Tomato Juice Can Reduce Oxidative Stress from Vigorous Physical Activity
Reactive oxygen species (ROS) that include oxygen ions, hydroxyl ions and peroxides play an important role in the development of cancer and aging process. They react with cell components such as proteins, lipids, and DNA and bring about chemical modifications in the cells, causing what is known as oxidative stress.
Under normal conditions, anti-oxidants present in the cell fight ROS and bring down their levels thereby minimizing damage to the cells. Regular physical activity or exercise and diet rich in antioxidants, thus, protect against oxidative stress, especially DNA based damage.
Oxidative stress induced DNA damage is measured by the concentration of 8-Oxo-2'-deoxyguanosine (8-oxo-dG) present within the cell.
So, to investigate whether tomato juice protects against ROS induced by extensive physical exercise in untrained individuals, Swedish researchers Mats Harms-Ringdahl and colleagues from Centre for Radiation Protection Research (CRPR), Department of Genetics, Microbiology and Toxicology, Stockholm University, Sweden, used 8-oxodG as 'sensitive marker' of oxidative stress.
They monitored serum levels of 8-oxodG using a modified ELISA. Fifteen untrained healthy subjects were given 150 ml tomato juice per day for two 5- week periods with a 5- week-without- tomato-juice period in between the two periods. Blood samples were taken before and after each period. At the day of blood collection, the subjects performed a 20-minute acute physical exercise using an ergometer bicycle.
The results showed that -
• Blood serum 8-oxodG increased significantly in all subjects after an acute physical exercise. This suggests a positive correlation between 8-oxodG in serum and ROS production.
• Tomato juice intake (15 mg lycopene) of 150 ml per day significantly protected the nucleotide pool of the DNA from ROS produced in response to extensive physical activity.
Besides lycopene, tomatoes also contain vitamin C, tocopherols and polyphenols but lycopene is found to be the most abundant and stable in food processing. Therefore, the researchers believed that lycopene is responsible for the antioxidant activity in tomato juice.
They concluded - 'Long term intake of tomato juice may reduce oxidative stress levels in patients with enhanced level of oxidative stress, for example, patients with diabetes, cardiovascular diseases or inflammation'.
Reference: Harms-Ringdahl M, Jenssen D, Haghdoost S. Tomato juice intake suppressed serum concentration of 8-oxodG after extensive physical activity. Nutr J. 2012 May 2;11(1):29. http://www.nutritionj.com/content/pdf/1475-2891-11-29.pdf