Antioxidant Responses to Exercise and Cherry Consumption

Study Design: This will be a single blinded, randomized, cross-over design in healthy humans. There will be four study visits for the four different treatments: 1) a high-fat meal alone, 2) a high-fat meal with tart cherry consumption, 3) prior exercise to a high-fat meal alone, and 4) prior exercise to a high-fat meal with tart cherry consumption. All participants will complete all 4 treatments in a random order. There will be a 7-day washout period between each visit.

Subjects: We will recruit 25 apparently healthy, physically active (structured exercise > 3h/week) adult men, ages 18-30 years. All subjects will be normal weight based on body mass index (BMI = 18-24.9kg/m2) or body composition (14-24% body fat). The IRB proposal has been submitted and will be reviewed this month. The entire study will take place at the CTRU and sample analysis will take place in the Dept. of Food Science and Technology.

Protocol: For 24h prior to testing, participants will be provided with all food and beverages. This will allow us to control their antioxidant intake prior to testing. The lead-in diet will be representative of a standard American diet and be low in total antioxidants. Estimated total daily energy needs will be based on each participants predicted resting metabolic rate and multiplied by a moderate physical activity value (1.65). Participants will consume all foods that are provided and no additional foods or beverages, may be consumed. Participants will arrive at the CTRU at 0700 hours in the fasted state (no food or drink for 8-12h) and will have abstained from exercise for 48h, unless participating in one of the 2 exercise treatment visits. Baseline measurements of height, weight, blood pressure, and body fat percentage will be taken. An intravenous catheter will be placed in the antecubital vein and a baseline sample will be taken.

Participants will then complete a high-fat meal challenge, either with or without tart cherries depending on their treatment visit. The meals will have tart cherry juice or a placebo consumed with a high-fat meal. The placebo will be designed to match the tart cherry juice for volume and macronutrient content, but without the phytonutrient content of the tart cherries. The high-fat breakfast meal will be a Sausage Biscuit and Hash Browns (McDonalds Corporation). Blood draws will then be obtained at 1, 2 and 3 hours postprandially for antioxidant and oxidative stress measurements.

Acute Exercise Protocol: Two of the four treatments will include an acute bout of submaximal aerobic exercise performed 15 hours (1600 hours; 4:00p.m.) prior to the high-fat meal test. The exercise will consist of 30 minutes of treadmill running at 70% of each participants' calculated heart rate reserve (HRR). This will be a supervised session where participants will wear a heart rate monitor. Participants will also be asked to give their ratings of perceived exertion every 10 minutes during the exercise bout. Participants will be instructed to consume the dinner meal provided to them after this exercise session is complete, which will also be 8-12h prior to the high-fat meal test.

Sample Analysis: Plasma will be tested for total anthocyanins content by HPLC-UV/VIS as well as HPLC-ESI-MS. Antioxidant capacity, oxidative stress measurements will be performed by H-ORACFL and FRAP assays.