1.
Effect of a Protein Supplement on the Gut Microbiota of Endurance Athletes: A Randomized, Controlled, Double-Blind Pilot Study.
Moreno-Pérez, D, Bressa, C, Bailén, M, Hamed-Bousdar, S, Naclerio, F, Carmona, M, Pérez, M, González-Soltero, R, Montalvo-Lominchar, MG, Carabaña, C, et al
Nutrients. 2018;10(3)
-
-
-
-
Free full text
Plain language summary
Protein supplements are popular among athletes to improve performance and increase muscle mass. However, their effect on other aspects of health is less well known. Dietary changes can affect gut microbiota balance, with beneficial or harmful consequences for the host. This small pilot study was performed on cross-country runners whose diets were complemented with a protein supplement (whey isolate and beef hydrolysate) or maltodextrin (control) for 10 weeks. Microbiota, water content, pH, ammonia, and short-chain fatty acids (SCFAs) were analysed in faecal samples, and oxidative stress markers were measured in blood plasma and urine. Faecal pH, water content, ammonia, and SCFA concentrations did not change, indicating that protein supplementation did not increase the presence of these metabolites of fermentation. Similarly, it had no impact on plasma or urine malondialdehyde levels. Protein supplementation did however increase the abundance of the Bacteroidetes phylum and decrease the presence of health-related taxa including Roseburia, Blautia, and Bifidobacterium longum. The authors concluded that long-term protein supplementation may have a negative impact on gut microbiota. Further research is needed to establish the impact of protein supplements on gut microbiota.
Expert Review
Conflicts of interest:
None
Take Home Message:
- Long-term protein supplementation may have a negative impact on gut microbiota.
- Further research is needed to establish the impact of protein supplements on gut microbiota and whether there is a differential impact between protein from animal and plant sources.
Evidence Category:
-
X
A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
-
B: Systematic reviews including RCTs of limited number
-
C: Non-randomized trials, observational studies, narrative reviews
-
D: Case-reports, evidence-based clinical findings
-
E: Opinion piece, other
Summary Review:
This is a very interesting study that is relevant to athletic populations.
Clinical practice applications:
Potentially there is a role for probiotics / prebiotics when increasing protein intake (particularly of animal origin) to maintain microbiota diversity and prevent ensuing health complications.
Considerations for future research:
Further, larger scale, research is needed to understand whether the same effect of protein supplementation would be seen with plant-based proteins or whether this is unique to animal based protein supplementation. For example, is the hydrolysation of the proteins to account for the largest effect or could a whole food protein, i.e. not hydrolysed, elicit the same effects?
Also, is this effect seen in other sports, e.g. non-endurance. What about the effect under different conditions e.g. energy deficit vs. energy excess?
Abstract
Nutritional supplements are popular among athletes to improve performance and physical recovery. Protein supplements fulfill this function by improving performance and increasing muscle mass; however, their effect on other organs or systems is less well known. Diet alterations can induce gut microbiota imbalance, with beneficial or deleterious consequences for the host. To test this, we performed a randomized pilot study in cross-country runners whose diets were complemented with a protein supplement (whey isolate and beef hydrolysate) (n = 12) or maltodextrin (control) (n = 12) for 10 weeks. Microbiota, water content, pH, ammonia, and short-chain fatty acids (SCFAs) were analyzed in fecal samples, whereas malondialdehyde levels (oxidative stress marker) were determined in plasma and urine. Fecal pH, water content, ammonia, and SCFA concentrations did not change, indicating that protein supplementation did not increase the presence of these fermentation-derived metabolites. Similarly, it had no impact on plasma or urine malondialdehyde levels; however, it increased the abundance of the Bacteroidetes phylum and decreased the presence of health-related taxa including Roseburia, Blautia, and Bifidobacterium longum. Thus, long-term protein supplementation may have a negative impact on gut microbiota. Further research is needed to establish the impact of protein supplements on gut microbiota.
2.
Postoperative changes of the microbiome: are surgical complications related to the gut flora? A systematic review.
Lederer, AK, Pisarski, P, Kousoulas, L, Fichtner-Feigl, S, Hess, C, Huber, R
BMC surgery. 2017;17(1):125
-
-
-
Free full text
Plain language summary
Infections following gastrointestinal surgery are common and patients routinely receive antibiotic medications to reduce the risks involved. Recent reviews have suggested that some of these complications might be related to the patient’s gut bacteria profile. This systematic review of 10 studies, including 677 patients, aimed to identify the relationship between post-operative infections and the gut microbiome. All studies reported a post-operative change to the gut flora, with 5 studies showing a reduction in bacteria present. Surgery tended to lead to an increase in disease causing bacteria and a reduction in health giving bacteria. The rate of post-operative complications was lower in the groups treated with pre- and pro-biotics, suggesting that there might be a relationship between gut flora and infections following surgery. There remains uncertainty however, due to the shortcomings of the methodologies employed by the studies.
