A composition which can significantly accelerate equol production is provided. When formulated in a pharmaceutical preparation or a food or drink, this composition exerts effects of preventing a vascular disease by the cholesterol lowering function, preventing breast cancer or prostatic cancer, and preventing and/or treating osteoporosis. Also, when formulated in a feed or a pet food, the bone density is enhanced, so that it exerts effects to prevent weak legs of a pig, to strengthen egg shell of a laying hen, to prevent osteoporosis in a dog etc., and the like. It is a composition which comprises lactobionic acid, a salt of lactobionic acid or lactobionolactone as an active ingredient and a food or drink, a feed, a pet food or a pharmaceutical preparation, which contains the composition, and have effects to prevent and treat osteoporosis, an function to increase bone density, an effect to prevent breast cancer or prostatic cancer, and a cholesterol lowering function.