Isoflavone Research Initiative

The most recent findings on soy and isoflavones were presented in Washington DC on the occasion of the 9^th International Symposium on the Role of Soy in Health Promotion and Chronic Disease Prevention and Treatment (October 16-19, 2010). A major part of the topics was dedicated to safety and health benefits in menopausal women, and to the issue of soy and breast cancer.

Prof. Francesco Squadrito (Department of Clinical and Experimental Pharmacology, University of Messina, Italy) examined whether the already established effects of 54 mg genistein/day on parameters of bone mineral density and bone turnover (Marini et al. 2008) would reduce the risk of bone fractures (Squadrito et al. 2010). Genistein is an ER-β agonist, and as this receptor is responsible for protective effects on turnover in the bone it may be expected to have long-term beneficial effects.

The fracture risk assessment tool (FRAX) serves for the calculation of the 10-year probability of a major osteoporotic fracture and/or a hip fracture. Squadrito applied this model in a randomized, placebo-controlled trial involving 389 osteopenic postmenopausal women. Participants received either 54 mg of genistein (n = 191) or placebo (n = 189). Both treatments contained calcium and vitamin D3.

Fracture probability calculated by FRAX showed a significant reduction in the genistein group compared with placebo after two years (major osteoporotic fracture probability: mean difference -0.75; 95 % CI -1.009 to -0.408, p < 0.001; hip fracture probability: mean difference -0.41; 95 % CI -0.5425 to -0.2775, p < 0.001). Bone mineral density values at the femoral neck negatively correlated with fracture probability assessed by FRAX in the genistein group (major osteoporotic fracture: r = -0.77, 95 % CI -0.8130 to -0.7203, p < 0.0001; hip fracture: r = -0.7158, 95 % CI -0.7972 to -0.6980, p < 0.0001). According to these results, the supplementation of genistein to postmenopausal women represents an effective measure for the prevention of menopausal bone loss and osteoporotic fractures.

References

Marini H, Minutoli L, Polito F, Bitto A, Altavilla D, Atteritano M, Gaudio A, Mazzaferro S, Frisina A, Frisina N, Lubrano C, Bonaiuto M, D'Anna R, Cannata ML, Corrado F, Cancellieri F, Faraci M, Marini R, Adamo EB, Wilson S and Squadrito F (2008). OPG and sRANKL serum concentrations in osteopenic, postmenopausal women after 2-year genistein administration. J Bone Miner Res 23(5):715-720.

Squadrito F, Altavilla D, Bitto A, Polito F, Minutoli L and Marini H (2010). Genistein aglycone reduces FRAX rate in postmenopausal women. 9^th International Symposium on the Role of Soy in Health Promotion and Chronic Disease Prevention and Treatment, Washington DC, 16-19 October.