Humans can’t synthesize Vitamin E and therefore, must obtain it from the diet. Vitamin E exists in 8 different forms: alpha (α), beta (β), gamma (γ) delta (δ)-tocopherol, and α, β, γ, and δ-tocotrienol. The importance of Vitamin E during aging is illustrated by the finding that high blood levels of both tocopherols and tocotrienols are associated with a reduced risk (50%-90%) of developing mild cognitive impairment and Alzheimer’s disease in people older than 75 years (Mangialasche et. al 2010; Mangialasche et. al 2011).
However, is there a difference between tocopherols and tocotrienols, in terms of health? The answer is yes: tocotrienols have been shown to have better antioxidant properties (Serbinova et. al 1991), and, they have a greater ability to inhibit oxidative damage, relative to tocopherols (Kamat et. al 1997, Kamat, J. P. & Devasagayam 1995).
Tocotrienols have been used to reduce triglycerides (Zaiden et. al 2010), a well documented risk factor for cardiovascular disease (Austin et. al 1998). Tocotrienols have also been shown to reduce inflammation (Wu et. al 2008), to reduce DNA damage (Chin et. al 2008), to reduce the progression of both liver and lung cancer (Wada et. al 2005), and are neuroprotective (Khana et. al 2003, Nakagawa et. al 2007). Furthermore, tocotrienols have been shown to be effective against tumor angiogenesis (Shibata et. al 2008). Angiogenesis-the formation of new blood vessels-plays an important role in many pathological processes, such as the growth and metastasis of solid tumors, diabetic retinopathy, rheumatoid arthritis, and psoriasis (Kim et. al 1993)
For those of you who are endurance athletes, tocotrienol supplementation has been shown to increase endurance capacity, in rats (Lee et al. 2009). It’s important to note that no human studies to date have investigated the role of tocotrienol supplementation on aerobic exercise capacity. In the Lee study, rats given a low dose of (25 mg/kg) of a tocotrienol rich supplement for one month doubled their swim time to exhaustion, whereas a high dose of tocotrienols (50 mg/kg) increased their swim time to exhaustion by 2.5-fold. In contrast, rats given a low dose (25 mg/kg) of α-tocopherol did not significantly increase swim endurance capacity.
So, where can we find dietary tocotrienols? Whole grains have the highest tocotrienol content, approximately 3 mg of tocotrienols/kg food, when compared with all other food groups (Sookwong et. al 2010). Tocotrienols are second most abundant in nuts and seeds, at 1.5 mg/kg. Tocotrienols are almost completely absent in all other food groups. The attached table in the right corner of this article lists tocotrienol content (in nanograms, ng) per calorie in commonly consumed whole grains, nuts/seeds, beans and oils. α-tocotrienol is particularly rich in oats and barley; durum wheat has ~5-fold more β –tocotrienol than any other grain, although barley and soybeans are also good sources; corn contains the highest amount of γ-tocotrienol, approximately 4-fold more than barley; and, safflower oil contains the highest concentration of δ-tocotrienol, containing approximately 3-fold more δ-tocotrienol than adzuki beans.
Considering that both wheat and barley contain gluten, celiac disease-susceptible individuals may want to avoid these grains. However, celiac disease affects 1 in 133 Americans (http://www.uchospitals.edu/pdf/uch_007937.pdf), so 99.2% of the population should be able to eat these tocotrienol-rich grains without issue. It’s important to note that if you have celiac disease, you can obtain full tocotrienol coverage by eating the combination of cashews and peanuts, albeit at a far lower concentration than found in whole grains, as shown in the attached Table.
On a final note, sesame seeds have been shown to elevate the concentration of tocotrienols found in skin (Ikeda et al. 2001), so if you want to get the biggest nutritional bang for your buck, consume tocotrienol-containing foods with sesame seeds. I do!
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