Vitamins for Mental Health, VitaminA - Information and benefits
Mental Health > supplements-vitamins : VitaminA
Vitamin A
Vitamin A and Carotenes
Other Names
Retinol, Retinol Palmitate, Retinyl Acetate
Summary
Vitamin A is a fat-soluble nutrient that is stored in the liver. It is used primarily to improve vision and to support the immune system. Sources of vitamin A include fish liver oil, beef and chicken liver, eggs and dairy products. Beta-carotene, the vitamin A precursor, is found in plants including carrots, apricots, collard greens, kale, sweet potatoes, spinach and cantaloupe
Signs of vitamin A deficiency include poor wound healing, frequent infections, difficulty seeing at night and difficulty adjusting vision from light to dark. Signs of too much vitamin A, or toxicity, include dry cracking skin, brittle nails, hair loss, weight loss, irritability, headache and fatigue. The recommended daily allowance for vitamin A is 5,000 IU for men and 4,000 IU for women.
Uses
Vitamin A is used to maintain vision, and is often though of as a preventative for night blindness. It can also improve dry eyes. Vitamin A helps to maintain the epithelial tissue that lines the gastrointestinal and respiratory tracts. It is useful for inflammatory bowel diseases and ulcers. It boosts the immune system and can be helpful in treating infections of the upper respiratory tract, including colds and flu, sore throats, and sinus infections. It may also help to reduce the symptoms of allergies and asthma.
Vitamin A can be helpful in improving other infections as well, including measles in children and shingles in older patients. It is useful for treating skin problems such as acne, eczema and psoriasis and can help with wound healing and burns. It can help the body detoxify pollutants in the air, including second hand cigarette smoke. It helps build strong bones. It may also help improve fertility in both women and men.
Vitamin A may be benefit in cancer patients, especially those with breast or prostate cancer on chemotherapy by improving their response to the chemotherapy while at the same time decreasing the side effects. Vitamin A may also be useful in diabetics since it helps insulin control the blood sugar.
Proposed Mechanism of Action
Vitamin A is active in the retina of the eye where it combines with opsin to form rhodopsin, the visual pigment. It enhances the immune system, thus having reducing the symptoms of infection. This effect also supports its use in cancer. Vitamin A is a cofactor in the production of steroid hormones, cholesterol, and mucopolysaccharides, which are important for healthy joints.
Side Effects / Precautions
Women who are pregnant or planning to become pregnant should take no more than 5,000 IU of vitamin A daily since it can cause birth defects. Daily intake of greater than 5,000 IU daily should also be avoided by nursing mothers to prevent toxicity in the infant. Patients with liver disease are more likely to get vitamin A toxicity if supplements are taken.
Interactions
Cholestyramine and mineral oil bind vitamin A in the gut, and reduce its absorption. Neomycin also reduces absorption.
Vitamin E can increase the absorption and storage of vitamin A. It may or may not help prevent signs of toxicity.
Oral contraceptives increase Vitamin A levels in the blood. Concomitant use with retinoids, such as Accutane, can increase the chance of toxicity. Taken in large amounts, the effects of warfarin (Coumadin) can be increased.
Symptoms of Deficiency
Night blindness or even total blindness are major signs of vitamin A deficiency. There may be poor wound healing and more frequent infections. Other problems include weigh loss, poor tooth function and poor bone function
Symptoms of Toxicity
Symptoms of toxicity include dry cracking skin, brittle nails, hair loss, loss of appetite and weight loss, bone and joint pain, irritability, blurred vision, headache, dizziness, and fatigue. Eating too much beta-carotene will turn the skin a slight orange color but is not harmful.
Dosage and Administration
The RDA is 5,000 IU for men and 4,000 IU for women. Vitamin A stores are depleted during infection and high doses of 50,000 to 100,000 IU per day for one to two days can be beneficial. Toxicity has been seen in people taking 25,000 IU a day for several years. Palmitate is a synthetic form that is water soluble. It can be useful in people with difficulty absorbing fats.
Food Sources
Primary sources of Vitamin A include fish liver oil from cod, salmon, halibut and shark. Other animal sources include beef and chicken liver, eggs and dairy products.
Beta-carotene, the vitamin A precursor, is found in plants, primarily yellow-orange vegetables and green leafy vegetables. The body will make only as much vitamin A from the carotenoids and it needs, so toxicity from plant sources is not a problem. Carrots, apricots, collard greens, kale, sweet potatoes, spinach and cantaloupe are all good sources of beta-carotene. Other plant sources high in beta-carotene are turnip and mustard greens, mangos, sweet red peppers and broccoli.
Other Supplements to Consider
Enhance immunity: vitamin C, vitamin B complex, zinc
Cancer prevention: vitamin B complex, vitamin C, vitamin D, vitamin E, zinc, chromium, selenium
Skin problems: vitamin C, zinc, selenium