Ito Atsushi, Shoji Hiromichi, Arai Hiroko, Kakiuchi Satsuki, Sato Keigo, Jinno Shinji, Takahashi Naoto, Masumoto Kenichi, Yoda Hitoshi, Shimizu Toshiaki
Department of Pediatrics, The University of Tokyo Hospital, Hongo, Bunkyo-ku, Tokyo, Japan.
Department of Pediatrics and Adolescent Medicine, Juntendo University Graduate School of Medicine, Hongo, Bunkyo-ku, Tokyo, Japan.
PLoS One. 2025 May 28;20(5):e0324256. doi: 10.1371/journal.pone.0324256. eCollection 2025.
BACKGROUND/OBJECTIVES: Soaped palmitic acid (PA) has been reported to be excreted in stool after feeding infant formulas containing low sn-2 palmitate levels, which corresponds to high sn-1 or -3 palmitate levels. While an in vitro study showed that soaped PA inhibits the Bifidobacteria growth, few clinical studies have evaluated effects of soaped PA on intestinal environments of infants. In this study, we aimed to evaluate associations between increased fecal soaped PA levels and inhibition of growth of the intestinal microbiome using clinical data, and to evaluate changes in the intestinal environment with formula-feeding.
This study was conducted as a secondary analysis to our observational study of Japanese 1-month-old infants (n = 172). Infant formulas were classified into high sn-2 formula (≥ 50%) and low sn-2 formula (< 50%) according to the sn-2 binding ratio of PA. Multiple regression analyses and path analysis were performed as statistical analyses.
In the multiple regression analysis, the occupancy of Bifidobacteria was negatively correlated with the fecal soaped PA levels (β = -0.15, 95% confidence interval = -0.28- - 0.02). A path analysis suggested that low sn-2 formula feeding led to increased fecal soaped PA levels, decreased Bifidobacteria occupancy, and finally increased fecal pH.
Our clinical data showed significant associations between higher fecal soaped PA levels and lower Bifidobacteria occupancy in the newborn gut, which agreed well with the report of the in vitro study. Our study also suggests that feeding infant formula with low sn-2 palmitate causes changes in the intestinal environment through an increase in fecal soaped palmitic acids.
背景/目的：据报道，在喂养含低sn-2棕榈酸水平（即高sn-1或-3棕榈酸水平）的婴儿配方奶粉后，皂化棕榈酸（PA）会随粪便排出。虽然一项体外研究表明皂化PA会抑制双歧杆菌生长，但很少有临床研究评估皂化PA对婴儿肠道环境的影响。在本研究中，我们旨在利用临床数据评估粪便中皂化PA水平升高与肠道微生物群生长抑制之间的关联，并评估配方奶喂养对肠道环境的影响。
本研究是对我们对172名日本1月龄婴儿进行的观察性研究的二次分析。根据PA的sn-2结合率，将婴儿配方奶粉分为高sn-2配方奶粉（≥50%）和低sn-2配方奶粉（<50%）。采用多元回归分析和路径分析作为统计分析方法。
在多元回归分析中，双歧杆菌的占有率与粪便中皂化PA水平呈负相关（β = -0.15，95%置信区间 = -0.28 - -0.02）。路径分析表明，低sn-2配方奶粉喂养导致粪便中皂化PA水平升高、双歧杆菌占有率降低，最终导致粪便pH值升高。
我们的临床数据显示，新生儿肠道中粪便皂化PA水平较高与双歧杆菌占有率较低之间存在显著关联，这与体外研究的报告结果高度一致。我们的研究还表明，喂养低sn-2棕榈酸的婴儿配方奶粉会通过增加粪便中皂化棕榈酸导致肠道环境发生变化。
