Dark Sweet Cherry (Prunus avium) Supplementation Modulates Inflammation, Cognitive Function, and Intestinal Microbial Composition in Obese Individuals: A Single-Blind Randomized Clinical Trial

Abstract

Obesity is an underlying condition for the development of inflammatory and metabolic disorders such as hypertension and cardiovascular diseases. Moreover, obesity has been related to cognitive impairment and alterations of the intestinal microbiota composition, also known as dysbiosis. The consumption of polyphenol-rich foods has been inversely associated with the incidence of obesity and its associated health risks. Dark sweet cherries (DSC) are considered a good source of polyphenols, mostly phenolic acids, and anthocyanins which have been credited with multiple health benefits, including anti-inflammatory and antioxidant properties as well as preventing obesity-related metabolic disorders. However, most studies have shown such benefits using in vitro or animal models. The aim of this study was to evaluate the influence of DSC supplementation on inflammation, cognitive function, and the gut microbiota composition in obese individuals. In a single-blind randomized trial, 40 obese subjects (> 18 years old, BMI: 30-40 kg/m²) were instructed to drink 200 mL of DSC juice supplemented with 3 gr of cherry powder (n = 19) or a placebo drink (n = 21) twice a day for 30 days.

At the end of the 30-day intervention, DSC decreased systolic and diastolic blood pressure (BP) and lessened the levels of pro-inflammatory and cardiovascular disease biomarkers such as interferon-gamma (IFNγ) and monocyte chemoattractant protein-1 (MCP-1). These results were accompanied by improvements in specific cognitive abilities such as working memory and concentration skills in obese adults. Moreover, DSC supplementation limited the upregulation of neurotensin, which is a protein implicated in cognitive decline following obesity. Findings from this study also showed, for the first time, that DSC supplementation might induce changes in the relative abundance of intestinal bacteria relevant in the context of obesity. Specifically, DSC supplementation may favor the growth of butyrate-producing bacteria such as Roseburia spp. and Eubacterium spp. and might prevent increased levels of pro-inflammatory bacteria such as Bilophila spp and Alistipes spp.

In summary, DSC consumption may contribute to regulating BP levels, lessen inflammation, and enhance specific cognitive abilities in obese individuals. This study also highlights DSC intake as a dietary strategy aimed to promote the modulation of intestinal bacteria relevant in the context of obesity.