A method is provided for preventing or treating bone or musculoskeletal metabolism disorders or kidney malfunction in humans. It comprises providing to a subject in need of that a calcium containing or calcium enriched diet combined with the administration of an efficient amount of a plant extract of Solatium glaucophyllum comprising from about 0.8 to about 2.2 weight % of a mixture of 1,25-dihydroxyvitamin D3 glycosides and quercetin glycosides present in a ratio of about 1 : 100 to 1 :200 parts by weight. There are also provided food or dietary composition and food supplement designed for preventing or treating bone or musculoskeletal metabolism disorders or kidney malfunction in humans which comprises an efficient amount of the said plant extract of and a source of calcium.
