The metagenomes are deposited in European Bioinformatics Institute European Nucleotide Archive under accession no . PRJEB39223 . The non - metagenomic data used for analysis in this study are held by the Department of Twin Research at King 's College London . The data can be released to bona fide researchers using our normal procedures overseen by the Wellcome Trust and its guidelines as part of our core funding . We receive around 100 requests per year for our datasets and have three meetings per month with independent members to assess proposals . The application can be found at https://twinsuk.ac.uk/resources-for-researchers/ access - our - data/. This means that data need to be anonymized and conform to GDPR standards .