Effects of green tea consumption on cognitive dysfunction in an elderly population: a randomized placebo-controlled study.
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ABSTRACT: Green tea is a beverage with potential effects on cognitive dysfunction, as indicated by results of experimental studies. However, its effects in humans, especially at real-world (typical) consumption levels, are unclear.A double-blind, randomized controlled study was conducted to assess the effects of green tea consumption on cognitive dysfunction (Mini-Mental State Examination Japanese version (MMSE-J) score <28) in Japan. Participants were randomly allocated to the green tea or placebo group, and consumed either 2 g/day of green tea powder (containing 220.2 mg of catechins) or placebo powder (containing 0.0 mg of catechins), respectively, for 12 months. Cognitive function assessments were performed every 3 months using the MMSE-J and laboratory tests.Thirty-three nursing home residents with cognitive dysfunction were enrolled (four men, 29 women; mean age?±?SD, 84.8?±?9.3; mean MMSE-J score?±?SD, 15.8?±?5.4), of whom 27 completed the study. Changes of MMSE-J score after 1 year of green tea consumption were not significantly different compared with that of the placebo group (-0.61 [-2.97, 1.74], least square mean (LSM) difference [95 % CI]; P?=?0.59). However, levels of malondialdehyde-modified low-density lipoprotein (U/L), a marker of oxidative stress, was significantly lower in the green tea group (-22.93 [-44.13, -1.73], LSM difference [95 % CI]; P?=?0.04).Our results suggest that 12 months green tea consumption may not significantly affect cognitive function assessed by MMSE-J, but prevent an increase of oxidative stress in the elderly population. Additional long-term controlled studies are needed to clarify the effects.UMIN000011668.
SUBMITTER: Ide K
PROVIDER: S-EPMC4855797 | biostudies-other | 2016 May
REPOSITORIES: biostudies-other
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