Side Effects, Safety and Dosing For Vitamin A


Vitamin A is likely safe for most people when taken by mouth or given as a shot into the muscle in amounts less than 10,000 IU daily.

February 11, 2019

Vitamin A is a fat-soluble vitamin that is naturally present in many foods. Vitamin A is important for normal vision, the immune system, and reproduction. Vitamin A is required for the proper development and functioning of our eyes, skin, immune system, heart, lungs, kidneys and various parts of our bodies.

Side Effects & Safety:

Vitamin A is likely safe for most people when taken by mouth or given as a shot into the muscle in amounts less than 10,000 IU daily. However, it is possibly unsafe if taken in high doses orally. Taking high doses of vitamin A supplements might increase the chance of death from all causes and possibly other serious side effects. Higher doses might increase the risk of osteoporosis and hip fracture, particularly in older people. Adults who eat low-fat dairy products, which are fortified with vitamin A, and a lot of fruits and vegetables usually do not need vitamin A supplements or multivitamins that contain vitamin A.
Long-term use of large amounts of vitamin A might cause serious side effects including fatigue, irritability, mental changes, mild fever, excessive sweating, anorexia, stomach discomfort, nausea, vomiting and many other side effects. Taking too much vitamin A can increase the risk of osteoporosis and hip fracture in women who have passed menopause. Vitamin A is safe for children when taken in the recommended amounts. The recommended dose of vitamin A that are safe for children are based on age and is given below:

  • Less than 2000 IU/day in children up to 3 years old.
  • Less than 3000 IU/day in children ages 4 to 8 years old.
  • Less than 5700 IU/day in children ages 9 to 13 years old.
  • Less than 9300 IU/day in children ages 14 to 18 years old.

It is unsafe when taken in high doses orally by children. When taken more then the recommended dose, it may have side effects that include irritability, sleepiness, vomiting, diarrhea, loss of consciousness, headache, vision problems, peeling skin, increased risk of pneumonia and diarrhea, and other problems. Precautions should be taken while taking vitamin A supplement for the below conditions:

Pregnancy and breast-feeding:

Vitamin A is safe for pregnant or breast-feeding women when taken in recommended dose of less than 10,000 IU per day. When taken more then the recommended dose can cause birth defects. It is especially important for pregnant women to monitor their intake of vitamin A from all sources during the first three months of pregnancy. Forms of vitamin A are found in several foods including animal products, primarily liver, some fortified breakfast cereals, and dietary supplements.

Excessive use of alcohol:

Drinking alcohol may increase harmful effects on the liver because of vitamin A.

Anemia:

People who are anemic and have low levels of vitamin A might need to take iron along with a vitamin A supplement to treat this condition.

Disorders in which the body does not absorb fat properly:

People with conditions that affect fat absorption, such as celiac disease, short gut syndrome, jaundice, cystic fibrosis, pancreatic disease, and cirrhosis of the liver, are not able to absorb vitamin A properly. In these cases, vitamin A preparations that are water-soluble can be used to improve vitamin A absorption.

Type V hyperlipoproteinemia:

This is a type of high cholesterol that might increase the chance of vitamin A poisoning. Do not take vitamin A if you have this condition.

Intestinal infections:

Intestinal infections such as hookworm can reduce how much vitamin A the body absorbs.

Iron deficiency:

Iron deficiency might affect the ability of your body to breakdown and use vitamin A.

Liver disease:

Too much vitamin A might make liver disease worse. Do not take vitamin A if you have liver disease.

Malnutrition:

In people with severe protein malnutrition, taking vitamin A might result in having too much vitamin A in the body.

Zinc deficiency:

Zinc deficiency might cause symptoms of vitamin A deficiency to occur. Taking a combination of vitamin A and zinc supplements might be necessary to improve this condition.

Interactions of Vitamin A With Other Medicines:

Medications for skin conditions (Retinoids) interacts with VITAMIN A:

Some medications for skin conditions have vitamin A effects. Taking vitamin A pills and these medications for skin conditions could cause too much vitamin A effects and side effects. So, do not take this combination.

Antibiotics (Tetracycline antibiotics) interacts with VITAMIN A:

Vitamin A can interact with some antibiotics. Taking very large amounts of vitamin A along with some antibiotics can increase the chance of a serious side effect called intracranial hypertension. But taking normal doses of vitamin A along with tetracyclines may not cause this problem. Do not take large amounts of vitamin A if you are taking antibiotics like demeclocycline (Declomycin), minocycline (Minocin), and tetracycline (Achromycin).

