A composition, useful in the prevention of osteoporosis, wherein said composition comprises (a) least one isoflavone and/or isoflavone glycoside, preferably genistein and/or genistin; (b) at least one polyunsaturated fatty acid; (c) optionally vitamin D, and /or one or more derivatives thereof and/or vitamin K and/or one or more derivatives thereof; and (d) optionally adjuvants and excipients in quantities as required, preferably within the range of 0.1 to 20% by weight, based on the total weight of the composition. Dietary compositions and galenical forms made therefrom and the use of said compositions for preventing osteoporosis and stimulating osteogenesis in mammals.