The purpose of this study is to clarify the effects of tea catechin extracts on the frequency changes of micronuclei in peripheral lymphocytes compared with other oxidative stress markers in late middle aged healthy volunteers

Experimental studies have revealed that tea catechin extracts induce preventive effects on oxidative stress, but there have been few clinical trials conducted to verify the effects. Also, there have been few clinical markers indicating oxidative damage, and therefore, more accurate and reliable markers have been expected. The study is designed for evaluating the effects of tea catechin extracts on the frequency changes of micronuclei in peripheral lymphocytes as the indicator of oxidative damage, compared with other oxidative stress markers in late middle aged healthy volunteers.

Inclusion Criteria:

• aged 40 to 65 years old
• healthy volunteers
• obtained written informed concent before participation

Exclusion Criteria:

• participant who is not able to refrain from drinking tea for 2 weeks during the study
• participant taking supplements or herbal products including folate, vitamin B, C, E, coenzyme Q10, calcium, for 2 weeks before the study
• participant taking supplements or herbal products including folate, vitamin E for 3 months before the study
• participant possessing tea allergy