The ORAC Scale on Antioxidant Capacity from the USDA and Tufts University
A measure of the oxygen radical absorption capacity in foods
Free radicals, and the damage they can do at the cellular level, have received a lot of attention in the last few years. The oxidative stress caused by free radicals — which are produced during normal metabolism and cell function, as well as from stress and pollutants in our air, water and food — is implicated in everything from aging and wrinkling of skin to DNA damage, diabetes, cancer and heart disease.
This is clearly an issue for anyone concerned about their health, or just looking and feeling younger, and is especially important for those engaged in strenuous physical training.
Antioxidants to the rescue
The good news is that you're not left to the ravages of these free radicals. Antioxidants offer powerful, effective protection for your body and cells against their oxidative stress, by blunting the damaging effects of free radicals.
But, how are you to tell which foods or other natural substances offer you the best protection from the damaging effects of free radicals?
The ORAC Scale on antioxidant capacity
USDA researchers at Tufts University in Boston, Massachusetts, have developed a laboratory test to measure the oxygen radical absorption capacity of different foods and natural substances. Known as the ORAC scale, it is one of the most sensitive and reliable methods for measuring antioxidant capacity.
The first test of its kind, the ORAC (Oxygen Radical Absorbance Capacity) scale measures both the time and degree of free-radical inhibition.
All antioxidant capacity measures are estimated by Ferric Reducing Power, and are expressed as micromole Trolox equivalent (TE) per 100 grams (µTE/100 g). The ORAC test is accurate to +/- 5%.
Comparison of different foods and natural substances on the ORAC scale
Essential Oil Antioxidant Capacity
Foods Antioxidant Capacity
|Clove||1,078,700||Vitamin E oil||3,309|
|German chamomile||218,600||Tahitian Noni||1,506|
|Manuka||106,200||Red bell peppers||710|
|Bay laurel||98,900||Limu juice||305|
|Black pepper||79,700||Essential Oils Antioxidant Capacity|
|Blue cypress||73,100||Balsam fir||20,500|
|Citrus hystrix (limette)||69,200||Niaouli||18,600|
|Blue yarrow||55,900||Mountain savory||10,340|
A word of qualification about these ORAC scores
While it's possibly true that "numbers don't lie", they can be misread. Therefore, a word of qualification about the scores listed here needs to be made.
A word on marketing:
I was recently introduced to an antioxidant juice made with açia, MonaVie™. While I will admit — not knowing any better, at this point — that, ounce-for-ounce, açaia is the most potent antioxidant fruit anywhere, the claims made about this juice were off-the-wall.
Because the marketers missed the point that the ORAC scale measures 100 grams of the juice, not one ounce.1 So, when you hear claims about the antioxidant capacity of the many drinks on the market today, do your homework.
When you look at a number like 1,078,700 µTE, you must remember that we're talking about that level of Ferric Reducing Power in 100 grams, not per serving. I don't have any idea how many grams 3-6 drops of clove oil might be, but it would be a lot less than 100 grams; so there is no way you would get 1,078,700 µTE in a normal "serving". On the other hand, a serving of blueberries might be around 128 grams, giving you an ORAC score of roughly 3,072 µTE.
But, the point remains: Essential oils are still one of the richest sources of antioxidants on the earth.
A final word about ORAC
ORAC is indeed scientific.
- It was not developed by a private lab for the purpose of making money; it was developed, in essence, by the USDA — a government agency — working at Tufts University.
- The ORAC test was not developed for commercial reasons, but to insure that Americans had the information needed to protect themselves from free radical damage.
- The fact that only a few labs perform ORAC or S-ORAC testing is not due to its suspect value, but due to the fact that it is a patented process, and protected under the law. There is also a high level of sensitivity in the testing. Most labs just are not equipped to handle it.