Effects of Eicosapentaenoic Acid on Endothelial Function in Diabetic Subjects

Inclusion Criteria: * Age 30+ years * Hypertriglyceridemia (150-400 mg/dl) * Statin use for at least six months at the time of screening * Type 2 diabetes treated with diet and/or oral hypoglycemic agents diagnosed 1+ year * Ability to provide informed consent and provide blood samples * Willingness to abstain from fish oil, EPA, over the counter niacin, and other omega-3 fatty acid supplements during the study period (12 weeks) * Ability to travel to the study site at Brigham and Women's Hospital for 3 study visits * Reactive hyperemia index (RHI) of ≤ 2.0 Exclusion Criteria: * Eating disorder or heavy drinkers * Treatment with chronic prescription pharmacotherapy for metabolic or cardiovascular disease management or risk factor modification * Pregnant or lactating women * Statin use \<6 months at the time of screening * Allergy to EPA, fish oil, or other omega-3 fatty acids * Current use of insulin, cyclophosphamide, estrogen, fibrates, niacin, hormone replacement therapy, testosterone, oral contraceptives, growth hormones, insulin-like growth factor-1, and other systemic steroids. * Inability to provide informed consent or blood samples * History or prevalent diagnosis of cancer, asthma, kidney insufficiency, stroke, seizures, allergic disorders, or congestive heart failure * Diagnosis of diabetes \< 1 year prior to enrollment * Intention to move out of greater Boston area within one year * Current use of omega-3 supplements, fish oil, or \>2 servings of fish per week * Bleeding disorder or uncontrolled endocrine (i.e., thyroid) or metabolic disorders * Treatment with blood thinning drugs (i.e. warfarin and clopidogrel) * Major surgical operation 3 months before or after screening * Organ transplantation * Current participation in another trial or plan to do so during the study * Inability to give informed consent or to travel to the study center at Brigham and Women's Hospital * RHI of \>2.0 * Triglycerides \<150 mg/dl or \>400 mg/dl * Body mass index of 40+ kg/m2