The compound 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one (DDMP) possesses antioxidant properties; however, its effects on cognitive function are unclear. This study examined the effects of DDMP-containing beverages on the cognitive function of healthy middle-aged and older Japanese individuals. We conducted a randomized, double-blind, and placebo-controlled parallel study. The study protocol was registered with the University Hospital Medical Network Clinical Trials Registry (UMIN000052639). In this study, 220 participants who were aware of their memory decline were enrolled and randomly assigned to the intervention or placebo group. The participants ingested the test food [65 mL lactic acid bacteria (LAB) beverage containing 2.2 mg DDMP] or placebo food (65 mL LAB beverage without DDMP) once a day for 12 wk. Cognitive function was assessed before the test and after 12 wk. The primary endpoint was verbal memory, while other cognitive function items and oxidative stress markers were set as the secondary outcomes. Differences in changes among the groups were assessed using analysis of covariance. After 12 wk, verbal and composite memory scores were considerably higher in the DDMP group than in the placebo group. However, no significant differences in oxidative stress markers were noticed. Therefore, consumption of a LAB beverage containing DDMP can markedly improve verbal and composite memory in middle-aged and older individuals with memory deterioration.