PROVIDED IS AN OIL OR FAT COMPOSITION, INCLUDING A VITAMIN B1 DERIVATIVE OR A SALT THEREOF AT A CONTENT OF 44 TO 8,000 PPM IN TERMS OF THIAMINE AND HAVING A HYDROXYL VALUE OF 9 TO 100 MG-KOH/G, IN WHICH THE CONTENT C (PPM) OF THE VITAMIN B1 DERIVATIVE OR THE SALT THEREOF IN TERMS OF THIAMINE AND THE HYDROXYL VALUE X (MG-KOH/G) SATISFY A RELATIONSHIP OF THE FOLLOWING EXPRESSION (1): [LN(C/143)]/X