Effects of Milkfat on the Gut Microbiome of Patients After Bariatric Surgery, a Pilot Study

Background The efficacy of bariatric surgery may be in part attributed to altered metabolism via new gut microbiome. Milkfat may promote the growth of microbes that are beneficial in long-term weight loss. Understanding the specific gut microbiome changes after surgery and their relationship to milkfat consumption may yield important strategies for managing obesity after bariatric procedures. Methods In this pilot study, stool samples were collected from nine patients before and at the time of surgery, and at 1, 3, and 6 months post-surgery. At each time-point, dairy consumption was determined from dietary surveys. 16 s rRNA gene sequencing was performed followed by alpha diversity analysis. Comparisons of relative abundances of microbial taxa and analyses of fatty acids changes were performed. Results Bariatric surgery led to enrichment of (i) Roseburia , associated with weight loss and (ii) Christensenellaceae , inversely related to body mass index. High milk-fat consumption correlated with enrichment of Blautia , inversely associated with visceral fat accumulation. Faecalibacterium , possibly associated with obesity, increased in patients with low milk-fat consumption. Butter was associated with decreased alpha diversity in all subjects ( p -value = 0.038) and the frequency of its use was associated with decreased alpha diversity in patients (correlation = − 0.68, p -value = 0.042). Low-milk-fat consumers showed higher concentration of saturated fatty acids. Conclusions Our results suggest that incorporating dairy products in post-bariatric-surgery dietary plans may help cultivate a gut microbiome that is effective in regulating fat storage as well as digesting beneficial metabolites. These observations will be helpful for the management of obesity in general population as well. Graphical abstract