What Is Hypervitaminosis A?
Hypervitaminosis A, or vitamin A toxicity,
occurs when you have too much vitamin A in your body.
This condition may be acute or chronic. Acute
toxicity occurs after consuming large amounts of vitamin A over a short period
of time, typically within a few hours or days. Chronic toxicity occurs when
large amounts of vitamin A build up in the body over a long period of time.
Symptoms include visual changes, bone pain,
and skin changes. Chronic toxicity can lead to liver damage and increased
pressure on the brain.
This condition can be diagnosed using blood
tests to check your vitamin A levels. Most people improve simply by decreasing
their intake of vitamin A.
Causes of Hypervitaminosis
Excess amounts of vitamin A are stored in the
liver and it accumulates over time. Most people develop vitamin A toxicity by
taking high-dose dietary supplements. This may be because of megavitamin
therapy. A megavitamin therapy involves consuming very large doses of certain
vitamins in an attempt to prevent or treat diseases.
It may also be caused by long-term use of
certain acne treatments that
contain high doses of vitamin A.
Acute vitamin A toxicity is usually the
result of an accidental ingestion when it occurs in children.
Getting the Right Amount of
Vitamin A in Your Diet
Vitamin A is important for eye health in
children and adults. Vitamin A is also important in the development of a fetus,
specifically the heart, ears, eyes, and limbs.
You can get most of the vitamin A your body
needs from a healthy diet alone. Foods that contain vitamin A include:
- fish and fish oils
- dark fruits
- leafy, green vegetables
- orange and yellow vegetables
(sweet potatoes, carrots)
- tomato products
- some vegetable oils
- eating foods that are fortified
(have added vitamins) like cereal
How Much Vitamin A Do You Need?
According to the National Institutes of Health (NIH), the recommended dietary allowances for vitamin A are:
- 0 to 6 months old: 400 micrograms
- 7 to 12 months: 500 mcg
- 1 to 3 years: 300 mcg
- 4 to 8 years: 400 mcg
- 9 to 13 years: 600 mcg
- 14 to 18 years: 900 mcg for
males, 700 mcg for females
- 14-18 years/pregnant females: 750
- 14 to 18 years/breastfeeding
females: 1,200 mcg
- 19+ years: 900 for males, 700 for
- 19+ years/pregnant females: 770
- 19+ years/breast-feeding females:
Taking more than the recommended daily
allowance for several months can cause vitamin A toxicity. This condition can
occur more quickly in infants and children, because their bodies are smaller.
Symptoms vary based on whether toxicity is
acute or chronic. Headaches and rash are common in both forms of the illness.
Symptoms of acute vitamin A toxicity include:
- abdominal pain
- increased pressure on the brain
Symptoms of chronic vitamin A toxicity include:
- blurry vision or other visual
- swelling of the bones
- bone pain
- poor appetite
- nausea and vomiting
- sensitivity to sunlight
- dry, rough skin
- itchy or peeling skin
- cracked fingernails
- skin cracks at the corners of
- mouth ulcers
- yellowed skin (jaundice)
- hair loss
- respiratory infection
In infants and children, symptoms may also
- softening of the skull bone
- bulging of the soft spot on the
top of an infant’s skull (fontanel)
- double vision
- bulging eyeballs
- inability to gain weight
Contact your doctor if you or your children
are experiencing any of these symptoms.
The correct amount of vitamin A is crucial
for the development of a fetus. However, excess vitamin A consumption during
pregnancy is known to cause birth defects that may affect the eyes, skull,
lungs, and heart.
Other potential complications of excess
vitamin A include:
- liver damage
- osteoporosis (a condition causing
bones to become brittle, weak, and prone to breaks)
- excessive calcium buildup in the body
- kidney damage due to excess
Your doctor will start by asking you about
your symptoms and medical history. They will also want to know about your diet
and any supplements you’re taking. Your doctor may order blood tests to check
the levels of vitamin A in your blood as well.
How Hypervitaminosis A Is
The most effective way to treat this
condition is to stop taking high-dose vitamin A supplements. Most people make a
full recovery within a few weeks. Any complications that occurred from the
excess vitamin A, such as kidney or liver damage, will be treated
Outlook depends on the severity of the
vitamin A toxicity and how quickly it was treated. Most people make a full
recovery once they stop taking vitamin A supplements. For those who develop
complications, such as kidney or liver damage, outlook will depend on the
severity of the damage.
Talk to your doctor before you begin taking
any supplements, or if you’re concerned that you aren’t getting enough
nutrients from your diet.