β-Lactolin Enhances Neural Activity, Indicated by Event-Related P300 Amplitude, in Healthy Adults: A Randomized Controlled Trial

Background: Epidemiological studies have shown that dairy product consumption is beneficial for cognitive function in elderly individuals. β-lactolin is a Gly-Thr-Trp-Tyr lacto-tetrapeptide rich in fermented dairy products that improves memory retrieval, attention, and executive function in older adults with subjective cognitive decline and prevents the pathology of Alzheimer's disease in rodents. There has been no study on the effects of β-lactolin on neural activity in humans. Objective: We investigated the effects of β-lactolin on neural activity and cognitive function in healthy adults. Methods: In this randomized, double-blind, placebo-controlled study, 30 participants (45-64 years old) consumed β-lactolin or placebo for 6 weeks. Neural activity during auditory and language tasks was measured through 64-channel electroencephalography. Moreover, verbal fluency tests were performed at baseline and after 6 weeks. Results: The β-lactolin group had a significantly higher P300 amplitude at the Cp2 site (a part of the parietal lobe near the center of brain, p=0.011), and C4 site (the area between the frontal and parietal lobe, p=0.02) during the auditory tasks after 6 weeks than the placebo group. Thus, β-lactolin supplementation promoted neural activity in the parietal area, which increases concentration and attention during auditory cognitive tasks. Compared with the placebo group, the β-lactolin group also showed significant changes in the scores of verbal fluency test after 6 weeks (p=0.033). Conclusion: Our findings provide insight into the mechanisms underlying the effects of β-lactolin on attention in healthy adults.