Vitamin A
Signs of overdose toxicity include headache, nausea, vomiting, drowsiness, and shedding or peeling of the skin after 24 hours. Blurred vision and frontal headaches are often the first signs of toxicity. Overdose during the 1st trimester has been linked to birth defects such as facial and nerve abnormalities.
Vitamin D
Signs of overdose toxicity include muscle weakness, headache, loss of appetite, nausea, vomiting, and bone pain.** Maternal overdose can cause mental and/or physical retardation in infants.**
Vitamin E
Signs of overdose toxicity include nausea, headache, fatigue, easy bruising and bleeding,** double vision (at dosages as low as 200 mg), and muscle weakness.**
Vitamin C
High doses can cause diarrhea and upset stomach, and can also cause newborn scurvy.
Vitamins B1, B2, B12, and Folate
Vitamin B overdoses may, at times, be generally asymptomatic.
Vitamin B2 turns the urine yellow-orange.
Vitamin B1 (i.e., thiamine) toxicity effects may include the following:
- Rapid heart beat
- Low blood pressure
- Irregular heart beat
- Headache
- Symptoms of allergic reaction
- Weakness
- Convulsions
Vitamin B3 (i.e., niacin)
Signs of overdose toxicity include skin flushing, itching, wheezing, headache, diarrhea, and vomiting.
Vitamin B6 (i.e., pyridoxine)
Signs of overdose toxicity include rapid breathing, burning pains, loss of muscle coordination, clumsiness, and paralysis.
Folate (folic acid)
High doses greater than 1000µg per day can mask a potential deficiency of B12, and very high doses of 15,000µg per day or more can cause central nervous system damage.
Calcium
Early signs of overdose can include constipation (severe), dryness of mouth, headache (continuing), increased thirst, irritability, loss of appetite, mental depression, metallic taste, unusual fatigue or weakness.
Iron
Early symptoms of iron overdose can include diarrhea (may contain blood), fever, nausea, stomach pain or cramping (sharp),** severe vomiting (may contain blood). **Symptoms of iron overdose may not occur for up to 60 minutes or more after the overdose was taken. By this time you should have had emergency room treatment. Do not delay going to the emergency room while waiting for signs to appear. High doses around the time of delivery may cause complications.
Zinc
Rare side effects seen with large doses include chills, continuing ulcers or sores in mouth or throat, fever, heartburn, indigestion, nausea, sore throat, unusual fatigue or weakness. Elevated doses during 3rd trimester can cause premature birth and stillbirth.