Objective: To systematically evaluate the levels of vitamin C, vitamin E and β-carotene in the plasma of Alzheimer's disease( AD) patients.
Methods: In this study, literature of the levels of vitamin C, vitamin E and β-carotene in the plasma of AD patients were collected by retrieving the database of Pub Med, Science Direct, CNKI and Wan Fang( from they were built to July 2017).
Results: Meta-analysis result showed that, compared with the control group, the level of vitamin E in the plasma of AD patients declined significantly( SMD =-1. 49 μmol/L, 95% CI-2. 08--0. 89 μmol/L, P <0. 001). However, no differences were determined in the levels of the plasma vitamin C and β-carotene between the two groups( vitamin C: SMD =-1. 43 μmol/L, 95% CI-3. 05-0. 19 μmol/L, P = 0. 083; β-carotene: SMD =-0. 61 μmol/L, 95% CI-1. 40-0. 18 μmol/L, P = 0. 131).
Conclusion: Increasing vitamin E level in the plasma through vitamin E riched diet may be useful to prevent AD. However it is not yet believed the benefical role on AD to increase vitamin C and β-carotene.
Keywords: Alzheimer's disease; Meta-analysis; vitamin C; vitamin E; β-carotene.