PROBLEM TO BE SOLVED: To provide an amyotrophy inhibitor, and food/drink for preventing amyotrophy, a nutritive composition for preventing amyotrophy and feeds for preventing amyotrophy in which the amyotrophy inhibitor is blended, which suppress atrophy of muscle in a living body by preventing reduction of muscle mass or increasing muscle mass, and are useful in preventing and treating myopathy such as sarcopenia and disuse amyotrophy.SOLUTION: There is provided an amyotrophy inhibitor which contains milk-derived basic protein fraction and/or a decomposed product of milk-derived basic protein fraction as an active ingredient. The amyotrophy inhibitor according to the present invention has significant effect of preventing reduction of muscle mass or increasing muscle mass, and is useful in preventing and treating various myopathy such as sarcopenia and disuse amyotrophy.【課題】筋肉量の低下を防止する、あるいは、筋肉量を増加させることにより、生体内の筋肉の萎縮を抑制し、サルコペニアや廃用性筋萎縮等の種々の筋疾患の予防や治療に有用である筋萎縮防止剤及び、該筋萎縮防止剤を配合した筋萎縮防止用飲食品、筋萎縮防止用栄養組成物、筋萎縮防止用飼料を提供することを課題とする。【解決手段】乳由来塩基性タンパク質画分及び／又は乳由来塩基性タンパク質画分分解物を有効成分として含有することを特徴とする筋萎縮防止剤。本発明の筋萎縮防止剤は、筋肉量の低下を防止する効果や筋肉量を増加させる効果が顕著であるため、サルコペニアや廃用性筋萎縮等の種々の筋疾患の予防や治療に有用である。【選択図】なし
