King's College London, Faculty of Life Sciences and Medicine, Department of Nutritional Sciences, London, UK.
Queen Mary University of London, Barts and The London School of Medicine & Dentistry, Wingate Institute of Neurogastroenterology, London, UK.
Clin Nutr. 2019 Feb;38(1):165-173. doi: 10.1016/j.clnu.2018.01.003. Epub 2018 Feb 15.
BACKGROUND & AIM: Prunes (dried plums) are perceived to maintain healthy bowel function, however their effects on gastrointestinal (GI) function are poorly researched and potential mechanisms of action are not clear. We aimed to investigate the effect of prunes on stool output, whole gut transit time (WGTT), gut microbiota and short-chain fatty acids (SCFA) in healthy adults METHODS: We conducted a parallel group, randomised controlled trial with three treatment arms in 120 healthy adults with low fibre intakes and stool frequency of 3-6 stools/wk. Subjects were randomised to 80 g/d prunes (plus 300 ml/d water); 120 g/d prunes (plus 300 ml/d water) or control (300 ml/d water) for 4 weeks. Stool weight was the primary outcome and determined by 7-day stool collection. Secondary outcomes included stool frequency and consistency (stool diary), WGTT (radio-opaque markers), GI symptoms (diary), microbiota (quantitative PCR) and SCFA (gas liquid chromatography). Group assignment was concealed from the outcome assessors.
There were significantly greater increases in stool weight in both the 80 g/d (mean + 22.2 g/d, 95% CI -1-45.3) and 120 g/d (+32.8 g/d, 95% CI 13.9-51.7) prune groups compared with control (-0.8 g/d, 95% CI -17.2 to 15.6, P = 0.026). Stool frequency was significantly greater following 80 g/d (mean 6.8 bowel movements/wk, SD 3.8) and 120 g/d (5.6, SD 1.9) prune consumption compared with control (5.4, SD 2.1) (P = 0.023), but WGTT was unchanged. The incidence of flatulence was significantly higher after prune consumption. There were no significant differences in any of the bacteria measured, except for a greater increase in Bifidobacteria across the groups (P = 0.046). Prunes had no effect on SCFA or stool pH.
In healthy individuals with infrequent stool habits and low fibre intake, prunes significantly increased stool weight and frequency and were well tolerated. Prunes may have health benefits in populations with low stool weight.
ISRCTN42793297 http://www.isrctn.com/ISRCTN42793297.
李子（干李子）被认为有助于维持肠道健康，但它们对胃肠道（GI）功能的影响尚未得到充分研究，其潜在作用机制也不明确。我们旨在研究李子对健康成年人的粪便排出量、全肠道传输时间（WGTT）、肠道菌群和短链脂肪酸（SCFA）的影响。
我们进行了一项平行组、随机对照试验，共纳入 120 名低纤维摄入量、每周排便频率为 3-6 次的健康成年人，将其随机分为 3 组：80g/d 李子（加 300ml/d 水）；120g/d 李子（加 300ml/d 水）或对照组（300ml/d 水），治疗周期为 4 周。粪便重量是主要观察终点，通过 7 天粪便收集来确定。次要终点包括粪便频率和稠度（粪便日记）、WGTT（放射性标记物）、胃肠道症状（日记）、菌群（定量 PCR）和 SCFA（气相色谱法）。结果评估者对分组情况设盲。
与对照组相比，80g/d 李子组（平均增加 22.2g/d，95%CI-1-45.3）和 120g/d 李子组（平均增加 32.8g/d，95%CI13.9-51.7）的粪便重量均显著增加（P=0.026），而对照组则减少了 0.8g/d（95%CI-17.2-15.6，P=0.026）。与对照组相比，80g/d（平均 6.8 次/周，SD3.8）和 120g/d（5.6 次/周，SD1.9）李子组的粪便频率明显增加（P=0.023），但 WGTT 无明显变化。食用李子后，腹胀的发生率明显升高。除双歧杆菌外，各组间的细菌数量无显著差异（P=0.046）。李子对 SCFA 或粪便 pH 值无影响。
在排便习惯不规律、纤维摄入量低的健康人群中，李子可显著增加粪便重量和频率，且耐受性良好。李子可能对低粪便量人群具有健康益处。
ISRCTN42793297（http://www.isrctn.com/ISRCTN42793297）。
