Effects of a novel synbiotic intervention on abdominal visceral fat reductions and gut microbiota in overweight and obese adults: A randomized, double-blind, placebo-controlled trial.

Synbiotic supplementation significantly reduced visceral adipose tissue (VAT) area compared to placebo from baseline to week 12.

• The primary endpoint was change in VAT area quantified by dual-energy X-ray absorptiometry (DXA).
• The reduction reached statistical significance compared with placebo (p = 0.048).
• The trial was a 12-week, double-blind, randomized, placebo-controlled, parallel-group design.
• 112 participants with BMI 24.0–34.9 kg/m² were enrolled and received daily synbiotic or matched placebo.

The effect of synbiotic intervention on VAT reduction was more pronounced in men than in women.

• Subgroup analysis by gender showed the effect was more pronounced in men than in women (p = 0.051).
• The effect in women did not reach conventional statistical significance.
• No significant changes occurred in BMI or waist circumference in the overall study population.

VAT reduction was highly significant in individuals with BMI in the range of 24 ≤ BMI < 28 (overweight subgroup).

• Subgroup analysis by BMI showed the VAT reduction was highly significant in individuals with 24 ≤ BMI < 28 (p = 0.003).
• This effect was more pronounced than in the overall study population (p = 0.048).
• The effect was specific to the overweight subgroup and not reported as significant in the obese (BMI ≥ 28) subgroup.

Subcutaneous adipose tissue (SAT) increased in the 24 ≤ BMI < 28 subgroup receiving the synbiotic.

• SAT increased in the 24 ≤ BMI < 28 subgroup (p = 0.027).
• This finding suggests a potential redistribution of adipose tissue from visceral to subcutaneous depots in overweight individuals.
• SAT was a secondary outcome measured by DXA.

No significant changes were observed in blood biochemistry, BMI, or waist circumference with synbiotic supplementation.

• Blood biochemical parameters did not show statistically significant changes in the synbiotic group compared to placebo.
• BMI and waist circumference also did not change significantly.
• These were among the secondary outcomes assessed.

The synbiotic group showed a trend toward greater total body fat reduction between weeks 12 and 18 (post-intervention follow-up period).

• The trend toward greater total body fat reduction occurred between weeks 12–18 (p = 0.077).
• This period corresponded to the 6-week post-intervention follow-up after cessation of the synbiotic.
• The effect did not reach conventional statistical significance.

Microbiota analysis revealed transient enrichment of probiotic strains B. animalis subsp. lactis (ASV110) and L. rhamnosus (ASV473) during the intervention, which dissipated by week 18.

• B. animalis subsp. lactis (ASV110) and L. rhamnosus (ASV473) were transiently enriched in the synbiotic group.
• Enrichment dissipated by week 18 (end of 6-week post-intervention follow-up).
• Fecal microbiota characterization was a secondary outcome.
• The probiotic strains used included Bifidobacterium animalis subsp. lactis CECT 8145 and three Lacticaseibacillus rhamnosus strains.

The synbiotic formulation tested comprised four probiotic strains, two prebiotics, and Chrysanthemum morifolium extract.

• Probiotic strains included Bifidobacterium animalis subsp. lactis CECT 8145 and three Lacticaseibacillus rhamnosus strains.
• Prebiotics included inulin and fructooligosaccharides.
• Chrysanthemum morifolium extract was also included as a component.
• The intervention was administered daily for 12 weeks followed by a 6-week post-intervention follow-up.