Seven days of high carbohydrate ingestion does not attenuate post-exercise IL-6 and hepcidin levels

Purpose: This investigation examined if a high carbohydrate (CHO) diet, maintained across a seven-day training period, could attenuate post-exercise interleukin-6 (IL-6) and serum hepcidin levels. Methods: Twelve endurance-trained male athletes completed two seven-day running training blocks whilst consuming either a high (8 g kg⁻¹) versus a low (3 g kg⁻¹) CHO isoenergetic diet. Each training block consisted of five running sessions performed on days 1, 2, 4, 5, and 7, with the intensity and duration of each session matched between training weeks. Serum levels of Interleukin-6 (IL-6) and hepcidin were measured pre- and either immediately (IL-6) or 3-h (hepcidin) post-exercise on days 1 and 7 of each training week. Results: During each training week, the immediate post-exercise IL-6 and 3-h post-exercise serum hepcidin levels were significantly elevated (both p = 0.001) from pre-exercise on days 1 and 7. These increases were not different between trials. Conclusions: These results suggest that the ingestion of a high (compared to low) CHO diet over a seven-day training period is ineffective in attenuating post-exercise IL-6 and hepcidin responses. Such results may be due to the modest training load, the increased protein intake in the low-CHO trial, and a 48 h recovery period prior to sample collection on day 7, allowing a full recovery of muscle glycogen status between exercise sessions.