Healthy Food Chart

Q. In researching antioxidants, I've come across lists of foods ranked by ORAC and flavanol content. Which is more important if one wishes to eat a very high antioxidant diet? Also, how does the older ORAC compare with the newer ORAC-fn measure? Could different measures rank foods differently? 

A. There are hundreds--maybe thousands--of compounds in foods that have antioxidant activity. We haven't come close to identifying them all.  Plus, they work together synergistcally, so the total effect is more than the sum of the individual actions.

The value of tests like ORAC (Oxygen Radical Absorbance Capacity) is that they attempt measure the actual antioxidant activity of a food, rather than measuring individual nutrients, like vitamin C, or even families of nutrients, like flavanols.

There are a number of lab assays that try to measure total antioxidant capacity of foods--ORAC is one of the better known. But none of these can truly be considered definitive. When you think about it, it's silly to think of any food as having a fixed antioxidant capacity. Just like other nutritional values, antioxidant capacity will vary from sample to sample, depending on freshness, storage, ripeness, where it was grown, how it was processed, and so on.

And if you're just trying to choose foods that are high in antioxidants, it's really not worth worrying about whether pomegranates rank #4 or #5 out of 100 fruits, or whether they fall just above or just below wild blueberries.

How to use ORAC values

Lists of foods with high ORAC values or high flavanol content can be useful.  Obviously, blueberries (with an ORAC of 6552) pack a bigger antioxidant punch than bananas (879). And who would have guessed that kidney beans (8549) were antioxidant powerhouses? But I wouldn't make too much out of the fact that the ORAC of ground cloves is a whopping 314,446, while cinnamon is "only" 267,536.

First of all, these ORAC values are based on 100g quantities. A half teaspoon of cloves or cinnamon is just 1 gram. So, in the quantity that you're actually likely to use these spices, you're talking ORAC values of 3144 for cloves vs. 2675 for cinnamon, which puts both spices in the same category as a small pear or apple.

How much ORAC do you need?

More importantly, the body can only use so many antioxidants at a time. Dr. Ronald Prior, an antioxidant researcher who worked on the ORAC reports for the USDA, estimates that anything above about 5,000 ORAC units a day is probably overkill. The body can only make use of so many antioxidants; the excess is simply excreted by the kidneys. So, those supplements and fruit extracts that promise 25,000 ORAC units a pop? A waste of money and kidney power.

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