Sterol ester (27:1/20:4), sterol ester (27:1/22:6), phosphatidylcholine (20:4_0:0), phosphatidylcholine (16:0_20:4), sphingomyelin (d38:1), and sphingomyelin (d42:2) were found to reduce the risk of IBD and CD by decreasing CD6. The gene discussed is CD6; the disease is Cowden disease.