IL-6 in Exercise-Induced Anorexia

This study investigates the effect of high intensity exercise, with and without the inflammation inhibitor, ibuprofen, on plasma levels of IL-6 and other selective biomarkers of inflammation and appetite on food intake and subjective ratings of appetite in normal-weight boys.

Fifteen normal-weight boys (aged 13-18y) were randomly assigned in a crossover design to four sessions: 1) Water + Rest; 2) Rest + ibuprofen; 3) Water + high intensity exercise; 4) high intensity exercise + ibuprofen. High intensity exercise consisted of three 10min bouts of high intensity exercise at 75% VO2peak at 60-70RPM with 1:30min active rest interposed. IBU was given in a 300mg liquid solution. EI, visual analog scale ratings and plasma biomarkers of appetite, inflammation, stress and glucose control were measured.

Water control and ibuprofen solution contained 0.8 g of Sucralose (Heartland Food Products Group, Amsterdam, HP, Netherlands) and 1.2 g of orange flavored Kool-Aid (Kraft Foods, Northfield, IL, United States) to mask the taste of the Motrin solution. To match sweetness and calorie content of the ibuprofen Motrin drink, the water control also contained 6 mL high fructose corn syrup (ACH Food Companies, Mississauga, ON, Canada).

HIEX, with and without the inflammation inhibitor, ibuprofen, on plasma levels of IL-6 and other selective biomarkers of inflammation and appetite on food intake and subjective ratings of appetite in normal-weight boys.

Participants were provided with ad libitum lunch meal, consisting of rice (Uncle Ben's, Bolton, ON, Canada), beef meatballs (President's Choice, Brampton, ON, Canada) and tomato sauce (Ragu, Mount Prospect, IL, USA) at 100 - 120 min. The meatballs were cut into small and uniform pieces and were mixed homogeneously with the other ingredients in a bowl. One bowl was a 479.5 g portion which represented 827.5 kcal, 30.8 g fat, 104.8 g carbohydrate and 30.2 g protein based on the weight consumed and the compositional information provided by the manufacturers. Two portions we served in 10 min intervals and FI from the pizza meal was calculated based on the weight consumed during the lunch. Participants were instructed to eat until comfortably and stay seated during the duration of the meal.

Visual Analog Scales were employed to assess subjective appetite based on the following questionnaires: Determination to Eat, Hunger, Fullness and Prospective Food Consumption.

Active Ghrelin, Blood Glucose, Insulin, Peptide-YY and Glucagon-like peptide-1 were determined as appetite biomarkers.

Fifteen normal-weight (BMI for age percentile: 15th-85th) boys aged 13-18yrs completed the study. Sample size was determined through previous studies in our lab. A telephone questionnaire was employed to determine eligibility for this study. Boys who answered "yes" to one of the questions of the physical activity readiness questionnaire, displayed a form of heamatophobia, dieters, have been diagnosed with diabetes or other metabolic diseases, and those scoring ≥11 on an Eating Habit Questionnaire were excluded from the study.

Inclusion Criteria: 13-18 yrs, healthy, male Exclusion Criteria: female, heamatophobia, following a diete, diagnosed with diabetes or other metabolic diseases, scoring ≥11 on an Eating Habit Questionnaire

Individual participant data will not be made available to other researchers.Participant's identities will be kept confidential. Records will be kept in a locked filing cabinet in the Fitzgerald building at 150 College Street, room 437. Access will be restricted to those directly involved with the project, such as the investigator and the co-investigators. Following recruitment and attainment of informed consent, participants will be given an ID # which will be used on all forms and data analysis. Informed consent forms will be kept in a locked cabinet in a locked office, contain participant names. Research records will be identified by initials, ID number, test and date. Results identified by date and ID number will only be entered on password-protected personal computers kept in locked laboratories or offices at the University of Toronto. Any electronic data will be held on encrypted computers and USB sticks for the same period of time.

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