Fat-soluble Vitamins And Toxicity

The fat-soluble vitamins A, D, E and K require the presence of dietary fat in order to be properly absorbed in the body. Unlike water-soluble vitamins, the body can store fat-soluble vitamins for use when your dietary intake is not sufficient. Although this can be helpful in preventing vitamin deficiencies, it can lead to vitamin toxicities.

Vitamin A

One of the most common fat-soluble vitamin toxicities occurs with the overconsumption of vitamin A. Vitamin A toxicity is medically referred to as hypervitaminosis A. Vitamin A toxicity is caused by overconsumption of preformed vitamin A, which is found in foods from animal sources, such as liver, eggs and milk. Symptoms of vitamin A toxicity include nausea, headache, fatigue, loss of appetite, dizziness, dry skin, and bone and joint pain, according to the Linus Pauling Institute. If left untreated, vitamin A toxicity can result in liver damage and even death.

Vitamin D

Overconsumption of vitamin D can also cause a vitamin toxicity, called hypervitaminosis D. Vitamin D toxicity can cause loss of calcium from the bones as well as increased absorption of calcium in the intestines, according to "Nutrition and You" by Joan Salge Blake. If the bones release too much calcium, it can lead to increased levels of calcium in the bloodstream, a condition referred to as hypercalcemia. This can lead to loss of appetite, nausea, vomiting and constipation.

Vitamin E

There are no known adverse effects from consuming too much vitamin E through food sources, but excess supplemental intake of the vitamin can have negative health effects. Too much vitamin E supplementation can interfere with proper blood clotting and lead to an increased risk of hemorrhaging.

Vitamin K

According to "Nutrition and You" by Joan Salge Blake, there are no known adverse effects from consuming too much vitamin K from either food sources or supplements. If you are taking an anti-coagulant, however, you should closely monitor your intake of vitamin K since it can affect blood clotting.

Prevention

To prevent fat-soluble vitamin toxicities, the Food and Nutrition Board, which is a subgroup of the Institute of Medicine, developed upper tolerable intake levels, or UL, for some of the vitamins. This level represents the highest amount of a specific vitamin that you can consume each day without experiencing any adverse health effects.

The UL for vitamin A is set at no more than 10,000 IU per day for adult men and women over the age of 19. The UL for vitamin D has been set at 2,000 IU for adults. The UL for vitamin E is set at 1,000mg per day for adults, but this number applies to supplements only. There is no UL for vitamin K.