Vitamin A is fat-soluble vitamin that is part of a family of compounds including retinol, retinal and beta-carotene. Beta-carotene is also known as pro-vitamin A because it can be converted into vitamin A when additional levels are required. Food sources include organ meats such as liver and kidney, egg yolks, butter, fortified dairy products such as milk and some margarines and cod liver oil. 

·  Skin health (as both a topical cosmetic and an oral dietary supplement) 皮膚健康

·  Treats Acne or other skin ailments 治療痤瘡

·  Promotes eyesight and vision 促進視力

·  Prevents infection 預防感染

·  Anti-aging 抗老化

·  Anti-cancer 抗癌 

Vitamin A is needed by all of the body’s tissues for general growth and repair processes and is especially important for bone formation, healthy skin/hair, night vision and function of the immune system. Because of these myriad functions, the health claims associated with vitamin A are numerous. 

Vitamin A may help boost immune system function and resistance to infection. Vitamin A derivatives are widely used in cosmetics and dermatological treatments for skin preparations designed to combat skin aging and treat acne. Vitamin A has been used for decades as a treatment for various vision-related conditions, including night blindness, cataracts, conjunctivitis, retinopathy and macular degeneration. It may also help to prevent or treat such conditions as Crohn’s disease, diarrhea, heavy menstruation, peptic ulcer, and premenstrual syndrome. 

Be aware that as a fat-soluble vitamin, vitamin A can be stored in the body and levels can build up over time. Possible toxicity can result with high dose supplementation (50,000 IU/day) leading to vomiting, headaches, joint pain, skin irritation, gastrointestinal distress and hair loss. Extreme caution should be exercised during pregnancy, as high dose vitamin A has been associated with teratogenic effects (birth defects) on the fetus of pregnant women. Maximum intake of 5000 IU of vitamin A is suggested during pregnancy. 

High dose supplements of any isolated nutrient is generally not recommended. Virtually all standard multi-vitamin supplements contain either preformed vitamin A and/or beta-carotene as an ingredient. 

The Daily Value for vitamin A is 5,000 IU for adults. Children should consume no more than 3,500IU daily. Although there is no established DV for beta carotene, a daily intake of 5-20 mg has been advocated by some nutrition experts.