Editing Vitamin E (section)

=== Tocotrienols ===
The four [[tocotrienol]]s (alpha, beta, gamma, delta) are similar in structure to the four tocopherols, with the main difference being that the former have hydrophobic side chains with three carbon-carbon double bonds, whereas the tocopherols have saturated side chains. For ''alpha(α)''-tocotrienol each of the three "R" sites has a methyl group (CH<sub>3</sub>) attached. For ''beta(β)''-tocotrienol: R1 = methyl group, R2 = H, R3 = methyl group. For ''gamma(γ)''-tocotrienol: R1 = H, R2 = methyl group, R3 = methyl group. For ''delta(δ)''-tocotrienol: R1 = H, R2 = H, R3 = methyl group. Tocotrienols have only a single [[chirality|chiral center]], which exists at the 2' chromanol ring carbon, at the point where the isoprenoid tail joins the ring. The other two corresponding centers in the phytyl tail of the corresponding tocopherols do not exist as chiral centers for tocotrienols due to unsaturation (C-C double bonds) at these sites. Tocotrienols extracted from plants are always [[dextrorotatory]] stereoisomers, signified as d-tocotrienols. In theory, [[levorotatory]] forms of tocotrienols (l-tocotrienols) could exist as well, which would have a 2S rather than 2R configuration at the molecules' single chiral center, but unlike synthetic dl-alpha-tocopherol, the marketed tocotrienol [[dietary supplement]]s are extracted from palm oil or rice bran oil.<ref name="Ahsan2015">{{cite journal |vauthors=Ahsan H, Ahad A, Siddiqui WA |title=A review of characterization of tocotrienols from plant oils and foods |journal=J Chem Biol |volume=8 |issue=2 |pages=45–59 |date=April 2015 |pmid=25870713 |pmc=4392014 |doi=10.1007/s12154-014-0127-8 }}</ref>

Tocotrienols are not essential nutrients; government organizations have not specified an estimated average requirement or recommended dietary allowance. A number of health benefits of tocotrienols have been proposed, including decreased risk of age-associated cognitive impairment, heart disease and cancer. Reviews of human research linked tocotrienol treatment to improved [[Biomarker (medicine)|biomarkers]] for [[inflammation]] and [[cardiovascular disease]], although those reviews did not report any information on clinically significant disease outcomes.<ref>{{cite journal |url = http://www.eurekaselect.com/article/19696 |vauthors = Prasad K |title = Tocotrienols and cardiovascular health |journal = Current Pharmaceutical Design |volume = 17 |issue = 21 |pages = 2147–54 |date = 2011 |pmid = 21774782 |doi = 10.2174/138161211796957418 |access-date = 12 December 2022 |archive-date = 10 December 2022 |archive-url = https://web.archive.org/web/20221210053123/http://www.eurekaselect.com/article/19696 |url-status = live }}</ref><ref>{{cite journal |vauthors=Khor BH, Tiong HC, Tan SC, Wong SK, Chin KY, Karupaiah T, Ima-Nirwana S, Abdul Gafor AH |title=Effects of tocotrienols supplementation on markers of inflammation and oxidative stress: A systematic review and meta-analysis of randomized controlled trials |journal=PLOS ONE |volume=16 |issue=7 |pages=e0255205 |date=2021 |pmid=34297765 |pmc=8301652 |doi=10.1371/journal.pone.0255205 | doi-access = free | title-link = doi |bibcode=2021PLoSO..1655205K |url=}}</ref><ref>{{cite journal |vauthors=Rafique S, Khan DA, Farhat K, Khan MA, Noor M, Sharif M |title=Comparative efficacy of tocotrienol and tocopherol (vitamin E) on atherosclerotic cardiovascular diseases in humans |journal=J Pak Med Assoc |volume=74 |issue=6 |pages=1124–29 |date=June 2024 |pmid=38948984 |doi=10.47391/JPMA.9227 |url=| doi-access = free | title-link = doi |doi-broken-date=17 February 2025 }}</ref> Biomarkers for other diseases were not affected by tocotrienol supplementation.<ref>{{cite journal |vauthors=Li F, Xu B, Soltanieh S, Zanghelini F, Abu-Zaid A, Sun J |title=The effects of tocotrienols intake on obesity, blood pressure, inflammation, liver and glucose biomarkers: a meta-analysis of randomized controlled trials |journal=Crit Rev Food Sci Nutr |volume=62 |issue=26 |pages=7154–67 |date=2022 |pmid=33909529 |doi=10.1080/10408398.2021.1911926 |url=}}</ref>