Soy consumption protects older women's bones

Consuming soy products helps protect bones of older women, especially those in early menopause. Previous studies have suggested that the plant estrogens found in soy help sustain bone mineral density, but there have been no large studies assessing the association between soy consumption and the risk of fracture. Researchers from the Vanderbilt University School of Medicine in Nashville, Tennessee, USA, analysed the data from the Shanghai Women's Health Study, conducted in a population that has a wide range of soy food consumption. The analysis included postmenopausal women with no history of fracture or hormone therapy use, who completed a food frequency questionnaire and were then questioned approximately 4.5 years later regarding the occurrence of fractures. Roughly 24,000 women reported a total of 1770 fractures. Higher soy protein consumption was significantly associated with lower risk of fracture, even after accounting for age, calorie intake, socio-economic status, other nutrients and osteoporosis risk factors. The protective effect was most evident among women who were within ten years of menopause. For this subgroup, the risk of fracture was reduced by 48 percent among those with the highest intake of soy protein compared to those with the lowest consumption. For women who had been menopausal for more than ten years, the risk reduction was 29 percent. The findings suggest that soy consumption may be particularly beneficial in preventing menopause-related bone loss, but less effective at reversing established bone loss. However, other studies are needed before generalisations to other populations can be made.