When taking vitamin supplements, more isn't always better. Exceeding
the recommended daily allowance of certain vitamins and minerals can
cause harmful side effects. This is often referred to as vitamin toxicity,
hypervitaminosis, or vitamin poisoning.
Vitamin D is one of the most toxic vitamin supplements. Large doses
of vitamin D have been linked to vomiting, loss of appetite, nausea,
joint pain, and diarrhea. If taken over a long period of time, large
doses of vitamin D can lead to irreversible damage to the kidneys, lungs,
and heart. In adults, a toxic dose of vitamin D can be a single dose
of 50 mg or a daily dose of 1 to 2 mg consumed over a long time period.
Vitamin A is another example a toxic vitamin supplement. Large doses
of vitamin A have been linked to headaches, bone pain, fatigue, and constipation.
Other symptoms of a vitamin A overdose include hair loss and brittle
nails. A toxic dose of vitamin A is usually 20 mg per day. However, pregnant
women should take less than 10 mg per day to prevent an increased risk
of birth defects.
Many people take large doses of vitamin C to try to prevent or cure
colds and other minor illnesses. However, large doses of these vitamin
supplements can be toxic in people with a family history of gallbladder
or kidney stones. Vitamin C produces calcium oxalate, the primary component
of gallbladder and kidney stones. The recommended daily allowance for
vitamin C is no more than 60 mg per day.
Most symptoms of vitamin toxicity will disappear as soon as the patient
stops taking vitamin supplements. The exceptions to this rule are severe
vitamin D toxicity and birth defects caused by large doses of vitamin
A during pregnancy. To prevent vitamin toxicity, always consult your
physician before taking vitamin supplements. |
