5. Conclusions
The benefits of the MedDiet to human health are well known. However, its benefits in the Asian population, who are unfamiliar with the MedDiet, is relatively unexplored. To the best of our knowledge, this is the first study to examine the effects of olives, a typical MedDiet ingredient, on cognitive function in the Japanese older adults. In particular, trying desert olive tree pearls (DOTPs), which are rich in hydroxytyrosol (HYD), which is known to have positive effects on cognitive function, was a challenge. The results of this study showed that HYD-rich DOTPs can improve cognitive function in Japanese middle-aged and older adults. In particular, there were significant effects on complex attention, psychomotor speed, reaction time, cognitive flexibility, processing speed, and executive function among the cognitive function items compared to the placebo group. These results suggest that DOTPs in the MedDiet, which is unfamiliar to Japanese middle-aged and older adults, may be a soft solution to the problems of the elderly in Japan. However, these changes were representative of our study, which was conducted over a short period of 12 weeks. Further long-term intervention studies are warranted to track changes in the cognitive function of this population.