Effects of Cranberry Powder Supplements on Gut Microbiota Diversity and Metabolic Syndrome

It is of major importance to refine prevention strategies in order to alleviate inflammation, insulin resistance and metabolic syndrome and it appear that improving gut health and microbiota represent a promising strategy. Cranberry-enriched diets may help prevent metabolic syndrome and its associated chronic diseases by a protective effect of gut health and microbiota. It is therefore highly relevant to test the hypothesis that a whole cranberry powder supplements (which include a mixture of polyphenols, free and fiber-associated proanthocyanidins, and fruits fibers) is associated with changes on the gut health and microbiota playing a major role in alleviating inflammation and obesity-associated metabolic disorders.

Over the past decade it has become clear that the gut microbiota is a key determinant of obesity and that its perturbations by nutritional insults play a significant role in the development of metabolic complications such as insulin resistance, type 2 diabetes, cardiovascular diseases and non-alcoholic fatty liver disease. Indeed, there is growing amounts of studies that have shown that dysbiosis of the intestinal microbiota promotes obesity-linked chronic inflammation, and is causally related to diet-induced type 2 diabetes. Our group recently published that a polyphenol-rich cranberry extract exert striking effect on the gut microbiota of high-fat and high-sucrose fed mice, which was associated with prevention of diet-induced weight gain, visceral obesity, insulin resistance and hepatic steatosis. Notably, metagenomic analyses of feces of the cranberry extract-treated mice suggested that these metabolic effects were associated with a dramatic increase in the proportion of Akkermansia muciniphila, a dominant commensal bacterium in the intestinal mucus layer which has received particular attention in the last few years since its abundance is associated with improved metabolic health and beneficial responses to various interventions in both mice and humans with obesity and diabetes. Polyphenols are now recognized as potent molecules capable to protect against obesity-linked metabolic diseases and dysbiosis. Among polyphenols, there is increasing evidence supporting the beneficial impact of dietary proanthocyanidins. Cranberries being rich in proanthocyanidins, we believe that these phyto-elements could be associated to their beneficial effects. On the other hand, apart from the recognized beneficial effects of fibers on gut health, their association with high molecular proanthocyanidins could also contribute to their health benefits.

The main objective of this study is to investigate in a cross-over randomized placebo-controlled clinical trial the beneficial properties of a whole cranberry powder on gut microbiota, intestinal health and metabolic syndrome parameters in overweight men.

Eligibility Criteria:
Inclusion Criteria:

* overweight
* fasting insulin \> 42 pmol/L
* non smoking
* Stable weight in the past 3 months

Exclusion Criteria:

* chronic diseases
* Taking drugs that could affect glucose or lipid metabolism
* Taking anti-inflammatory, immunosuppressant or anticoagulant drugs
* Inflammatory bowel disease
* vegetarians, vegan or following any restrictive dietary pattern or if they are big consumers of berries (\>1 portion/day)
* taking pre- and probiotics
* antibiotics in the past 3 months or change in their regular medication
* Major surgery in the past 3 months
* taste aversion for cranberries or cranberry allergy or allergies to other ingredients used in the placebo