Q. Can you talk about the differences between the different types of Vitamin E?
A. I'd be happy to!
There are two forms of vitamin E: tocopherol and tocopheryl acetate. Tocopherol is naturally-occurring, while tocopheryl acetate is synthetic. Both are used in cosmetics as antioxidants, keeping oils from turning rancid, and for their reported benefits on skin (healing, anti-aging).
The term "vitamin E" actually refers not just to one molecule, but a family of molecules that are chemically similar. That's why sometimes you'll see the words "mixed tocopherols" on a vitamin E label. There are multiple forms of tocopherol, including alpha and gamma, and a sub-family of compounds called tocotrienols. All of these compounds have the same chemical formula (same amount and ratio of atoms) just in slightly different arrangements (called isoforms.) To simplify, instead of listing out each and every isoform, we refer to these compounds collectively, as "vitamin E." The most predominant molecule in the vitamin E family is alpha-tocopherol, and most of the time, when one says "tocopherol," they are referring to alpha-tocopherol. (As I will be doing for the purposes of this discussion.)
Tocopheryl acetate is the ester of tocopherol. On a molecular level it is an tocopherol molecule with an acetate group added. It is more stable than tocopherol, typically giving products a longer shelf-life. In order for the body to absorb and use vitamin E, it must somehow remove the acetate group. Thus, many claim that tocopherol is more bioavailable to skin and for internal use because it can be absorbed without additional metabolism. (Source)
Interestingly, both tocopherol and tocopheryl acetate can be made synthetically. So, while tocopherol is usually touted as "natural tocopherol," it may still be synthetic.
Tocopheryl acetate requires more steps and ingredients for production:
Dichloromethane-->Sodium chloride-->Xylene-->Zinc chloride-->Isopropyl ether-->PASSION FLOWER OIL-->SOYBEAN OIL-->SODIUM SULFATE DECAHYDRATE-->Isophytol-->Trimethylhydroquinone-->Vitamin E-->(POLYOL) (Source)
Whereas synthetically-produced tocopherol requires fewer steps:
Acetic anhydride-->Isophytol-->Trimethylhydroquinone (Source)
You'll notice, though, that both of these processes use a chemical called trimethylhydroquinone. This is one of the biggest problems that the Cosmetics Database has with both forms of vitamin E, because the finished products can contain traces of hydroquinone. Hydroquinone is in a class of chemicals called aromatic organic compounds. This means not just that it's aromatic in the sense of it being fragrant, but it contains a benzene ring. If you're a reader of this blog, you'll know that I view most compounds with simple benzene rings with caution for their possible xenoestrogenic effects. Animal studies have found hydroquinone to alter immune function and to increase the "incidence of renal tubule cell tumors and leukemia in F344 rats." (Source) While the Cosmetics Industry Review board states that cosmetic use is unlikely to cause these effects, they do recommend its use at less than 1% in a product, and state that it should not be used in leave-on products. So, if one were cautious about what they put on their skin, hydroquinone and hydroquinone-contaminated vitamin E would be an ingredient that I would recommend avoiding.
What to look for
Now that we know that even "natural tocopherol" can be a synthetic compound and laced with hydroquinone, does this mean that all vitamin E should be avoided? No. There are safe forms of vitamin E. Unfortunately, you're not able to tell the difference just by looking at a label. You have to dig deeper and ask the manufacturer of the product you're using.
The best form of vitamin E when considering contamination concerns, is vacuum-distilled. This means that they'll take an oil with naturally-occurring vitamin E and basically suck the vitamin E out. Vitamin E has a different evaporation point than the fatty acids in the oil. So, under certain pressures the vitamin E separates from the oil, evaporates up through a tube, and is thus completely extracted.
The oils most frequently used for vitamin E production are corn, soy, and rapeseed/canola. Unfortunately, in the US, 90% or so of these oils are from genetically-modified crops. So, if you want to take it a step further, ask if the vitamin E in the product is certified non-GMO. Certified organic products cannot contain any genetically modified material, so the USDA organic seal on a product would ensure that the vitamin E used is non-GMO.
Is Vitamin E Safe and Beneficial?
Contamination concerns aside, the Cosmetics Database still gives tocopherol a little flag for "cancer," albeit the risk is low. (See the listing here)
The Database gives vitamin E a mark for cancer based on a 1985 study where vitamin E mixed with soybean oil were injected in to mice and tumors formed. (Whether the soy was GMO or the vitamin E vacuum-distilled or synthetic, the study doesn't specify.) Either ingredient injected separately did not cause this effect, but for some reason, the ingredients created these tumors when mixed together. The study was repeated again in 1991, researchers found that tocopherol acetate alone caused tumors to form when injected, but tocopherol alone did not.
The particular tumors that were formed in this study are called fibrosarcomas. Fibrosarcomas are cancers of the connective tissue, and typically form under the skin at sites where vaccines have been administered. The exact mechanism whereby these tumors form is still unknown, but it is believed that an inflammatory response occurs at injection site and triggers the cell mutation. (Source) Ingestion or topical application of vitamin E do not cause these tumors; it is unique to areas where multiple injections have been made, and these tumorigenic effects have not been proven to apply to humans.
So, is vitamin E safe? The answer is yes. It's not just safe, but highly beneficial and a vital nutrient the body cannot live without. One thing that I see as a flaw with The Cosmetics Database is that they don't factor in any positive information when scoring ingredients. An ingredient could be the cure for cancer, but if it caused an allergic reaction in a test study in 1945, it would still get a negative score.
Ingestion and topical application of vitamin E has proven to be a powerful force against cancer. This study found vitamin E to help reduce lung tumors in animals. This study found vitamin E to be anti-inflammatory in the lungs and colon. This study found vitamin E to have a potential role in breast cancer prevention. Applied topically, vitamin E also shows strong anti-oxidant and anti-inflammatory properties. This study found reduced inflammation and incidence of skin cancer in mice treated topically with vitamin E. This study confirmed this potential in humans. Additionally, very recent studies have found that tocotrienols may have the most health-promoting benefits. (Source) Tocotrienols are not found in tocopheryl acetate, and can be found in the highest concentration in solvent-free, vacuum-distilled vitamin E.
What about soy?
Most vacuum-distilled vitamin E is extracted from soybean oil. There are many people who avoid soy based on hormonal concerns, thyroid issues, and allergies. Only in cases of extreme soy allergy would I suggest avoiding a soy-extracted vitamin E. Vitamin E extracted from soy does not contain any of the isoflavone phytoestrogens, so it is not a concern for the thyroid or hormonal balance. (Isoflavones are largely insoluble in water and in oil, and are not found in soybean oil [Source]. The vaccuum extraction of the vitamin E from the oil further insures no isoflavone content in the finished vitamin E product, as isoflavones have a largely differing evaporation point than the mixed tocopherols. [Source][Source]) Naturally-extracted vitamin E is highly purified, and also lacks the most of the compounds that trigger allergies associated with soy.