(retinol, retinyl esters)
Vitamin A can be found in the diet but can also be made from what is referred to as provitamin A carotenoids such as alpha-carotene and beta-carotene. Lycopene, lutein and zeaxanthin are also carotenoids but they are not converted to vitamin A.
Dietary Sources for Vitamin A (retinol, retinyl esters): meat, liver, kidney, butter and eggs.
Dietary Sources for Provitamin A (alpha-carotene, beta-carotene): sweet potatoes, carrots, butternut squash, red peppers, tomatoes, pumpkin, spinach, collards, cantaloupe, apricots, peaches and broccoli. (Lightly sautéing or steaming makes them easier to absorb the beta-carotene.
Recommended daily amounts (RDA): *Note dosing can be listed as international units (IU) or as micrograms (mcg) or retinol activity equivalents (RAE) to account for different absorptions rates.
RDA Vitamin A
Men 19yrs and older = 900mcg RAE (equivalent to 3,000 IU)
Women 19yrs and older = 700mcg RAE (equivalent to 2,000 IU)
Tolerable Upper Intake Level (UL) is the maximum daily intake unlikely to cause harmful effects on health = 3,000 mcg of Vitamin A (retinol, retinyl esters)
Signs of Deficiency:
Mild – fatigue, susceptibility to infections and infertility
Serious – Xerophthalmia (severe dryness of eye which can lead to blindness), Nyctalopia/night blindness, irregular patches on the white of the eyes, dry skin/hair
Signs of Toxicity:
Vitamin A (retinol) is a fat-soluble vitamin which means if it is not needed immediately is absorbed and stored in fat tissue or the liver. Large amounts stored can become toxic.
Signs: vision changes such as blurry sight, bone pain, nausea & vomiting, dry skin, sensitivity to bright light like sunlight
Adults 19yrs or older = 5-15mg/day (8,000-25,000 IU/day) – Natural Forms ONLY (synthetic can be harmful) look for “natural beta-carotene”, “from D. Salina”, “from an algae source” or “from a palm source”.
Drugs that DECREASE levels:
Acid blocking drugs for heartburn, antacids, cholestyramine resin (Questran), mineral oil, prescription fat blockers (Xenical and Alli), and Olestra (fat substitute found in chips).