Reducing effect of ingesting tannic acid on the absorption of iron, but not of zinc, copper and manganese by rats
Reducing effect of ingesting tannic acid on the absorption of iron, but not of zinc, copper and manganese by rats
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DOI：
10.1271/bbb.68.584
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发表时间：
2004-03-01
影响因子：
1.6
通讯作者：
Hara, H
中科院分区：
文献类型：
--
作者：
Afsana, K;Shiga, K;Hara, H
对多酚（包括单宁酸（TA））的有益作用的兴趣正在增加，尽管这些化合物也有不利影响;例如，对铁（Fe）和可能的其他微量矿物质的吸收。我们研究了分级剂量的TA对大鼠铁吸收的影响，并与锌（Zn）、铜（Cu）和锰（Mn）的吸收进行了比较。我们还研究了TA对盲肠发酵的影响，盲肠发酵在吸收中起作用。在实验1中，为了确定铁的最佳剂量，将驯化后的雄性Sprague-Dawley大鼠（体重70-90 g）饲喂不同水平的膳食铁（5、10、20、30和35 mg/ kg）。我们观察到，红细胞压积（Ht），血清铁浓度和转铁蛋白饱和度（%），分别降低在那些大鼠喂养低于20毫克/公斤铁剂量依赖性的方式。在实验2中，大鼠喂食试验饮食含有最低所需水平的铁，30毫克/公斤的饮食，（5，10，15和20克/公斤的饮食）或没有TA为期三周。饲喂含有超过10 g TA/kg饲料的饲料，但不是5 g TA/kg饲料，由于铁吸收减少，血红蛋白浓度（Hb），Ht和血清铁浓度降低。与此相反，锌，铜和锰的吸收不受TA喂养的影响。还表明，肝铁，但不是锌，铜和锰的含量，低于TA组比在TA的自由对照组。饲喂TA略微降低盲肠内容物的pH值，增加主要短链脂肪酸池。在每个TA饲喂组的粪便中回收了约15%的摄入TA。我们的研究结果表明，超过10克TA/公斤的饮食诱导贫血减少铁的吸收，虽然没有影响其他重要的微量元素的吸收。我们的研究结果表明，通常摄入的多酚是相对安全的，但高摄入量的补充或饮食习惯的单宁只影响铁的水平。
Interest in the beneficial effects of polyphenols, including tannic acid (TA), is increasing, although, these compounds also have adverse effects; for example, on the absorption of iron (Fe), and possibly other trace minerals. We examined the effect of a graded dose of TA on the absorption of Fe and compared with that of zinc (Zn), copper (Cu) and manganese (Mn) in rats. We also investigated the effect of TA on cecal fermentation which plays a role in absorption. In Experiment 1, to set the optimum dose of Fe, male Sprague-Dawley rats (weighing 70-90 g) after acclimatization were fed with different levels of dietary Fe (5, 10, 20, 30 and 35 mg/ kg). We observed that the hematocrit (Ht), serum Fe concentration and transferrin saturation (%) were each reduced in those rats fed less than 20 mg/kg Fe in a dose-dependant manner. In Experiment 2, the rats were fed with test diets containing the minimum required level of Fe, 30 mg/kg diet, with (5, 10, 15 and 20 g/kg diet) or without TA for a period of three weeks. Feeding a diet containing more than 10 g TA/kg diet, but not 5 g TA/kg diet, reduced the hemoglobin concentration (Hb), Ht and serum Fe concentration due to decreased Fe absorption. In contrast, the Zn, Cu and Mn absorption was not affected by TA feeding. It is also demonstrated that liver Fe, but not the Zn, Cu and Mn contents, were lower in the TA groups than in the TA-free control group. Feeding TA slightly decreased the pH value of the cecal contents with an increase in the major short-chain fatty acid pool. About 15% of the ingested TA were recovered in the feces of each TA-fed group. Our results demonstrate that more than 10 g TA/kg diet induced anemia by reducing the Fe absorption, although there was no effect on the absorption of other important trace-minerals. Our findings suggest that the usual intake of polyphenols is relatively safe, but that a high intake by supplementation or by dietary habit of tannin affects only the Fe level.