Division of Applied Biosciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
J Sci Food Agric. 2021 Jan 15;101(1):272-278. doi: 10.1002/jsfa.10639. Epub 2020 Aug 13.
Magnesium (Mg) is highly bioavailable in kombu compared with other edible seaweeds. However, a considerable amount of Mg is lost during industrial processing and cooking of kombu. We hypothesized that thinly shaved kombu (TSK), a traditional Japanese kombu product, is a suitable Mg source for daily diets because TSK hardly loses Mg during processing. Rats were fed diets containing TSK or magnesium oxide (MgO) to satisfy 25%, 50%, 75%, or 100% of their Mg requirements. We determined the relative Mg bioavailability of TSK compared to MgO and examined factors affecting Mg bioavailability in TSK.
The relative bioavailability of Mg in TSK compared with MgO was calculated as 92.3%, 111.4%, and 87.2% from apparent absorption, urinary excretion, and femoral concentration of Mg, respectively. The ultrafiltrable Mg concentration was lower in the cecal content of rats given TSK than those given MgO. However, the mRNA expression of TRPM6, an Mg channel responsible for Mg absorption, was higher in the cecum of rats given TSK than those given MgO.
Enhancement of TRPM6 expression in the large intestine negates the low bioaccessibility of Mg in TSK, and thus TSK shows Mg bioavailability comparable with MgO. © 2020 Society of Chemical Industry.
与其他可食用海藻相比，裙带菜中的镁（Mg）具有很高的生物利用度。然而，裙带菜在工业加工和烹饪过程中会损失相当一部分 Mg。我们假设，传统的日本裙带菜产品——薄切裙带菜（TSK）是一种适合日常饮食的 Mg 来源，因为 TSK 在加工过程中几乎不会损失 Mg。我们用 TSK 或氧化镁（MgO）喂养大鼠，以满足其 25%、50%、75%或 100%的 Mg 需求。我们确定了 TSK 与 MgO 相比的相对 Mg 生物利用度，并研究了影响 TSK 中 Mg 生物利用度的因素。
通过表观吸收率、尿排泄率和股骨 Mg 浓度计算，TSK 中 Mg 的相对生物利用率分别为 MgO 的 92.3%、111.4%和 87.2%。给予 TSK 的大鼠盲肠内容物中可过滤 Mg 浓度低于给予 MgO 的大鼠。然而，给予 TSK 的大鼠盲肠中负责 Mg 吸收的 Mg 通道 TRPM6 的 mRNA 表达高于给予 MgO 的大鼠。
大肠中 TRPM6 表达的增强抵消了 TSK 中 Mg 低生物利用度的影响，因此 TSK 表现出与 MgO 相当的 Mg 生物利用度。 © 2020 英国化学学会。
