Adequate intake of vitamins from a balanced diet is important in maintaining good health, and also in the prevention of diseases that result from deficiencies of certain vitamins, such as night blindness (caused by deficiency of Vitamin A).
However, there are instances whereby an individual is considered to have consumed excess vitamins. Excessive consumption of vitamins is discouraged because it has serious effects on the body.
Taking too much vitamins results in a condition referred to as Hypervitaminosis.
Hypervitaminosis is a medical condition that occurs as a result of excess consumption of one or more types of vitamins, which may lead to toxic symptoms. The names of these different conditions are derived from the specific vitamin(s) involved. For instance, excessive consumption of Vitamin C will result in a medical condition referred to as Hypervitaminosis C, while excessive intake of Vitamin D results in Hypervitaminosis D.
Usually, toxic levels of vitamins are a result of high intake of vitamin supplements, not from dietary sources. In the case of fat soluble vitamins for instance, toxicity is usually caused by excessive consumption of highly fortified foods, but the foods which are not fortified rarely cause toxicity.
The Dietary Reference Intake composed by the US Department of Agriculture clearly defines the ideal amount of intake for all vitamins.
Excessive Intake of Fat Soluble Vitamins
There are certain types of vitamins that can be broken down by fats and then stored in the human body. They are Vitamins A, K, D and E. Since they are stored, excessive consumption will lead to toxicity. For instance, consumption of more than 3000 Mg of Vitamin A is discouraged because it results in yellowing of the skin/jaundice.
Since Vitamin D is important in the absorption of Calcium, excessive consumption (more than 4,000 IU every day) may lead to excess Calcium in the body, resulting in damage to the kidneys, or irregular heart rate.
Consumption of more than 1,000 mg of Vitamin E every day is considered excess, and is very dangerous because it results in straining of the heart, which may cause a heart attack.
The daily consumption of more than 150 Mg of Vitamin E is discouraged because it results in the permanent damage of cell membranes, and complications of the liver.
Excessive Consumption of Water Soluble Vitamins
Water soluble vitamins such as Foliate, Riboflavin and Niacin, are never stored in the human body. They are used immediately, while any extra amounts are excreted. Therefore, they have low risk of being toxic.
However, excessive consumption results in gastric-intestinal distress, exhibited through symptoms such as cramps, nausea and diarrhea.