The move could ultimately influence the decisions of supplement and functional food formulators, choosing between a variety of antioxidant compounds on the market, and help them to make more accurate claims about the amount of the disease-fighting chemicals in their products.
There are currently between 25 and 100 different methods used to measure antioxidants, according to John Finley, chair of the meeting organizing committee and an associate editor of the Journal of Agricultural and Food Chemistry.
This makes it difficult to compare one plant extract to another, or the disease prevention potential of one functional beverage compared to another.
"Right now, it's difficult to compare the antioxidant content of a can of blueberries to a fruit smoothie," said Finley. "There's no uniformity in the way antioxidants are evaluated. You don't know what you're getting, and that's not fair to consumers."
The three-day meeting, the First International Congress on Antioxidant Methods, held on 16-18 June in Orlando, attracted 144 industry experts and scientists from 19 countries. While there was widespread agreement that antioxidant measurements need to be standardized, the best method to measure the beneficial compounds remained highly controversial.
Antioxidants are thought to reduce the risk of cancer and heart disease as well as fight ageing, arthritis and Alzheimer's disease. They can be found to varying degrees in vitamins C and E, plants like green tea and olives, and many herbal remedies.
However while the market for natural antioxidants in particular is growing fast, "a little difference in methodology can make a huge difference in results," according to Finley, also chief technical officer at US botanical extracts supplier A.M. Todd. "We need to identify the four or five best methods and make them consistent," he said.
After intense debate, the participants decided to form a multidisciplinary group of scientists to work on setting standards on the methodology used to measure antioxidants. Official standard methods could take two to three years to develop and must be tested in multiple labs to ensure the methods are valid, he noted.
Once official standards are established, the Journal of Agricultural and Food Chemistry will require that contributors adhere to agreed-upon standards in reporting antioxidant levels in samples, said Finley. Other scientific journals are likely to follow these standards, he added.
However for some, the intense focus on methodology distracts from the real significance of antioxidants for consumers, which is their potential health benefit. Antioxidant news is increasingly capturing the attention of health-conscious consumers, but there is little scientific data on the actual effect of these compounds in humans. More studies are needed in this area, researchers said.
"The bottom line is the same: eat more fruits and veggies," said Ronald L. Prior, a meeting co-organizer and lead author of a recent US department of agriculture study, that is considered the largest, most comprehensive analysis to date of the antioxidant content of commonly consumed foods.
Max Blum, scientific expert at vitamins company DSM, agreed that more human research is needed.
"In vitro antioxidant tests are a good indicator but they are of limited value when it comes to predicting what actually happens in the body," he told NutraIngredients.com.
"What we really need to understand is how to better measure the in vivo effect of a particular antioxidant and relate it to heart disease and cancer for example."
Publication of preliminary recommendations from the meeting has been tentatively scheduled for September.
A second meeting on antioxidant methods is expected to take place next year, with plans to also include more participation from the dietary supplement and cosmetic industries.