A Thirst for Knowledge About Vitamin E

A few weeks ago, we threw open the doors to questions from readers, and by the miracle of e-mail, fax machines and even the U.S. Postal Service, we got what we asked for (and then some). As we indicated, we cannot answer most of these questions personally, but we will try to address as many as possible in this column. In the mail we received were a lot of really good inquiries about our column on vitamin E, “Vitamin E: One Case in Which the Hype May Be True,” Sept. 27). Since this is a big and complicated subject, we’re not surprised that there is still some confusion about it. Hopefully this will help.

Question: Some vitamins and minerals are quantified using milligrams and some using IUs. Why are there two systems and how does one convert IUs to milligrams?

Answer: This is a good question that is asked often and can be very difficult to answer. But we’ll give it a try. IUs, or international units, are a designation that indicates biological activity, whereas milligrams denote weight. Because there are so many types of vitamin E, each of which has somewhat different activity in the body, the IU measurement allows for some standardization and comparison. The RDA lists vitamin E in milligrams because it is a reference standard used in food composition tables. This is why the amount of vitamin E listed in foods is always given in milligrams, which indicate the weight of the compound present, regardless of which compound it is. Vitamin E supplements are sold in IUs. For practical purposes, it isn’t usually necessary for anybody to calculate the equivalent amounts.

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Q: In your column about vitamin E, in the list of foods containing significant amounts of vitamin E, all the vegetables were cooked. Is vitamin E available in raw foods and does freezing destroy the vitamin?

A: Vitamin E is a very stable substance in foods, and is not easily destroyed by cooking or freezing, as are some other vitamins. It also does not require cooking to free it up, like, for instance, lycopene (an antioxidant found in tomatoes that is far more available in processed sauces). Therefore, raw foods have the same amount of vitamin E as cooked. However, with the exception of some oils and nuts, the amount of vitamin E in foods is not that great and the absorption of vitamin E from foods is quite variable (20% to 80% of the amount present). This is why, although we normally recommend getting vitamins and minerals from food, vitamin E (in the amounts recommended to achieve the maximum effect) is so important that it is probably better taken in a supplement form that is more available to the body. It is worth noting that one way to destroy vitamin E is by exposing it to light and air, so supplements should be stored in dark, airtight containers.

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Q: There is some confusion about the spelling and designation of natural versus synthetic vitamin E. What is tocopheryl (as opposed to tocopherol), and what does the addition of acetate or succinate mean?

A: In our previous column, we indicated that vitamin E labeled “dl alpha tocopherol” is synthetic and “d-alpha tocopherol” or mixed tocopherols will be the natural version. We also recommended that the best form of vitamin E to take (in terms of activity) is the natural form. Four hundred IU of dl-alpha tocopherol may or may not have the same biological activity as 400 IU of d-alpha tocopherol. The two spellings (tocopherol and tocopheryl) can be used interchangeably, but any vitamin E that is combined with a salt (such as succinate or acetate) must be labeled tocopheryl.

When you see the word “succinate” in connection with vitamin E, it means that a chemical compound has been added that allows the vitamin E to be present in a powdered form. The content and availability is the same as the capsules. Adding acetate to vitamin E merely serves to further stabilize the vitamin and has no effect on its potency.

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Q: Can people who are taking blood-thinning drugs and daily doses of aspirin take vitamin E?

A: Vitamin E is a powerful antioxidant and also a mild anticoagulant (keeps blood from clotting). Its anticoagulant properties may be one of the reasons it seems to protect against heart disease. If you are taking vitamin E supplements and your doctor has prescribed a blood-thinning medication, be sure to discuss the dosage of both because you may need to make some adjustments to continue getting the antioxidant effects of vitamin E. This is also true if you are taking a daily baby aspirin or even gingko biloba, which also has a similar effect. However, taking just baby aspirin and vitamin E together should not pose any problems.

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Q: Can vitamin E be taken with other vitamins? Must it be taken with foods that contain fat?

A: Vitamin E does not destroy the potency of other vitamins taken at the same time. It is a good idea to take it with some food, and a small amount of fat will help in the absorption. Almost any food will do.

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Q: What should we know about tocotrianols, which are related to vitamin E, and pycnogenols? Can they be taken instead of vitamin E?

A: Tocotrianols are another group of powerful antioxidants in the vitamin E family. The research on them is in its early stages, and we will be following it closely. Pycnogenol is yet another antioxidant, but it does not seem to act in the same way as vitamin E and cannot really be substituted for it. Far less is known about the recommended dose and action of pycnogenol, but as more research emerges, we will keep you posted.

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Questions? Please send them by e-mail to daogar@uclink4.berkeley.edu; by fax to (510) 642-2857; or by U.S. mail to Dale Ogar, School of Public Health, UC Berkeley, CA 94720-7360. We regret that we cannot answer questions personally.