For healthy eyes, skin and mucous membraneVitamin A is an essential fat-solulable vitamin, it`s absolute necessary for eyes and healthy vision. Additional it supports the healthy cell growth of skin and mucous membranes and strength the immune system. Especially pregnant women, smoker and older people have in many cases an increased requirement of vitamin A. EuRho®Vital Vitamin A capsules are helping to supply the body`s demand of vitamin A.
1. General information about Vitamin A :
Vitamin A is linked to a family of similarly shaped molecules, the retinoids. Vitamin A can be found in various forms:
retinol, the form of vitamin A absorbed when eating animal food sources, is a yellow, fat-soluble, vitamin with importance in vision and bone growth. Since the alcohol form is unstable.
other retinoids, a class of chemical compounds that are related chemically to vitamin A, are used in medicine.
Approximately 80% of vitamin A is absorbed in the human system. It is passed along with fat through the lymphatic system into the bloodstream. The absorption of vitamin A increases if it is taken with fats. Absorption is more rapid in men than in women. The absorption of this vitamin is poor in cases of diarrhoea, jaundice, and abdominal disorders. Vitamin A is stored in the liver. A healthy person can store about 97.2 mcg of vitamin A per g of liver. Thus an average liver weighing 1500 g can store 150,000 mcg of vitamin A.
Specific recommendations depend on age, gender, and other factors (such as pregnancy). Women who are pregnant or producing breast milk (lactating) need higher amounts.
It is also known as retinol because it produces the pigments in the retina of the eye.Vitamin A promotes good vision, especially in low light. The role of vitamin A in the vision cycle is specifically related to the retinal form. Within the eye, 11-cis-retinal is bound to rhodopsin (rods) and iodopsin (cones) at conserved lysine residues. As light enters the eye the 11-cis-retinal is isomerized to the all-"trans" form. The all-"trans" retinal dissociates from the opsin in a series of steps called bleaching. This isomerization induces a nervous signal along the optic nerve to the visual center of the brain. Rhodopsin is needed to see black and white as well as see at night. It is for this reason that a deficiency in vitamin A will inhibit the reformation of rhodopsin and lead to night blindness
Healthy skin
Vitamin A appears to function in maintaining normal skin health. The mechanisms behind retinoid's therapeutic agents in the treatment of dermatological diseases are being researched. For the treatment of acne, the most effective drug is 13-cis retinoic acid (isotretinoin). Although its mechanism of action remains unknown, it is the only retinoid that dramatically reduces the size and secretion of the sebaceous glands. Isotretinoin reduces bacterial numbers in both the ducts and skin surface. This is thought to be a result of the reduction in sebum, a nutrient source for the bacteria. Isotretinoin reduces inflammation via inhibition of chemotatic responses of monocytes and neutrophils.
Growth, Reproduction and Maintenance of life
Both vitamin A excess and deficiency are known to cause birth defects. Retinol and retinoic acid (RA) are essential for embryonic development. During fetal development, RA functions in limb development and formation of the heart, eyes, and ears. Additionally, RA has been found to regulate expression of the gene for growth hormone.
Enhance immunity
Vitamin A is commonly known as the anti-infective vitamin, because it is required for normal functioning of the immune system.The skin and mucosal cells (cells that line the airways, digestive tract, and urinary tract) function as a barrier and form the body's first line of defense against infection. Retinol and its metabolites are required to maintain the integrity and function of these cells.Vitamin A and retinoic acid (RA) play a central role in the development and differentiation of white blood cells, such as lymphocytes, which play critical roles in the immune response.
Prevention of aging
Anti aging treatment today often includes vitamin and mineral supplements, and skin care products that contain vitamins and minerals, because of the evidence that these things help slow aging. Many of the so-called anti aging vitamins are antioxidants. Antioxidants remove free radicals, byproducts of metabolism that damage cells and contribute to aging and disease. Free radicals are always being produced in our bodies, so a continuous supply of antioxidants is needed to prevent cell damage. Vitamins and minerals included in the antioxidant group include vitamins A, B-6, B-12, C, E, and selenium.
