An examination into the effects of tocotrienols (TheraPrimE® rice) on cognitive abilities and sleep in healthy adults: a randomised, double-blind, placebo-controlled trial

Abstract

Background/objectives: Tocotrienols are a form of vitamin E that may have neuroprotective effects. However, there have been no studies examining its effects on cognitive function when delivered as a stand-alone intervention. The purpose of this two-arm, 12-week, randomised, double-blind, placebo-controlled trial was to examine the effects of supplementation with tocotrienols derived from rice bran (TheraPrimE® rice) on memory and sleep in adults with subjective memory complaints. Methods: Ninety-one adults aged 40–80 were supplemented with a placebo or 100 mg of tocotrienols daily. Outcome measures included the Test of Memory and Learning (version 2), and self-report questionnaires assessing executive function and sleep quality. Moreover, changes in blood markers associated with inflammation, oxidative stress, and neurotropic activity were examined. Results: Compared to the placebo, tocotrienol supplementation was associated with greater improvements in general memory (p = 0.045, 95% CI: 0.34, 32.21). Memory changes were primarily due to improvements in non-verbal memory (p = 0.039, 95% CI: 0.68, 26.63). However, there were no group differences in changes in verbal memory. Moreover, there were no group differences in changes in self-reported executive function, although there were greater improvements in sleep disturbance in the tocotrienols group (p = 0.015, 95% CI: −4.80, −0.55). An examination of blood markers revealed a statistically significant larger increase in Tumour Necrosis Factor-α in the placebo group (p = 0.043) and a larger increase in C-reactive protein (p = 0.039) in the tocotrienols group. Tocotrienols were not associated with any serious adverse reactions. Conclusion: This is the first controlled study demonstrating the cognitive-enhancing and sleep-promoting effects of stand-alone supplementation with tocotrienols. However, future research is required to substantiate this study’s results and examine the potential mechanisms of action. Clinical trial registration: https://www.anzctr.org.au/ACTRN12624000351516.aspx, Identifier ACTRN12624000351516.