BALLERUP, DENMARK. Ipriflavone (7-isopropoxy-isoflavone) is a synthetic daidzein derivative of natural isoflavones. Animal and some human experiments have found ipriflavone effective in inhibiting bone resorption and thereby preventing bone loss (osteoporosis). A group of Belgian, Danish, French and Italian researchers now report that ipriflavone supplementation does not prevent bone loss in postmenopausal women. Their randomized, double-blind, placebo- controlled, four-year clinical trial involved a total of 474 postmenopausal women (aged 45 to 75 years) with baseline bone mineral densities (BMDs) of less than 0.86 grams/cm2. Half the women (234) were assigned to receive 200 mg of ipriflavone three times per day with meals while the other half (240) received placebo capsules. All the participants also received 500 mg per day of calcium. After three years there were no significant differences between the ipriflavone and the placebo groups in the annual change in BMD (lumbar spine and thigh bone). There also were no significant differences in the number of new vertebral fractures experienced by the women in the two groups. The researchers did note a significant drop in lymphocytes in the blood cells of the women in the ipriflavone group. This drop, however, did not translate into an increased number of infections or other immune system related effects. The researchers conclude that ipriflavone does not prevent bone loss in postmenopausal women and may induce lymphocytopenia (a decrease in lymphocyte concentration) in a significant number of women. NOTE: This study was funded by Cheisi Farmaceutici (Parma, Italy) a manufacturer of ipriflavone.
Alexandersen, Peter, et al. Ipriflavone in the treatment of postmenopausal osteoporosis: a randomized controlled trial. Journal of the American Medical Association, Vol. 285, March 21, 2001, pp. 1482-88