A randomized, double-blind, placebo-controlled study on the memory-enhancing effect of lactobacillus fermented Saccharina japonica extract

Introduction Memory problems are more common with ageing and are related to the development of Alzheimer’s disease. This study investigated whether the intake of lactobacillus fermented Saccharina japonica (FSJ) extract improved the cognitive function during working memory processing and whether biomarkers were associated with task performance. Methods Eligible participants were assigned to either a control group or an experimental group by computerized randomization. Participants were asked to take either 2 capsules, once a day for 4 weeks of lactobacillus FSJ for the experimental group or placebo control capsules for the control group. The cognitive function was determined using the Beck depression inventory (BDI), Korean Wechsler Adult Intelligence Scale (K-WAIS), operation-word span task and Raven’s test-based quantitative EEG test. Levels of amyloid-β, superoxide dismutase (SOD) in the serum using the ELISA were also measured. Results There was no significant difference between these two groups in all cognitive function tests using the independent sample t-test. However, the experimental group showed a significant difference in the correct answer percentage, concentration and left and right brain activity of space perception as assessed by the Raven test-based quantitative EEG test by a paired-sample t-test. Biochemical measurements showed, a slightly decreasing trend in amyloid-β, whereas SOD level was not significantly different between groups (P > 0.05). Conclusion These results suggest that FSJ may have the potential to improve cognitive function as evaluated by the Raven’s test via, regulation of SOD antioxidant system. Our findings provide preliminary evidence of the safety of FSJ and its potential to improve memory.