Alternative names: Beta Carotene or Retinol.
Unfortunately, many people consider vitamin A to be a "toxic vitamin" or one of little value because its potential dangers have been exaggerated. Toxicity is related to dosage and form – almost everything becomes harmful at some level. Water-soluble vitamin A does not bioaccumulate in the liver as the typical fat-soluble form does. Very high doses (above 100,000 IU per day) of the water-soluble form are routinely used by many alternative doctors for a variety of conditions with a much greater degree of safety.
There are two ways to get the fat-soluble vitamin A though the diet; as preformed retinol compounds found in liver, dairy products, and fish; and as provitamin A, primarily beta-carotene found in carrots, yellow squash, and a host of other fruits and vegetables.
Healthy adults produce vitamin A from vegetable carotenes, but many people, particularly infants, diabetics and individuals with poor thyroid function, do so less efficiently. Vitamin supplements can be an important source of vitamin A for such people, yet many vegetarian and prenatal products contain only beta carotene, which appears to convert to vitamin A at a fixed rate. Preformed vitamin A delivers the desired dosage more reliably; it is found naturally in foods such as yellow and dark-green vegetables, fruits, dairy foods, eggs and cod liver oil.
The unit measurements of vitamin A are a bit confusing. One retinol equivalent is defined as 1mcg of retinol. One U.S.P. unit (and also the International unit IU) is equivalent to 0.3mcg of retinol. That means that 3 IUs equals 1 retinol equivalent. That said, 6mcg of beta-carotene is considered to be equal to 1mcg of retinol or 3 IU.
The current US RDA for Vitamin A is 5,000 IU. Both synthetic and natural sources of Vitamin A are available. Most natural sources are from fish liver oil (FLO).
Vitamin A is involved in a number of systems in the body where it plays a role in cell differentiation.
Vitamin A helps the body overcome the problem of thickening and hardening of the artery walls (disseminated sclerosis) in the circulatory system. It helps reduce blood cholesterol, and is essential for the normal structure and function of epithelial cells which protect the body from all kinds of environmental contamination. Vitamin A is a very powerful antioxidant for your heart and circulatory system.
Vitamin A is best known as the vitamin for the eyes. In fact, as far back as ancient Egypt night blindness and some eye disorders were treated with topical application of the juice of cooked livers (high in vitamin A). It was estimated that around the world over 500,000 children become blind each year due to vitamin A deficiency.
The World Health Organization recommends large doses of vitamin A to treat measles – a leading killer in developing countries. The late nutrition pioneer, Carlton Fredericks, Ph.D., recommended single doses of vitamin A as high as 200,000 IU for three to five days to stop the onset of a cold. Since vitamin A is important for the body's first line of defense, the mucous membrane, it may well be the anti-infective vitamin of choice. Therapeutic doses also help treat glaucoma and conjunctivitis (an inflammation of the mucous membrane that lines the eyelids). In this instance, topical, sterile vitamin A is used.
Although women of child-bearing age must be extremely cautious (consult a doctor before taking over 10,000 IU of either form), in other circumstances vitamin A can have profound therapeutic effects. It fights infection and supports the immune system right along with zinc lozenges, vitamin C and echinacea.
There is no question that, when taken in excess, fat-soluble vitamins can accumulate in tissues and cause symptoms of toxicity. A 1995 study reported that women who take more than 10,000 IU of preformed vitamin A daily during the first three months of pregnancy run an increased risk of having a child with birth defects. [Rothman, K. "Teratogenicity of high vitamin A intake," New England Journal of Medicine 333: pp.1369-73, Nov. 23, 1995] The study neglects to point out, however, that a vitamin A deficiency also puts an unborn child at risk and that vitamin E may prevent vitamin A from oxidizing and becoming toxic.
Toxicity symptoms include chapped lips, dry skin, headache, fatigue, emotion swings and muscle or joint pain.
Higher doses (>6,000 IU per dose) of vitamin A, found in some multivitamins or immune-enhancing products should be avoided by pregnant women as this may be harmful to the pre-born baby. This is not true of beta-carotene and higher doses may be ingested with little to no harm.
Retinoids – synthetic versions of vitamin A – can be applied as a topical ointment or taken orally. This doesn't cause the same side-effects as corticosteroids, but may irritate the mucous membranes of the mouth.
Vitamin A is important for tissue synthesis and enhances resistance to infection.
Vitamin A is important for a healthy gut. Vitamin A deficiency can worsen diarrhea symptoms in IBS because of reduced mucous membrane health. Diarrhea can also cause loss of vitamin A, which leads to a vicious cycle.
Some practitioners believe that vitamin A may slightly delay vision loss. According to a study reported in the Archives of Ophthalmology on June 14, 1993, most adults with blinding retinitis pigmentosa should take a daily 15,000 IU vitamin A supplement, based on results from this large, randomized clinical trial.
Eliot L. Berson, MD, the study's principal investigator and Professor of Ophthalmology at Harvard Medical School, said that adults who supplemented their diets with 15,000 IU of vitamin A daily had on average about a 20% slower annual decline of remaining retinal function than those not taking this dose.
