Public Health and Nutrition

Rapidly aging societies around the world, the number of patients with cognitive dysfunction, particularly Alzheimer’s disease (AD),

is gradually increasing. Though the several drugs for AD are available, no fundamental curative therapy has been established.

Therefore, prevention and modification of AD is important to improve the elderly health status.

Catechins and theanine are major components of green tea. In vitro and in vivo experimental studies, catechins and theanine are

reported to have anti-oxidative, anti-inflammatory, anti-atherosclerotic, and neuroprotective effects. However, the clinical effects on cognitive dysfunction remain inconclusive. Several epidemiological studies have shown a negative association between tea consumption and cognitive dysfunction; however, some studies reported no correlation. Moreover, only a limited number of

interventional studies have been reported.

Based on this background, we conducted two clinical interventional studies to investigate the effects of green tea consumption on cognitive dysfunction in the elderly. In the first study, elderly nursing home residents with cognitive dysfunction [Mini-Mental

State Examination (MMSE) score: <28] participated in the study (mean age, 88 years). The participants consumed green tea powder

(2 g/day) for 3 months. Then, MMSE scores significantly improved (15.3 ± 7.7 vs. 17.0 ± 8.2; p = 0.03). Triglyceride levels were also significantly lower than those measured at baseline. Next, we attempted to clarify the effecs on cognitive dysfunction in oneyear randomized controlled study. The results showed that change of MMSE scores was not significant, whereas malondialdehydemodified low-density lipoprotein, a marker of oxidative stress, was significantly lower in the green tea group.