More than 70 percent of Americans take vitamins or other supplements in the hopes of better health, according to a 2003 article in the "New York Times" by Gina Kolata. However, it is possible to get too much of a good thing and overdose on some vitamins, especially those that are fat soluble.
Types
Unlike the water-soluble vitamins, which include the B vitamins and vitamin C, fat-soluble vitamins like A, D, E and K are stored in the body and do not need to be replenished daily. These vitamins are only needed in small amounts, and there are negative health effects if you take too much of them, according to Colorado State University Extension.
Misconceptions
Some people are under the impression that when it comes to vitamins, the more the better. This is especially true when studies are published in journals touting the health benefits of the various vitamins, including antioxidants like vitamins A and E. However, the Institute of Medicine, or IOM, has set tolerable upper recommended intake levels which shouldn't be exceeded due to health risks.
Warning
Overly high intakes of fat-soluble vitamins can cause serious health problems. Fetuses are especially sensitive to high levels of Vitamin A, which can cause abnormal fetal development. Overdose of this vitamin in adults or children also may cause dry skin, nausea, drowsiness and other mild symptoms. More serious symptoms include osteoporosis, liver damage and excess calcium in the blood, which can lead to kidney damage. Vitamin A toxicity can cause failure to thrive in children. Taking too much vitamin D can cause dehydration and hypercalcemia, which can lead to kidney stones and kidney damage. People taking statins or blood thinning medications can have complications if they take too much vitamin E. Excessive doses of vitamin K can lead to liver damage and the breakdown of red blood cells.
Prevention/Solution
Get most of your fat-soluble vitamins from food, since you are unlikely to get excessive amounts of these vitamins from food alone. Be aware of the tolerable upper intake levels for these vitamins when you purchase any supplements, so you do not exceed these levels. Using supplements containing beta-carotene instead of retinol can limit the chances of getting too much vitamin A, since this form must be converted into retinol and excess amounts are likely to be excreted rather than converted.
Expert Insight
The majority of the population doesn't need to take supplementary vitamins, according to Colorado State University Extension. Those that are at a higher risk for vitamin D deficiency should eat foods that are fortified with vitamin D rather than taking supplements. Those who take supplements need to calculate how much of the fat-soluble vitamins they are getting in their diet and through fortified foods so they can choose a supplement that won't have them exceeding safe fat-soluble vitamin levels.
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