Supplements

Vitamin A (Retinol, Carotene)

Vitamin A is available in two forms, retinol, derived only from animals, and pro-vitamin A, or carotene, which is derived from both plants and animals.

Vitamin A, which is fat-soluble, requires fat, as well as minerals, to be properly absorbed. A lack of zinc, vitamin C, vitamin E or protein can inhibit the proper absorption and function of vitamin A in the body.

Protein cannot be utilized by the body without Vitamin A.

Dry Vitamin A, or water-soluble Vitamin A, is available for persons who suffer from upset stomachs due to oil consumption: anyone suffering from acne, or any skin condition where oil might exacerbate the problem. If you are prone to continual pimply eruptions you may find, through a simple blood test, that you are deficient in vitamin A. The skin typically clears on a strong supplement program, using a dosage between 200,000 IU and 500,000 IU per day for three or four months. (Note: a physician should be consulted when taking such high doses.)

An effective protocol for the treatment of psoriasis is 100,000 IU of Vitamin A along with supplemental Vitamin D.

Persons seeking to reduce fat in the their diet may use Vitamin A in its dry form.

Vitamin A stimulates white blood cell function and increases antibody response. Vitamin A enhances the immune system because it is an antioxidant, protecting against colds, flu and infections of the kidneys, bladder, lungs and mucous membranes. As an antioxidant it helps to protect the cells against cancer and other diseases and is necessary for new cell growth.

Vitamin A helps to prevent night blindness and other eye problems. Vitamin A protects against heart disease and stroke; lowers cholesterol levels and slows the aging process.

Vitamin A is required during the growth of cell membranes and also for repair of cell membranes during wound healing.

Other functions of vitamin A include glycogen synthesis, protein metabolism, hormone synthesis, and as a coenzyme in the skin, bone, retina, liver and adrenal glands.

Deficiency: Vitamin A depletion may play a significant role in Chron's disease and gastric ulcers. Dry skin and hair, dryness of the conjunctiva and cornea may indicate Vitamin A deficiency. When the body is deficient in vitamin A, mucus-producing cells are replaced by keratin-producing cells. The secretion of mucus diminishes and the mucous membranes which become tough and relatively inflexible, leaving the body defenseless against invading organisms. Other indications of deficiency include insomnia, fatigue, sinusitis, abscesses in the ears, pneumonia, weight loss, skin disorders such as acne, and reproductive difficulties.

Depleting Agents: Antibiotics, sulfa drugs, contraceptive drugs, alcohol, cortisone, estrogen, mineral oil, coffee, some types of indoor lighting, air pollution, laxatives and some cholesterol-lowering drugs either prevent absorption or interfere with the absorption of vitamin A.

Sources: Butter, whole milk, liver, fortified low fat and skim milk, dark green leafy vegetables and yellow and orange vegetables. Foods that contain significant amounts include apricots, asparagus, beet greens, broccoli, cantaloupe, carrots, collards, dandelion greens, dulse, fish liver and fish liver oil, garlic, kale, mustard greens, papayas, peaches, pumpkin, red peppers, mustard greens, papayas, peaches, pumpkin, red peppers, spinach, spirulina, sweet potatoes, Swiss chard, turnip greens, watercress and yellow squash. Animal sources of vitamin A are up to six times as strong as vegetable sources.

Herb sources: Alfalfa, borage leaves, burdock root, cayenne (capsicum), chickweed, eyebright, fennel seed, hops, horsetail, kelp, lemongrass, mullein, nettle, oat straw, paprika, parsley, peppermint, plantain, raspberry leaf, red clover, rose hips, sage, uva ursi, violet leaves, watercress, and yellow dock.

Precautions: Excess consumption of Vitamin A in either supplement form or in cod liver oil may result in toxicity.

If you have a liver disease do not take over 10,000 IU in pill form or any amount of cod liver oil. If you are pregnant, do not take more than 6,000 IU per day as toxicity of the fetus can occur.