Gene regulation
Vitamin A, in the retinoic acid form, plays an important role in gene transcription.The conversion of retinal to retinoic acid is an irreversible step, meaning that the production of retinoic acid is tightly regulated, due to its activity as a ligand for nuclear receptors.
Red Blood Cell formation
Red blood cells, like all blood cells, are derived from precursor cells called stem cells. Stem cells are dependent on retinoids for normal differentiation into red blood cells. Additionally, vitamin A appears to facilitate the mobilization of iron from storage sites to the developing red blood cell for incorporation into hemoglobin, the oxygen carrier in red blood cells.
Prolonged deficiency of vitamin A may result in inflammation of the eyes, poor vision, and night blindness. There is an increased susceptibility to infections, especially of the respiratory tract, in the form of frequent and prolonged common colds. Vitamin A deficiency may lead to lack of appetite and vigor, defective teeth and gums, skin disorders such as acne, boils and premature wrinkles. When vitamin A is present in insufficient amounts, the mucous membranes of the nose, throat and mouth, the bronchial tubes, lungs, intestinal tract, kidneys and vagina are greatly affected. Eventually the mucous membranes of the entire body lose their ability to secrete the normal quantities of mucus needed to protect them from irritation, and the body degenerates rapidly. Other deficiency symptoms include retarded growth in children, dry and dull hair, dandruff, excessive hair loss, ridged nails, and a poor sense of taste and smell.
Vitamin A comes from animal sources, such as eggs, meat, milk, cheese, cream, liver and kidney. Sources of beta-carotene are carrots, pumpkin, sweet potatoes, cantaloupe, pink grapefruit, apricots, broccoli, and spinach, and most dark green, leafy vegetables. The more intense the color of a fruit or vegetable, the higher the beta-carotene content. These vegetable sources of beta-carotene are free of fat and cholesterol.
Derivatives of vitamin A, retinoids, are used to treat skin disorders such as acne. Isotretinoin may cause severe side effects and should be used only for severe resistant acne. Isotretinoin must not be used in women who are pregnant, plan to become pregnant, or have a chance of being pregnant due to a risk of severe birth defects. These medications should be prescribed and coordinated by a qualified licensed healthcare professional. Vitamin A supplements should not be used simultaneously due to a risk of increased toxicity.
The prescription drug All- Trans -Retinoic Acid is a vitamin A derivative that is an established treatment for acute promyelocytic leukemia and improves median survival in this disease.
3. Eye disorders (Bitot's spot)
Vitamin A deficiency can lead to Bitot's spot, or the buildup of keratin debris in the conjunctiva. Bitot's spot is a sign of xerophthalmia, and may be treated with vitamin A supplementation.
4. Measles (supportive agent)
Vitamin A should be administered to children diagnosed with measles in areas where vitamin A deficiency may be present. Measles is a viral disease that can lead to serious complications such as diarrhea, pneumonia, and encephalitis. Supplementation with vitamin A in children with measles has been shown to be beneficial, by decreasing the length and impact of the disease. Side effects such as diarrhea, pneumonia, and death have been reduced with the use of vitamin A. Management of measles should be under strict medical supervision.
5. Xerophthalmia (dry eye)
Oral vitamin A is the treatment of choice for xerophthalmia, due to prolonged vitamin A deficiency, and should be given immediately once the disorder is established.
6. Malaria (supportive agent)
Limited research suggests that vitamin A may reduce fever, morbidity, and parasite blood levels in patients with malaria ( Plasmodium falciparum infection). However, there is a lack of evidence suggesting that vitamin A is equivalent or superior to well-established drug therapies used for the prevention or treatment of malaria. Patients with malaria or living/traveling in endemic areas should speak with a physician about appropriate measures.
7. Retinitis pigmentosa
Retinitis pigmentosa is a genetic disorder that affects night vision. Early symptoms include night blindness and progressive loss of vision over time. Based on recent findings, vitamin A in the palmitate form has been recommended in patients with retinitis pigmentosa.
