For adults, 19 and older, the tolerable upper limit for vitamin A is 10,000 IU per day. Talk to your doctor before taking any dose close to that amount.
The Recommended Dietary Allowance (RDA) for men and women is 900 and 700 μg retinol activity equivalents (RAE)/day, respectively. The Tolerable Upper Intake Level (UL) for adults is set at 3,000 μg/day of preformed vitamin A.
Chronic toxicity results from the ingestion of high amounts of preformed vitamin A for months or years. Daily intakes of > 25 000 IU for > 6 y and > 100,000 IU for > 6 mo are considered toxic, but there is wide interindividual variability for the lowest intake required to elicit toxicity (19, 20, 42).
If you take vitamin A for its antioxidant properties, keep in mind that the supplement might not offer the same benefits as naturally occurring antioxidants in food. The recommended daily amount of vitamin A is 900 micrograms (mcg) for adult men and 700 mcg for adult women.
The total vitamin A content of a food is usually expressed as micrograms (µg) of retinol equivalents (RE). The amount of vitamin A adults aged 19 to 64 need is: 700 µg a day for men. 600 µg a day for women.
The recommended daily allowance (RDA) for men is 900 MCG REA, or 3,000 international units (IU). For women the RDA is 700 mcg RAE, or 2,330 (IU). For all adults, the Tolerable Upper Intake Level (UL) — the most vitamin A one can take without experiencing negative health effects — is 3,000 mcg RAE, or 10,000 IU.
Normal values range from 20 to 60 micrograms per deciliter (mcg/dL) or 0.69 to 2.09 micromoles per liter (micromol/L). Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples.
Intakes of more than 25,000 IU/day for over 6 years, or more than 100,000 IU/day for over 6 months are considered toxic, but there is wide interindividual variability (35). Severe cases of hypervitaminosis A may result in liver damage, bleeding (hemorrhage), and coma.
You should only take the doses recommended on the product label or by your health care provider. Vitamins A, D, E and K are fat-soluble vitamins. That means they're stored in your liver and fatty tissue. If you take too much of them, you could experience vitamin toxicity, which could affect different organs.
Most people with vitamin A toxicity have a headache and rash. Consuming too much vitamin A over a long period of time can cause coarse hair, partial loss of hair (including the eyebrows), cracked lips, and dry, rough skin. Chronic consumption of large doses of vitamin A can cause liver damage.
As a fat-soluble vitamin, the vitamin A you consume can stay in your body for weeks, months, or even years.
Vitamin A deficiency can result from inadequate intake, fat malabsorption, or liver disorders. Deficiency impairs immunity and hematopoiesis and causes rashes and typical ocular effects (eg, xerophthalmia, night blindness).
Vitamin A, D, E and K (also known as 'ADEK') are all fat-soluble vitamins that have high bioavailability on their own, but by adding enough fat to your day, you can enhance absorption even more. Consider cooking your vegetables with healthy oil or fat to help the absorption of these essential fat-soluble vitamins.
When taken by mouth: Vitamin A is likely safe when taken in amounts less than 10,000 units (3,000 mcg) daily. Vitamin A is available in two forms: pre-formed vitamin A (retinol or retinyl ester) and provitamin A (carotenoids). The maximum daily dose relates to only pre-formed vitamin A.
Vitamin a toxicity is treated by stopping the use of vitamin A supplements. Generally, signs and symptoms will resolve on their own with 1–4 weeks, depending on their severity. Birth defects caused by vitamin A toxicity during pregnancy are irreversible.
Megadoses have been described as the consumption or administration of nutrients in supraphysiological doses that exceed the recommended dietary ration ten or more times.
Acute vitamin A poisoning occurs quickly. It can happen when an adult takes several hundred thousand international units (IUs) of vitamin A. Chronic vitamin A poisoning may occur over time in adults who regularly take more than 25,000 IUs a day. Babies and children are more sensitive to vitamin A.
Vitamin A-Forte 200000 IU plays an essential role in the function of retina and is essential for growh and differentiation of epithelial tissue.
It was concluded that at least in some western countries chronic vitamin A consumption might represent an appreciable cause of chronic liver disease, the recognition of which mainly relies on expert liver biopsy interpretation.
Acute systemic vitamin A toxicity typically arises when an individual consumes over 100,000 RAE within a short period, often from supplements or high-dose medications. The toxicity symptoms include nausea, vomiting, headache, dizziness, irritability, blurred vision, and muscular incoordination.
For adults, 19 and older, the tolerable upper limit for vitamin A is 10,000 IU per day. Talk to your doctor before taking any dose close to that amount.