January 13/Manchester, U.K./University of Manchester -- The health benefits of drinking cranberry juice by the gallon may have been overrated after University of Manchester research suggests antioxidants may be harmful to cell processes.

The study, by Professor Enrique Amaya and his team at The Healing Foundation Centre in the Faculty of Life Sciences, looked at the regeneration system in tadpoles.

Results showed that levels of the molecule Hydrogen Peroxide (better known as bleach) increased in cells undergoing regeneration after cutting off the tadpole’s tail.

Other bleach-like chemicals, known as oxidizing agents or Reactive Oxygen Species (ROS), have previously been linked to damaging DNA and causing aging.

However, the study proved that ROS production is in fact essential to a signalling path found in every tissue regeneration system, including those found in humans.

Amaya said, “We were very surprised to find these high levels of ROS during tail regeneration. Traditionally, ROS have been thought to have a negative impact on cells.

The group also found that factors that block ROS –- such as commonly-cited health food favorite, antioxidants –- actually inhibit the regeneration process.

Amaya said, “It was also striking that our study showed that antioxidants had such a negative impact on tissue regrowth, as we are often told that antioxidants should be beneficial to health."

The paper, published in science journal Nature, comes just days after a study by Nobel Prize winner and co-discoverer of the structure of DNA, James Watson, suggested antioxidants could be harmful to people in the later stages of cancer.

Amaya said, "Our findings and those of others are leading to a reversal in our thinking about the relative beneficial versus harmful effects that oxidants and antioxidants may have on human health.”

With a better understanding, Amaya and his team hope to apply their findings to human health to identify whether manipulating ROS levels in the body could improve the ability to heal and regenerate tissues better.