Vitamin A

"A deficiency of vitamin A is not only disease causing, but it can kill."

Wikipedia: Retinol

"Deficiency of Vitamin A can cause night-blindness, pale, dry skin."

Wikipedia: Retinol

"A deficiency of vitamin A

· may lead to eye problems with dryness of the conjunctiva and cornea,

· dry skin and hair,

· night blindness as well as

· poor growth.

· Dry itchy eyes that tire easily are normally a warning of too little vitamin A. If the deficiency becomes severe, the cornea can ulcerate and permanent blindness can follow."

Sallamander Concepts: Vitamin A (retinol and beta-carotene) information page

· "Abscesses forming in the ear,

· Sinusitis,

· Frequent cold and respiratory infections as well as

· Skin disorders, such as acne, boils and a bumpy skin, as well as

· Weight loss

might be indicative of the vitamin being in short supply.

· Insomnia,

· Fatigue and

· Reproductive difficulties

may also be indicative of the vitamin in short supply.

· Your hair and scalp can also become dry with a deficiency, especially if protein is also lacking."

Sallamander Concepts: Vitamin A (retinol and beta-carotene) information page

Antioxidant Effects

"Retinol, Vitamin A or beta-carotene: It has been discovered that beta-carotene protects dark green, yellow and orange vegetables and fruits from solar radiation damage and it is thought that it plays a similar role in human body."

Wikipedia: Antioxidant

Retinol

"Retinol, the most useful form of vitamin A, (along with retinal and retinoic acid) is a fat-soluble,

· antioxidant vitamin

· important in vision and bone growth. It is

· sometimes used in the treatment of severe acne.

As can be seen from the structure, this is a compound synthesized from isoprene."

Wikipedia: Retinol

More Effects

"Vitamin A is needed to

· Maintain healthy skin,

· Prevent night blindness and

· Protect against cancer and other diseases;

· It may also help keep your blood sugar balanced."

eHow.com: How to Best Absorb Vitamin A Supplements

· "It also assists your sense of taste

· as well as helping the digestive and urinary tract and many believe that it helps slow aging.

· It is required for development and maintenance of

the epithelial cells,
in the mucus membranes, and
your skin, and

· is important in the formation of bone and teeth,

· storage of fat and

· the synthesis of protein and glycogen."

Sallamander Concepts: Vitamin A (retinol and beta-carotene) information page

Sources

Vitamin A

Must be Consumed Raw

"Vitamin A gets destroyed at about 40 degrees Celsius [104 degrees Fahrenheit], hence these foods [carrots, spinach, milk, eggs] must be consumed raw in order to avail maximum benefit."

Wikipedia: Retinol

Some Sources

"The richest food sources of vitamin A are

· liver,

· fish liver oil,

· dark green and orange vegetables, and

· milk products."

eHow.com: How to Best Absorb Vitamin A Supplements

"Vitamin A is found in:

· Carrots,

· Spinach,

· Milkand

· Eggs"

Wikipedia: Retinol

· "Carrots,

· squash,

· broccoli,

· sweet potatoes,

· tomatoes,

· kale,

· collards,

· cantaloupe,

· peaches and

· apricots

are particularly rich sources of beta-carotene."

Wikipedia: Antioxidant

Water-Soluble Forms of Vitamin A

Less Absorbable

"The other forms of Vitamin A, generally found in multi-vitamins, are in a solid state at room temperature and are less absorbable by the body."

Biological Basis for Perceptual Deficits: Vitamin A and G Proteins: FAQ

Vitamin A Palmitate

"Many items on the market, such as skim milk and baby formula, use Vitamin A in the form of A Palmitate, which is water-soluble. These children [children with autism] need the lipid-soluble [fat soluble] form of Vitamin A found in liver, kidney, milk fat and cod liver oil."

Biological Basis for Perceptual Deficits: Vitamin A and G Proteins: FAQ

Beta-Carotene

"The first (pro vitamin A) is also known as carotene and can be found in yellow, orange and green vegetables and fruits and is converted to Vitamin A by the body.

