Comparative efficacy of tocotrienol and tocopherol (vitamin E) on atherosclerotic cardiovascular diseases in humans.

To compare the efficacy of tocotrienol and tocopherol in the management of patients with atherosclerotic cardiovascular diseases. The systematic review was conducted in line with Preferred Reporting Items for Systematic Reviews and Meta- Analyses guidelines 2020, and comprised literature search from 2002 till January 5, 2023, on PubMed, Google Scholar, Cochrane Library, Google, Wiley-Inter Science Library, Medline, SpringerLink, Taylor and Francis databases. The search was conducted using key words, such as: "tocopherol", "tocotrienol", "vitamin E", "dyslipidaemia", "cardiovascular diseases" "cardioprotective", "hypercholesterolemia" and "atherosclerosis" along with Boolean operators. Human clinical studies regarding the use of tocotrienol or tocopherol or comparison of its efficacy in patients having atherosclerosis, dyslipidaemia leading to cardiovascular diseases, and studies including details of efficacy of any of the four alpha, beta, gamma, delta isomers of tocopherol or tocotrienol were included. Pertinent data from the eligible studies was retrieved and reviewed. Of the 516 articles identified, 26 (5%) articles met eligibility criteria. Of them 5(19%) were subjected to detailed analysis. Tocotrienol showed significant anti-oxidant efficacy at (250 mg/d) by decreasing cholesterol and serum inflammatory biomarkers i.e C-reactive protein (40%), malondialdehyde (34%), gamma-glutamyl transferase (22%) (p<0.001). Total anti-oxidant status (TAS) levels raised 22% (p<0.001) and Inflammatory cytokines i.e resistin, interleukin (IL)-1, IL-12, Interferon-gamma were decreased 15-17% (p<0.05-0.01) respectively by tocotrienol. Several microRNA (miRNA-133a, miRNA-223, miRNA-214, miRNA-155) were modulated by δ-tocotrienol. Whereas, tocopherol showed heterogeneity of results by either decreasing or increasing the risk of mortality in atherosclerotic cardiovascular diseases. Compared to tocopherol, tocotrienol was found to be safe and potential candidate for improving cardiovascular health in the management of atherosclerotic cardiovascular diseases.