You can have too much of a good thing – even when it comes to vitamins. Vitamin A is a fat-soluble vitamin necessary for a variety of roles in your body, including cell reproduction, vision, a healthy immune system, reproduction, growth and wound healing. You get vitamin A from animal and plant sources, and it's rare to have a deficiency in this nutrient. Excessive amounts, however, can be toxic to your health, so always speak to your doctor before taking more than the recommended amount of vitamin A.
Vitamin A Dosage
You get vitamin A from beef, eggs, liver, fish and dairy products. Your body also manufactures vitamin A from carotenoids, which are found in dark, green leafy vegetables and yellow and orange fruits. Men over 19 years of age need 900 micrograms of vitamin A daily and women in that age range need 700 micrograms. Pregnant and breastfeeding women over 18 years need 770 and 1,300 micrograms respectively. The Tolerable Upper Limit for adults is 3,000 micrograms. Vitamin A toxicity typically comes from taking a supplement, and it's often found in vitamin formulas for wellness, skin, eyes, immune system and colds, so always check what's in the vitamin formula you are taking.
Symptoms of Toxicity
Although rare, acute vitamin A toxicity may cause you to experience nausea, dizziness, headache, fatigue, decreased appetite, dry skin and peeling, and swelling in your brain. You're more likely to experience symptoms from too much vitmain A over time. When that occurs, you can also develop bone and joint pain. Severe toxicity can result in liver damage, coma and even death.
If you're pregnant or thinking about becoming pregnant, you need vitamin A to ensure proper growth and development of your fetus. Taking too much of this vitamin during pregnancy, however, can cause birth defects. Prenatal vitamins contain vitamin A, so avoid taking an additional vitamin A supplement. The Linus Pauling Institute at Oregon State University recommends pregnant women take a prenatal supplement with no more than 1,500 micrograms of vitamin A.
According to the University of Maryland Medical Center, vitamin A and beta-carotene may raise your triglyceride levels. Triglycerides are fats in your blood. High triglyceride levels are associated with high cholesterol and heart disease, so these supplements may elevate your risk of heart disease, especially if you are a smoker. Beta-carotene supplementation is also associated with an increased risk of lung cancer in smokers. If you have liver disease or diabetes, you shouldn't take vitamin A supplements unless your doctor recommends them.