Albihn P B, Savage G P
Department of Food Science, Swedish University of Agricultural Science, Uppsala, Sweden.
J Urol. 2001 Aug;166(2):420-2.
It is believed that soluble oxalate has higher bioavailability than insoluble oxalate. Oca (Oxalis tuberosa) is moderately high in oxalate and contains oxalate in soluble form only. We estimated the bioavailability of oxalate in oca based on the urinary excretion of oxalate after oxalate loading with oca to estimate the bioavailability of oxalate in oca. We also clarified whether bioavailability differs in various oxalate loads from the same food source and studied the effect of an additional calcium source on the bioavailability of oxalate from oca.
Four men and 4 women ingested 50, 100 and 150 gm. oca as well as 100 gm. oca with 100 gm. sour cream. Oxalate was measured in a 6-hour urine sample from each volunteer.
The mean bioavailability of oxalate from oca plus or minus standard deviation was 1.44% +/- 1.31% during the 6-hour period after intake. There was no significant difference in oxalate bioavailability among oxalate intake levels in this study, although oca consumption with sour cream significantly decreased the uptake of oxalate (p <0.01). The variation in bioavailability among individuals was high in our study.
The bioavailability of oxalate in oca appears to be similar to that in spinach. However, bioavailability varies among individuals and depends on other constituents of a combined meal.
据信可溶性草酸盐的生物利用度高于不溶性草酸盐。块茎酢浆草（Oxalis tuberosa）的草酸盐含量适中，且仅含有可溶形式的草酸盐。我们通过给受试者摄入块茎酢浆草后测定草酸盐的尿排泄量来评估块茎酢浆草中草酸盐的生物利用度。我们还阐明了来自同一食物来源的不同草酸盐负荷下生物利用度是否存在差异，并研究了额外添加钙源对块茎酢浆草中草酸盐生物利用度的影响。
4名男性和4名女性分别摄入50克、100克和150克块茎酢浆草，以及100克块茎酢浆草加100克酸奶油。对每位志愿者6小时的尿液样本进行草酸盐测定。
摄入后6小时内，块茎酢浆草中草酸盐的平均生物利用度（±标准差）为1.44%±1.31%。本研究中，不同草酸盐摄入量水平下的草酸盐生物利用度无显著差异，不过与酸奶油一起食用块茎酢浆草会显著降低草酸盐的吸收（p<0.01）。在我们的研究中，个体间生物利用度的差异很大。
块茎酢浆草中草酸盐的生物利用度似乎与菠菜中的相似。然而，生物利用度因个体而异，并且取决于混合餐中的其他成分。
