Increasing Doses of Blueberry Polyphenols Alters Colonic Metabolism and Calcium Absorption in Ovariectomized Rats

• Published in: Molecular nutrition & food research 2020-06, Vol.64 (12), p.e2000031-n/a
• Main Authors: Cladis, Dennis P., Debelo, Hawi, Lachcik, Pamela J., Ferruzzi, Mario G., Weaver, Connie M.
• Format: Article
• Language: English
• Subjects: Absorption; Animals; Anthocyanins; Blueberries; Blueberry Plants - chemistry; Body weight; Calcium; Calcium (blood); Calcium - pharmacokinetics; Calcium absorption; Calcium isotopes; Calcium metabolism; Colon - drug effects; Colon - metabolism; colonic metabolism; Diet; Dietary Supplements; Dosage; Dose-Response Relationship, Drug; Female; Flavonoids - urine; Flavonols; Hippurates - urine; Hippuric acid; Intestinal Absorption - drug effects; Intestine; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Metabolism; Metabolites; Ovariectomy; Pharmacokinetics; Phenolic acids; Phenols; Phenols - metabolism; Phenols - urine; Polyphenols; Polyphenols - administration & dosage; Polyphenols - analysis; Polyphenols - pharmacology; Rats, Sprague-Dawley; Vaccinium
• ISSN: 1613-4125; 1613-4133; 1613-4133
• DOI: 10.1002/mnfr.202000031

Scope Blueberries are rich sources of bioactive polyphenols that may provide health benefits when consumed regularly, leading to their increased marketing as dietary supplements. However, the metabolic changes associated with consuming concentrated doses of purified polyphenols, as may be present in dietary supplements, are unknown, especially when considering the colonic metabolites formed. This study aimed to evaluate the pharmacokinetics of high doses of purified blueberry polyphenols. Methods and results 5‐month old, ovariectomized Sprague‐Dawley rats are acutely dosed with purified blueberry polyphenols (0, 75, 350, and 1000 mg total polyphenols per kg body weight (bw)) and 45Ca to measure calcium absorption. Blood and urine are collected for 48 h after dosing and phenolic metabolites measured via ultra high‐pressure liquid chromatography–tandem mass spectrometry (UPLC‐MS/MS). The most prominent metabolites are colonically generated cinnamic and hippuric acids. Smaller amounts of other phenolic acids, flavonols, and anthocyanins are also detected. Most metabolites follow a dose–response relationship, though several show saturated absorption. Maximal metabolite concentrations are reached within 12 h for a majority of compounds measured, while some (e.g., hippuric acid) peaked up to 24 h post‐dosing. Calcium absorption is significantly increased in the highest dose group (p = 0.03). Conclusion These results indicate that increased doses of blueberry polyphenols induce changes in intestinal phenolic metabolism and increase calcium absorption. Blueberry‐derived polyphenols positively influence health, leading to their increased consumption as dietary supplements. Here, it is reported that increasing doses of blueberry polyphenols cause shifts in their colonic metabolism, leading to increased calcium absorption and alterations in GI function.