In this randomized, double-blind controlled study, 30 healthy subjects were daily supplemented with either 1 mg or 30 mg of lycopene or 7mg of lycopène plus 10 g of dark chocolate or 10 g of dark chocolate. Supplementation was performed during 1 month.

Results of the study showed that by the end of the trial there were dose-dependent changes in the gut microbiota profile in all lycopene groups with an increase of relative abundance of Bifidobacterium adolescentis and Bifidobacterium longum. This was also accompanied by dose-dependent changes in the blood, liver metabolism, skeletal muscle and skin parameters. Consumption of dark chocolate resulted in increased relative abundance of Lactobacillus genus and a reduction of corneocyte exfoliation.

In conclusion, systemic effect of lycopene or dark chocolate, including improvement of gut, blood, liver lipid metabolism and, skeletal muscles and skin parameters could be not just due to the carotenoid and dark chocolate properties themselves, but are likely also to modulate the gut microbiome increasing the relative abundance of putatively beneficial bifidobacteria and lactobacilli.

Wiese M, Bashmakov Y, Chalyk N, Nielsen DS, Krych Ł, Kot W, Klochkov V, Pristensky D, Bandaletova T, Chernyshova M, Kyle N, Petyaev I. Prebiotic Effect of Lycopene and Dark Chocolate on Gut Microbiome with Systemic Changes in Liver Metabolism, Skeletal Muscles and Skin in Moderately Obese Persons. Biomed Res Int. 2019 Jun 2;2019:4625279.