Children are most susceptible to vitamin A toxicity, especially if they take multiple vitamins along with fortified foods; they should not take more than 18,000 IU daily.

Beta-carotene is the best source of vitamin A because the liver converts on the amount of Vitamin A it actually needs. However, anyone with diabetes or hypothyroidism should not take beta carotene as it cannot be converted to vitamin A. Those with these diseases who are consuming beta-carotene in large amounts may be putting unnecessary stress on their liver.

Vitamin A toxicity (hypervitaminosis A) has been widely studied. Tolerance varies among individuals and may be related to liver function status as well as other variables such as body weight. Some people have tolerated doses of 1 million IUs taken daily for five years, while others show symptoms of toxicity with doses as low as 25,000 IU per day. Overdoses or chronic excesses affect the same body systems that are affected by vitamin A deficiency, and some of the symptoms of toxicity and deficiency are the same.

The most common symptom of toxicity is increased intracranial pressure exhibited as chronic headache. Other symptoms of vitamin A toxicity and deficiency are as follows: abdominal pain, muscle and joint pain, fatigue, dry, cracking skin and lips, dry eyes, conjunctivitis, alopecia, anorexia, nausea, diarrhea, leukocytosis, and bone fractures.

Patients must be closely monitored by their provider for any symptoms of toxicity during high dose therapy for skin conditions using isotretinoin (Accutane).

Most multivitamins contain the RDA of 5,000 IU of vitamin A. Dairy products and fortified foods contribute an additional 2,500 IU/day or more. Patients should be careful of using additional fish liver oil supplements or products formulated for "eye health," "immune system enhancement," "skin formulas," "acne formulas," or "bone or joint repair." Any of these formulas are likely to contain additional vitamin A. Always check the labels for vitamin A content, and be careful that daily intake does not exceed the recommended safety levels.

Vitamin A is contraindicated for use in individuals with chronic kidney or liver disease.

Overuse of alcohol makes vitamin A toxicity more likely to occur.

Dosage Ranges and Duration of Administration: As of 1980, vitamin A is measured as retinol equivalents or RE. One RE corresponds to the biological activity of 1 mcg of retinol. However, supplemental vitamin A is still most commonly expressed in international units or IU. One RE is equal to 3.33 IU of retinol.

The current RDAs expressed in RE are 1,000 mcg RE for men, and 800 mcg RE for women. However, for convenience in determining supplement dosages, the following RDA information is expressed in both RE and IU.

• Infants up to 1 year: 1,875 IU400 mcg RE
• 1 to 3 years: 2,000 IU400 mcg RE
• 4 to 6 years: 2,500 IU500 mcg RE
• 7 to 10 years: 3,500 IU700 mcg RE
• Males over 10 years: 5,000 IU1,000 mcg RE
• Females over 10 years: 4,000 IU800 mcg RE
• Pregnant women: 5,000 IU1,000 mcg RE
• Lactating women: 6,500 IU1,200 mcg RE

Dr Atkins recommends 5,000 IU of vitamin A every day. For a retinol-deficiency ­related illness, you may need to take up to 100,000 IU per day. Micellized, or emulsified (as in cod liver oil) will help enhance absorption.

To reverse vitamin A deficiency or to prevent deficiency during acute viral infection, a single oral dose of 50,000 IU for one or two days is safe even for infants. Adults and children over 8 years can tolerate up to 50,000 IU daily for up to two weeks. In general, daily doses of up to five times the RDA (25,000 IU for adults and 12,000 IU for children) have been found to be safe. However, a health care provider must continue to monitor any high dose therapy. This applies especially to treatments for skin disorders. For other health issues, beta-carotene is the preferred supplement, as it may be administered in significantly higher doses without the same risk of toxicity. Pregnant women must avoid any type of vitamin A supplements (beyond what is found in prenatal vitamins), due to the higher risk of birth defects.