Brooks Jennifer D, Ward Wendy E, Lewis Jacqueline E, Hilditch John, Nickell Leslie, Wong Evelyn, Thompson Lilian U
Department of Nutritional Sciences, University of Toronto, Toronto, Canada.
Am J Clin Nutr. 2004 Feb;79(2):318-25. doi: 10.1093/ajcn/79.2.318.
Phytoestrogens, which are abundant in flaxseed and soy, have chemical structures resembling those of endogenous estrogens and have been shown to exert hormonal effects, thereby affecting chronic diseases.
We compared the effects of consuming equal amounts of flaxseed or soy on estrogen metabolism and biochemical markers of bone metabolism in postmenopausal women.
In a parallel design, the diet of postmenopausal women (n = 46) was supplemented with either a placebo, soy (25 g soy flour), or flaxseed (25 g ground flaxseed) muffin for 16 wk. Blood and 24-h urine samples were collected at baseline and at the endpoint. Urine samples were analyzed for phytoestrogens, estrogen metabolites (2-hydroxyestrone, 16alpha-hydroxyestrone), and serum hormones (estradiol, estrone, estrone sulfate). Serum and urine samples were also analyzed for biochemical markers of bone metabolism.
Urinary concentrations of 2-hydroxyestrone, but not of 16alpha-hydroxyestrone, increased significantly in the flaxseed group (P = 0.05). In the flaxseed group, the ratio of 2-hydroxyestrone to 16alpha-hydroxyestrone was positively correlated with urinary lignan excretion (r = 0.579, P = 0.02). In the soy and placebo groups, no significant correlation was observed. No significant change in serum hormones or biochemical markers of bone metabolism was observed within or between the treatment groups.
Supplementation with flaxseed modifies urinary estrogen metabolite excretion to a greater extent than does supplementation with an equal amount of soy. This modification by flaxseed is associated with an increase in urinary lignan excretion. Despite the shift in estrogen metabolism to favor the less biologically active estrogens, a negative effect on bone cell metabolism was not observed.
植物雌激素在亚麻籽和大豆中含量丰富，其化学结构与内源性雌激素相似，并已被证明具有激素效应，从而影响慢性疾病。
我们比较了绝经后女性食用等量亚麻籽或大豆对雌激素代谢及骨代谢生化标志物的影响。
采用平行设计，对46名绝经后女性的饮食进行补充，分别给予安慰剂、大豆（25克大豆粉）或亚麻籽（25克磨碎的亚麻籽）松饼，为期16周。在基线和终点时采集血液和24小时尿液样本。分析尿液样本中的植物雌激素、雌激素代谢物（2-羟雌酮、16α-羟雌酮）和血清激素（雌二醇、雌酮、硫酸雌酮）。还分析血清和尿液样本中的骨代谢生化标志物。
亚麻籽组2-羟雌酮的尿浓度显著升高，但16α-羟雌酮未升高（P = 0.05）。在亚麻籽组中，2-羟雌酮与16α-羟雌酮的比值与尿木脂素排泄呈正相关（r = 0.579，P = 0.02）。在大豆组和安慰剂组中，未观察到显著相关性。在各治疗组内或组间，血清激素或骨代谢生化标志物均未观察到显著变化。
与等量大豆补充相比，亚麻籽补充对尿雌激素代谢物排泄的改变更大。亚麻籽的这种改变与尿木脂素排泄增加有关。尽管雌激素代谢向生物活性较低的雌激素方向转变，但未观察到对骨细胞代谢的负面影响。