In plants, Vitamin A is found mainly in the form of beta-carotene. Beta-carotene is converted to Vitamin A in a process, which ensures that Vitamin A levels do not become excessive. Therefore beta-carotene is generally considered non-toxic."

www.anewlife.co.uk: Facts About Vitamin A

"Beta-carotene rich vegetables and fruit must not be soaked in water for long periods, since the nutrients can be lost like that."

Sallamander Concepts: Vitamin A (retinol and beta-carotene) information page

Fat-Soluble Forms of Vitamin A

Retinol

"The second type of Vitamin A is known as retinol. This is known as a pre-formed A and can be found in foods of animal origin."

www.anewlife.co.uk: Facts About Vitamin A

"Retinol is destroyed by

light,
high temperatures as well as
when using copper or iron cooking utensils."

Sallamander Concepts: Vitamin A (retinol and beta-carotene) information page

Fish Liver Oil

· Arousal: Essential Fatty Acids (EFAs): Things to Avoid: Too Much Fish, Farm-Raised Fish

· Arousal: Essential Fatty Acids (EFAs): Things to Avoid: Dangerous Levels of Vitamin A

· Arousal: Essential Fatty Acids (EFAs): Things to Avoid: Omega-3 Supplements

Absorption

Recommendations

"Take vitamin A with

· B group vitamins,

· vitamins C, D and E,

· choline,

· essential fatty acids

together with

· calcium,

· phosphorus and

· zinc

for the best results."

Sallamander Concepts: Vitamin A (retinol and beta-carotene) information page

· "Take vitamin A supplements with fatty foods, which will help with absorption. Vitamin A needs fat in order to be absorbed properly.

· Take vitamins A and E together. Vitamin E is necessary for vitamin A to be properly metabolized.

· Take zinc with vitamin A if you are using a zinc supplement. It also helps vitamin A metabolize."

eHow.com: How to Best Absorb Vitamin A Supplements

Conditions Requiring more Vitamin A

"More of this vitamin is required when you

· consume alcohol,

· on a low-fat diet, or a

· diet high in polyunsaturated fatty acids,

· if you smoke or live in a polluted area.

It may also be indicated if you

· suffer from diabetes or

· have an under-active thyroid gland.

Be careful of vitamin A in pregnancy."

Sallamander Concepts: Vitamin A (retinol and beta-carotene) information page

· "Smoking may increase your need. Vitamin A is an antioxidant and can help protect against the…damage caused by smoking.

· Avoid using mineral oil laxatives [some antacids also contain mineral oil]. They destroy vitamin A in the body.

· Use antacids only when you really need to. They inhibit vitamin A absorption.

· Check whether your prescription drugs inhibit vitamin A absorption. Some drugs do, such as colchicine, used for gout, and several cholesterol medications.

· Decrease your alcohol consumption if you are a heavy drinker. Besides its other adverse effects, alcohol will interfere with vitamin A absorption."

eHow.com: How to Best Absorb Vitamin A Supplements

"Absorption of vitamin A may be impaired if you have a disorder that impairs fat absorption, such as pancreatitis, celiac disease or cystic fibrosis. Check with your doctor, because you may have a deficiency."

eHow.com: How to Best Absorb Vitamin A Supplements

More Information

· Vitamins: Things to Consider: Absorption

Tips

· "Consider using beta-carotene. Beta-carotene is what gives foods such as sweet potatoes and pumpkins their yellow-orange color. It is a precursor to vitamin A, and is not toxic even in very large doses.

· Take a beta-carotene complex rather than single carotenoids.

· Take other minerals separately, since they can block absorption of carotenoids.

· Use a micellized version of vitamin A if you are sick and in need of extra antioxidant protection. Micellized means that the vitamin has gone through a special process that has made it water soluble, so that it is now more quickly absorbed."

eHow.com: How to Best Absorb Vitamin A Supplements

Links

· DrWeil.com: Ask Dr. Weil: How Much Vitamin A Is Safe?

· Biological Basis for Perceptual Deficits: Vitamin A and G Proteins: FAQ

· Dr. Mary Megson: The Biological Basis for Perceptual Deficits in Autism

Back to 'Vitamins'