Combination of Selenium and Green Tea on bowel health

Interventions: 30 healthy volunteers (>50yrs) at-risk for CRC by virtue of age and /or other standard risk factors will be recruited to participate in a randomised, three cohort dietary intervention study. with a parallel design to test the effects of Se and green tea alone and in combination on molecular biomarkers for CRC prevention in the normal rectal epithelial cells. They will be instructed to maintain their usual diet during the study but to avoid supplementation with any green tea-related food or drink (limited to <3 cups of black tea per day), and Se-rich foods such as octopus, crab and tuna, liver and kidney or additional Brazil nuts or other nuts (except those Brazil nuts and green tea extract prescribed by us). The study will consist of dietary intervention period of 6 weeks, preceded by a run in period of 4 weeks.
The volunteers will be randomised (randomisation will be computer generated) into one of three groups of 10, receiving
1) Se, supplied as Brazil nuts (6 Brazil nuts daily will provide 48micrograms Se/day);
2) Green tea, supplied as a green tea extract capsule (4 capsules daily will provide 800mg EGCG/day); and
3) Se + green tea (6 Brazil nuts daily + 4 green tea extract capsules daily (will provide 48micrograms Se/day and 800mg EGCG/day).
Six Brazil nuts has been chosen because the average Se concentration (2.7 micrograms Se/g) in Brazil nuts (supplied from Charlesworth, Australia) is relatively low compared to that of the report by Thomson et al, where the Se concentration is 6.4micrograms Se/g, and average weight for one nut is 4g, 2 nuts provided 53 micrograms Se/day (Am J Clin Nutr 2008;87:379-3840). Since the average weight of one Brazil nut (supplied from Charlesworth, Australia) is 3g, 6 Brazil nuts daily will provide 48microgra
Primary outcome(s): Effects of combination diet (Se + green tea) on biomarkers of Wnt pathway (catenin), inflammation (COX-2) and DNA repair (MGMT) in rectal epithelium. Rectal biopsies will be collected and examined by RT-PCR and immunohistochemistry for the expression of these biomarkers at gene and protein levels[Commencement of Intervention (Baseline),
End of intervention (6 weeks) ]
Study Design: Purpose: Prevention; Allocation: Randomised controlled trial; Masking: Open (masking not used);Assignment: Parallel;Type of endpoint: Efficacy