Science Update

New review demonstrates the effects of prebiotics and probiotics for obesity and metabolic syndrome

According to a new review published last month, researchers demonstrated the efficacy of prebiotics and probiotics in obesity and metabolic syndrome. Previous research has demonstrated the association of the gut microbiome with undesirable metabolic markers and type II diabetes.

Research suggests that it is not body fat alone, but the associated increased low-grade inflammation and metabolic dysfunction that cause disease. This promotes insulin resistance in the liver and the release of inflammatory mediators from the adipose tissue. In addition, increased intestinal permeability allows translocation of proinflammatory lipopolysaccharides.

Advances in stool testing technology have revealed associations between a variety of specific bacteria and increased weight gain with metabolic dysfunction and inflammation. The gut microbiome has a direct impact on metabolism, mucosal barrier integrity, and systemic immune function.

Other research has indicated that obesity has a microbial component that alters the caloric extraction from ingested food. For example, if one has more Bacteroidetes bacteria, the individual tends to be leaner. High Firmicutes: Bacteroidetes ratios have been known to increase the caloric extraction from food; individuals with such a ratio tend to be more obese. This also ties together the importance of dietary fiber and prebiotics for weight loss.

In this review, only randomized placebo-controlled trials with more than 50 subjects were included. Additionally, all results included assessments of biomarkers of insulin resistance or obesity, such as BMI, lipid profile, inflammatory markers, and the homeostasis model assessment of insulin resistance (HOMA-IR).

Prebiotics impair the uptake of dietary cholesterol and reduce the absorption of bile acids. They also increase bacterial fermentation in the colon, which affects gut barrier function and cholesterol metabolism, regulates GLP-1, and reduces translocation of lipopolysaccharides.

Several meta-analyses and large review studies have demonstrated a beneficial effect of probiotics on weight loss and metabolic syndrome. Probiotic organisms have important strain-specific differences that may account for variations in the weight loss effect; however, many studies show improved lipids and inflammatory markers.

Synbiotics—combining probiotics with prebiotics—show clear beneficial effects on waist and hip circumference, BMI, visceral fat areas, circulating leptin levels, lipid profile, and total oxidative stress.

I attended a probiotic workshop at Yale and I remember one of the presentations from Max Nieuwdorp, MD, PHD, an internist and endocrinologist from Amsterdam. He went into detail on the microbiota and metabolism. He showed how butyrate, a short-chain fatty acid (SCFA), improved insulin resistance and brown fat activation. In general, low SCFAs are associated with low diversity and abundance of the commensal bacteria. When patients introduce probiotics and increase their dietary fiber intake by consuming fruits and vegetables, the beneficial bacteria, butyrate, and other SCFAs increase.

Probiotics help encourage microbial diversity, especially if the probiotic supplement contains mixed species. In ecological terms, it’s more stable to have diverse populations in any ecosystem, and the same is true for the gastrointestinal microbiome. When supporting patients with insulin resistance and obesity, it makes sense to use a combination of prebiotics and probiotics. Although many prebiotics are effective, common ones such as inulin, fructooligosaccharides, and galacto-oligosaccharides often require one to consume a relatively large amount, which may cause undesired gastrointestinal systems. I would consider using xylooligosaccharides, as these are unique prebiotic fibers that don’t require a large dose and are less likely to induce the gastrointestinal side effects.

By Michael Jurgelewicz, DC, DACBN, DCBCN, CNS

Source: Ferrarese R, Ceresola ER, et al. Probiotics, prebiotics and synbiotics for weight loss and metabolic syndrome in the microbiome. Euc Rev Med Pharmacol Sci. 2018 Nov;22(21):7588-7605. doi: 10.26355/eurrev_201811_16301.