What’s the latest in Prebiotic Research? – January 2023 Edition

This monthly feature provides an overview of some of the latest studies on prebiotics. We’ll share key findings and insights from the studies. Have a study you’d like us to cover? Email GPA Communications Director Traci Kantowski traci@prebioticassociation.org.

Circulating bile acids as a link between the gut microbiota and cardiovascular health: impact of prebiotics, probiotics and polyphenol-rich foods

Beneficial effects of probiotic, prebiotic and polyphenol-rich interventions on fasting lipid profiles have been reported, with changes in the gut microbiota composition believed to play an important role in lipid regulation. The gut microbiota  converts bile acids into secondary substances, some of these are not easily absorbed and thus new bile must be made which lowers low density lipoproteins (LDLs).  This suggests that bile acids may help to explain the relationship between the gut microbiota and cardiovascular health. Thus, the concentration of circulating bile acids is considered to be a potential novel biomarker of disease risk. This narrative review provides an overview of bile acid metabolism and discusses the role of probiotics, prebiotics and polyphenol-rich foods in modulating circulating bile acids and lipid risk markers for CVD. Prebiotic consumption is thought to improve cardiovascular health via favorable effects on the blood lipid profile as has been demonstrated in humans with consumption of barley. Consumption of beta glucans has been shown to enhance bile acid synthesis using circulating cholesterol. Animal model studies have demonstrated an effect of prebiotics, probiotics and polyphenol-rich foods/extracts on the FXR/FGF-15 axis as well as generally increasing expression of hepatic CYP7A1 (the rate-limiting enzyme for bile acid synthesis) and potential effects on endogenous cholesterol synthesis via SREBP and HMGR genes leading to the enhanced clearance of circulating LDL. It is evident that further research in humans is needed to fully define the relationship between diet and bile acid metabolism to determine the mechanisms behind the beneficial effects of these dietary components on host health and CVD risk.

Key takeaways:

  • Probiotics, prebiotics and polyphenols have been shown to benefit the microbiota and to reduce risk of CVD.
  • The connection is thought to lie in their effect on bile acid synthesis
  • The concentration of circulating bile acids is considered to be a potential novel biomarker of disease risk.

Access the study: https://pubmed.ncbi.nlm.nih.gov/33926590/

Reference. Pushpass, R. G., Alzoufairi, S., Jackson, K. G., & Lovegrove, J. A. (2022). Circulating bile acids as a link between the gut microbiota and cardiovascular health: impact of prebiotics, probiotics and polyphenol-rich foods. Nutrition research reviews, 35(2), 161–180. https://doi.org/10.1017/S0954422421000081

Prebiotics improve osteoporosis indicators in a preclinical model: systematic review with meta-analysis

A systematic review and meta-analysis was conducted using PubMed, Science Direct, Web of Science, Scielo, and Google through March 2022 for studies that investigated the impact of prebiotics on bone mineral density (BMD), bone mineral content (BMC), and bone biomechanics. Eight preclinical rat studies were included. Prebiotics improved indicators of osteoporosis, BMD, BMC, and bone biomechanics in ovariectomized rats. The beneficial results observed in studies with prebiotics are said to be due to the ability to selectively stimulate the growth and/or activity of beneficial native bacteria, leading to an increase in the production of short chain fatty acids (SCFAs) in the lower gastrointestinal tract and a consequent decrease in luminal pH and an increase in the solubility and absorption of minerals, mainly Ca and Mg. Studies in humans are needed.

Key takeaways:

  • Prebiotics have been shown to benefit parameters related to osteoporosis in preclinical parameters
  • The benefits is from the changes in SCFA
  • More human research is needed

Access the study https://pubmed.ncbi.nlm.nih.gov/36474436/

Reference Artoni de Carvalho, J. A., Magalhães, L. R., Polastri, L. M., Batista, I. E. T., de Castro Bremer, S., Caetano, H. R. D. S., Rufino, M. N., & Bremer-Neto, H. (2022). Prebiotics improve osteoporosis indicators in a preclinical model: systematic review with meta-analysis. Nutrition reviews, nuac097. Advance online publication. https://doi.org/10.1093/nutrit/nuac097

The use of probiotics and prebiotics can enable the ingestion of dairy products by lactose intolerant individuals

This systematic review discusses the efficiency of the clinical application of probiotic and prebiotic supplements in reducing symptoms of lactose intolerance. Five studies were included. Two studies used the prebiotic GOS (RP-G28) for the treatment of lactose intolerance (LI), they included 462 subjects. The results showed improvement of LI symptoms during treatment phase and up to 30 days after cessation of GOS use (RP-G28). Three studies used the probiotics Bifidobacterium bifidum 900791, Limosilactobacillus reuteri DSM 17938 (Lactobacillus reuteri), and Lactobacillus acidophilus DDS-1 to evaluate their effects on LI and comprised 117 subjects. The results showed that B. bifidum 900791 did not significantly improve LI symptoms, and only Limosilactobacillus reuteri DSM 17938 showed significant improvement in symptoms and in reduction of expired hydrogen, while Lactobacillus acidophilus DDS-1 showed significant improvement for LI symptoms.

Key takeaway:

  • Few studies exist exploring the relationship between probiotics, prebiotics and LI
  • The studies that do exist show promise
  • The probiotics Limosilactobacillus reuteri DSM 17938 and Lactobacillus acidophilus DDS-1 showed the best results in the management of LI symptoms.
  • The prebiotic GOS (RP-G28) appeared to be more efficient in reducing post-treatment symptoms.

Access the study: https://pubmed.ncbi.nlm.nih.gov/36308983/

Reference: Oliveira, L. S., Wendt, G. W., Crestani, A. P. J., & Casaril, K. B. P. B. (2022). The use of probiotics and prebiotics can enable the ingestion of dairy products by lactose intolerant individuals. Clinical nutrition (Edinburgh, Scotland), 41(12), 2644–2650. https://doi.org/10.1016/j.clnu.2022.10.003