PROBLEM TO BE SOLVED: To provide a composition comprising an organic selenium compound that improves insulin activity and inhibits sugar production.SOLUTION: The present invention provides a composition comprising selenium compounds such as 5'-methylselenoadenosine C and γ-glutamyl-methylseleno-cysteine represented by a compound (C) and a combination of them.SELECTED DRAWING: None【課題】インスリン活性を向上させ、糖産生を阻害する有機セレン化合物を含有する組成物の提供。【解決手段】化合物(C)で表される5’-メチルセレノアデノシンCやγ-グルタミル-メチルセレノ-システイン等のセレン化合物及びこれらの組み合わせを含む組成物。【選択図】なし