Abstract
BACKGROUND The purpose of this review was to identify the relationship between the gut microbiome and the development of postoperative complications like anastomotic leakage or a wound infection. Recent reviews focusing on underlying molecular biology suggested that postoperative complications might be influenced by the patients' gut flora. Therefore, a review focusing on the available clinical data is needed. METHODS In January 2017 a systematic search was carried out in Medline and WebOfScience to identify all clinical studies, which investigated postoperative complications after gastrointestinal surgery in relation to the microbiome of the gut. RESULTS Of 337 results 10 studies were included into this analysis after checking for eligibility. In total, the studies comprised 677 patients. All studies reported a postoperative change of the gut flora. In five studies the amount of bacteria decreased to different degrees after surgery, but only one study found a significant reduction. Surgical procedures tended to result in an increase of potentially pathogenic bacteria and a decrease of Lactobacilli and Bifidobacteria. The rate of infectious complications was lower in patients treated with probiotics/symbiotics compared to control groups without a clear relation to the systemic inflammatory response. The treatment with synbiotics/probiotics in addition resulted in faster recovery of bowel movement and a lower rate of postoperative diarrhea and abdominal cramping. CONCLUSIONS There might be a relationship between the gut flora and the development of postoperative complications. Due to methodological shortcomings of the included studies and uncontrolled bias/confounding factors there remains a high level of uncertainty.
3.
Clinical trial: effect of active lactic acid bacteria on mucosal barrier function in patients with diarrhoea-predominant irritable bowel syndrome.
Zeng, J, Li, YQ, Zuo, XL, Zhen, YB, Yang, J, Liu, CH
Alimentary pharmacology & therapeutics. 2008;28(8):994-1002
-
-
-
Free full text
-
Plain language summary
Impaired intestinal mucosal barrier function may be involved in the pathogenesis of diarrhoea-predominant IBS (D-IBS) accompanied by persistent low-grade intestinal inflammation. Attenuating the inflammation and preserving mucosal barrier function may be a potential therapeutic target in D-IBS. This study investigates whether probiotic fermented milk containing multistrain lactic acid bacteria (LAB) can improve intestinal mucosal barrier function in D-IBS. 30 Chinese adults with D-IBS and 12 asymptomatic controls were randomized (1:1 ratio) to consume a probiotic fermented milk (containing Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus acidophilus and Bifidobacterium longum) or a placebo drink twice daily half an hour before meals for 4 weeks. IBS symptoms and intestinal permeability were evaluated at weeks 0 and 4. Before treatment, intestinal permeability of the 30 patients with D-IBS was increased compared to normal controls. After treatment, intestinal permeability in the probiotics group decreased significantly, compared to the placebo group. IBS symptoms score in the probiotics group improved compared with baseline values, but not in the placebo group. This study found that small intestinal permeability was significantly increased in D-IBS patients compared with normal controls. The results indicate that multistrain LAB was associated with the improvement in intestinal barrier function as measured by a reduction in small bowel permeability, in turn accompanied by relief of IBS symptoms, which suggests that increased intestinal permeability may partially contribute to the pathogenesis of IBS symptoms. The mechanisms of increased intestinal permeability involvement in D-IBS were lacking.
Abstract
BACKGROUND The intestinal permeability is increased in patients with diarrhoea-predominant irritable bowel syndrome (D-IBS). AIM: To determine the possible efficacy of lactic acid bacteria on the increased intestinal permeability in D-IBS. METHODS Treatment was employed for 4 weeks in a randomized single blind placebo controlled study with 30 D-IBS patients. Patients were given either probiotic fermented milk (Streptococcus thermophilus, Lactobacillus bulgaricus, Lactobacillus acidophilus and Bifidobacterium Longum) or milk beverage containing no bacteria. The clinical symptoms were scored and intestinal permeability was measured by a triple sugar test before and after treatment. RESULTS Small bowel permeability was measured as the ratio of lactulose and mannitol recovery and colonic permeability was measured as the total mass of sucralose excretion (mg). After probiotics treatment, small bowel permeability decreased significantly from 0.038 (0.024) at baseline to 0.023 (0.020) (P = 0.004), the proportion of patients with increased small bowel permeability was lower than baseline (28.6% vs. 64.3%, P = 0.023). However, colonic permeability improved neither in the probiotics group nor in the placebo group at week 4. Treatment with probiotics significantly decreased the mean global IBS scores compared with the baseline scores (9.62 +/- 1.05 vs. 7.64 +/- 1.24, P < 0.001). CONCLUSION Short-term active lactic acid bacteria treatment for D-IBS improved mucosal barrier function.