A Lin28a activator includes a polysaccharide containing one or more selected from the group consisting of ribose, xylose, and derivatives thereof as an active ingredient. A dedifferentiation inducer of a monocyte includes a macrophage colony-stimulating factor and a polysaccharide containing one or more selected from the group consisting of ribose, xylose, and derivatives thereof as active ingredients. A therapeutic agent against diseases relating to damage in cells, tissues, or organs includes a polysaccharide containing one or more selected from the group consisting of ribose, xylose, and derivatives thereof as an active ingredient. A food or beverage product for preventing or alleviating diseases relating to damage in cells, tissues, or organs includes a polysaccharide containing one or more selected from the group consisting of ribose, xylose, and derivatives thereof. A cosmetic product includes a polysaccharide containing one or more selected from the group consisting of ribose, xylose, and derivatives thereof.
