What is Vitamin A?

Vitamin A is a nutrient that helps keep your eyes and skin healthy. It also boosts your immune system, which helps your body fight off infections.

Most people get enough vitamin A from their diet. Good sources include carrots, sweet potatoes, spinach, and squash. You can also get it from fortified foods such as milk and cereal.

If you don’t get enough vitamin A, you may have trouble seeing in the dark or at night. You may also be more likely to get sick.

Too much vitamin A can be harmful. Getting too much over time can lead to liver damage and bone problems. Pregnant women should be especially careful not to get too much, as it can harm the developing baby.

If you think you are not getting enough vitamin A, talk to your doctor. You may need to take a supplement.

Vitamin A

Health Benefits

Vitamin A is important for many different body functions.

For example, it helps:

Keep your eyes healthy. Vitamin A keeps the surface of your eyes moist and prevents dryness and infection. It also helps you see at night.

Boost your immune system. Vitamin A helps your body fight off infections by making white blood cells that destroy germs.

Build strong bones. Vitamin A helps your body absorb calcium, which is important for bone health.

Keep your skin healthy. Vitamin A helps your skin renew itself and protects against UV damage.

Possible Side Effects

Getting too much vitamin A can be harmful. Symptoms of too much vitamin A include:

Nausea

Vomiting

Diarrhea

Headache

Dizziness

Bone pain

Dry skin

Hair loss

Yellowing of the skin or whites of the eyes (jaundice)

Liver damage

If you think you are getting too much vitamin A, stop taking supplements and talk to your doctor.

Pregnant women should be especially careful not to get too much vitamin A. Too much can harm the developing baby. Talk to your doctor about how much is safe for you to take during pregnancy.

Interactions

Vitamin A can interact with certain medications, including:

Acetaminophen (Tylenol)

Isoniazid (for tuberculosis)

Oral contraceptives (birth control pills)

Retinoids (for acne or other skin conditions)

Statin drugs (for high cholesterol)

Thiazide diuretics (water pills)

Tretinoin (Retin-A, for acne or other skin conditions)

Some interactions can increase your risk of side effects. Others can make the medication less effective.

Be sure to tell your doctor and pharmacist about all the medications you take, including over-the-counter drugs, vitamins, and herbal supplements.

Dosage and Recommendations

The amount of vitamin A you need depends on your age and gender. Women who are pregnant or breast-feeding need more vitamin A than other women.

The Recommended Dietary Allowance (RDA) for vitamin A is:

Age Male Female Pregnant Breastfeeding

0-6 months* 400 mcg RAE (retinol activity equivalents) 400 mcg RAE

7-12 months* 500 mcg RAE

1-3 years 300 mcg RAE

4-8 years 400 mcg RAE

9-13 years 600 mcg RAE

14-18 years 900 mcg

19+ years 900 mcg

*Adequate Intake (AI)

Pharmacokinetics

Vitamin A is a fat-soluble vitamin that is stored in the liver. It is slowly released into the bloodstream as needed.

The half-life of vitamin A is about 28 days. This means that it takes about 28 days for the level of vitamin A in your body to decrease by half.

Vitamin A is excreted in the feces. Most of the excess vitamin A that your body does not need is stored in the liver.

Deficiency

Vitamin A deficiency is rare in developed countries, but it is common in developing countries. It can lead to night blindness and other vision problems. It can also make you more susceptible to infections.