Related Webinar: Annatto Tocotrienol: The Superior Source of Vitamin E

Vitamin E is a complex consisting of 8 sub-fractions: 4 tocopherols and 4 tocotrienols. While the tocopherols (alpha-tocopherol, in particular) are known to have health benefits, the tocotrienols are no slackers. They have quite impressive effects of their own—effects not seen with tocopherols.

Antioxidant power: Tocotrienols for the win

Vitamin E is a potent antioxidant. In fact, you might have seen “mixed tocopherols” listed on food labels. They’re used as preservatives, because they help reduce or delay oxidation (rancidity) of fats and oils. But tocopherols and tocotrienols don’t only prevent oxidation in foods; they work on the fats in animal tissues, too—our tissues, and things like cell membranes. Tocotrienols may be more potent than tocopherols for this purpose. A rat study showed that the antioxidant capacity of alpha-tocotrienol may be as much as 40-60 times higher than that of alpha-tocopherol.  Delta-tocotrienol was found to have the greatest antioxidant properties among the four tocotrienol isomers against at least three different free radical sources. In studies that tested the oxygen radical absorbance capacity (ORAC) of various vitamin E sub-fractions delta- and gamma-tocotrienols had the highest antioxidant value –  5.5 and 3 times the potency of alpha-tocopherol, respectively.

Vitamin E: The “eyes” have it

Vitamin E has long been regarded as a beneficial nutrient to support eye health. (Maybe it’s not a coincidence that “eye” has two Es in it!) It was included in the original Age-Related Eye Disease Study (AREDS) and in AREDS2, studies from the National Institutes of Health’s National Eye Institute. The first AREDS trial was intended to assess the effect of high doses of supplemental vitamin E, vitamin C, beta-carotene, zinc and copper on the progression of cataracts and age-related macular degeneration. AREDS2 eliminated beta-carotene and added omega-3 fats, and the antioxidants lutein and zeaxanthin. The form of vitamin E used in AREDS was alpha-tocopherol only, but newer studies suggest that tocotrienols warrant dedicated research. Tocotrienols have been shown to inhibit angiogenesis—the formation of new blood vessels.  For this reason, they may have application in improving ocular conditions related to abnormal blood vessel growth, such as macular degeneration and diabetic retinopathy. Alpha-tocopherol does not have this effect.

A rat study confirmed that alpha-tocotrienol accumulates in the eye, whereas alpha-tocopherol does not. Cataracts are among the most common eye problems in older people. Rodent models show that tocotrienol administration delayed the onset and progression of cataract by reducing oxidative stress in the lens of the eyes. (It should be noted, however, that these studies employed eye drops that delivered tocotrienols topically. Tocotrienols delivered orally might not have the same effect, but the AREDS studies certainly indicate that vitamin E can be helpful for eye health, at least when taken along with other supportive nutrients.)

Potential for Radiation Protection

In the aftermath of the accident at Japan’s Fukushima nuclear power plant, and taking into consideration the United States’ aging nuclear infrastructure, there’s growing concern about radiation. The Armed Forces Radiobiology Research Institute in Bethesda, Maryland, has conducted extensive research on tocotrienols as radiation countermeasure agents. Oxidative damage from free radicals are the primary source of radiation-induced damage, and tocotrienols, as potent antioxidants, appear to be effective radioprotectors, supporting one researcher’s contention that “strong antioxidants make strong radioprotectors.” The first line of insult by radiation to the human body is the bone marrow, which produces blood. Delta- and gamma-tocotrienols display a clear stimulatory effect on hematopoietic (blood-forming) tissue, helping to restore a fresh blood supply after damage from ionizing radiation.

The effects of tocotrienols on biological effects from radiation may have implications for first responders to nuclear fallout areas, radiation workers, and patients receiving radiation therapy for cancer. It will be interesting to follow emerging research and new therapeutic applications for tocotrienols, an underappreciated fraction of vitamin E typically overshadowed by alpha-tocopherol.

Sources:

1. Serbinova, E., et al., Free radical recycling and intramembrane mobility in the antioxidant properties of alpha-tocopherol and alpha-tocotrienol. Free Radic Biol Med, 1991. 10(5): p. 263-75.
2. Muller, L., K. Theile, and V. Bohm, In vitro antioxidant activity of tocopherols and tocotrienols and comparison of vitamin E concentration and lipophilic antioxidant capacity in human plasma. Mol Nutr Food Res, 2010. 54(5): p. 731-42.
3. Shibata, A., et al., alpha-Tocopherol suppresses antiangiogenic effect of delta-tocotrienol in human umbilical vein endothelial cells. J Nutr Biochem, 2015. 26(4): p. 345-50.
4. Nasir NAA, Agarwal R, Vasudevan S, Tripathy M, Alyautdin R, Ismail NM. Effects of topically applied tocotrienol on cataractogenesis and lens redox status in galactosemic rats. Molecular Vision. 2014;20:822-835.
5. Tanito, M., et al., Distribution of tocopherols and tocotrienols to rat ocular tissues after topical ophthalmic administration. Lipids, 2004. 39(5): p. 469-74.
6. Ghosh, S.P., et al., Gamma-tocotrienol, a tocol antioxidant as a potent radioprotector. Int J Radiat Biol, 2009. 85(7): p. 598-606.
7. Satyamitra, M.M., et al., Hematopoietic Recovery and Amelioration of Radiation-Induced Lethality by the Vitamin E Isoform delta-Tocotrienol. Radiat Res, 2011. 175(6): p. 736-45.