ORAC index
A laboratory measure of a food's capacity to neutralise free radicals (Oxygen Radical Absorbance Capacity), long used to rank the antioxidant power of foods.
ORAC measures, in vitro, how many free radicals a food extract can absorb. Spices (cloves, cinnamon), cocoa, berries (açaí, blueberries) and some dried fruits show very high ORAC values.
An original angle (the official withdrawal): a little-known fact: the USDA (US Department of Agriculture), which hosted the largest ORAC database, withdrew it in 2012. The reason? ORAC values measured in a test tube do not predict real effects in the body.
Why this gap? Because:
- Antioxidants are poorly absorbed (see polyphenols)
- Once digested and metabolised, their antioxidant power changes completely
- The real biological effect often works through cell signalling (activating defence enzymes), not through direct neutralisation of radicals
ORAC has therefore become a marketing argument (« superfood with record ORAC! ») disconnected from physiological reality. A food with a high ORAC is not necessarily more beneficial.
The lesson: be wary of seductive in vitro scores. The true measure of a food’s value is its effect measured in humans, not in a test tube. Eating a varied, colourful diet remains the best advice, without obsessing over scores.