What are liposoluble vitamins and what is the difference between them and hidrosoluble vitamins? Judging by the way in which they are absorbed, vitamins can be either hidrosoluble or liposoluble. Liposoluble vitamins can be absorbed from the human gastrointestinal tract only in the presence of fat. Vitamins ingested through the gastrointestinal tract are absorbed in the duodenum. Which are the liposoluble vitamins?

1. Vitamin A or retinol is the first liposoluble vitamin. It is a key component of the pigments contained in the cells of the retina. This pigment is necessarily for both low-light and diurnal vision.  It can also be found in retinoic acid which has an important role in epithelial growth. Lack of vitamin A can affect the way in which our eyes accommodate to low-light vision and create overall sight problems. Vitamin A can be found as retinol in meat or as carotenes in carrots, broccoli, sweet potatoes and butter.
2. Vitamin D is generally used to refer to vitamin D3 or cholecalciferol but the general term refers to both D3 and D2. Vitamin D is a secosteroid produced in the skin after exposure to ultraviolet light. Keep in mind that sunscreen, even with an UV factor of 5 negates the production of vitamin D. It has a major role in the absorption of calcium from the gastrointestinal tract, reabsorption from blood and depositing it in our bones. So no matter how many calcium supplements you take keep in mind that they are going to be useless without vitamin D.
3. Vitamin E or tocopherol is a fat soluble antioxidant that stops the production of reactive oxygen species that generally occur when fat undergoes oxidation. However this is not the only role of vitamin E, its actions also include: inhibition of platelet aggregation, protection of the nervous system and many others. Great sources of vitamin E are: wheat germ oil, sunflower, and safflower oils.
4. Vitamin K is an essential factor in the overall blood coagulation process but also plays important roles in the nervous system where it seems to delay and protect from the effects of Alzheimer disease and in the skeletal system as well. Like vitamin D, vitamin K is normally produced by the human body and like all fat soluble vitamins it is stored the human fatty tissue. Lack of vitamin K may lead to clotting disorders and bleeding.