Lab Assays Bacterial diversity: The gut bacterial diversity and composition from stool samples will be measured using molecular techniques such as quantitative polymerase chain reaction (PCR) from bacterial ribosomal DNA and next generation sequencing (metagenomics). These techniques will also be used to look at the composition of bacteria associated with mucosal tissue biopsies. Changes in overall gut bacteria composition using standard numerical indices will be measured across the 6 faecal samples collected over the 12 month period, as well as between groups.