Vitamins are essential compounds that are needed by the body in small amounts for proper function. There are two types of vitamins -- water-soluble and fat-soluble. Water-soluble vitamins dissolve in water in the body and excess amounts are excreted in the urine. Fat-soluble vitamins bind to fat in the body and can be stored in the liver and fat cells for later use. There are four categories of fat-soluble vitamins.
Vitamin A
Vitamin A, also commonly referred to as retinol, plays a number of roles in the body. One of the most important functions is proper eye health. Vitamin A allows for both night vision and color vision. The vitamin is also essential for proper bone and tooth development, reproduction and cell division. The richest sources of vitamin A are orange fruits and vegetables, such as oranges and carrots, green leafy vegetables like spinach and kale, and liver. Fortified milk is also a good source of vitamin A. According to the Food and Nutrition Board, adult females should consume 700 micrograms of vitamin A daily and adult males should consume 900 micrograms per day.
Vitamin D
Vitamin D is often referred to as the "sunshine vitamin" because it can be synthesized in the body with the help of ultraviolet rays from the sun. Vitamin D increases calcium absorption and aids in the body's use of phosphorus. The best food sources of vitamin D include fortified milk and oily fish, such as herring and sardines. Egg yolks, liver and fortified cereals are also good sources of the vitamin, according to Kids Health. The Food and Nutrition Board provides daily reference intakes for vitamin D for those for whom adequate exposure to the sun is not possible. These reference intakes are 5 micrograms per day for both men and women.
Vitamin E
The most important role of vitamin E is as an antioxidant. Antioxidants destroy free radicals and prevent them from causing harm to the body. Vitamin E may also help prevent heart disease and cancer. Approximately 60 percent of Vitamin E in the American diet comes from vegetable oil. Other good sources include fruits, vegetables, grains, nuts and fortified cereals. The daily reference intakes for vitamin E are 15 mg per day for both adult men and women.
Vitamin K
Vitamin K is essential for proper blood clotting and also plays a role in bone health. Vitamin K can be produced by the bacteria that normally live in the intestines, but must be consumed through the diet as well. The best sources of vitamin K are green vegetables and vegetable oils. Adult females should consume 90 micrograms of vitamin K daily, while adult males should consume 120 micrograms per day.
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