Study design
sore
This study was a double-blind, crossover, randomized trial with a 6-wk baseline period and 3 intervention periods followed by washout periods, each lasting for 6 wk (Human study design. Participants were dosed with After baseline, participants were randomly assigned to a sequence of 3 intervention periods, each corresponding to a low (17.5 g/d), medium (35 g/d), or high (70 g/d) dose of freeze-dried BB powder equivalent to 0.75, 1.5, or 3 cups of fresh blueberries. Each intervention lasted for 6 wk and was followed by a 6-wk washout period, determined to be optimal by simulation modeling of data from prior studies. Participants were instructed to maintain their usual exercise and dietary habits during the study. The intervention products were provided in a double-blind manner between February and November 2018. Products were coded by research staff prior to dispensing them to the participants by the study coordinator. Unconsumed foods were collected weekly during each intervention to monitor adherence. Participants received a list of polyphenol-rich foods to avoid and/or limit. Participants were instructed to complete a 4-d dietary record at the end of baseline and each intervention and washout period to quantify habitual intakes of energy and bone-relevant nutrients. The records were analyzed with the use of the Nutrition Data System for Research (2018 ed.; University of Minnesota). Participants collected 24-h urine weekly during the intervention and every 3 wks during washout to monitor During the trial, one participant reported that the BB drink irritated a mouth sore, which was resolved by diluting the drink. The institutional review board suspended the study to amend the consent form to include a statement that consumption of products with BB powder may cause oral irritation. The phases interrupted by suspension were repeated (