Effects of Orally Ingested Paprika Xanthophylls on Respiratory Metabolism during Endurance Exercise: Study Protocol for an Interventional Randomised Controlled Trial

Objective: Xanthophylls are a type of carotenoid with particularly high antioxidative capacity, and ingestion of paprika xanthophylls is expected to have the effect of reducing oxidative stress during exercise. In the present study, the effects of ingested paprika xanthophylls on oxidative stress and respiratory metabolism during endurance exercise were investigated in male university student athletes. Methods: In a randomized, double-blind intergroup comparative experiment, 21 male athletes ingested capsules containing 4.5 mg paprika xanthophylls (PA group; n=11) or placebo capsules (CON group; n=10). Blood was collected before ingestion, at 4 weeks after ingestion, and at 8 weeks after ingestion, and carotenoid levels, oxidative stress, and blood antioxidative capacity were analyzed. In addition, cycling exercise (60% maximal oxygen consumption for 30 min) was carried out before and at 4 and 8 weeks after ingestion, and respiratory gases were analyzed. Results: Total carotenoids and total xanthophylls in the erythrocytes showed significantly higher values in the PA group than in the CON group at both 4 and 8 weeks after ingestion (4 weeks, p<0.01; 8 weeks, p<0.001). In addition, the heart rate during cycling exercise was significantly lower in the PA than in the CON group at 4 and 8 weeks after ingestion (4 weeks, p<0.05; 8 weeks, p<0.01 and p<0.001). Conclusion: These results suggest that the ingestion of paprika xanthophylls may improve energy efficiency during endurance exercise.

Author(s):

Mizuki Yamada, Tomoka Matsuda, Takashi Ichihara and Mikako Sakamaki-Sunaga M

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