What’s the Latest in Prebiotic Research? – October 2023 Edition

Pomegranate (Punica granatum L.) peel extract ameliorates metabolic syndrome risk factors in patients with non-alcoholic fatty liver disease: a randomized double-blind clinical trial

Non-alcoholic fatty liver disease (NAFLD) is a metabolic syndrome-related liver illness associated with obesity, insulin resistance, type 2 diabetes, dyslipidemia, hypertension, and cardiovascular disease. Despite causing high morbidity and mortality, its multifactorial pathophysiology hinders the development of effective treatment therapies. No approved drugs are currently available for NAFLD; only lifestyle changes such as weight loss through diet and physical activity are recommended treatments. Therefore, this randomized, double-blind, placebo-controlled trial aimed to investigate the effects of pomegranate peel extract (PP) as a dietary supplement on the hepatic status and metabolic syndrome risk factors in NAFLD patients. Seventy-six NAFLD patients (51.3 % females, aged 43.1 ± 8.6) received 1500 mg of the placebo or PP capsules with a 500-kcal deficit diet for eight weeks. Following the intervention, the mean body weight, waist circumference, body mass index, body fat index, trunk fat, systolic and diastolic blood pressure, total cholesterol, triglyceride, low-density lipoprotein cholesterol, fat-free mass, and fasting blood sugar decreased significantly in the PP group compared to the placebo group in both the raw model and with confounders adjusted. High-density lipoprotein cholesterol, liver steatosis, and stiffness all improved in the PP group. However, fasting insulin and homeostatic model assessment for insulin resistance were not significantly different when comparing the two groups in the raw and adjusted models of the study. Therefore, an 8-week supplementation of 1500 mg PP extract with a weight-loss diet improved metabolic syndrome risk factors and reduced hepatic steatosis in NAFLD patients. Further studies are warranted to determine the precise molecular pathways and the best effective dose of supplementation of PP extract in NAFLD.

Key takeaways:

  • NAFLD is a metabolic disease-linked hepatic disorder, affecting various extra-hepatic organs and causing high morbidity and mortality.
  • The most common treatment therapy for NAFLD is lifestyle changes such as dietary interventions and physical activity.
  • Pomegranate peel extract at 1500 mg in addition to a weight-loss diet used for eight weeks improved metabolic syndrome risk factors and reduced hepatic steatosis in patients with NAFLD.

Access to the study: https://pubmed.ncbi.nlm.nih.gov/37605174/ 

Reference: Barghchi, H., Milkarizi, N., Belyani, S., Norouzian Ostad, A., Askari, V. R., Rajabzadeh, F., Goshayeshi, L., Ghelichi Kheyrabadi, S. Y., Razavidarmian, M., Dehnavi, Z., Sobhani, S. R., & Nematy, M. (2023). Pomegranate (Punica granatum L.) peel extract ameliorates metabolic syndrome risk factors in patients with non-alcoholic fatty liver disease: a randomized double-blind clinical trial. Nutrition journal, 22(1), 40. https://doi.org/10.1186/s12937-023-00869-2 

Effects of synbiotic supplementation on intestinal microbiota composition in children and adolescents with exogenous obesity: (Probesity-2 trial)

Obesity is originated by multiple causes, including genetic predisposition and environmental factors. Gut microbial composition is also an overweight- and obesity-associated factor, and its manipulation may be a potential therapeutic target for reducing host energy storage. To date, there is limited information regarding the effects of synbiotics on intestinal microbiota composition in children and adolescents with obesity. Therefore, this randomized, double-blinded, placebo-controlled trial tested a multispecies synbiotic on intestinal microbiota composition in children and adolescents with exogenous obesity for 12 weeks. Children aged between 8 and 17 years were randomly allocated into two groups at a ratio of 1:1. Group 1 received the synbiotic supplementation containing a total of 2.5 × 109 CFU of Lactobacillus acidophilus, Lacticaseibacillus rhamnosus, Bifidobacterium bifidum, Bifidobacterium longum, Enterococcus faecium and 625 mg of fructooligosaccharides (FOS), while group 2 received the placebo once daily. In the synbiotic group, PrevotellaCoprococcus, and Lachnospiraceae at the genus level and Prevotella copriCoprococcus eutactus, and Ruminococcus spp. at the species level increased compared to baseline (predominance of Eubacterium dolichumLactobacillus ruminisClostridium ramosum, and Bulleidia moorei), in addition to improving BMI values. After the 12-week intervention, Bacteroides eggerthi species were dominant in the placebo group, while Collinsella stercoris species were dominant in the synbiotic group. This study is the first pediatric obesity study to show that a 12-week synbiotic supplementation is well-tolerated and associated with changes in intestinal microbiota composition and a decrease in BMI.

Key takeaways:

  • Microbiota-manipulating approaches used early in life make an important preventative strategy for obesity.
  • This randomized, double-blinded, placebo-controlled trial may be the first to explore the effects of synbiotic supplementation on the anthropometric measurements and intestinal microbiota composition in the obese pediatric population.
  • Synbiotics may manipulate intestinal microbial composition, an associated factor in overweight and obesity.

