Synbiotic supplementation of high-fibre diet promising for weight loss

An open-label, randomized, parallel-design clinical trial demonstrates weight loss as well as decreases in fasting glucose, insulin and insulin resistance in overweight and obese Hong Kong Chinese individuals after high-fibre dietary intervention supplemented with synbiotics.

According to the 2020–2022 Population Health Survey conducted by Hong Kong’s Department of Health, 32.6 percent of individuals aged 15–84 years were obese (ie, body-mass index [BMI] ≥25.0 kg/m²) and another 22.0 percent were overweight (ie, BMI 23.0–<25.0  kg/m²). [https://www.chp.gov.hk/en/healthtopics/content/25/8802.html]

“Our weight loss programme emphasized increased fruit and vegetable consumption based on the Healthy Eating Food Pyramid in Hong Kong, [as] a high-fibre diet has been associated with an increase in microbiota-accessible carbohydrate-degrading bacteria and microbial diversity, which are essential to maintaining gut homeostasis,” wrote the researchers from the Chinese University of Hong Kong. Furthermore, a growing body of research shows that dietary interventions in obesity using synbiotics, which are comprised of probiotic(s) and prebiotic(s), may facilitate weight loss. [Crit Rev Food Sci Nutr 2020;60:584-596]

Therefore, a clinical trial was conducted to evaluate changes in gut microbiota and parameters of metabolic syndrome in Hong Kong Chinese individuals before and after 8-week dietary intervention with increased fruit and vegetable consumption and/or synbiotic supplementation (with probiotics, Lactobacillus acidophilus NCFM and Bifidobacterium lactis HN019, and a prebiotic, polydextrose). Fifty-five overweight or obese individuals were assigned to the synbiotic group (SG; n=19; mean BMI, 28.0 kg/m²), the dietary intervention group (DG; n=18; mean BMI, 30.6 kg/m²), or the group receiving both interventions (DSG; n=18; mean BMI, 28.0 kg/m²). [Nutrients 2023;15:4248]

Intragroup comparisons of anthropometric measures revealed no significant changes in SG. On the contrary, both DG and DSG reported significant reductions in body weight, BMI, body fat mass, trunk fat mass, and visceral fat rating vs baseline. The relative decreases in body weight, BMI, body fat mass, and trunk fat mass were significantly more pronounced in DSG vs DG. The relative decrease in visceral fat rating was significantly greater in DSG compared with that in SG and DG.

“It has been proposed that 5 percent weight loss could be clinically significant if maintained after 1 year of treatment. While no participants lost >5 percent of their initial weight in SG, 22 percent and 50 percent of participants in DG and DSG achieved weight loss of ≥5 percent, respectively,” highlighted the researchers. [Obesity 2015;23:2319-2320]

Compared with baseline, a significant decrease in fasting glucose was shown in DSG but not in SG or DG. Fasting insulin level and homeostasis model assessment of insulin resistance (HOMA-IR) values were significantly lowered in DG and DSG vs baseline. There was a significantly greater relative decrease in fasting glucose, fasting insulin and HOMA-IR in DSG compared with SG. “Our study shows that when a synbiotic supplement is taken with a high-fibre diet, the decreases in fasting glucose, fasting insulin and HOMA-IR are significantly greater than with synbiotic supplementation alone,” explained the researchers.

Furthermore, DSG decreased the abundance of Megamonas, which was positively associated with BMI, body fat mass and trunk fat mass. “Our data link the synergistic action of [high-fibre] weight loss diet and synbiotic supplement to favourable changes in gut microbiota genera associated with obesity indicators,” concluded the researchers.