Despite the importance of vitamins to improve our health and protect us from many diseases, taking high doses of vitamins can damage all the organs of the body, and the most toxic vitamins are the following:
Vitamin A
Symptoms of mild vitamin A toxicity can include mild headache, nausea, hair loss, and blurred vision. The main adverse effects of vitamin A toxicity include birth defects, liver abnormalities, decreased bone mineral density and central nervous system disorders, according to the National Institutes of Health. Although the upper limit for adults is 3,000 mcg of vitamin A per day. However, the recommended daily allowance is only 700 mcg for women and 900 mcg for men.
Vitamin D
Excessive amounts of vitamin D accumulate in the liver and can cause bone calcification, headache, weakness, nausea, vomiting, constipation, kidney stones, frequent thirst, and urination. Serious symptoms range from kidney damage, weak bones, and growth retardation in infants and children. The maximum amount of vitamin D per day is 100 micrograms per day, you only need to eat 20 micrograms per day to maintain your health.
Vitamin E
Mild vitamin E toxicity has no symptoms, but severe toxicity can cause nausea and digestive problems. People taking blood thinners or cholesterol-lowering medications should not take vitamin E supplements without consulting a doctor. Because vitamin E is a natural blood thinner, when taken with anticoagulant medications it may increase the risk of excessive bleeding. The maximum allowable dose of this vitamin is 1,000 milligrams per day, which is more than 60 times the recommended daily intake of the vitamin of 15 milligrams.
Vitamin C and B complex vitamins
Vitamin C is a water soluble vitamin that can be toxic at very high levels. Large doses taken without food can cause indigestion. Symptoms of vitamin C toxicity include nausea, diarrhea, increased nausea, headache, kidney stones, and increased iron absorption. The maximum obtainable dose of vitamin C is 2,000 milligrams per day, which is much more than the daily requirement, which ranges from 75 to 90 milligrams.
High doses of some B vitamins can cause this, for example excessive intake of niacin can cause skin burns (niacin flush) and can also lead to cirrhosis of the liver. While excessive intake of vitamin B6 can cause nerve damage.