 Study design and recruitment. Study participants will be patients aged 30-80 arriving to Rabin Medical Center with suspected CAD and able to provide informed consent. Participants will provide medical, lifestyle, and nutritional questionnaires. Blood pressure and heart-rate measurements will be taken during hospitalization as well as blood tests and fecal samples andor rectal swabs. In order to evaluate andor treat suspected atherosclerotic disease participants will undergo cardiac CT andor cardiac catheterization in accordance with the standard of care and based upon the decision of the treating cardiologist. Diagnostics and treatment options will be based only on participants medical condition and regardless of the aforementioned study protocol. 