8. Antioxidant
The benefits to humans of potential antioxidant activity are not clear.
9. Breast cancer
Research results are not clear as to whether vitamin A is beneficial in the treatment or prevention of breast cancer. Patients receiving chemotherapy or radiation therapy for cancer should speak with their doctor(s) before taking antioxidants such as vitamin A during treatment, due to possible interference.
10. Cataract prevention
Vitamin A has been suggested to prevent cataract formation. Carotenoids such as beta-carotene, lutein, and zeaxanthin may decrease the risk of severe cataracts. There is not sufficient evidence to form a clear conclusion at this time.
11. Diarrhea
Vitamin A may reduce the severity and duration of diarrheal episodes in malnourished children but not in well-nourished children. Since diarrhea is a major cause of morbidity and mortality in developing countries, vitamin A supplementation may be considered in undernourished children with diarrhea.
12. HIV Infection
The role of vitamin A in the prevention, transmission, or treatment of HIV is controversial and not well established. A clear conclusion cannot be formed based on the available scientific research.
13. Immune function
Vitamin A deficiency may compromise immunity, but there is no clear evidence that additional vitamin A supplementation is beneficial for immune function in patients who are not vitamin A deficient.
14. Infant mortality
There is a limited amount of research in this area, with mixed results. Some evidence suggests possible decreases in infant mortality with vitamin A supplementation, while other research reports no benefits. A clear conclusion cannot be formed based on the available scientific research.
15. Iron deficiency anemia
Vitamin A supplementation in combination with iron may have beneficial effects in patients with iron deficiency anemia, including children and pregnant women. It is not clear that there are benefits in individuals who are not vitamin A deficient. This area remains controversial, and further evidence is necessary before a clear conclusion can be drawn.
16. Pancreatic cancer
Vitamin A supplementation has not been shown to improve response to gemcitabine in pancreatic cancer. It is unclear whether vitamin A may provide any benefits in patients with pancreatic cancer. More research is needed in this area.
17. Parasite infection (Acaris reinfection)
After deworming, children supplemented with vitamin A may be less prone to Ascaris parasite reinfection. These benefits may be less in children with stunted growth.
18. Photoreactive keratectomy
Photoreactive keratectomy is a type of laser eye surgery used to correct nearsightedness. High-dose vitamin A supplementation in addition to vitamin E has been suggested to help improve ocular healing after surgery and to improve visual acuity, although additional evidence is necessary before a definitive conclusion can be reached.
19. Pneumonia (children)
One study found no effect of a moderate dose of vitamin A supplementation on the duration of uncomplicated pneumonia in underweight or normal-weight children aged younger than five years. However, a beneficial effect was seen in children with high basal serum retinol concentrations.
20. Polyp prevention
Alpha-carotene and vitamin A may protect against recurrence of polyps and adenoma in nonsmokers and nondrinkers or be indicative of compliance or another healthy lifestyle factor that reduces risk. Further research is needed before a conclusion can be drawn
21. Pregnancy-related complications
Maternal vitamin A deficiency is common in developing countries. Beta-carotene may reduce pregnancy-related complications and mortality in such individuals. However, excess intake of vitamin A has been reported to increase the risks of some birth defects. Vitamin A supplementation above the RDA is therefore not recommended in pregnancy.
22. Skin aging (improving aging skin appearance)
Some studies suggest that topical vitamin A may improve the appearance and integrity of aged skin.
23. Skin cancer prevention
It is not clear if vitamin A or beta-carotene, taken by mouth or used on the skin with sunscreen, is beneficial in the prevention or treatment of skin cancers or wrinkles.
24. Weight loss
Daily vitamin A with calcium has been suggested for weight loss, and in one study an average loss of two pounds was reported after two years of supplementation in young women.
25. Wound healing
In preliminary study, retinol palmitate significantly reduced rectal symptoms of radiation proctopathy, perhaps because of wound-healing effects. Further research is needed to confirm these results.
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