Primary bile acids (BAs) are made in the liver from cholesterol. They are released into the small intestine, where they aid fat digestion and absorption. Most BAs are reabsorbed from the gut, yet a small amount gets modified by the gut bacteria, forming secondary BAs destined for faecal excretion. Excess secondary BAs have negative health consequences. The different types of primary BAs influence many physiological functions. Such as glucose regulation, fat metabolism and absorption, intestinal inflammation and immunity, as well as gut bacteria diversity. For optimal BA metabolism, they are tightly regulated by the body, as minimal changes in BA pool and composition can have a significant impact on overall health. The composition of the BA pool can be influenced by gut bacteria, metabolic disorders, pathologies of the liver and gut, and diet. Dietary polyphenols, a plant-based compound, have been of particular interest here. This study sought to investigate the impact of supplementary freeze-dried blueberry powder (BBP), a rich polyphenol source, on the faecal BA pool composition in people at risk of metabolic syndrome. For this 11 men and 13 women were supplemented for 8 weeks. When compared to the data before the intervention, no significant changes in total BAs were observed. However, the composition of the BA pool changed leading to the accumulation of particular BAs and a reduction in secondary BA levels. This suggested that the consumption of blueberries can be considered a potential clinical intervention to aid the elimination of toxic secondary BAs. As the mechanisms leading to such modifications and their consequences for human health are complex, the authors advocate for investigation in larger population groups and also alert that such changes may be subject to interindividual variability and health status.