A multi-species synbiotic supplement has led to measurable improvements in weight, metabolic control and cardiovascular risk markers in elderly people with type 2 diabetes, according to results from a randomised controlled trial. The findings add to growing evidence that modulation of the gut microbiome may support cardiometabolic health in older patients at high risk.
Trial in High-Risk Older Adults
The study enrolled 96 patients aged 65 years and over with type 2 diabetes mellitus (T2DM) and elevated cardiovascular risk between January 2022 and May 2023. Participants were randomly assigned to receive either a synbiotic supplement or a placebo for four months. The synbiotic combined multiple probiotic species with fructooligosaccharides, a prebiotic fibre designed to promote beneficial gut bacteria.
The primary outcome was the difference in weight change between groups. Secondary outcomes included changes in body fat mass, lean body mass and biochemical markers related to glucose metabolism, lipid profiles and vascular inflammation. Eighty-five participants completed the study and were included in the final analysis.
Significant Reductions in Weight
Patients receiving the synbiotic experienced significantly greater weight loss than those given placebo. On average, body weight fell by 1.16 kg compared with placebo, alongside a reduction in body mass index of 0.44 kg/m². Body fat mass decreased by 0.99 kg, while lean body mass was maintained, an important consideration in older populations where muscle loss can worsen frailty.
Improvements in Metabolic Markers
The synbiotic group also showed clear metabolic benefits. Fasting plasma glucose fell by 22.83 mg/dl compared with placebo, and insulin resistance improved, with a reduction in the homeostatic model assessment for insulin resistance (HOMA-IR) of 1.31.
Cardiovascular risk markers improved in parallel. Low-density lipoprotein cholesterol decreased by 10.83 mg/dl, while total cholesterol fell by 11.78 mg/dl. Levels of vascular cell adhesion molecule-1 (VCAM-1), a marker of endothelial dysfunction and vascular inflammation, were reduced by 85.70 ng/L in the synbiotic group compared with placebo. No serious adverse events were reported during the trial.
The authors conclude that multi-species synbiotic supplementation can deliver modest but clinically relevant improvements in weight, lipid levels, glycaemic control and vascular inflammation in elderly patients with T2DM. They suggest synbiotics may represent a safe, adjunctive approach to reducing cardiovascular risk in this growing patient population.
Reference
Dolatkhah N et al. The promising effects of a multi-species synbiotic preparation on metabolic profile in elderly patients with type 2 diabetes and high cardiovascular risk: a randomized, triple-blind, placebo-controlled trial. Nutrition & Diabetes. 2025; https://doi.org/10.1038/s41387-025-00408-4.
