Plant sterol is stably dispersed in a water-based food product or emulsified food product without detracting from the flavor of the food product.A complex of plant sterol and egg yolk lipoprotein is provided. This complex can be obtained by stirring and mixing egg yolk liquid and plant sterol (preferably 185 parts by mass or less of plant sterol per 1 part by mass of egg yolk solids) in a water-based medium. This complex can be used in food products as a liquid dispersion or can be used as a dried powder.

There are provided an oral skin improving agent that exhibits good skin improving effects when orally ingested, suppresses problems of discoloration and generation of unpleasant odor during storage, and has excellent storage stability; a food composition for improving skin containing this skin improving agent; and a skin improving method. The oral skin improving agent contains as a principal component refined hyaluronic acid having a purity of at least 90%, preferably at least 95%, and an average molecular weight in a range of 750,000 to 1,200,000, preferably 800,000 to 1,000,000. A person's skin can be improved by having the person ingest the oral skin improving agent such that the ingestion amount thereof is at least 5 mg per day.