VITAMINS V I TA M I N A VERSION 1.0 What is it? Vitamin A is a fat-soluble vitamin. There are different forms of vitamin A including retinol, retinal, retinoic acid, and retinyl ester, which are collectively referred to as ‘retinoids’. The strongest form of vitamin A is retinol. Why you may need vitamin A Acne, eczema, psoriasis – vitamin A is important for maintenance of epithelial tissue, which covers the external surface of your body – your skin. Cataracts – a high dietary intake of vitamin A is associated with a reduced risk of cataracts. Urinary, respiratory, gastrointestinal and vaginal infections – vitamin A assists immune function and Doses used in clinical trials increases resistance to infection. The linings inside our 10,000–25,000 IU daily for up to two weeks has been body are made up of epithelial tissue called mucous used in adults with clinical deficiency of vitamin A. membranes. These include linings of the mouth, nose, stomach, intestines, lungs, bladder and vagina. Symptoms of deficiency Vitamin A is important for helping to maintain healthy Symptoms of deficiency include the following – night mucous membranes. Changes in this lining can blindness, xerophthalmia (the cornea and conjuctiva increase the susceptibility to infection. become dry, thick and wrinkled), bitots spots (triangular grey spots on the eye), visual impairment Breast cancer – studies have found a link between and blindness, dryness of the skin, plugged hair high dietary intake of vitamin A and a reduced risk of follicles, increased susceptibility to respiratory, urinary breast cancer among pre-menopausal women with a tract and vaginal infections, kidney stones diarrhea, family history of breast cancer. loss of appetite, anemia, stunted bone growth in children and tooth decay. Anaemia – vitamin A deficiency can impair iron mobilisation from body stores. Food sources The best dietary sources of vitamin A include eggs, How much do you need? whole milk, butter, meat, animal liver and fish liver oils Recommended Daily Intake (RDI) eg cod and halibut (the liver stores retinol – vitamin A). Adults (over 19 years): 2500 IU (750 mcg) daily Pregnancy: 2500 IU (750 mcg) daily Other reasons why you may need more Breastfeeding: 4000 IU (1.2 mg) daily Good digestion plays a very important role in Children over 7 years: 1666–2500 IU (500–750 mcg) maintaining adequate vitamin A levels. You may need daily more if you have a malabsorption disorder such as Children under 7 years: 1000–1415 IU (300–425 mcg) coeliac disease, cystic fibrosis, pancreatic disease or daily cirrhosis of the liver. If fat absorption is difficult for you, best to choose a water-miscible vitamin A supplement. …..continued over THIS INFORMATION IS NOT INTENDED TO TREAT OR DIAGNOSE. ALWAYS CONSULT YOUR HEALTHCARE PROFESSIONAL BEFORE TAKING NUTRITIONAL OR HERBAL SUPPLEMENTS. VITAMINS V I TA M I N A continued VERSION 1.0 Gastrointestinal infections or infestations such as Excessive intake of vitamin A (hypervitaminosis) can giardia and hookworm can reduce vitamin A lead to a deficiency in blood clotting factor thrombin, absorption. causing increased bleeding time. Vitamin K can correct the problem. The liver is the main organ that stores retinol. Conditions such as marasmus and kwashiorkor are Since vitamin A is a fat-soluble vitamin it can be stored caused by severe protein malnutrition. The liver and easily accumulated in the body. Always check with reduces the release of retinol and doesn’t increase your healthcare professional when supplementing with until protein status has normalised. high doses of vitamin A. Toxicity symptoms include severe headache, sore mouth, bleeding gums, If you are zinc deficient, your vitamin A levels may not dizziness, loss of appetite, nausea, vomiting, be too crash hot either. Zinc is required in the liver for diarrhoea, weight loss, blurred vision, irritability, synthesis of retinol binding protein and without fatigue, insomnia, painful bones, dry itchy peeling skin, adequate zinc, vitamin A also suffers. rashes, cracked lips, hair loss, brittle nails, cessation of menstruation, high calcium and lipids in the blood and Safety notes jaundice. Back to the liver – if you have liver disease or drink alcohol in excess, there is an increased risk of vitamin A toxicity. Your liver can only handle so much! High doses of vitamin A have been shown to be cause birth defects. Studies have been done to work out the threshold. The levels in studies vary from 10,000– 30,000 IU daily. The Therapeutic Goods Administration of Australia recommends the following for pregnant women ‘The recommended adult daily amount of vitamin A from all sources is 2500 IU. When taken in excess of 8,000 IU vitamin A can cause birth effects. If you are pregnant, do not take vitamin A supplements without consulting your doctor or pharmacist.’ During pregnancy a well balanced healthy diet should cover your vitamin A requirements and further supplementation should not be necessary. You should discuss any conditions you have with your healthcare professional to assess if they may influence your vitamin A status. Large doses of vitamin A increase the need for vitamin E to protect against the oxidation effects of vitamin A. THIS INFORMATION IS NOT INTENDED TO TREAT OR DIAGNOSE. ALWAYS CONSULT YOUR HEALTHCARE PROFESSIONAL BEFORE TAKING NUTRITIONAL OR HERBAL SUPPLEMENTS.