Patients with psoriasis are increasingly turning to the use of alternative and complementary medicine to manage their psoriasis. Patients often inquire about what dietary supplements may be beneficial, including the use of oral vitamin D, vitamin B12, selenium, and omega-3 fatty acids in fish oils. In this review we examine the extent to which each of these common nutritional interventions has been studied for the treatment of psoriasis. We weighed evidence from both controlled and uncontrolled prospective trials. The evidence of benefit was highest for fish oils. For other supplements, there is need for additional large, randomized clinical trials to establish evidence of efficacy.