How Can HDL Be Increased At The Age Of 24

how can HDL be increased at the age of 24 yrs , the present HDL is 32 ( last month it was 35 ) ( last to last month it was 39 )despite taking a 35 minute walk daily for the last two months and eating an apple daily and yohurt 4,5 times a week. Does homochek medicine reduces HDL , ( It was taken for 4 weeks to reducce hocysteine level). Kindly guide and oblige.