Wakai K, Egami I, Kato K, Kawamura T, Tamakoshi A, Lin Y, Nakayama T, Wada M, Ohno Y
Department of Preventive Medicine, Nagoya University School of Medicine, Japan.
Nutr Cancer. 1999;33(2):139-45. doi: 10.1207/S15327914NC330204.
We examined the dietary intake and sources of isoflavones (daidzein and genistein) among Japanese subjects based on dietary records (DRs). The subjects comprised two groups: 1,232 who completed one-day DRs (Group 1) and 88 men and women who kept four four-day (16-day) DRs. For quantitative data on the level of daidzein and genistein in soy foods, we extensively reviewed the literature, particularly for Japanese soy foods, and adopted the median value for each food. The median intake of daidzein was 12.1 and 9.5 mg/day among Groups 1 and 2, respectively, while the corresponding values for genistein were 19.6 and 14.9 mg/day. The top four foods (tofu, miso, natto, and fried tofu) covered about 90% of the population intake of daidzein and genistein. It did not seem feasible to estimate one's intake of isoflavones by using dietary recording/recall in epidemiological studies, since the day-to-day variation in intake was too large, the within-person coefficient of variation being 89.1% for daidzein and genistein. Therefore, we should use other methods, such as food-frequency questionnaires, focusing on the four major sources of isoflavones, to assess individual isoflavone intake.
我们基于饮食记录（DR）研究了日本受试者异黄酮（大豆苷元和染料木黄酮）的饮食摄入量及来源。受试者分为两组：1232名完成一日饮食记录的受试者（第一组）以及88名进行了四次为期四天（共16天）饮食记录的男性和女性。对于大豆食品中大豆苷元和染料木黄酮含量的定量数据，我们广泛查阅了文献，特别是关于日本大豆食品的文献，并采用了每种食品的中位数。第一组和第二组中大豆苷元的中位数摄入量分别为12.1毫克/天和9.5毫克/天，而染料木黄酮的相应数值分别为19.6毫克/天和14.9毫克/天。前四种食物（豆腐、味噌、纳豆和炸豆腐）占大豆苷元和染料木黄酮总摄入量的约90%。在流行病学研究中，通过饮食记录/回忆来估计一个人的异黄酮摄入量似乎不可行，因为摄入量的每日变化太大，大豆苷元和染料木黄酮的个体内变异系数为89.1%。因此，我们应该使用其他方法，如食物频率问卷，重点关注异黄酮的四大主要来源，以评估个体异黄酮摄入量。
