Spence Lisa A, Lipscomb Elaine R, Cadogan Jo, Martin Berdine, Wastney Meryl E, Peacock Munro, Weaver Connie M
Department of Foods and Nutrition, Purdue University, West Lafayette, IN, USA.
Am J Clin Nutr. 2005 Apr;81(4):916-22. doi: 10.1093/ajcn/81.4.916.
Evidence suggests that soy isoflavones act as estrogen agonists and have beneficial skeletal effects, but the effects on calcium metabolism in humans are not known.
This study tested whether soybean isoflavones, soy protein, or both alter calcium metabolism in postmenopausal women.
Calcium metabolism in 15 postmenopausal women was studied by using metabolic balance and kinetic modeling in a randomized, crossover design of three 1-mo controlled dietary interventions: soy protein isolate enriched with isoflavones (soy-plus diet), soy protein isolate devoid of isoflavones (soy-minus diet), and a casein-whey protein isolate (control diet).
There was no significant difference between the diets in net acid excretion (P = 0.12). Urinary calcium excretion was significantly (P < 0.01) less with consumption of either of the soy diets (soy-plus diet: 85 +/- 34 mg/d; soy-minus diet: 80 +/- 34 mg/d) than with consumption of the control diet (121 +/- 63 mg/d), but fractional calcium absorption was unaffected by treatment. Endogenous fecal calcium was significantly (P < 0.01) greater with consumption of the soy-minus diet than with consumption of the other diets. Total fecal calcium excretion, bone deposition and resorption, and calcium retention were not significantly affected by the dietary regimens.
The lower urinary calcium seen with the consumption of an isolated soy protein than with that of an isolated milk protein was not associated with improved calcium retention. This finding reinforces the importance of evaluating all aspects of calcium metabolism. Soy isoflavones did not significantly affect calcium metabolism.
有证据表明大豆异黄酮可作为雌激素激动剂，对骨骼有益，但对人体钙代谢的影响尚不清楚。
本研究旨在测试大豆异黄酮、大豆蛋白或两者是否会改变绝经后女性的钙代谢。
采用代谢平衡和动力学模型，对15名绝经后女性进行钙代谢研究，采用随机交叉设计，进行为期1个月的三种对照饮食干预：富含异黄酮的大豆分离蛋白（大豆加饮食）、不含异黄酮的大豆分离蛋白（大豆减饮食）和酪蛋白-乳清蛋白分离物（对照饮食）。
各饮食组间净酸排泄无显著差异（P = 0.12）。食用任何一种大豆饮食（大豆加饮食：85±34mg/d；大豆减饮食：80±34mg/d）时，尿钙排泄量均显著低于（P < 0.01）对照饮食（121±63mg/d），但钙分数吸收不受治疗影响。食用大豆减饮食时，内源性粪钙显著高于（P < 0.01）其他饮食。总粪钙排泄、骨沉积和吸收以及钙潴留不受饮食方案的显著影响。
食用分离大豆蛋白时尿钙较低，而食用分离乳蛋白时尿钙较高，这与钙潴留改善无关。这一发现强化了评估钙代谢各个方面的重要性。大豆异黄酮对钙代谢无显著影响。
