In total , 2,501 men ( mean age = 61 y ) and women ( mean age = 63 y ) were randomized in a 22 factorial design to : 1 ) 0.56 mg 5-methyl-tetrahydrofolate , 3 mg vitamin B6 , 0.02 mg vitamin B12 ; 2 ) 600 mg eicosapentaenoic and docosahexaenoic acids in a 21 ratio ; 3 ) B vitamins and n-3 fatty acids combined ; or 4 ) placebo .