How certain foods alter oxidative stress responses during and after high-intensity exercise

How certain foods alter oxidative stress responses during and after high-intensity exercise

A new randomized study shows how simple food choices before and after fasting HIIT can alter the body's oxidative stress and recovery patterns, and offers practical guidance for adjusting nutrient timing to support exercise goals.

Researchers at the University of Vienna recently conducted a randomized controlled trial to compare the effectiveness of polyphenol-rich foods and carbohydrate-rich foods in alleviating oxidative stress during exercise. The results, published in the journalAntioxidantshighlighted the benefits of carbohydrates during exercise and polyphenols during recovery under fasted, high-intensity conditions and in a sedentary female population.

ROS dynamics during intense physical exercise

Exercise-induced oxidative stress is a well-known disease in sports. Reactive oxygen species (ROS) produced during exercise have both beneficial and detrimental effects, depending on concentration and timing.

Excessive ROS production is associated with impaired muscle contraction, poor recovery, and muscle soreness. Chronic exposure to ROS increases the risk of various diseases, including cardiovascular disease, diabetes, and age-related diseases.

On the other hand, physiological ROS levels play a crucial role in strengthening muscles and improving antioxidant defense mechanisms. This dual role of ROS highlights the existence of an optimal physiological state in which moderate levels of oxidative stress and inflammation optimize exercise performance and recovery.

Diet plays an essential role in regulating oxidative stress caused by exercise. Carbohydrates can attenuate oxidative stress by reducing physiological stress and inflammatory responses rather than directly scavenging ROS in vivo, although glucose and sucrose have shown radical scavenging properties in vitro.

Polyphenols, a diverse group of plant compounds, have gained significant attention in medical science due to their powerful antioxidant and anti-inflammatory properties. Polyphenol-enriched whole foods have shown significantly greater physiological relevance in alleviating oxidative stress than traditional high-dose vitamin supplements, as vitamins at higher concentrations have been found to suppress the body's antioxidant defense system.

To provide a comprehensive overview of the effects of nutritional interventions on exercise-induced oxidative stress, researchers at the University of Vienna designed a randomized controlled trial to examine the effectiveness of carbohydrate- and polyphenol-rich foods in alleviating oxidative stress during high-intensity interval resistance circuit training.

Randomized study design and protocol

This randomized controlled trial initially randomized 45 women, 30 of whom completed the full protocol, including healthy, sedentary women aged 19 to 33 years. The study analyzed four types of foods, including two polyphenol-rich foods (pomegranate juice and blueberries) and two carbohydrate-rich foods (whole-grain bread and rolls).

Participants were randomly assigned to two study arms: one included blueberries, whole-wheat bread, and rolls, and the other included pomegranate juice. Within each study arm, participants randomly consumed each of the included foods after a 12-hour fast, with a washout period of at least seven days between intervention days. Water intake served as a control condition in both study arms.

On each intervention day, participants performed resistance training and blood samples were collected at baseline, immediately before training, immediately after training, and 15 minutes after training. The samples were analyzed to measure ROS (electron paramagnetic resonance spectroscopy) and total antioxidant capacity (Ferric Reduction Capability of Plasma Assay, FRAP).

Carbohydrates reduce acute oxidative stress

Analysis of participants in the control group (water intake) revealed a significant increase in ROS levels and total antioxidant capacity after the training session. However, the magnitude of these changes was modest and subject to interindividual variation, indicating a significant physiological stress response.

Analysis of participants in the intervention group revealed that intake of carbohydrate-rich foods significantly attenuated the exercise-induced increase in total antioxidant capacity and showed a non-significant trend to attenuate the exercise-induced increase in ROS levels compared to intake of polyphenol-rich foods or water. These observations highlight the protective role of carbohydrates against oxidative stress, primarily through effects on FRAP rather than consistent significant effects on ROS.

When it comes to consuming polyphenol-rich foods, the study found significant effectiveness in improving post-exercise recovery. Compared to carbohydrate intake, polyphenol intake significantly reduced ROS levels during the post-exercise recovery period, although no significant differences were observed compared to water.

Regarding total antioxidant capacity, a continuous increase was observed during the recovery period, reflecting the effects of high-intensity training sessions, although there were no significant differences between intervention foods during recovery and the changes were due to the kinetics of the redox system rather than increased antioxidant capacity.

Nutritional strategies for physical recovery

The study highlights the protective effectiveness of carbohydrates against exercise-induced oxidative stress and the effectiveness of polyphenols in accelerating the normalization of ROS levels after exercise.

The observed benefit from polyphenol intake is particularly significant because chronic exposure to oxidative stress is associated with impaired recovery, reduced muscle function, and increased risk of tissue damage.

The observed benefits of carbohydrate intake may reflect the fact that adequate carbohydrate availability reduces exercise-induced oxidative stress by reducing dependence on fat oxidation and minimizing mitochondrial ROS production.

These effects are particularly relevant in endurance training, where carbohydrates attenuate cumulative oxidative stress responses during repeated training sessions and maintain performance. However, excessive suppression of ROS production can impair training adaptations such as muscle strengthening, highlighting the importance of dosage in carbohydrate strategies.

Overall, this study provides valuable information for both athletes and coaches to optimize their performance and training adaptations through nutrition. However, the results should be interpreted with caution because the study population consisted of sedentary young women, the intervention assessed acute, single session effects, and the fasted high-intensity interval training (HIIT) protocol did not fully reflect typical training environments.

Given the results, researchers suggest incorporating polyphenol-rich foods into pre- and post-workout meals. When it comes to carbohydrate-rich foods, they emphasize personalized approaches based on exercise intensity, duration and energy needs, but acknowledge that the effects on performance were not directly measured in this trial.

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