Soy and health: Where does the science stand?
Dr Mark Messina, adjunct associate professor in the Dept of Nutrition at Loma Linda University, summed up the evidence on soy and health for delegates:
Cardiovascular disease: The evidence for soy protein and cholesterol reduction is well established, while soy isoflavones may also improve blood vessel endothelial cell function, he said.
Bone health: Here the evidence is weak, he said. "Although there are epidemiologic data from Asia and the US showing intake is protective against fracture, the results from clinical studies are very inconsistent. Most importantly, the three largest multi-year trials failed to find that isoflavone supplements affect postmenopausal bone mineral density."
Hot flashes/menopause: The evidence is strong, he said. "A recent meta-analysis that included 17 placebo-controlled studies found soy isoflavone supplements significantly alleviated both hot flash frequency and severity by approximately 50-60%."
Skin health: The evidence that soy could boost skin health is "preliminary".
Breast cancer risk: Although animal data raised concerns that soy consumption could be harmful to breast cancer patients, a pooled analysis that included 9,514 survivors found that post-diagnosis soy intake was associated with a statistically significant 25% reduction in recurrence, said Dr Messina. Meanwhile, consuming soy, especially in childhood, could help reduce the risk of developing breast cancer, he said.
"Overall, the epidemiologic data, and especially the clinical data, are supportive of soy consumption providing several benefits to postmenopausal women."