Although catechins have been considered beneficial in protecting against various diseases caused by oxidative stress and ROS, such as CVD and diabetes [237], and in hematology [173], their effects on CVD biomarkers such as the levels of C-reactive protein, B-type natriuretic peptide, N-terminal pro-atrial natriuretic peptide, aldosterone, renin, fibrinogen, D-dimer, plasminogen-activator inhibitor type 1, homocysteine, and the urinary albumin-to-creatinine ratio are not fully assessed. The gene discussed is REN; the disease is diabetes mellitus.