Fasting serum hippuric acid is elevated after bilberry (Vaccinium myrtillus) consumption and associates with improvement of fasting glucose levels and insulin secretion in persons at high risk of developing type 2 diabetes

Scope Urinary hippuric acid has been proposed as a biomarker for fruit, vegetable, and polyphenol consumption. We assessed how serum hippuric acid changes after a bilberry‐enriched diet (BB; high anthocyanin intake) and another berry diet including strawberries, raspberries, and cloudberries (SRC; lower anthocyanin intake) and how these changes associate with insulin and glucose metabolism. Methods and results Hippuric acid was measured with LC‐QTOF‐MS metabolite profiling analysis from fasting serum samples at baseline and after an 8‐week intervention in 47 individuals with features of the metabolic syndrome who were randomized to either a BB diet (n = 15), an SRC diet (n = 20) or a control diet (n = 12). Fasting serum hippuric acid increased significantly (3.5‐fold, p = 0.001) only in the BB group and correlated with changes in fasting plasma glucose concentration (r = –0.54, p