Determining the Gut Microbiota-dependent Impacts of Anthocyanin-rich Aronia Berries on Obese Individuals of Distinct Inflammatory Phenotypes

Anthropometrics. Measurements were collected from participants using the validated segmental multifrequency bioelectrical impedance analysis (SECA mBCA 515, Hamburg, Germany). Fat mass (%) and estimated visceral adipose (L) were used for analysis.

High-Fat Meal Challenge. The high-fat meal contained salted butter (58.3 g, Tillamook) over 3 pieces of whole wheat toast (127.5 g; Wheat Montana). Total energy content of the meal was 714 kcal, with 43.1% from fat, with a macronutrient breakdown of 50 g fat, 54 g carbohydrate, and 12 g protein. Water was provided with the meal; caffeinated black tea was provided instead for participants who identified as habitual coffee consumers.

Blood Sampling. Participants were instructed to avoid alcohol consumption and strenuous physical activity in the 24 hours before their visit and to complete an overnight fast (10 - 12 hours) before blood collection. Participant blood samples were collected by a certified nurse or physician in the morning before ingestion of the meal and hourly for 4 hours after meal ingestion, totaling five time points. Whole blood in serum separating tubes was allowed to clot for 15 minutes before centrifugation at 1200 RPM for 15 minutes with resulting serum aliquoted and stored at -80ºC until analysis.

Determination of blood markers. Blood markers of metabolic syndrome were determined from whole blood run on Picollo Xpress Chemistry Analyzer lipid panels (Abaxis, Union City, USA). Serum insulin (INS) was determined using an insulin ELISA kit (MP Biomedicals, Solon, OH) performed according to manufacturer instructions. Cytokine measurement was performed using high-sensitivity multiplexing technology (Bio-Rad Bio-Plex 200 HTS) following procedures by Millipore (EMD Millipore Corporation, Billerica, USA). Classic systemic pro-inflammatory cytokines were measured and include granulocyte macrophage colony stimulating factor (GM-CSF), interleukin (IL)-1B, IL-6, tumor necrosis factor (TNF)-α. InterleukinI-17 and IL-23, both of which serve a pro-inflammatory and regulatory role in the gut mucosa, were also measured. Serum samples at each time point during the high-fat meal challenge were run in duplicate.

Stool Sample Collection. Collection kits were provided and participants were asked to follow included instructions for the self-collection of a stool sample in the 24 hours before their blood collection visit. After initial collection into a sterile disposable commode, a small portion of the sample was transferred into a sterile Eppendorf tube and transported to researchers. Samples were prepared and aliquoted in an anaerobic chamber then frozen at -80ºC until analysis.