Medications that can harm the liver (Hepatotoxic drugs) interacts with VITAMIN A:

Taking large amounts of vitamin A might harm the liver. Taking large amounts of vitamin A along with medications that might also harm the liver can increase the risk of liver damage. Do not take large amounts of vitamin A if you are taking a medication like acetaminophen (Tylenol and others), amiodarone (Cordarone), carbamazepine (Tegretol), isoniazid (INH), methotrexate (Rheumatrex), methyldopa (Aldomet), fluconazole (Diflucan), itraconazole (Sporanox), erythromycin (Erythrocin, Ilosone, others), phenytoin (Dilantin), lovastatin (Mevacor), pravastatin (Pravachol), simvastatin (Zocor), and many others.

Warfarin (Coumadin) interacts with VITAMIN A:

Warfarin (Coumadin) is used to slow blood clotting. Large amounts of Vitamin A can also slow blood clotting. Taking Vitamin A along with warfarin (Coumadin) can increase the chances of bruising and bleeding. Make sure to have your blood checked regularly. The dose of your warfarin (Coumadin) might need to be changed.

Dosing:

The amount of vitamin A you need depends on your age and reproductive status. Vitamin A dosage is most commonly expressed in IU, but dosage in micrograms is sometimes used. Eating 5 servings of fruits and vegetables per day provides about 50% to 65% of the adult RDA for vitamin A
Recommended Dietary Allowance (RDA) levels for adults in different conditions are:

  • For 14 years and older male- 900 mcg/day (3000 IU)
  • For 14 years and older women- 700 mcg/day (2300 IU)
  • 14 to 18 years pregnancy- 750 mcg/day (2500 IU)
  • 19 years and older- 770 mcg/day (2600 IU)
  • lactation 14 to 18 years- 1200 mcg/day (4000 IU)
  • 19 years and older- 1300 mcg/day (4300 IU).

Tolerable Upper Intake Levels (UL) for vitamin A have also been established. The UL is the highest level of intake that a person can take with no risk of harmful effects. The ULs for vitamin A are for preformed vitamin A (retinol) and do not include provitamin A carotenoids. These include:

  • adolescents 14 to 18 years including pregnancy and lactation- 2800 mcg/day (9000 IU)
  • adults age 19 and older including pregnancy and lactation- 3000 mcg/day (10,000 IU).

Oral Leukoplakia or Precancerous Lesions in the Mouth:

Weekly dose of 200,000-300,000 IU of vitamin A has been used for 6-12 months

Diarrhea After Pregnancy:

Weekly doses of 23,000 IU of vitamin A have been used before, during, and after pregnancy.

For reducing death during pregnancy:

Weekly doses of 23,000 IU of vitamin A have been used before and during pregnancy.

For Reducing Night Blindness During Pregnancy:

Weekly doses of 23,000 IU of vitamin A have been used before, during, and after pregnancy. It seems to work best if taken in combination with 35 mg of zinc daily in women who also have low levels of zinc.

For eye disease affecting the retina (retinitis pigmentosa):

Daily doses of 15,000 IU of vitamin A, sometimes along with 400 IU of vitamin E daily, has been used. Recommended Dietary Allowance (RDA) levels for children in different conditions are:

  • birth to 6 months- 400 mcg/day (1300 IU)
  • 7 to 12 months- 500 mcg/day (1700 IU).
  • children 1 to 3 years- 300 mcg/day (1000 IU)
  • 4 to 8 years- 400 mcg/day (1300 IU)
  • 9 to 13 years- 600 mcg/day (2000 IU).

Tolerable Upper Intake Levels (UL) for vitamin A have also been established. The UL is the highest level of intake that a person can take with no risk of harmful effects. The ULs for vitamin A are for preformed vitamin A (retinol) and do not include provitamin A carotenoids. These include:

  • infants and children from birth to 3 years- 600 mcg/day (2000 IU)
  • children 4 to 8 years, 900 mcg/day (3000 IU)- 9 to 13 years-1700 mcg/day (6000 IU)
  • 14 to 18 years including pregnancy and lactation- 2800 mcg/day (9000 IU).

For measles:

Vitamin A 100,000 to 200,000 IU orally for at least two doses has been used in children less than 2 years-old.

Foods Rich in Vitamin A:

Vitamin A is found naturally in many foods and is added to some foods, such as milk and cereal. Therefore you can get recommended amounts of vitamin A by eating a variety of foods. These include:

  • Beef liver and other organ meats (but these foods are also high in cholesterol, so limit the amount you eat).
  • Dairy products, which are among the major sources of vitamin A for Americans.
  • Fortified breakfast cereals.
  • Some types of fish, such as salmon.
  • Green leafy vegetables and other green, orange, and yellow vegetables, such as broccoli, carrots, and squash.
  • Fruits, including cantaloupe, apricots, and mangos.

Vitamin A Dietary Supplements:

  • Vitamin A is available in dietary supplements, usually in the form of
  • retinyl acetate or retinyl palmitate (preformed vitamin A)
  • beta-carotene (provitamin A)
  • a combination of preformed and provitamin A.

Most multivitamin-mineral supplements contain vitamin A. Dietary supplements that contain only vitamin A are also available.