Amrit Kaur Sakhi

View summary

Background and aim: Intensive exercise of long duration increases blood levels of oxidative damage- and inflammatory biomarkers. Different polyphenols in blueberries and red grapes have antioxidant properties and prevent oxidative damage, thereby, contributing in prevention of different oxidative stress related diseases like cancer, stroke, cardiovascular diseases, neurodegenerative diseases and diabetes. The aim of our study was to study the effect of polyphenol-rich juice on the plasma antioxidants, inflammation, oxidative- and muscle damage- biomarkers in elite athletes practicing endurance exercise. Methods: The study is randomized, double-blind and followed a parallel design with 5-8 week intervention period. Norwegian male athletes competing in endurance sports at national team levels exercising 15 hours or more per week were recruited through Olympiatoppen. After washout period of one week, the participants were invited to give fasting blood samples and anthropometric measurements. The juice group consumed two boxes of European blueberry/red grape juices (2 x 330 mL) every day in the intervention period. The placebo group received a placebo drink (2 x 330 mL) every day with similar carbohydrate and energy amount as the juice. The participants registered their physical exercise every day during the intervention period. We have measured 35 different plasma/erythrocyte antioxidants including 12 different polyphenols, plasma total antioxidant capacity, 5 different plasma/erythrocyte oxidative damage biomarkers, marker for muscle damage, 23 different inflammatory markers in fasting blood samples taken before and after 5-8 weeks of intervention. Results: Among the antioxidants measured, polyphenols increased significantly in the juice group (p<0.05). The muscle damage biomarker creatine kinase decreased significantly in the juice group (p=0.055) and most of the inflammation biomarkers decreased in the juice group. Conclusion: The results indicate that the blueberry and red grape juice increases the concentration of different polyphenols in the plasma and may reduce muscle damage and inflammation in elite athletes. Supported by: The Norwegian Cancer Society, The Research Council of Norway, Throne Holst Foundation and Tine BA.

View summary

Background: The main aim of the research group of professor Rune Blomhoff is to elucidate mechanisms behind protective effects of fruits and vegetable intake in inflammation and oxidative stress related diseases like cancer, cardiovascular disease, cataract and other neurodegenerative diseases. In order to study these mechanisms, we have systematically done various approaches: 1. Identification of plants that are rich in antioxidants. 2. Developed cells and transgenic mice using the reporter luciferase controlled by small oxidative stress- or inflammation related response elements. Studying the effect of antioxidant-rich plant foods on these response elements. 3. Human intervention studies with different groups of participants in order to study the effect of antioxidant-rich plant diet on different antioxidant and oxidative stress biomarkers. Here are some of the intervention studies we already have conducted. • Head and neck cancer patients (samples are collected before and after radiotherapy and studied association of plasma antioxidants and oxidative stress biomarkers with survival) • Top athlete study (samples are collected before and after intervention with blueberry/grape juice in elite athletes competing in endurance sport) • Oslo antioxidant study (samples are collected before and after intervention with antioxidant rich foods in middle-aged smoking men) • Prostate cancer study (patients with prostate cancer is treated with dietary antioxidants before surgery or radiation) • Follicular lymphoma study (patients with follicular lymphoma are studies with different oxidative stress and inflammation biomarkers) 4. Gene-array analysis in some of above mentioned human intervention studies. Methods and results: We have collected plasma samples and in some studies red blood samples from participants. The plasma samples are collected in different anticoagulant tubes (heparin, EDTA and citrate) and the samples are frozen in -80 ºC. We have analysed some antioxidant biomarkers like GSH, GSSG, total thiols (cysteine, homocysteine, cysteinyl glycine), carotenoids (lutein, zeaxanthine, -cryptoxanthine, -carotene, -carotene and lycopene), tocpherols (, -, -, and -), vitamin C (both reduced and oxidized forms) and total anatioxidant capacity measured by e.g. by FRAP or ORAC. Among oxidative stress biomarkers, we have analyzed 8-iso PGF2 and d-ROMs (total hydroperoxides). We have also analyzed cytokines in some of the human intervention studies. Future plans: After establishing gene-array analysis in some of these studies, we want to further analyse metabolomics such that we can study the different processes/pathways from gene-array analysis results in a more complete manner. We have a LC-MS-MS at our lab that we are planning to use for this purpose. From the transgenic mice, we have also different tissue samples that are frozen in -80 ºC. Samples from these animals are collected almost continuously such that sample collection procedures can be modified if required.