Five weeks of drinking 150 ml per day of tomato juice was associated with a reduction in levels of 8-dihydro-2’-deoxyguanosine (8-oxodG), a marker of oxidative DNA damage, in 15 untrained healthy subjects.
Results published in the Nutrition Journal indicated that exercise increased 8-oxodG by between 42 and 84% during the control phase of the study, but tomato juice prevented any such increases.
“It might be hypothesized that 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,” reported scientists from Stockholm University in Sweden.
Oxygen-breathing organisms naturally produce reactive oxygen species (ROS), which play an important role in a range of functions, including cell signaling. However, over production of these ROS from smoking, pollution, sunlight, high intensity exercise, or simply aging, may overwhelm the body’s antioxidant defenses and lead to oxidative stress.
The Stockholm-based researchers recruited 15 untrained healthy subjects to participate in their study. Participants were asked to perform a 20 min physical exercise at 80% of maximum pulse using an ergometer, and had their blood taken before and 60 minutes after the exercise.
The subjects then consumed 150 ml of tomato juice providing 15 mg of lycopene every day for five weeks. They re-performed the exercise. This was followed by a five week ‘washout’ period and then five more weeks of tomato juice consumption.
Results showed the initial bout of exercise increased 8-oxodG levels by 42%, while no such increases were observed after the first five weeks of tomato juice consumption.
After the five week washout period, exercise increased 8-oxodG levels by an average of 84%, said the Stockholm-based researchers. Five more weeks of tomato juice consumption again prevented any such increases in 8-oxodG levels.
“It is important to mention that beside lycopene tomatoes also contain vitamin C, tocopherols and polyphenols,” said the researchers. “It has been shown that among all antioxidants (in particular carotenoids) present in tomato juice, lycopene is the most abundant and stable during industrial food processing.
“Vitamin C and tocopherols in fresh tomato are destroyed by heating during food processing. Not much is known about the polyphenols in tomato juice.
“Therefore, we believe that the antioxidant activity of tomato juice is primarily due to its content of lycopene.”
Source: Nutrition Journal
2012, 11:29, doi:10.1186/1475-2891-11-29
“Tomato juice intake suppressed serum concentration of 8-oxodG after extensive physical activity”
Author: M. Harms-Ringdahl, D. Jenssen, S. Haghdoost