Compositions contain γ-oryzanol and biocompatible particles that incorporate γ-oryzanol inside thereof. The biocompatible particle may contain polylactideglycolide copolymer with a number mean particle size of 2.5 to 1,000 nm or a polyethylene glycol modification thereof. Such compositions are used for improvement of insulin resistance. In addition, such compositions are used for treatment or prevention of diseases selected from the group consisting of obesity, dyslipidemia, impaired glucose tolerance, diabetes mellitus, arteriosclerosis, and inflammatory diseases.