Based on this finding, Dr. Berson and his colleagues estimated that an average patient in the study who started taking a 15,000 IU vitamin A capsule at age 32 would retain some useful vision until age 70, whereas a patient not on this dose would lose useful vision by age 63.
In one study, serum retinol levels (a measure of vitamin A levels) were found to be significantly lower in women with menorrhagia than in healthy controls. One should not exceed 10,000 IU per day if at risk of becoming pregnant.
Vitamin A at 75,000 IU per day for 2 months or until Pap smear results improve, then 25,000 IU per day as a maintenance dose. The preferred form is water-soluble vitamin A. However, doses of vitamin A over 10,000 IU/day should not be considered if pregnancy is a possibility. Vitamin A injections into the cervix have been used successfully when other methods have failed.
Vitamin A has been shown to be beneficial in reducing PMS symptoms when given in doses of 100,000 to 300,000 IU per day in the second half of the menstrual cycle. These levels should only be achieved by a water-soluble form of vitamin A and supervised by a doctor.
Beta-carotenes may be better indicated since they are less toxic and endogenous regulation of conversion to retinol helps maintain more appropriate levels. The enzymatic conversion of beta-carotene to vitamin A is increased twofold during mid-ovulation. It is believed that there is a storage capacity for beta-carotene, which is converted to retinol as needed by the corpus luteum.
The risk of vitamin A deficiency is higher for young children whose mothers are vitamin A deficient. Maternal vitamin A deficiency results in reduced fetal stores and lower levels of vitamin A in breastmilk.
Infants and young children who are vitamin A deficient are at an increased risk of appetite loss, eye problems, lower resistance to infections, more frequent and severe episodes of diarrhea and measles, iron deficiency anemia, and growth failure. Infections and inflammation accelerate the use and loss of vitamin A.
The increased risk of illness leads to an increased risk of death. Studies show that in communities where vitamin A deficiency is prevalent, improving vitamin A status reduces child deaths by an average of 23%. Vitamin A is particularly protective against deaths due to diarrhea and measles and may reduce the severity of malaria symptoms.
In the first six months of life, breastmilk protects the infant against infectious diseases that can deplete vitamin A stores and interfere with vitamin A absorption. Vitamin A intake of a breastfed child depends on the vitamin A status of the mother, the stage of lactation, and the quantity of breastmilk consumed. From birth to about six months of life, frequent breastfeeding can provide the infant with all the vitamin A needed for optimal health, growth, and development. Breastmilk is generally higher in nutritional value than alternative foods and liquids fed to children in developing countries. Consumption of other foods decreases the amount of breastmilk consumed and may disrupt the infant's absorption of vitamins and minerals from the breastmilk. Therefore, exclusive breastfeeding until six months of age helps ensure sufficient vitamin A intake.
Vitamin A deficiency appears to be both a consequence of Lyme disease (Borrelia burgdorferi infection) and a factor in the resulting arthritis susceptibility.
If detected early, treat with 30,000 IU of vitamin A daily for a week. In cases of advanced Vitamin A Deficiency, 20,000 IU of vitamin A per kg of body weight is given every day for at least 5 days. Treatment needs to be started as soon as possible. If it is delayed too long, problems may become permanent.
The (obvious) treatment is to stop taking vitamin A immediately. The symptoms usually improve in a few days.
Recent research shows that Type II diabetics who consumed foods high in vitamin A were the most efficient insulin users. [Facchini, F., et al. "Relation between dietary vitamin intake and resistance to insulin-mediated glucose disposal in healthy volunteers," Am J of Clin Nutr 63: pp.946-9, June 1996]
Vitamin A ( a water-soluble kind only) taken orally at 100,000IU /day for a month, then 50,000IU/day for 1 month, then 25,000IUK/day may cause warts to disappear. Vitamin A helps normalize cell resistance and assists the immune system. Do not take over 10,000IU/day if there is any chance of pregnancy.
Vitamin A can be useful in any skin healing process. Levels of 10-15,000 IUs are usually sufficient.
Vitamin A has been shown to be effective in treating acne when used at very high doses (300,000 to 400,000IU per day) for many months, but caution must be advised because vitamin A toxicity can result. The toxicity potential means that this therapy must be monitored closely, conducted with a water-soluble form of vitamin A and probably be used in lower doses (100,000 to 200,000IU) along with other therapies, not as a single treatment.
Vitamin A and vitamin D3 inhibit breast cancer cell division and can induce cancer cells to differentiate into mature, noncancerous cells. Vitamin D3 works synergistically with tamoxifen (and melatonin) to inhibit breast cancer cell proliferation. Breast cancer patients should take 4000 to 6000 IU of vitamin D3 every day on an empty stomach. Water-soluble vitamin A can be taken in doses of 100,000 to 300,000 IU every day. Monthly blood tests are needed to make sure toxicity does not occur in response to these relatively high daily doses of vitamin A and vitamin D3. After 4 to 6 months, the doses of vitamin D3 and vitamin A can be reduced. If pregnancy is a possibility, these doses of vitamin A should not be used.
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