Data_Sheet_1_Daily Fermented Whey Consumption Alters the Fecal Short-Chain Fatty Acid Profile in Healthy Adults.docx

Gut microbiota influences many aspects of host health including immune, metabolic, and gut health. We examined the effect of a fermented whey concentrate (FWC) drink rich in L-(+)-Lactic acid, consumed daily, in 18 healthy men (n = 5) and women (n = 13) in free-living conditions.
Objective: The aims of this 6-weeks pilot trial were to (i) identify changes in the gut microbiota composition and fecal short chain fatty acid (SCFA) profile, and (ii) to monitor changes in glucose homeostasis.
Results: Total fecal SCFA (mM) concentration remained constant throughout the intervention. Proportionally, there was a significant change in the composition of different SCFAs compared to baseline. Acetate levels were significantly reduced (−6.5%; p < 0.01), coupled to a significant increase in the relative amounts of propionate (+2.2%; p < 0.01) and butyrate (+4.2%; p < 0.01), respectively. No changes in the relative abundance of any specific bacteria were detected. No significant changes were observed in glucose homeostasis in response to an oral glucose tolerance test.
Conclusion: Daily consumption of a fermented whey product led to significant changes in fecal SCFA metabolite profile, indicating some potential prebiotic activity. These changes did not result in any detectable differences in microbiota composition. Post-hoc analysis indicated that baseline microbiota composition might be indicative of participants likely to see changes in SCFA levels. However, due to the lack of a control group these findings would need to be verified in a rigorously controlled trial. Future work is also required to identify the biological mechanisms underlying the observed changes in microbiota activity and to explore if these processes can be harnessed to favorably impact host health.
Clinical Trial Registration: www.clinicaltrials.gov, identifier NCT03615339; retrospectively registered on 03/08/2018.

肠道菌群（gut microbiota）可影响宿主健康的诸多方面，涵盖免疫、代谢与肠道健康范畴。本研究针对18名健康受试者（男性5名、女性13名），在自由生活状态下每日饮用富含L-(+)-乳酸的发酵乳清浓缩物（fermented whey concentrate, FWC）饮品，探究其对宿主的影响。

本项为期6周的预试验目标为：① 明确肠道菌群组成与粪便短链脂肪酸（short chain fatty acid, SCFA）谱的变化情况；② 监测葡萄糖稳态的动态改变。

试验全程中，粪便总短链脂肪酸（以mM计）浓度维持稳定。与基线水平相比，各短链脂肪酸的组成比例发生显著变化：乙酸盐水平显著降低6.5%（p < 0.01），同时丙酸盐与丁酸盐的相对含量分别显著升高2.2%（p < 0.01）与4.2%（p < 0.01）。未检测到任一特定细菌的相对丰度出现变化。口服葡萄糖耐量试验结果显示，受试者的葡萄糖稳态未观察到显著改变。

每日饮用发酵乳清制品可使粪便短链脂肪酸代谢谱发生显著变化，提示其具备一定潜在益生元活性。但此类变化未导致肠道菌群组成出现可检测到的差异。事后分析显示，受试者的基线肠道菌群组成或可预测其短链脂肪酸水平是否会发生改变。不过由于本试验未设置对照组，上述发现需在严格对照的临床试验中进一步验证。未来仍需开展相关研究，阐明肠道菌群活性变化背后的生物学机制，并探索能否利用这些过程对宿主健康产生有益影响。

临床试验注册：www.clinicaltrials.gov，注册号NCT03615339；于2018年8月3日完成回溯注册。