Vitamin E is an important vitamin that has antioxidant properties in your body. It helps protect cells by fighting off highly reactive free radicals. While this fat soluble vitamin has an array of functions, certain types have more biological activity in your body than others. Alpha-tocopherol is a natural form of the vitamin and is the only form of vitamin E stored in your body with the help of the alpha-tocopherol transfer protein in your liver, according to Maret G. Traber, Ph.D., Professor of Nutrition with Linus Pauling Institute.
Types of Vitamin E
The term "vitamin E" refers to a group of eight different compounds, including alpha, beta, delta and gamma tocopherol, as well as alpha, beta, delta and gamma tocotrienol. Alpha tocopherol has the highest measurable amount of biological activity in your body and has the highest concentrations in your blood, says the Office of Dietary Supplements. Since alpha tocopherol is so prevalent in the human body it is the only one acknowledged to meet the Recommended Dietary Allowance, or RDA of vitamin E. Tocopheryl acetate is the ester form of tocopherol, meaning it has an alcohol in the structure. Alpha tocopheryl acetate has equivalent bioavailability to alpha tocopherol.
Natural vs. Synthetic
Natural vitamin E has only one isomer, which is a compound that has the same chemical makeup of vitamin E, but different structure. Synthetic vitamin E is esterified to form eight isomers, only one of which has the identical chemical makeup of natural vitamin E. The remaining seven isomers have limited bioactivity in your body and have about half the function of natural vitamin E. In supplements and fortified foods, natural vitamin E has a "d" or "RRR" before the compound name, such as "d-alpha tocopherol" or "d-alpha tocopheryl acetate". Synthetic forms of the nutrient have "dl" or "all-rac" in front of the name, like "dl-alpha-tocopherol".
Vitamin E provides protection against free radicals, molecules that can damage cells, including brain cells, tissues and organs. According to MedlinePlus, vitamin E supports the immune system, which fights attacks from viruses and bacteria, it aids in red blood cell production and helps your body use vitamin K. On their websites, NYU Langone Medical Center, Harvard School of Public Health and University of Maryland Medical Center review the results of numerous vitamin E studies which failed to prove any benefit for heart disease, stroke, cancer, diabetes, dementia, age-related macular degeneration and many other diseases and health problems. Many of the remaining studies were inconclusive.
Since d-alpha tocopheryl acetate has the same bioavailability as alpha tocopherol, the recommendations are the same, explains the Linus Pauling Institute. As an adult, you need 15 milligrams, or 22.4 international units of vitamin E in either of these forms each day. According to the Office of Dietary Supplements, the tolerable upper intake levels for vitamin E are based on its ability to cause bleeding. For adult men and women, the upper levels are 1,000 milligrams per day, which is equivalent to 1,500 international units per day of the natural form or 1,100 international units per day of the synthetic form.
Dietary alpha tocopherol comes from wheat germ, almonds, peanuts, soybean oil, spinach and sunflower seeds. You can get natural d-alpha tocopheryl acetate from supplements, but check with your physician before you begin supplementation.
Vitamin E Interacts With Medications
The University of Maryland Medical Center warns the vitamin E can cause bleeding if taken with blood thinners, such as warfarin and aspirin. It may also interact with calcium channel blockers, beta-blockers, antipsychotic medications and chemotherapy drugs. If you are taking any prescription medication, consult your doctor before taking vitamin E.