Oil or vitamin E capsule. Pair of tweezers holds an oil or vitamin E capsule. Capsules like these are taken as dietary supplements because they contain fatty acids which are essential for good health; some oils also contain the fat-soluble vitamins A, D, E and K. Vitamin E (tocopherol) is an important vitamin principally concerned with protecting fats from oxidation in the body. It is needed for maintenance of normal cell structure, for sustaining the action of certain enzymes, and it protects the lungs and other tissues from damaging pollutants.