Vitamin E is a fat-soluble vitamin found in seeds, nuts, leafy vegetables, and vegetable oils. It is a type of antioxidant and helps prevent cell damage caused by free radicals (highly reactive chemicals). It is being studied in the prevention and treatment of some types of cancer. Vitamin E has been used as an oral or parenteral supplement and as a solution for topical application. Vitamin E has been examined in management of diarrhea, mucositis, peripheral neuropathy, skin effects, cognitive impairment, and hot flashes.
Chan, A.S., Cheung, M.C., Law, S.C., & Chan, J.H. (2004). Phase II study of alpha-tocopherol in improving the cognitive function of patients with temporal lobe radionecrosis. Cancer, 100(2), 398–401.
The study was conducted to determine if vitamin E (alpha-tocopherol) could improve cognitive function in patients with nasopharyngeal carcinoma and temporal lobe radionecrosis.
Participants were administered 1,000 IU of vitamin E twice daily for one year. Assessments were conducted prior to the initiation of vitamin E dispensal and after the completion of one year of treatment.
The study was a single-site project at the neurology clinic of Queen Elizabeth Hospital in Hong Kong.
The study employed a pre- and post-test design with a treatment and control group.
There was no significant difference in cognitive performance at baseline between the two groups. In the treatment group, there was significant improvement from baseline on
Improved executive function was also measured in the treatment group, as seen in average reaction times (p = 0.001) and scores on the Cognitive Flexibility Test (p = 0.04); these improvements were not found in the treatment group. No significant differences were found in sustained attention for either group. There was a slight, but not statistically significant, increase in participant ratings after one year of treatment for the treatment group. The control group reported a slight worsening of function on their subjective ratings (p = ns).
Vitamin E may be a promising complementary intervention for improvement in verbal and visual memory, global cognitive function, and cognitive flexibility.
Jatoi, A., Kahanic, S.P., Frytak, S., Schaefer, P., Foote, R.L., Sloan, J., & Petersen, R.C. (2005). Donepezil and vitamin E for preventing cognitive dysfunction in small cell lung cancer patients: Preliminary results and suggestions for future study designs. Supportive Care in Cancer, 13(1), 66–69.
The study was conducted to test oral donepezil and oral vitamin E in patients with small-cell lung cancer after completion of all cancer therapy and prophylactic cranial irradiation.
A randomization procedure was conducted after participant stratification in the following ways.
The treatment group received 5 mg/day of oral donepezil, which increased to 10 mg/day after one month of therapy if tolerated well. Treatment group participants also received 1000 IU/day of oral vitamin E. The control group was given an identical oral placebo. Assessments were performed at study enrollment, one month, and every three months until cancer recurrence or treatment failure.
The study took place at the North Central Cancer Treatment Group and the Mayo Clinic.
The study was a double-blind, placebo-controlled trial.
There were no notable differences in cognitive stability, adverse events, or quality of life between treatment arms. Only one patient, who received donepezil and vitamin E, manifested a three-point drop in cognitive scores as measured by the MMSE. There was a slight trend of increased gastrointestinal side effects among patients treated with donepezil and vitamin E.
The median time spent in the study was 42 or 69 days for the treatment or control group, respectively.
Due to low enrollment and retention, the effect of oral doses of vitamin E and donepezil on cognitive function could not be determined.