Effect of an Antioxidant-rich Diet During Moderate Altitude Training

Study Overview
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Brief Summary
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Athletes, especially in endurance sports, are at increased risk of oxidative stress and inflammation-related diseases and injuries. The production of reactive oxygen and nitrogen species (RONS) and inflammatory markers increase during exercise and especially during altitude training. Antioxidant supplementation is commonly used among athletes in the belief that it prevents oxidative stress and oxidative damage. A transient increase of RONS is however necessary to activate signaling cascades initiating training adaptation. Antioxidant supplementation has been shown to inhibit the exercise effects in several independent studies, possibly by interfering/reducing the signal cascades initiated by RONS. However, it is unknown whether a high intake of antioxidant rich foods can affect the amount of RONS, inflammation markers and/or training adaptation. The investigators want to examine whether an increased intake of natural antioxidants in the form of antioxidant-rich foods fruits, vegetables and berries, in line with the official Norwegian dietary advice can affect antioxidant status, immune function and training adaptation associated with altitude training in Norwegian elite athletes.

Official Title
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The Effect of an Increased Intake of Antioxidant-rich Foods on Training Adaptation, Redox-balance and Inflammation Among Elite Athletes During a Moderate Altitude Training Camp

Conditions
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Oxidative Stress, Adaptation Reaction, Inflammation

Intervention / Treatment
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* Other: Antioxidant-rich snacks
* Other: Control snacks


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: National team athletes, summer endurance sports Exclusion Criteria: Allergies in conflict with the intervention foods Use of medication that could affect training and performance Injuries that could affect training and performance

Ages Eligible for Study
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Minimum Age: 16 Years
Maximum Age: 42 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Antioxidant-rich snacks<br>The participants received antioxidant-rich snacks every day during 21 days of moderate altitude training (2300 meters above sea level). The snack included fruits and vegetable smoothies, dark chocolate, walnuts, dried fruits and berries. | Other: Antioxidant-rich snacks<br>* Bama Smoothies (Bama, Oslo, Norway), Freia Premium Dark Chocolate (Freia, Oslo, Norway), Walnuts (Eldorado, Norway), Dried fruits and berries (Cranberries, Gojiberries, apricots)(Bama, Oslo, Norway and Rema 1000, Norway)<br>|
| Placebo Comparator: Control snacks<br>The participants received antioxidant-depleted snacks every day during 21 days of moderate altitude training (2300 meters above sea level). The snack included milkshake, and other milk-based drinks, biscuits (both sweet and salty), white chocolate. | Other: Control snacks<br>* Milkshake (Tine, Oslo, Norway), YT restitusjonsdrikk (Tine, Oslo, Norway), Bixit (Sætre, Oslo, Norway), Ritz (Mondelez, Oslo, Norway), White chololate (Freia, Oslo, Norway)<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percent change in performance (sport specific tests will be aggregated to one outcome by the use of percent change) | Cycling: 10 000 m on a bike roller; Rowing: 2000 meter on Concept2-apparatus; Paddling: 1000 meter Concept2-apparatus; Swimming: 200 meter | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| Training adaptation | change in Vo2-max | Measured one week before, and one week after the moderate altitude training camp | 
| Training adaptation for swimmers | For swimming only: 100 meter max speed | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in biomarkers of inflammation | change in cytokine profile e.g. IL-6 ,TNF, CRP measured by multiplex technology | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| change in lean body mass | measured by DXA (iDXA; GE Healthcare) | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| Bone mineral density | measured by DXA (iDXA; GE Healthcare) | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| change in fat mass | measured by DXA (iDXA; GE Healthcare) | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| change in body composition | measured by DXA (iDXA; GE Healthcare) | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| change in body weight | measured by standardized scale | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| Dietary intake (change in food and nutrient intake) | measured by repeated 24 hour recalls | Measured one and three week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| Change in antioxidant status | e.g. FRAP, ORAC, dROM, isoprostanes measured by HPLC | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| biomarkers of antioxidant-rich foods | e.g. carotenoids, flavonoids measured by HPLC | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| Change in whole blood gene expression | Fasting blood samples (PAX-tubes) and samples taken after physical stress test (PAX-tubes). RNA will be isolated and gene expression measured | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| Change in blood lipids |  | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| Change hormones |  | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| Change in micronutrients | e.g. iron status | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| change response to stress test |  | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| Change in hemoglobin | CO-rebreathing-method | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| change in blood volume | CO-rebreathing-method | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| change in plasma volume | CO-rebreathing-method | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| Change in lactate |  | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 
| Total training load | Training diary | Measured one week before, during (in week 1 and 3 of the camp) and one week after the moderate altitude training camp | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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altitude training, antioxidants, oxidative stress, elite athletes, inflammation, diet