Types

• Vitamin A is a fat-soluble vitamin that is derived from two sources: preformed retinoids and provitamin carotenoids. Retinoids are found in animal sources like organ meats, eggs and dairy foods. Carotenoids like beta-carotene are mainly found in yellow and green vegetables.
  
  

Identification

• Retinol is not the same as Retin-A, although they are related. Retin-A is a brand of retinoic acid, or tretinoun, a derivative of vitamin A. Retinol is found in over-the-counter skin care products, while retinoic acid products must be prescribed by a dermatologist or other physician.
  
  

Significance

• Retinol is commonly found in facial and body lotions, creams and oils, as well as anti-wrinkle and skin rejuvenation products. Retinol has many benefits for improving skin appearance, such as attracting moisture and increasing water content of the skin. It sloughs off the top layer of skin, eliminating old and dead cells. It increases cell production and collagen, which minimizes fine lines. It also reduces pigmentation caused by the sun.
  
  

Considerations

• High concentrations of retinol are needed to achieve significant results for skin rejuvenation. However, the higher concentrations can make people more susceptible to sunburn. Although Retin-A sometimes causes skin irritation, retinol usually does not. With higher levels of retinol, people sometimes, though rarely, experience a warm or stinging sensation, or itching.
  
  

Warning

• As a supplement, vitamin A can cause toxicity in high doses, but this is rare. The recommended dietary allowance is between 2,310 and 3,000 international units (IUs), and toxicity only occurs with consumption of 25,000 to 50,000 IUs daily for several weeks or months. Toxicity includes symptoms of headache, dizziness, fatigue, blurry vision, bone pain and nausea. Acute toxicity can cause intracranial pressure, more severe bone problems, eye damage and liver damage. Excessive vitamin A supplementation is also associated with increased risk for osteoporosis and hip fractures. Retinol may disrupt the main activity of vitamin D, which is facilitating calcium absorption.
  
  

Effects

• Children are more susceptible to vitamin A toxicity at intake levels as low as 1,500 IUs. Pregnant women should avoid high-dose vitamin A supplements because of the possibility of birth defects. Some people with liver disease and who consume many alcoholic drinks are more at risk for vitamin A toxicity.