Twenty-five years ago the term “antioxidant” was new to the public. Today it’s big business, with sales of products making antioxidant-related claims reaching $65 billion in the U.S. in 2011.
You’ll find antioxidant claims made not just for dietary supplements, but also for everything from juice, cereal and power bars to tea, chocolate and even bottled water. Antioxidant—a substance that helps mop up cell-damaging substances known as free radicals—has become synonymous with overall good health and disease prevention.
A more recent trend is for companies to advertise specific antioxidant levels or scores, or to compare their products to others in antioxidant power. For instance,cereals from Silver Palate boast 7,300 ORAC units per 100 grams, while Mystic Harvest Purple Corn Tortilla Chips list 6,000 ORAC units (ORAC, which stands for oxygen radical absorbance capacity, is one of several measures of antioxidant status developed by scientists). A baobab fruit powder that you add to oatmeal, yogurt or other foods lists an ORAC value of 1,400 per gram. And tea extracts from Green Cell Technologies claim to have ORAC scores of up to 1.7 million per 100 grams.
It’s hard to say what all those numbers mean. But they probably don’t mean a whole lot in terms of health. The science and significance of antioxidants is much more complicated than a single number on a package can convey. The Food and Drug Admininstration (FDA) has issued warnings to Lipton and other companies for making misleading and illegal claims about antioxidants—but many other iffy ones slip through the cracks.
Despite all the label claims, there’s no standardized method for measuring antioxidant status and no official definitions for antioxidant capacity, ability, activity, power, efficiency or other words you might see on packages or websites.
Rather, scientists have developed a variety of tests, all with four-letter acronyms—besides ORAC, there are TEAC, TOSC, FRAP, TRAP and others. These don’t necessarily measure the same things or provide consistent results. For instance, a 2009 study inFood Chemistrynoted that TEAC, which is simpler and cheaper, underestimates the antioxidant capacity of some foods, compared to ORAC.
Even different labs using the same test can come up with different results. Some companies specify ORAC values, but others don’t even say how they came up with their values.
Moreover, ORAC and other tests measure antioxidant capacity of substances only in test tubes. How well the antioxidants suppress oxidation and protect against free radicals in people is pretty much anyone’s guess.