Access to the study: https://pubmed.ncbi.nlm.nih.gov/37474971/ 

Reference: Kilic Yildirim, G., Dinleyici, M., Vandenplas, Y., & Dinleyici, E. C. (2023). Effects of synbiotic supplementation on intestinal microbiota composition in children and adolescents with exogenous obesity: (Probesity-2 trial). Gut pathogens, 15(1), 36. https://doi.org/10.1186/s13099-023-00563-y

The Effects of Agave Fructans in a Functional Food Consumed by Patients with Irritable Bowel Syndrome with Constipation: A Randomized, Double-Blind, Placebo-Controlled Trial

Irritable bowel syndrome (IBS) is a chronic functional disorder of the gastrointestinal tract with an unknown etiology. IBS symptoms include recurrent abdominal pain and discomfort as well as alterations in bowel function, frequency, and appearance, manifested as constipation (IBS-C), diarrhea (IBS-D), or both (IBS-Mixed, IBS-M). In most cases, the treatment approach is different for each subtype. For example, IBS-D is treated with a low-fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAP) diet, while IBS-C employs probiotics and prebiotics as the intervention approach. As such, this randomized, double-blinded, placebo-controlled, time-limited pilot study aimed to assess the effects of 8 g of agave fructans as a functional food in prebiotic jelly on the clinical symptoms, quality of life, anxiety, depression, and stool frequency in IBS-C patients for four weeks. The study evaluated changes in the frequency and type of bowel movements and condition improvement using quality of life and anxiety-depression scales. The number of bowel movements increased by >80%, with at least one stool per day from fifteen days onwards, without a laxative effect for the group treated. Additionally, the quality of life in the IBS-C group improved significantly compared to the placebo group in all studied domains, in addition to a significant reduction in anxiety and depression. 

Key takeaways: 

  • IBS is a common gastroenterology condition, with an unknown cause. 
  • This study assessed the short-term effects of agave fructans administration on the clinical symptoms of IBS with constipation.
  • Further studies exploring the mechanisms of action of agave fructans and the specific changes in the intestinal microbiota are necessary.

Access to the study: https://pubmed.ncbi.nlm.nih.gov/37630717/ 

Reference: Camacho-Díaz, B. H., Arenas-Ocampo, M. L., Osorio-Díaz, P., Jiménez-Aparicio, A. R., Alvarado-Jasso, G. M., Saavedra-Briones, E. V., Valdovinos-Díaz, M. Á., & Gómez-Reyes, E. (2023). The Effects of Agave Fructans in a Functional Food Consumed by Patients with Irritable Bowel Syndrome with Constipation: A Randomized, Double-Blind, Placebo-Controlled Trial. Nutrients, 15(16), 3526. https://doi.org/10.3390/nu15163526 

Effects of gut microbial therapy on lipid profile in individuals with non-alcoholic fatty liver disease: an umbrella meta-analysis study

Recent evidence points towards the role of gut dysbiosis and microbial metabolites as risk factors in the pathophysiology of NAFLD. This umbrella review study aimed to summarize the results of meta-analyses of randomized controlled trials assessing the impact of gut microbial therapies, including probiotics, prebiotics, and synbiotics, on the impaired lipid profiles observed in NAFLD patients. Four databases were used, including PubMed, Scopus, Web of Science, and Cochrane Library, retrieving studies published through November 1, 2022. Meta-analyses that surveyed the impact of microbial therapies on lipid profile parameters, including triglycerides, high-density lipoprotein, low-density lipoprotein, and total cholesterol in NAFLD patients, were of interest. A total of fifteen studies included in this study showed that microbial therapies (i.e., probiotics, prebiotics, and synbiotics) significantly reduced triglycerides, total cholesterol, and low-density lipoprotein in NAFLD patients; however, the effect on the high-density lipoprotein was not statistically significant. Therefore, microbial therapies may be recommended as alternative treatment options in NAFLD patients. 

Key takeaways:

  • NAFLD lacks approved treatments, with increasing evidence pointing toward the promising role of microbial therapies in this disease.
  • Prebiotics, probiotics, and synbiotics may help manage the lipid profiles of NAFLD and its associated metabolic complications. 
  • Further well-designed, randomized, controlled trials are needed to explore the optimal regimen, duration, and specific microbial strains that yield the most benefits. 

Access the study: https://pubmed.ncbi.nlm.nih.gov/37605283/ 

Reference: Naghipour, A., Amini-Salehi, E., Orang Gorabzarmakhi, M., Shahdkar, M., Fouladi, B., Alipourfard, I., & Sanat, Z. M. (2023). Effects of gut microbial therapy on lipid profile in individuals with non-alcoholic fatty liver disease: an umbrella meta-analysis study. Systematic reviews, 12(1), 144. https://doi.org/10.1186/s13643-023-02299-x