SEATTLE, WA—Higher levels of vitamin E improve spatial memory performance in sleep-deprived women, according to data presented at SLEEP 2015.
An earlier rodent-model study had shown that vitamin E lessened sleep deprivation-induced spatial memory impairment. Previous research also demonstrated that women with higher vitamin E levels perform better on tests of psychomotor speed. Alexis L. Taylor, of the Division of Sleep and Chronobiology, Perelman School of Medicine, University of Pennsylvania, examined 41 adults aged 21–50 years (18 females and 23 males) to see if vitamin E intake impacted memory performance in adults undergoing sleep restriction. Participants experienced two ights of baseline sleep (B1 for 10 hours per nighttime in bed, and B2 for 10/12 hours per nighttime in bed) followed by five nights of sleep restriction ([SR] 4 hours per nighttime in bed, from 4:00AM–8:00AM).
Participants completed the Visual Object Learning Task (VOLT), a spatial working memory test, as part of a larger test battery each morning. VOLT performance was evaluated using a standard score that accounted for the accuracy and response speed. Food and drink intake data were entered into a food processing program to obtain amount of vitamin E consumption. Food and drink were ad libitum, but not allowed during testing.
Researchers observed varied VOLT performance across protocol days (P<0.001). Participants showed improvement from B2 to SR2 and then a decline in performance from SR2 to SR5. At baseline, vitamin E intake was not related to VOLT performance in men or women (Ps>0.21). During sleep restriction, vitamin E intake was positively correlated with VOLT performance in women (r=0.46; P=0.053) but not in men (r=0.14; P=0.51). Among women, those who had higher vitamin E intake performed significantly better on the VOLT during sleep restriction than those who had lower levels of vitamin E (P=0.029; Cohen’s d=1.13).
Dr. Taylor noted that the present study focused on VOLT scores for accuracy and speed. Further research is ongoing to assess whether vitamin E is related to memory accuracy, response time for memory tasks, or both.